Quagga Routing Suite

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Quagga

1. Overview
2. Installation
3. Basic commands
4. Zebra
5. RIP
6. RIPng
7. OSPFv2
8. OSPFv3
9. BGP
10. VTY shell
11. Filtering
12. Route Map
13. IPv6 Support
14. Kernel Interface
15. SNMP Support
A. Zebra Protocol
B. Packet Binary Dump Format
Command Index
VTY Key Index

1. Overview

Quagga is a routing software package that provides TCP/IP based routing services with routing protocols support such as RIPv1, RIPv2, RIPng, OSPFv2, OSPFv3, BGP-4, and BGP-4+ (see section 1.4 Supported RFC). Quagga also supports special BGP Route Reflector and Route Server behavior. In addition to traditional IPv4 routing protocols, Quagga also supports IPv6 routing protocols. With SNMP daemon which supports SMUX protocol, Quagga provides routing protocol MIBs (see section 15. SNMP Support).

Quagga uses an advanced software architecture to provide you with a high quality, multi server routing engine. Quagga has an interactive user interface for each routing protocol and supports common client commands. Due to this design, you can add new protocol daemons to Quagga easily. You can use Quagga library as your program's client user interface.

Zebra is distributed under the GNU General Public License.

1.1 About Quagga		Basic information about Quagga
1.2 System Architecture		The Quagga system architecture
1.3 Supported Platforms		Supported platforms and future plans
1.4 Supported RFC		Supported RFCs
1.5 How to get Quagga
1.6 Mailing List		Mailing list information
1.7 Bug Reports		Mail address for bug data

1.1 About Quagga

Today, TCP/IP networks are covering all of the world. The Internet has been deployed in many countries, companies, and to the home. When you connect to the Internet your packet will pass many routers which have TCP/IP routing functionality.

A system with Quagga installed acts as a dedicated router. With Quagga, your machine exchanges routing information with other routers using routing protocols. Quagga uses this information to update the kernel routing table so that the right data goes to the right place. You can dynamically change the configuration and you may view routing table information from the Quagga terminal interface.

Adding to routing protocol support, Quagga can setup interface's flags, interface's address, static routes and so on. If you have a small network, or a stub network, or xDSL connection, configuring the Quagga routing software is very easy. The only thing you have to do is to set up the interfaces and put a few commands about static routes and/or default routes. If the network is rather large, or if the network structure changes frequently, you will want to take advantage of Quagga's dynamic routing protocol support for protocols such as RIP, OSPF or BGP. Quagga is with you.

Traditionally, UNIX based router configuration is done by ifconfig and route commands. Status of routing table is displayed by netstat utility. Almost of these commands work only if the user has root privileges. Quagga has a different system administration method. There are two user modes in Quagga. One is normal mode, the other is enable mode. Normal mode user can only view system status, enable mode user can change system configuration. This UNIX account independent feature will be great help to the router administrator.

Currently, Quagga supports common unicast routing protocols. Multicast routing protocols such as BGMP, PIM-SM, PIM-DM may be supported in Quagga 2.0. MPLS support is going on. In the future, TCP/IP filtering control, QoS control, diffserv configuration will be added to Quagga. Quagga project's final goal is making a productive, quality free TCP/IP routing software.

1.2 System Architecture

Traditional routing software is made as a one process program which provides all of the routing protocol functionalities. Quagga takes a different approach. It is made from a collection of several daemons that work together to build the routing table. There may be several protocol-specific routing daemons and zebra the kernel routing manager.

The ripd daemon handles the RIP protocol, while ospfd is a daemon which supports OSPF version 2. bgpd supports the BGP-4 protocol. For changing the kernel routing table and for redistribution of routes between different routing protocols, there is a kernel routing table manager zebra daemon. It is easy to add a new routing protocol daemons to the entire routing system without affecting any other software. You need to run only the protocol daemon associated with routing protocols in use. Thus, user may run a specific daemon and send routing reports to a central routing console.

There is no need for these daemons to be running on the same machine. You can even run several same protocol daemons on the same machine. This architecture creates new possibilities for the routing system.

+----+  +----+  +-----+  +-----+
|bgpd|  |ripd|  |ospfd|  |zebra|
+----+  +----+  +-----+  +-----+
                            |
+---------------------------|--+
|                           v  |
|  UNIX Kernel  routing table  |
|                              |
+------------------------------+

    Quagga System Architecture

Multi-process architecture brings extensibility, modularity and maintainability. At the same time it also brings many configuration files and terminal interfaces. Each daemon has it's own configuration file and terminal interface. When you configure a static route, it must be done in zebra configuration file. When you configure BGP network it must be done in bgpd configuration file. This can be a very annoying thing. To resolve the problem, Quagga provides integrated user interface shell called vtysh. vtysh connects to each daemon with UNIX domain socket and then works as a proxy for user input.

Quagga was planned to use multi-threaded mechanism when it runs with a kernel that supports multi-threads. But at the moment, the thread library which comes with GNU/Linux or FreeBSD has some problems with running reliable services such as routing software, so we don't use threads at all. Instead we use the select(2) system call for multiplexing the events.

When zebra runs under a GNU Hurd kernel it will act as a kernel routing table itself. Under GNU Hurd, all TCP/IP services are provided by user processes called pfinet. Quagga will provide all the routing selection mechanisms for the process. This feature will be implemented when GNU Hurd becomes stable.

1.3 Supported Platforms

Currently Quagga supports GNU/Linux, BSD and Solaris. Below is a list of OS versions on which Quagga runs. Porting Quagga to other platforms is not so too difficult. Platform dependent codes exist only in zebra daemon. Protocol daemons are platform independent. Please let us know when you find out Quagga runs on a platform which is not listed below.

• GNU/Linux 2.0.37
• GNU/Linux 2.2.x and higher
• FreeBSD 2.2.8
• FreeBSD 3.x
• FreeBSD 4.x
• NetBSD 1.4
• OpenBSD 2.5
• Solaris 2.6
• Solaris 7

Some IPv6 stacks are in development. Quagga supports following IPv6 stacks. For BSD, we recommend KAME IPv6 stack. Solaris IPv6 stack is not yet supported.

• Linux IPv6 stack for GNU/Linux 2.2.x and higher.
• KAME IPv6 stack for BSD.
• INRIA IPv6 stack for BSD.

1.4 Supported RFC

Below is the list of currently supported RFC's.

RFC1058

Routing Information Protocol. C.L. Hedrick. Jun-01-1988.

RF2082

RIP-2 MD5 Authentication. F. Baker, R. Atkinson. January 1997.

RFC2453

RIP Version 2. G. Malkin. November 1998.

RFC2080

RIPng for IPv6. G. Malkin, R. Minnear. January 1997.

RFC2328

OSPF Version 2. J. Moy. April 1998.

RFC2370

The OSPF Opaque LSA Option R. Coltun. July 1998.

RFC3101

The OSPF Not-So-Stubby Area (NSSA) Option P. Murphy. January 2003.

RFC2740

OSPF for IPv6. R. Coltun, D. Ferguson, J. Moy. December 1999.

RFC1771

A Border Gateway Protocol 4 (BGP-4). Y. Rekhter & T. Li. March 1995.

RFC1965

Autonomous System Confederations for BGP. P. Traina. June 1996.

RFC1997

BGP Communities Attribute. R. Chandra, P. Traina & T. Li. August 1996.

RFC2545

Use of BGP-4 Multiprotocol Extensions for IPv6 Inter-Domain Routing. P. Marques, F. Dupont. March 1999.

RFC2796

BGP Route Reflection An alternative to full mesh IBGP. T. Bates & R. Chandrasekeran. June 1996.

RFC2858

Multiprotocol Extensions for BGP-4. T. Bates, Y. Rekhter, R. Chandra, D. Katz. June 2000.

RFC2842

Capabilities Advertisement with BGP-4. R. Chandra, J. Scudder. May 2000.

When SNMP support is enabled, below RFC is also supported.

RFC1227

SNMP MUX protocol and MIB. M.T. Rose. May-01-1991.

RFC1657

Definitions of Managed Objects for the Fourth Version of the Border Gateway Protocol (BGP-4) using SMIv2. S. Willis, J. Burruss, J. Chu, Editor. July 1994.

RFC1724

RIP Version 2 MIB Extension. G. Malkin & F. Baker. November 1994.

RFC1850

OSPF Version 2 Management Information Base. F. Baker, R. Coltun. November 1995.

1.5 How to get Quagga

Quagga is still beta software and there is no officially released version. Once Quagga is released you can get it from GNU FTP site and its mirror sites. We are planning Quagga-1.0 as the first released version.

Zebra's official web page is located at:

http://www.gnu.org/software/zebra/zebra.html.

The original Zebra web site is located at:

http://www.zebra.org/.

As of this writing, development by zebra.org on Zebra has slowed down. Some work is being done by third-parties to try maintain bug-fixes and enhancements to the current Zebra code-base, which has resulted in a fork of Zebra called Quagga, see:

http://www.quagga.net/.

for further information, as well as links to additional zebra resources.

1.6 Mailing List

There is a mailing list for discussions about Quagga. If you have any comments or suggestions to Quagga, please subscribe to http://lists.quagga.net/mailman/listinfo/quagga-users.

There is an additional mailing list, ZNOG for general discussion of zebra related issues and network operation. To subscribe send an email to znog-subscribe@dishone.st with a message body that includes only:

subscribe znog

To unsubscribe, send an email to znog-unsubscribe@dishone.st with a message body that includes only:

unsubscribe znog

Alternatively, you may use the web interface located at http://www.dishone.st/mailman/listinfo/znog. Links to archives of the znog list are available at this URL.

1.7 Bug Reports

If you think you have found a bug, please send a bug report to http://bugzilla.quagga.net. When you send a bug report, please be careful about the points below.

• Please note what kind of OS you are using. If you use the IPv6 stack please note that as well.
• Please show us the results of netstat -rn and ifconfig -a. Information from zebra's VTY command show ip route will also be helpful.
• Please send your configuration file with the report. If you specify arguments to the configure script please note that too.

Bug reports are very important for us to improve the quality of Quagga. Quagga is still in the development stage, but please don't hesitate to send a bug report to http://bugzilla.quagga.net.

2. Installation

There are three steps for installing the software: configuration, compilation, and installation.

2.1 Configure the Software
2.2 Build the Software
2.3 Install the Software

The easiest way to get Quagga running is to issue the following commands:

% configure
% make
% make install

2.1 Configure the Software

Quagga has an excellent configure script which automatically detects most host configurations. There are several additional configure options you can use to turn off IPv6 support, to disable the compilation of specific daemons, and to enable SNMP support.

`--enable-guile'

Turn on compilation of the zebra-guile interpreter. You will need the guile library to make this. zebra-guile implementation is not yet finished. So this option is only useful for zebra-guile developers.

`--disable-ipv6'

Turn off IPv6 related features and daemons. Quagga configure script automatically detects IPv6 stack. But sometimes you might want to disable IPv6 support of Quagga.

`--disable-zebra'

Do not build zebra daemon.

`--disable-ripd'

Do not build ripd.

`--disable-ripngd'

Do not build ripngd.

`--disable-ospfd'

Do not build ospfd.

`--disable-ospf6d'

Do not build ospf6d.

`--disable-bgpd'

Do not build bgpd.

`--disable-bgp-announce'

Make bgpd which does not make bgp announcements at all. This feature is good for using bgpd as a BGP announcement listener.

`--enable-netlink'

Force to enable GNU/Linux netlink interface. Quagga configure script detects netlink interface by checking a header file. When the header file does not match to the current running kernel, configure script will not turn on netlink support.

`--enable-snmp'

Enable SNMP support. By default, SNMP support is disabled.

`--enable-nssa'

Enable support for Not So Stubby Area (see RC3101) in ospfd.

`--enable-opaque-lsa'

Enable support for Opaque LSAs (RFC2370) in ospfd.

`--disable-ospfapi'

Disable support for OSPF-API, an API to interface directly with ospfd. OSPF-API is enabled if --enable-opaque-lsa is set.

`--disable-ospfclient'

Disable building of the example OSPF-API client.

`--enable-ospf-te'

Enable support for OSPF Traffic Engineering Extension (internet-draft) this requires support for Opaque LSAs.

`--enable-multipath=ARG'

Enable support for Equal Cost Multipath. ARG is the maximum number of ECMP paths to allow, set to 0 to allow unlimited number of paths.

`--enable-rtadv'

Enable support IPV6 router advertisement in zebra.

You may specify any combination of the above options to the configure script. By default, the executables are placed in `/usr/local/sbin' and the configuration files in `/usr/local/etc'. The `/usr/local/' installation prefix and other directories may be changed using the following options to the configuration script.

`--prefix=prefix'

Install architecture-independent files in prefix [/usr/local].

`--sysconfdir=dir'

Look for configuration files in dir [prefix/etc]. Note that sample configuration files will be installed here.

`--localstatedir=dir'

Configure zebra to use dir for local state files, such as pid files and unix sockets.

Additionally, you may configure zebra to drop its elevated privileges shortly after startup and switch to another user, there are three configure options to control zebra's behaviour.

`--enable-user=user'

Switch to user ARG shortly after startup, and run as user ARG in normal operation.

`--enable-group=group'

Switch real and effective group to group shortly after startup.

`--enable-vty-group=group'

Create Unix Vty sockets (for use with vtysh) with group owndership set to group. This allows one to create a seperate group which is restricted to accessing only the Vty sockets, hence allowing one to delegate this group to individual users, or to run vtysh setgid to this group.

The default user and group which will be configured is 'quagga' if no user or group is specified. Note that this user or group requires write access to the local state directory (see --localstatedir) and requires at least read access, and write access if you wish to allow daemons to write out their configuration, to the configuration directory (see --sysconfdir).

On systems which have the 'libcap' capabilities manipulation library (currently only linux), the quagga system will retain only minimal capabilities required, further it will only raise these capabilities for brief periods. On systems without libcap, quagga will run as the user specified and only raise its uid back to uid 0 for brief periods.

% ./configure --disable-ipv6

This command will configure zebra and the routing daemons.

There are several options available only to GNU/Linux systems: (1).

2.2 Build the Software

After configuring the software, you will need to compile it for your system. Simply issue the command make in the root of the source directory and the software will be compiled. If you have *any* problems at this stage, be certain to send a bug report See section 1.7 Bug Reports.

% ./configure
.
.
.
./configure output
.
.
.
% make

2.3 Install the Software

Installing the software to your system consists of copying the compiled programs and supporting files to a standard location. After the installation process has completed, these files have been copied from your work directory to `/usr/local/bin', and `/usr/local/etc'.

To install the Quagga suite, issue the following command at your shell prompt: make install.

%
% make install
%

Quagga daemons have their own terminal interface or VTY. After installation, you have to setup each beast's port number to connect to them. Please add the following entries to `/etc/services'.

zebrasrv      2600/tcp		  # zebra service
zebra         2601/tcp		  # zebra vty
ripd          2602/tcp		  # RIPd vty
ripngd        2603/tcp		  # RIPngd vty
ospfd         2604/tcp		  # OSPFd vty
bgpd          2605/tcp		  # BGPd vty
ospf6d        2606/tcp		  # OSPF6d vty
ospfapi       2607/tcp		  # ospfapi
isisd         2608/tcp		  # ISISd vty

If you use a FreeBSD newer than 2.2.8, the above entries are already added to `/etc/services' so there is no need to add it. If you specify a port number when starting the daemon, these entries may not be needed.

You may need to make changes to the config files in `/usr/local/etc/*.conf'. See section 3.1 Config Commands.

3. Basic commands

There are five routing daemons in use, and there is one manager daemon. These daemons may be located on separate machines from the manager daemon. Each of these daemons will listen on a particular port for incoming VTY connections. The routing daemons are:

• ripd, ripngd, ospfd, ospf6d, bgpd
• zebra

The following sections discuss commands common to all the routing daemons.

3.1 Config Commands		Commands used in config files
3.2 Common Invocation Options		Starting the daemons
3.3 Virtual Terminal Interfaces		Interacting with the daemons

3.1 Config Commands

3.1.1 Basic Config Commands		Some of the generic config commands
3.1.2 Sample Config File		An example config file

In a config file, you can write the debugging options, a vty's password, routing daemon configurations, a log file name, and so forth. This information forms the initial command set for a routing beast as it is starting.

Config files are generally found in:

• `/usr/local/etc/*.conf'

Each of the daemons has its own config file. For example, zebra's default config file name is:

• `/usr/local/etc/zebra.conf'

The daemon name plus `.conf' is the default config file name. You can specify a config file using the -f or --config-file options when starting the daemon.

3.1.1 Basic Config Commands

Command: hostname hostname {}

Set hostname of the router.

Command: password password {}

Set password for vty interface. If there is no password, a vty won't accept connections.

Command: enable password password {}

Set enable password.

Command: log stdout {}

Command: no log stdout {}

Set logging output to stdout.

Command: log file filename {}

If you want to log into a file please specify filename as follows.

log file /usr/local/etc/bgpd.log

Command: log syslog {}

Command: no log syslog {}

Set logging output to syslog.

Command: write terminal {}

Displays the current configuration to the vty interface.

Command: write file {}

Write current configuration to configuration file.

Command: configure terminal {}

Change to configuration mode. This command is the first step to configuration.

Command: terminal length <0-512> {}

Set terminal display length to <0-512>. If length is 0, no display control is performed.

Command: who {}

Command: list {}

List commands.

Command: service password-encryption {}

Encrypt password.

Command: service advanced-vty {}

Enable advanced mode VTY.

Command: service terminal-length <0-512> {}

Set system wide line configuration. This configuration command applies to all VTY interfaces.

Command: show version {}

Show the current version of the Quagga and its build host information.

Command: line vty {}

Enter vty configuration mode.

Command: banner motd default {}

Set default motd string.

Command: no banner motd {}

No motd banner string will be printed.

Line Command: exec-timeout minute {}

Line Command: exec-timeout minute second {}

Set VTY connection timeout value. When only one argument is specified it is used for timeout value in minutes. Optional second argument is used for timeout value in seconds. Default timeout value is 10 minutes. When timeout value is zero, it means no timeout.

Line Command: no exec-timeout {}

Do not perform timeout at all. This command is as same as exec-timeout 0 0.

Line Command: access-class access-list {}

Restrict vty connections with an access list.

3.1.2 Sample Config File

Below is a sample configuration file for the zebra daemon.

!
! Zebra configuration file
!
hostname Router
password zebra
enable password zebra
!
log stdout
!
!

'!' and '#' are comment characters. If the first character of the word is one of the comment characters then from the rest of the line forward will be ignored as a comment.

password zebra!password

If a comment character is not the first character of the word, it's a normal character. So in the above example '!' will not be regarded as a comment and the password is set to 'zebra!password'.

3.2 Common Invocation Options

These options apply to all Quagga daemons.

`-d'

`--daemon'

Runs in daemon mode.

`-f file'

`--config_file=file'

Set configuration file name.

`-h'

`--help'

Display this help and exit.

`-i file'

`--pid_file=file'

Upon startup the process identifier of the daemon is written to a file, typically in `/var/run'. This file can be used by the init system to implement commands such as .../init.d/zebra status, .../init.d/zebra restart or .../init.d/zebra stop.

The file name is an run-time option rather than a configure-time option so that multiple routing daemons can be run simultaneously. This is useful when using Quagga to implement a routing looking glass. One machine can be used to collect differing routing views from differing points in the network.

`-A address'

`--vty_addr=address'

Set the VTY local address to bind to. If set, the VTY socket will only be bound to this address.

`-P port'

`--vty_port=port'

Set the VTY TCP port number. If set to 0 then the TCP VTY sockets will not be opened.

`-u user'

`--vty_addr=user'

Set the user and group to run as.

`-v'

`--version'

Print program version.

3.3 Virtual Terminal Interfaces

VTY -- Virtual Terminal [aka TeletYpe] Interface is a command line interface (CLI) for user interaction with the routing daemon.

3.3.1 VTY Overview		Basics about VTYs
3.3.2 VTY Modes		View, Enable, and Other VTY modes
3.3.3 VTY CLI Commands		Commands for movement, edition, and management

3.3.1 VTY Overview

VTY stands for Virtual TeletYpe interface. It means you can connect to the daemon via the telnet protocol.

To enable a VTY interface, you have to setup a VTY password. If there is no VTY password, one cannot connect to the VTY interface at all.

% telnet localhost 2601
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.

Hello, this is zebra (version 0.96)
Copyright 1997-2000 Kunihiro Ishiguro


User Access Verification

Password: XXXXX
Router> ?
  enable            Turn on privileged commands
  exit              Exit current mode and down to previous mode
  help              Description of the interactive help system
  list              Print command list
  show              Show running system information
  who               Display who is on a vty
Router> enable
Password: XXXXX
Router# configure terminal
Router(config)# interface eth0
Router(config-if)# ip address 10.0.0.1/8
Router(config-if)# ^Z
Router#

'?' is very useful for looking up commands.

3.3.2 VTY Modes

There are three basic VTY modes:

3.3.2.1 VTY View Mode		Mode for read-only interaction
3.3.2.2 VTY Enable Mode		Mode for read-write interaction
3.3.2.3 VTY Other Modes		Special modes (tftp, etc)

There are commands that may be restricted to specific VTY modes.

3.3.2.1 VTY View Mode

This mode is for read-only access to the CLI. One may exit the mode by leaving the system, or by entering enable mode.

3.3.2.2 VTY Enable Mode

This mode is for read-write access to the CLI. One may exit the mode by leaving the system, or by escaping to view mode.

3.3.2.3 VTY Other Modes

This page is for describing other modes.

3.3.3 VTY CLI Commands

Commands that you may use at the command-line are described in the following three subsubsections.

3.3.3.1 CLI Movement Commands		Commands for moving the cursor about
3.3.3.2 CLI Editing Commands		Commands for changing text
3.3.3.3 CLI Advanced Commands		Other commands, session management and so on

3.3.3.1 CLI Movement Commands

These commands are used for moving the CLI cursor. The C character means press the Control Key.

C-f

RIGHT

Move forward one character.

C-b

LEFT

Move backward one character.

M-f

Move forward one word.

M-b

Move backward one word.

C-a

Move to the beginning of the line.

C-e

Move to the end of the line.

3.3.3.2 CLI Editing Commands

These commands are used for editing text on a line. The C character means press the Control Key.

C-h

DEL

Delete the character before point.

C-d

Delete the character after point.

M-d

Forward kill word.

C-w

Backward kill word.

C-k

Kill to the end of the line.

C-u

Kill line from the beginning, erasing input.

C-t

Transpose character.

3.3.3.3 CLI Advanced Commands

There are several additional CLI commands for command line completions, insta-help, and VTY session management.

C-c

Interrupt current input and moves to the next line.

C-z

End current configuration session and move to top node.

C-n

DOWN

Move down to next line in the history buffer.

C-p

UP

Move up to previous line in the history buffer.

TAB

Use command line completion by typing TAB.

You can use command line help by typing help at the beginning of the line. Typing ? at any point in the line will show possible completions.

4. Zebra

zebra is an IP routing manager. It provides kernel routing table updates, interface lookups, and redistribution of routes between different routing protocols.

4.1 Invoking zebra		Running the program
4.2 Interface Commands		Commands for zebra interfaces
4.3 Static Route Commands		Commands for adding static routes
4.4 zebra Terminal Mode Commands		Commands for zebra's VTY

4.1 Invoking zebra

Besides the common invocation options (see section 3.2 Common Invocation Options), the zebra specific invocation options are listed below.

`-b'

`--batch'

Runs in batch mode. zebra parses configuration file and terminates immediately.

`-k'

`--keep_kernel'

When zebra starts up, don't delete old self inserted routes.

`-l'

`--log_mode'

Set verbose logging on.

`-r'

`--retain'

When program terminates, retain routes added by zebra.

4.2 Interface Commands

Command: interface ifname {}

Interface Command: shutdown {}

Interface Command: no shutdown {}

Up or down the current interface.

Interface Command: ip address address/prefix {}

Interface Command: ip6 address address/prefix {}

Interface Command: no ip address address/prefix {}

Interface Command: no ip6 address address/prefix {}

Set the IPv4 or IPv6 address/prefix for the interface.

Interface Command: ip address address/prefix secondary {}

Interface Command: no ip address address/prefix secondary {}

Set the secondary flag for this address. This causes ospfd to not treat the address as a distinct subnet.

Interface Command: description description ... {}

Set description for the interface.

Interface Command: multicast {}

Interface Command: no multicast {}

Enable or disables multicast flag for the interface.

Interface Command: bandwidth <1-10000000> {}

Interface Command: no bandwidth <1-10000000> {}

Set bandwidth value of the interface in kilobits/sec. This is for calculating OSPF cost. This command does not affect the actual device configuration.

Interface Command: link-detect {}

Interface Command: no link-detect {}

Enable/disable link-detect on platforms which support this. Currently only linux and with certain drivers - those which properly support the IFF_RUNNING flag.

4.3 Static Route Commands

Static routing is a very fundamental feature of routing technology. It defines static prefix and gateway.

Command: ip route network gateway {}

network is destination prefix with format of A.B.C.D/M. gateway is gateway for the prefix. When gateway is A.B.C.D format. It is taken as a IPv4 address gateway. Otherwise it is treated as an interface name. If the interface name is null0 then zebra installs a blackhole route.

ip route 10.0.0.0/8 10.0.0.2 ip route 10.0.0.0/8 ppp0 ip route 10.0.0.0/8 null0

First example defines 10.0.0.0/8 static route with gateway 10.0.0.2. Second one defines the same prefix but with gateway to interface ppp0. The third install a blackhole route.

Command: ip route network netmask gateway {}

This is alternate version of above command. When network is A.B.C.D format, user must define netmask value with A.B.C.D format. gateway is same option as above command

ip route 10.0.0.0 255.255.255.0 10.0.0.2 ip route 10.0.0.0 255.255.255.0 ppp0 ip route 10.0.0.0 255.255.255.0 null0

These statements are equivalent to those in the previous example.

Command: ip route network gateway distance {}

Installs the route with the specified distance.

Multiple nexthop static route

ip route 10.0.0.1/32 10.0.0.2
ip route 10.0.0.1/32 10.0.0.3
ip route 10.0.0.1/32 eth0

If there is no route to 10.0.0.2 and 10.0.0.3, and interface eth0 is reachable, then the last route is installed into the kernel.

If zebra has been compiled with multipath support, and both 10.0.0.2 and 10.0.0.3 are reachable, zebra will install a multipath route via both nexthops, if the platform supports this.

zebra> show ip route
S>  10.0.0.1/32 [1/0] via 10.0.0.2 inactive
                      via 10.0.0.3 inactive
  *                   is directly connected, eth0

ip route 10.0.0.0/8 10.0.0.2
ip route 10.0.0.0/8 10.0.0.3
ip route 10.0.0.0/8 null0 255

This will install a multihop route via the specified next-hops if they are reachable, as well as a high-metric blackhole route, which can be useful to prevent traffic destined for a prefix to match less-specific routes (eg default) should the specified gateways not be reachable. Eg:

zebra> show ip route 10.0.0.0/8             
Routing entry for 10.0.0.0/8
  Known via "static", distance 1, metric 0
    10.0.0.2 inactive
    10.0.0.3 inactive

Routing entry for 10.0.0.0/8
  Known via "static", distance 255, metric 0
    directly connected, Null0

Command: ipv6 route network gateway {}

Command: ipv6 route network gateway distance {}

These behave similarly to their ipv4 counterparts.

Command: table tableno {}

Select the primary kernel routing table to be used. This only works for kernels supporting multiple routing tables (like GNU/Linux 2.2.x and later). After setting tableno with this command, static routes defined after this are added to the specified table.

4.4 zebra Terminal Mode Commands

Command: show ip route {}

Display current routes which zebra holds in its database.

Router# show ip route Codes: K - kernel route, C - connected, S - static, R - RIP, B - BGP * - FIB route. K* 0.0.0.0/0 203.181.89.241 S 0.0.0.0/0 203.181.89.1 C* 127.0.0.0/8 lo C* 203.181.89.240/28 eth0

Command: show ipv6 route {}

Command: show interface {}

Command: show ipforward {}

Display whether the host's IP forwarding function is enabled or not. Almost any UNIX kernel can be configured with IP forwarding disabled. If so, the box can't work as a router.

Command: show ipv6forward {}

Display whether the host's IP v6 forwarding is enabled or not.

5. RIP

RIP -- Routing Information Protocol is widely deployed interior gateway protocol. RIP was developed in the 1970s at Xerox Labs as part of the XNS routing protocol. RIP is a distance-vector protocol and is based on the Bellman-Ford algorithms. As a distance-vector protocol, RIP router send updates to its neighbors periodically, thus allowing the convergence to a known topology. In each update, the distance to any given network will be broadcasted to its neighboring router.

ripd supports RIP version 2 as described in RFC2453 and RIP version 1 as described in RFC1058.

5.1 Starting and Stopping ripd
5.2 RIP Configuration
5.3 How to Announce RIP route
5.4 Filtering RIP Routes
5.5 RIP Metric Manipulation
5.6 RIP distance
5.7 RIP route-map
5.8 RIP Authentication
5.9 RIP Timers
5.10 Show RIP Information
5.11 RIP Debug Commands

5.1 Starting and Stopping ripd

The default configuration file name of ripd's is `ripd.conf'. When invocation ripd searches directory /usr/local/etc. If `ripd.conf' is not there next search current directory.

RIP uses UDP port 520 to send and receive RIP packets. So the user must have the capability to bind the port, generally this means that the user must have superuser privileges. RIP protocol requires interface information maintained by zebra daemon. So running zebra is mandatory to run ripd. Thus minimum sequence for running RIP is like below:

# zebra -d
# ripd -d

Please note that zebra must be invoked before ripd.

To stop ripd. Please use kill `cat /var/run/ripd.pid`. Certain signals have special meaningss to ripd.

`SIGHUP'

Reload configuration file `ripd.conf'. All configurations are reseted. All routes learned so far are cleared and removed from routing table.

`SIGUSR1'

Rotate ripd logfile.

`SIGINT'

`SIGTERM'

ripd sweeps all installed RIP routes then terminates properly.

ripd invocation options. Common options that can be specified (see section 3.2 Common Invocation Options).

`-r'

`--retain'

When the program terminates, retain routes added by ripd.

5.1.1 RIP netmask

5.1.1 RIP netmask

The netmask features of ripd support both version 1 and version 2 of RIP. Version 1 of RIP originally contained no netmask information. In RIP version 1, network classes were originally used to determine the size of the netmask. Class A networks use 8 bits of mask, Class B networks use 16 bits of masks, while Class C networks use 24 bits of mask. Today, the most widely used method of a network mask is assigned to the packet on the basis of the interface that received the packet. Version 2 of RIP supports a variable length subnet mask (VLSM). By extending the subnet mask, the mask can be divided and reused. Each subnet can be used for different purposes such as large to middle size LANs and WAN links. Quagga ripd does not support the non-sequential netmasks that are included in RIP Version 2.

In a case of similar information with the same prefix and metric, the old information will be suppressed. Ripd does not currently support equal cost multipath routing.

5.2 RIP Configuration

Command: router rip {}

The router rip command is necessary to enable RIP. To disable RIP, use the no router rip command. RIP must be enabled before carrying out any of the RIP commands.

Command: no router rip {}

Disable RIP.

RIP can be configured to process either Version 1 or Version 2 packets, the default mode is Version 2. If no version is specified, then the RIP daemon will default to Version 2. If RIP is set to Version 1, the setting "Version 1" will be displayed, but the setting "Version 2" will not be displayed whether or not Version 2 is set explicitly as the version of RIP being used. The version can be specified globally, and also on a per-interface basis (see below).

RIP Command: version version {}

Set RIP process's version. version can be `1" or `2".

RIP Command: network network {}

RIP Command: no network network {}

Set the RIP enable interface by network. The interfaces which have addresses matching with network are enabled.

This group of commands either enables or disables RIP interfaces between certain numbers of a specified network address. For example, if the network for 10.0.0.0/24 is RIP enabled, this would result in all the addresses from 10.0.0.0 to 10.0.0.255 being enabled for RIP. The no network command will disable RIP for the specified network.

RIP Command: network ifname {}

RIP Command: no network ifname {}

Set a RIP enabled interface by ifname. Both the sending and receiving of RIP packets will be enabled on the port specified in the network ifname command. The no network ifname command will disable RIP on the specified interface.

RIP Command: neighbor a.b.c.d {}

RIP Command: no neighbor a.b.c.d {}

Specify RIP neighbor. When a neighbor doesn't understand multicast, this command is used to specify neighbors. In some cases, not all routers will be able to understand multicasting, where packets are sent to a network or a group of addresses. In a situation where a neighbor cannot process multicast packets, it is necessary to establish a direct link between routers. The neighbor command allows the network administrator to specify a router as a RIP neighbor. The no neighbor a.b.c.d command will disable the RIP neighbor.

Below is very simple RIP configuration. Interface eth0 and interface which address match to 10.0.0.0/8 are RIP enabled.

!
router rip
 network 10.0.0.0/8
 network eth0
!

Passive interface

RIP command: passive-interface (IFNAME|default) {}

RIP command: no passive-interface IFNAME {}

This command sets the specified interface to passive mode. On passive mode interface, all receiving packets are processed as normal and ripd does not send either multicast or unicast RIP packets except to RIP neighbors specified with neighbor command. The interface may be specified as default to make ripd default to passive on all interfaces.

The default is to be passive on all interfaces.

RIP version handling

Interface command: ip rip send version version {}

version can be `1', `2', `1 2'. This configuration command overrides the router's rip version setting. The command will enable the selected interface to send packets with RIP Version 1, RIP Version 2, or both. In the case of '1 2', packets will be both broadcast and multicast.

The default is to send only version 2.

Interface command: ip rip receive version version {}

Version setting for incoming RIP packets. This command will enable the selected interface to receive packets in RIP Version 1, RIP Version 2, or both.

The default is to receive both versions.

RIP split-horizon

Interface command: ip split-horizon {}

Interface command: no ip split-horizon {}

Control split-horizon on the interface. Default is ip split-horizon. If you don't perform split-horizon on the interface, please specify no ip split-horizon.

5.3 How to Announce RIP route

RIP command: redistribute kernel {}

RIP command: redistribute kernel metric <0-16> {}

RIP command: redistribute kernel route-map route-map {}

RIP command: no redistribute kernel {}

redistribute kernel redistributes routing information from kernel route entries into the RIP tables. no redistribute kernel disables the routes.

RIP command: redistribute static {}

RIP command: redistribute static metric <0-16> {}

RIP command: redistribute static route-map route-map {}

RIP command: no redistribute static {}

redistribute static redistributes routing information from static route entries into the RIP tables. no redistribute static disables the routes.

RIP command: redistribute connected {}

RIP command: redistribute connected metric <0-16> {}

RIP command: redistribute connected route-map route-map {}

RIP command: no redistribute connected {}

Redistribute connected routes into the RIP tables. no redistribute connected disables the connected routes in the RIP tables. This command redistribute connected of the interface which RIP disabled. The connected route on RIP enabled interface is announced by default.

RIP command: redistribute ospf {}

RIP command: redistribute ospf metric <0-16> {}

RIP command: redistribute ospf route-map route-map {}

RIP command: no redistribute ospf {}

redistribute ospf redistributes routing information from ospf route entries into the RIP tables. no redistribute ospf disables the routes.

RIP command: redistribute bgp {}

RIP command: redistribute bgp metric <0-16> {}

RIP command: redistribute bgp route-map route-map {}

RIP command: no redistribute bgp {}

redistribute bgp redistributes routing information from bgp route entries into the RIP tables. no redistribute bgp disables the routes.

If you want to specify RIP only static routes:

RIP command: default-information originate {}

RIP command: route a.b.c.d/m {}

RIP command: no route a.b.c.d/m {}

This command is specific to Quagga. The route command makes a static route only inside RIP. This command should be used only by advanced users who are particularly knowledgeable about the RIP protocol. In most cases, we recommend creating a static route in Quagga and redistributing it in RIP using redistribute static.

5.4 Filtering RIP Routes

RIP routes can be filtered by a distribute-list.

Command: distribute-list access_list direct ifname {}

You can apply access lists to the interface with a distribute-list command. access_list is the access list name. direct is `in' or `out'. If direct is `in' the access list is applied to input packets.

The distribute-list command can be used to filter the RIP path. distribute-list can apply access-lists to a chosen interface. First, one should specify the access-list. Next, the name of the access-list is used in the distribute-list command. For example, in the following configuration `eth0' will permit only the paths that match the route 10.0.0.0/8

! router rip distribute-list private in eth0 ! access-list private permit 10 10.0.0.0/8 access-list private deny any !

distribute-list can be applied to both incoming and outgoing data.

Command: distribute-list prefix prefix_list (in|out) ifname {}

You can apply prefix lists to the interface with a distribute-list command. prefix_list is the prefix list name. Next is the direction of `in' or `out'. If direct is `in' the access list is applied to input packets.

5.5 RIP Metric Manipulation

RIP metric is a value for distance for the network. Usually ripd increment the metric when the network information is received. Redistributed routes' metric is set to 1.

RIP command: default-metric <1-16> {}

RIP command: no default-metric <1-16> {}

This command modifies the default metric value for redistributed routes. The default value is 1. This command does not affect connected route even if it is redistributed by redistribute connected. To modify connected route's metric value, please use redistribute connected metric or route-map. offset-list also affects connected routes.

RIP command: offset-list access-list (in|out) {}

RIP command: offset-list access-list (in|out) ifname {}

5.6 RIP distance

Distance value is used in zebra daemon. Default RIP distance is 120.

RIP command: distance <1-255> {}

RIP command: no distance <1-255> {}

Set default RIP distance to specified value.

RIP command: distance <1-255> A.B.C.D/M {}

RIP command: no distance <1-255> A.B.C.D/M {}

Set default RIP distance to specified value when the route's source IP address matches the specified prefix.

RIP command: distance <1-255> A.B.C.D/M access-list {}

RIP command: no distance <1-255> A.B.C.D/M access-list {}

Set default RIP distance to specified value when the route's source IP address matches the specified prefix and the specified access-list.

5.7 RIP route-map

Usage of ripd's route-map support.

Optional argument route-map MAP_NAME can be added to each redistribute statement.

redistribute static [route-map MAP_NAME]
redistribute connected [route-map MAP_NAME]
.....

Cisco applies route-map _before_ routes will exported to rip route table. In current Quagga's test implementation, ripd applies route-map after routes are listed in the route table and before routes will be announced to an interface (something like output filter). I think it is not so clear, but it is draft and it may be changed at future.

Route-map statement (see section 12. Route Map) is needed to use route-map functionality.

Route Map: match interface word {}

This command match to incoming interface. Notation of this match is different from Cisco. Cisco uses a list of interfaces - NAME1 NAME2 ... NAMEN. Ripd allows only one name (maybe will change in the future). Next - Cisco means interface which includes next-hop of routes (it is somewhat similar to "ip next-hop" statement). Ripd means interface where this route will be sent. This difference is because "next-hop" of same routes which sends to different interfaces must be different. Maybe it'd be better to made new matches - say "match interface-out NAME" or something like that.

Route Map: match ip address word {}

Route Map: match ip address prefix-list word {}

Match if route destination is permitted by access-list.

Route Map: match ip next-hop A.B.C.D {}

Cisco uses here <access-list>, ripd IPv4 address. Match if route has this next-hop (meaning next-hop listed in the rip route table - "show ip rip")

Route Map: match metric <0-4294967295> {}

This command match to the metric value of RIP updates. For other protocol compatibility metric range is shown as <0-4294967295>. But for RIP protocol only the value range <0-16> make sense.

Route Map: set ip next-hop A.B.C.D {}

This command set next hop value in RIPv2 protocol. This command does not affect RIPv1 because there is no next hop field in the packet.

Route Map: set metric <0-4294967295> {}

Set a metric for matched route when sending announcement. The metric value range is very large for compatibility with other protocols. For RIP, valid metric values are from 1 to 16.

5.8 RIP Authentication

Interface command: ip rip authentication mode md5 {}

Interface command: no ip rip authentication mode md5 {}

Set the interface with RIPv2 MD5 authentication.

Interface command: ip rip authentication mode text {}

Interface command: no ip rip authentication mode text {}

Set the interface with RIPv2 simple password authentication.

Interface command: ip rip authentication string string {}

Interface command: no ip rip authentication string string {}

RIP version 2 has simple text authentication. This command sets authentication string. The string must be shorter than 16 characters.

Interface command: ip rip authentication key-chain key-chain {}

Interface command: no ip rip authentication key-chain key-chain {}

Specifiy Keyed MD5 chain.

!
key chain test
 key 1
  key-string test
!
interface eth1
 ip rip authentication mode md5
 ip rip authentication key-chain test
!

5.9 RIP Timers

RIP command: timers basic update timeout garbage {}

RIP protocol has several timers. User can configure those timers' values by timers basic command.

The default settings for the timers are as follows:

• The update timer is 30 seconds. Every update timer seconds, the RIP process is awakened to send an unsolicited Response message containing the complete routing table to all neighboring RIP routers.

• The timeout timer is 180 seconds. Upon expiration of the timeout, the route is no longer valid; however, it is retained in the routing table for a short time so that neighbors can be notified that the route has been dropped.

• The garbage collect timer is 120 seconds. Upon expiration of the garbage-collection timer, the route is finally removed from the routing table.

The timers basic command allows the the default values of the timers listed above to be changed.

RIP command: no timers basic {}

The no timers basic command will reset the timers to the default settings listed above.

5.10 Show RIP Information

To display RIP routes.

Command: show ip rip {}

Show RIP routes.

The command displays all RIP routes. For routes that are received through RIP, this command will display the time the packet was sent and the tag information. This command will also display this information for routes redistributed into RIP.

Command: show ip protocols {}

The command displays current RIP status. It includes RIP timer, filtering, version, RIP enabled interface and RIP peer inforation.

ripd> show ip protocols
Routing Protocol is "rip"
  Sending updates every 30 seconds with +/-50%, next due in 35 seconds
  Timeout after 180 seconds, garbage collect after 120 seconds
  Outgoing update filter list for all interface is not set
  Incoming update filter list for all interface is not set
  Default redistribution metric is 1
  Redistributing: kernel connected
  Default version control: send version 2, receive version 2 
    Interface        Send  Recv
  Routing for Networks:
    eth0
    eth1
    1.1.1.1
    203.181.89.241
  Routing Information Sources:
    Gateway          BadPackets BadRoutes  Distance Last Update

5.11 RIP Debug Commands

Debug for RIP protocol.

Command: debug rip events {}

Debug rip events.

debug rip will show RIP events. Sending and receiving packets, timers, and changes in interfaces are events shown with ripd.

Command: debug rip packet {}

Debug rip packet.

debug rip packet will display detailed information about the RIP packets. The origin and port number of the packet as well as a packet dump is shown.

Command: debug rip zebra {}

Debug rip between zebra communication.

This command will show the communication between ripd and zebra. The main information will include addition and deletion of paths to the kernel and the sending and receiving of interface information.

Command: show debugging rip {}

Display ripd's debugging option.

show debugging rip will show all information currently set for ripd debug.

6. RIPng

ripngd supports the RIPng protocol as described in RFC2080. It's an IPv6 reincarnation of the RIP protocol.

6.1 Invoking ripngd
6.2 ripngd Configuration
6.3 ripngd Terminal Mode Commands
6.4 ripngd Filtering Commands

6.1 Invoking ripngd

There are no ripngd specific invocation options. Common options can be specified (see section 3.2 Common Invocation Options).

6.2 ripngd Configuration

Currently ripngd supports the following commands:

Command: router ripng {}

Enable RIPng.

RIPng Command: flush_timer time {}

Set flush timer.

RIPng Command: network network {}

Set RIPng enabled interface by network

RIPng Command: network ifname {}

Set RIPng enabled interface by ifname

RIPng Command: route network {}

Set RIPng static routing announcement of network.

Command: router zebra {}

This command is the default and does not appear in the configuration. With this statement, RIPng routes go to the zebra daemon.

6.3 ripngd Terminal Mode Commands

Command: show ip ripng {}

Command: show debugging ripng {}

Command: debug ripng events {}

Command: debug ripng packet {}

Command: debug ripng zebra {}

6.4 ripngd Filtering Commands

Command: distribute-list access_list (in|out) ifname {}

You can apply an access-list to the interface using the distribute-list command. access_list is an access-list name. direct is `in' or `out'. If direct is `in', the access-list is applied only to incoming packets.

distribute-list local-only out sit1

7. OSPFv2

OSPF version 2 is a routing protocol which described in RFC2328 - OSPF Version 2. OSPF is IGP (Interior Gateway Protocols). Compared with RIP, OSPF can provide scalable network support and faster convergence time. OSPF is widely used in large networks such as ISP backbone and enterprise networks.

7.1 Configuring ospfd
7.2 OSPF router
7.3 OSPF area
7.4 OSPF interface
7.5 Redistribute routes to OSPF
7.6 Showing OSPF information
7.7 Debugging OSPF

7.1 Configuring ospfd

There is no ospfd specific options. Common options can be specified (see section 3.2 Common Invocation Options) to ospfd. ospfd needs interface information from zebra. So please make it sure zebra is running before invoking ospfd.

Like other daemons, ospfd configuration is done in OSPF specific configuration file `ospfd.conf'.

7.2 OSPF router

To start OSPF process you have to specify the OSPF router. As of this writing, ospfd does not support multiple OSPF processes.

Command: router ospf {}

Command: no router ospf {}

Enable or disable the OSPF process. ospfd does not yet support multiple OSPF processes. So you can not specify an OSPF process number.

OSPF Command: ospf router-id a.b.c.d {}

OSPF Command: no ospf router-id {}

OSPF Command: ospf abr-type type {}

OSPF Command: no ospf abr-type type {}

type can be cisco|ibm|shortcut|standard More information regarding the behaviour controlled by this command can be found in draft-ietf-ospf-abr-alt-05.txt and draft-ietf-ospf-shortcut-abr-02.txt Quote: "Though the definition of the Area Border Router (ABR) in the OSPF specification does not require a router with multiple attached areas to have a backbone connection, it is actually necessary to provide successful routing to the inter-area and external destinations. If this requirement is not met, all traffic destined for the areas not connected to such an ABR or out of the OSPF domain, is dropped. This document describes alternative ABR behaviors implemented in Cisco and IBM routers."

OSPF Command: ospf rfc1583compatibility {}

OSPF Command: no ospf rfc1583compatibility {}

This rfc2328, the sucessor to rfc1583, suggests according to section G.2 (changes) in section 16.4 a change to the path preference algorithm that prevents possible routing loops that were possible in the old version of OSPFv2. More specifically it demands that inter-area paths and intra-area path are now of equal preference but still both preferred to external paths.

OSPF Command: passive interface interface {}

OSPF Command: no passive interface interface {}

OSPF Command: timers spf <0-4294967295> <0-4294967295> {}

OSPF Command: no timers spf {}

OSPF Command: refresh group-limit <0-10000> {}

OSPF Command: refresh per-slice <0-10000> {}

OSPF Command: refresh age-diff <0-10000> {}

OSPF Command: auto-cost refrence-bandwidth <1-4294967> {}

OSPF Command: no auto-cost refrence-bandwidth {}

OSPF Command: network a.b.c.d/m area a.b.c.d {}

OSPF Command: network a.b.c.d/m area <0-4294967295> {}

OSPF Command: no network a.b.c.d/m area a.b.c.d {}

OSPF Command: no network a.b.c.d/m area <0-4294967295> {}

This command specifies the OSPF enabled interface(s). If the interface has an address from range 192.168.1.0/24 then the command below enables ospf on this interface so router can provide network information to the other ospf routers via this interface.

router ospf network 192.168.1.0/24 area 0.0.0.0

Prefix length in interface must be equal or bigger (ie. smaller network) than prefix length in network statement. For example statement above doesn't enable ospf on interface with address 192.168.1.1/23, but it does on interface with address 192.168.1.129/25.

7.3 OSPF area

OSPF Command: area a.b.c.d range a.b.c.d/m {}

OSPF Command: area <0-4294967295> range a.b.c.d/m {}

OSPF Command: no area a.b.c.d range a.b.c.d/m {}

OSPF Command: no area <0-4294967295> range a.b.c.d/m {}

Summarize intra area paths from specified area into one Type-3 summary-LSA announced to other areas. This command can be used only in ABR and ONLY router-LSAs (Type-1) and network-LSAs (Type-2) (ie. LSAs with scope area) can be summarized. Type-5 AS-external-LSAs can't be summarized - their scope is AS. Summarizing Type-7 AS-external-LSAs isn't supported yet by Quagga.

router ospf network 192.168.1.0/24 area 0.0.0.0 network 10.0.0.0/8 area 0.0.0.10 area 0.0.0.10 range 10.0.0.0/8

With configuration above one Type-3 Summary-LSA with routing info 10.0.0.0/8 is announced into backbone area if area 0.0.0.10 contains at least one intra-area network (ie. described with router or network LSA) from this range.

OSPF Command: area a.b.c.d range IPV4_PREFIX not-advertise {}

OSPF Command: no area a.b.c.d range IPV4_PREFIX not-advertise {}

Instead of summarizing intra area paths filter them - ie. intra area paths from this range are not advertised into other areas. This command makes sense in ABR only.

OSPF Command: area a.b.c.d range IPV4_PREFIX substitute IPV4_PREFIX {}

OSPF Command: no area a.b.c.d range IPV4_PREFIX substitute IPV4_PREFIX {}

Substitute summarized prefix with another prefix.

router ospf network 192.168.1.0/24 area 0.0.0.0 network 10.0.0.0/8 area 0.0.0.10 area 0.0.0.10 range 10.0.0.0/8 substitute 11.0.0.0/8

One Type-3 summary-LSA with routing info 11.0.0.0/8 is announced into backbone area if area 0.0.0.10 contains at least one intra-area network (ie. described with router-LSA or network-LSA) from range 10.0.0.0/8. This command makes sense in ABR only.

OSPF Command: area a.b.c.d virtual-link a.b.c.d {}

OSPF Command: area <0-4294967295> virtual-link a.b.c.d {}

OSPF Command: no area a.b.c.d virtual-link a.b.c.d {}

OSPF Command: no area <0-4294967295> virtual-link a.b.c.d {}

OSPF Command: area a.b.c.d shortcut {}

OSPF Command: area <0-4294967295> shortcut {}

OSPF Command: no area a.b.c.d shortcut {}

OSPF Command: no area <0-4294967295> shortcut {}

OSPF Command: area a.b.c.d stub {}

OSPF Command: area <0-4294967295> stub {}

OSPF Command: no area a.b.c.d stub {}

OSPF Command: no area <0-4294967295> stub {}

OSPF Command: area a.b.c.d stub no-summary {}

OSPF Command: area <0-4294967295> stub no-summary {}

OSPF Command: no area a.b.c.d stub no-summary {}

OSPF Command: no area <0-4294967295> stub no-summary {}

OSPF Command: area a.b.c.d default-cost <0-16777215> {}

OSPF Command: no area a.b.c.d default-cost <0-16777215> {}

OSPF Command: area a.b.c.d export-list NAME {}

OSPF Command: area <0-4294967295> export-list NAME {}

OSPF Command: no area a.b.c.d export-list NAME {}

OSPF Command: no area <0-4294967295> export-list NAME {}

Filter Type-3 summary-LSAs announced to other areas originated from intra- area paths from specified area.

router ospf network 192.168.1.0/24 area 0.0.0.0 network 10.0.0.0/8 area 0.0.0.10 area 0.0.0.10 export-list foo ! access-list foo permit 10.10.0.0/16 access-list foo deny any

With example above any intra-area paths from area 0.0.0.10 and from range 10.10.0.0/16 (for example 10.10.1.0/24 and 10.10.2.128/30) are announced into other areas as Type-3 summary-LSA's, but any others (for example 10.11.0.0/16 or 10.128.30.16/30) aren't. This command makes sense in ABR only.

OSPF Command: area a.b.c.d import-list NAME {}

OSPF Command: area <0-4294967295> import-list NAME {}

OSPF Command: no area a.b.c.d import-list NAME {}

OSPF Command: no area <0-4294967295> import-list NAME {}

Same as export-list, but it applies to paths announced into specified area as Type-3 summary-LSAs.

OSPF Command: area a.b.c.d filter-list prefix NAME in {}

OSPF Command: area a.b.c.d filter-list prefix NAME out {}

OSPF Command: area <0-4294967295> filter-list prefix NAME in {}

OSPF Command: area <0-4294967295> filter-list prefix NAME out {}

OSPF Command: no area a.b.c.d filter-list prefix NAME in {}

OSPF Command: no area a.b.c.d filter-list prefix NAME out {}

OSPF Command: no area <0-4294967295> filter-list prefix NAME in {}

OSPF Command: no area <0-4294967295> filter-list prefix NAME out {}

Filtering Type-3 summary-LSAs to/from area using prefix lists. This command makes sense in ABR only.

OSPF Command: area a.b.c.d authentication {}

OSPF Command: area <0-4294967295> authentication {}

OSPF Command: no area a.b.c.d authentication {}

OSPF Command: no area <0-4294967295> authentication {}

OSPF Command: area a.b.c.d authentication message-digest {}

OSPF Command: area <0-4294967295> authentication message-digest {}

7.4 OSPF interface

Interface Command: ip ospf authentication-key AUTH_KEY {}

Interface Command: no ip ospf authentication-key {}

Set OSPF authentication key to a simple password. After setting AUTH_KEY, all OSPF packets are authenticated. AUTH_KEY has length up to 8 chars.

Interface Command: ip ospf message-digest-key KEYID md5 KEY {}

Interface Command: no ip ospf message-digest-key {}

Set OSPF authentication key to a cryptographic password. The cryptographic algorithm is MD5. KEYID identifies secret key used to create the message digest. KEY is the actual message digest key up to 16 chars. Note that OSPF MD5 authentication requires that time never go backwards, even across resets, if ospfd is to be able to promptly reestabish adjacencies with it's neighbours after restarts/reboots. The host should have system time be set at boot from an external source (eg battery backed clock, NTP, etc.) if MD5 authentication is to be expected to work reliably.

Interface Command: ip ospf cost <1-65535> {}

Interface Command: no ip ospf cost {}

Set link cost for the specified interface. The cost value is set to router-LSA's metric field and used for SPF calculation.

Interface Command: ip ospf dead-interval <1-65535> {}

Interface Command: no ip ospf dead-interval {}

Set number of seconds for RouterDeadInterval timer value used for Wait Timer and Inactivity Timer. This value must be the same for all routers attached to a common network. The default value is 40 seconds.

Interface Command: ip ospf hello-interval <1-65535> {}

Interface Command: no ip ospf hello-interval {}

Set number of seconds for HelloInterval timer value. Setting this value, Hello packet will be sent every timer value seconds on the specified interface. This value must be the same for all routers attached to a common network. The default value is 10 seconds.

Interface Command: ip ospf network (broadcast|non-broadcast|point-to-multipoint|point-to-point) {}

Interface Command: no ip ospf network {}

Set explicitly network type for specifed interface.

Interface Command: ip ospf priority <0-255> {}

Interface Command: no ip ospf priority {}

Set RouterPriority integer value. Setting higher value, router will be more eligible to become Designated Router. Setting the value to 0, router is no longer eligible to Designated Router. The default value is 1.

Interface Command: ip ospf retransmit-interval <1-65535> {}

Interface Command: no ip ospf retransmit interval {}

Set number of seconds for RxmtInterval timer value. This value is used when retransmitting Database Description and Link State Request packets. The default value is 5 seconds.

Interface Command: ip ospf transmit-delay {}

Interface Command: no ip ospf transmit-delay {}

Set number of seconds for InfTransDelay value. LSAs' age should be incremented by this value when transmitting. The default value is 1 seconds.

7.5 Redistribute routes to OSPF

OSPF Command: redistribute (kernel|connected|static|rip|bgp) {}

OSPF Command: redistribute (kernel|connected|static|rip|bgp) route-map {}

OSPF Command: redistribute (kernel|connected|static|rip|bgp) metric-type (1|2) {}

OSPF Command: redistribute (kernel|connected|static|rip|bgp) metric-type (1|2) route-map word {}

OSPF Command: redistribute (kernel|connected|static|rip|bgp) metric <0-16777214> {}

OSPF Command: redistribute (kernel|connected|static|rip|bgp) metric <0-16777214> route-map word {}

OSPF Command: redistribute (kernel|connected|static|rip|bgp) metric-type (1|2) metric <0-16777214> {}

OSPF Command: redistribute (kernel|connected|static|rip|bgp) metric-type (1|2) metric <0-16777214> route-map word {}

OSPF Command: no redistribute (kernel|connected|static|rip|bgp) {}

OSPF Command: default-information originate {}

OSPF Command: default-information originate metric <0-16777214> {}

OSPF Command: default-information originate metric <0-16777214> metric-type (1|2) {}

OSPF Command: default-information originate metric <0-16777214> metric-type (1|2) route-map word {}

OSPF Command: default-information originate always {}

OSPF Command: default-information originate always metric <0-16777214> {}

OSPF Command: default-information originate always metric <0-16777214> metric-type (1|2) {}

OSPF Command: default-information originate always metric <0-16777214> metric-type (1|2) route-map word {}

OSPF Command: no default-information originate {}

OSPF Command: distribute-list NAME out (kernel|connected|static|rip|ospf {}

OSPF Command: no distribute-list NAME out (kernel|connected|static|rip|ospf {}

OSPF Command: default-metric <0-16777214> {}

OSPF Command: no default-metric {}

OSPF Command: distance <1-255> {}

OSPF Command: no distance <1-255> {}

OSPF Command: distance ospf (intra-area|inter-area|external) <1-255> {}

OSPF Command: no distance ospf {}

Command: router zebra {}

Command: no router zebra {}

7.6 Showing OSPF information

Command: show ip ospf {}

Command: show ip ospf interface [INTERFACE] {}

Command: show ip ospf neighbor {}

Command: show ip ospf neighbor INTERFACE {}

Command: show ip ospf neighbor detail {}

Command: show ip ospf neighbor INTERFACE detail {}

Command: show ip ospf database {}

Command: show ip ospf database (asbr-summary|external|network|router|summary) {}

Command: show ip ospf database (asbr-summary|external|network|router|summary) link-state-id {}

Command: show ip ospf database (asbr-summary|external|network|router|summary) link-state-id adv-router adv-router {}

Command: show ip ospf database (asbr-summary|external|network|router|summary) adv-router adv-router {}

Command: show ip ospf database (asbr-summary|external|network|router|summary) link-state-id self-originate {}

Command: show ip ospf database (asbr-summary|external|network|router|summary) self-originate {}

Command: show ip ospf database max-age {}

Command: show ip ospf database self-originate {}

Command: show ip ospf refresher {}

Command: show ip ospf route {}

7.7 Debugging OSPF

Command: debug ospf packet (hello|dd|ls-request|ls-update|ls-ack|all) (send|recv) [detail] {}

Command: no debug ospf packet (hello|dd|ls-request|ls-update|ls-ack|all) (send|recv) [detail] {}

Command: debug ospf ism {}

Command: debug ospf ism (status|events|timers) {}

Command: no debug ospf ism {}

Command: no debug ospf ism (status|events|timers) {}

Command: debug ospf nsm {}

Command: debug ospf nsm (status|events|timers) {}

Command: no debug ospf nsm {}

Command: no debug ospf nsm (status|events|timers) {}

Command: debug ospf lsa {}

Command: debug ospf lsa (generate|flooding|refresh) {}

Command: no debug ospf lsa {}

Command: no debug ospf lsa (generate|flooding|refresh) {}

Command: debug ospf zebra {}

Command: debug ospf zebra (interface|redistribute) {}

Command: no debug ospf zebra {}

Command: no debug ospf zebra (interface|redistribute) {}

Command: show debugging ospf {}

8. OSPFv3

ospf6d is a daemon support OSPF version 3 for IPv6 network. OSPF for IPv6 is described in RFC2740.

8.1 OSPF6 router
8.2 OSPF6 area
8.3 OSPF6 interface
8.4 Redistribute routes to OSPF6
8.5 Showing OSPF6 information

8.1 OSPF6 router

Command: router ospf6 {}

OSPF6 Command: router-id a.b.c.d {}

Set router's Router-ID.

OSPF6 Command: interface ifname area area {}

Bind interface to specified area, and start sending OSPF packets. area can be specified as 0.

8.2 OSPF6 area

Area support for OSPFv3 is not yet implemented.

8.3 OSPF6 interface

Interface Command: ipv6 ospf6 cost COST {}

Sets interface's output cost. Default value is 1.

Interface Command: ipv6 ospf6 hello-interval HELLOINTERVAL {}

Sets interface's Hello Interval. Default 40

Interface Command: ipv6 ospf6 dead-interval DEADINTERVAL {}

Sets interface's Router Dead Interval. Default value is 40.

Interface Command: ipv6 ospf6 retransmit-interval RETRANSMITINTERVAL {}

Sets interface's Rxmt Interval. Default value is 5.

Interface Command: ipv6 ospf6 priority PRIORITY {}

Sets interface's Router Priority. Default value is 1.

Interface Command: ipv6 ospf6 transmit-delay TRANSMITDELAY {}

Sets interface's Inf-Trans-Delay. Default value is 1.

8.4 Redistribute routes to OSPF6

OSPF6 Command: redistribute static {}

OSPF6 Command: redistribute connected {}

OSPF6 Command: redistribute ripng {}

8.5 Showing OSPF6 information

Command: show ipv6 ospf6 [INSTANCE_ID] {}

INSTANCE_ID is an optional OSPF instance ID. To see router ID and OSPF instance ID, simply type "show ipv6 ospf6 ".

Command: show ipv6 ospf6 database {}

This command shows LSA database summary. You can specify the type of LSA.

Command: show ipv6 ospf6 interface {}

To see OSPF interface configuration like costs.

Command: show ipv6 ospf6 neighbor {}

Shows state and chosen (Backup) DR of neighbor.

Command: show ipv6 ospf6 request-list A.B.C.D {}

Shows requestlist of neighbor.

Command: show ipv6 route ospf6 {}

This command shows internal routing table.

9. BGP

BGP stands for a Border Gateway Protocol. The lastest BGP version is 4. It is referred as BGP-4. BGP-4 is one of the Exterior Gateway Protocols and de-fact standard of Inter Domain routing protocol. BGP-4 is described in RFC1771 - A Border Gateway Protocol 4 (BGP-4).

Many extentions are added to RFC1771. RFC2858 - Multiprotocol Extensions for BGP-4 provide multiprotocol support to BGP-4.

9.1 Starting BGP
9.2 BGP router
9.3 BGP network
9.4 BGP Peer
9.5 BGP Peer Group
9.6 BGP Address Family
9.7 Autonomous System
9.8 BGP Communities Attribute
9.9 BGP Extended Communities Attribute
9.10 Displaying BGP Routes
9.11 Capability Negotiation
9.12 Route Reflector
9.13 Route Server
9.14 How to set up a 6-Bone connection
9.15 Dump BGP packets and table

9.1 Starting BGP

Default configuration file of bgpd is `bgpd.conf'. bgpd searches the current directory first then /usr/local/etc/bgpd.conf. All of bgpd's command must be configured in `bgpd.conf'.

bgpd specific invocation options are described below. Common options may also be specified (see section 3.2 Common Invocation Options).

`-p PORT'

`--bgp_port=PORT'

Set the bgp protocol's port number.

`-r'

`--retain'

When program terminates, retain BGP routes added by zebra.

9.2 BGP router

First of all you must configure BGP router with router bgp command. To configure BGP router, you need AS number. AS number is an identification of autonomous system. BGP protocol uses the AS number for detecting whether the BGP connection is internal one or external one.

Command: router bgp asn {}

Enable a BGP protocol process with the specified asn. After this statement you can input any BGP Commands. You can not create different BGP process under different asn without specifying multiple-instance (see section 9.13.1 Multiple instance).

Command: no router bgp asn {}

Destroy a BGP protocol process with the specified asn.

BGP: bgp router-id A.B.C.D {}

This command specifies the router-ID. If bgpd connects to zebra it gets interface and address information. In that case default router ID value is selected as the largest IP Address of the interfaces. When router zebra is not enabled bgpd can't get interface information so router-id is set to 0.0.0.0. So please set router-id by hand.

9.2.1 BGP distance
9.2.2 BGP decision process

9.2.1 BGP distance

BGP: distance bgp <1-255> <1-255> <1-255> {}

This command change distance value of BGP. Each argument is distance value for external routes, internal routes and local routes.

BGP: distance <1-255> A.B.C.D/M {}

BGP: distance <1-255> A.B.C.D/M word {}

This command set distance value to

9.2.2 BGP decision process

1. Weight check

2. Local preference check.

3. Local route check.

4. AS path length check.

5. Origin check.

6. MED check.

9.3 BGP network

9.3.1 BGP route
9.3.2 Route Aggregation
9.3.3 Redistribute to BGP

9.3.1 BGP route

BGP: network A.B.C.D/M {}

This command adds the announcement network.

router bgp 1 network 10.0.0.0/8

This configuration example says that network 10.0.0.0/8 will be announced to all neighbors. Some vendors' routers don't advertise routes if they aren't present in their IGP routing tables; bgp doesn't care about IGP routes when announcing its routes.

BGP: no network A.B.C.D/M {}

9.3.2 Route Aggregation

BGP: aggregate-address A.B.C.D/M {}

This command specifies an aggregate address.

BGP: aggregate-address A.B.C.D/M as-set {}

This command specifies an aggregate address. Resulting routes inlucde AS set.

BGP: aggregate-address A.B.C.D/M summary-only {}

This command specifies an aggregate address. Aggreated routes will not be announce.

BGP: no aggregate-address A.B.C.D/M {}

9.3.3 Redistribute to BGP

BGP: redistribute kernel {}

Redistribute kernel route to BGP process.

BGP: redistribute static {}

Redistribute static route to BGP process.

BGP: redistribute connected {}

Redistribute connected route to BGP process.

BGP: redistribute rip {}

Redistribute RIP route to BGP process.

BGP: redistribute ospf {}

Redistribute OSPF route to BGP process.

9.4 BGP Peer

9.4.1 Defining Peer
9.4.2 BGP Peer commands
9.4.3 Peer filtering

9.4.1 Defining Peer

BGP: neighbor peer remote-as asn {}

Creates a new neighbor whose remote-as is asn. peer can be an IPv4 address or an IPv6 address.

router bgp 1 neighbor 10.0.0.1 remote-as 2

In this case my router, in AS-1, is trying to peer with AS-2 at 10.0.0.1.

This command must be the first command used when configuring a neighbor. If the remote-as is not specified, bgpd will complain like this:

can't find neighbor 10.0.0.1

9.4.2 BGP Peer commands

In a router bgp clause there are neighbor specific configurations required.

BGP: neighbor peer shutdown {}

BGP: no neighbor peer shutdown {}

Shutdown the peer. We can delete the neighbor's configuration by no neighbor peer remote-as as-number but all configuration of the neighbor will be deleted. When you want to preserve the configuration, but want to drop the BGP peer, use this syntax.

BGP: neighbor peer ebgp-multihop {}

BGP: no neighbor peer ebgp-multihop {}

BGP: neighbor peer description ... {}

BGP: no neighbor peer description ... {}

Set description of the peer.

BGP: neighbor peer version version {}

Set up the neighbor's BGP version. version can be 4, 4+ or 4-. BGP version 4 is the default value used for BGP peering. BGP version 4+ means that the neighbor supports Multiprotocol Extensions for BGP-4. BGP version 4- is similar but the neighbor speaks the old Internet-Draft revision 00's Multiprotocol Extensions for BGP-4. Some routing software is still using this version.

BGP: neighbor peer interface ifname {}

BGP: no neighbor peer interface ifname {}

When you connect to a BGP peer over an IPv6 link-local address, you have to specify the ifname of the interface used for the connection.

BGP: neighbor peer next-hop-self {}

BGP: no neighbor peer next-hop-self {}

This command specifies an announced route's nexthop as being equivalent to the address of the bgp router.

BGP: neighbor peer update-source {}

BGP: no neighbor peer update-source {}

BGP: neighbor peer default-originate {}

BGP: no neighbor peer default-originate {}

bgpd's default is to not announce the default route (0.0.0.0/0) even it is in routing table. When you want to announce default routes to the peer, use this command.

BGP: neighbor peer port port {}

BGP: neighbor peer port port {}

BGP: neighbor peer send-community {}

BGP: neighbor peer send-community {}

BGP: neighbor peer weight weight {}

BGP: no neighbor peer weight weight {}

This command specifies a default weight value for the neighbor's routes.

BGP: neighbor peer maximum-prefix number {}

BGP: no neighbor peer maximum-prefix number {}

9.4.3 Peer filtering

BGP: neighbor peer distribute-list name [in|out] {}

This command specifies a distribute-list for the peer. direct is `in' or `out'.

BGP command: neighbor peer prefix-list name [in|out] {}

BGP command: neighbor peer filter-list name [in|out] {}

BGP: neighbor peer route-map name [in|out] {}

Apply a route-map on the neighbor. direct must be in or out.

9.5 BGP Peer Group

BGP: neighbor word peer-group {}

This command defines a new peer group.

BGP: neighbor peer peer-group word {}

This command bind specific peer to peer group word.

9.6 BGP Address Family

9.7 Autonomous System

AS (Autonomous System) is one of the essential element of BGP. BGP is a distance vector routing protocol. AS framework provides distance vector metric and loop detection to BGP. RFC1930 - Guidelines for creation, selection, and registration of an Autonomous System (AS) describes how to use AS.

AS number is tow octet digita value. So the value range is from 1 to 65535. AS numbers 64512 through 65535 are defined as private AS numbers. Private AS numbers must not to be advertised in the global Internet.

9.7.1 AS Path Regular Expression
9.7.2 Display BGP Routes by AS Path
9.7.3 AS Path Access List
9.7.4 Using AS Path in Route Map
9.7.5 Private AS Numbers

9.7.1 AS Path Regular Expression

AS path regular expression can be used for displaying BGP routes and AS path access list. AS path regular expression is based on POSIX 1003.2 regular expressions. Following description is just a subset of POSIX regular expression. User can use full POSIX regular expression. Adding to that special character '_' is added for AS path regular expression.

.

Matches any single character.

*

Matches 0 or more occurrences of pattern.

+

Matches 1 or more occurrences of pattern.

?

Match 0 or 1 occurrences of pattern.

^

Matches the beginning of the line.

$

Matches the end of the line.

_

Character _ has special meanings in AS path regular expression. It matches to space and comma , and AS set delimiter { and } and AS confederation delimiter ( and ). And it also matches to the beginning of the line and the end of the line. So _ can be used for AS value boundaries match. show ip bgp regexp _7675_ matches to all of BGP routes which as AS number include 7675.

9.7.2 Display BGP Routes by AS Path

To show BGP routes which has specific AS path information show ip bgp command can be used.

Command: show ip bgp regexp line {}

This commands display BGP routes that matches AS path regular expression line.

9.7.3 AS Path Access List

AS path access list is user defined AS path.

Command: ip as-path access-list word {permit|deny} line {}

This command defines a new AS path access list.

Command: no ip as-path access-list word {}

Command: no ip as-path access-list word {permit|deny} line {}

9.7.4 Using AS Path in Route Map

Route Map: match as-path word {}

Route Map: set as-path prepend as-path {}

9.7.5 Private AS Numbers

9.8 BGP Communities Attribute

BGP communities attribute is widely used for implementing policy routing. Network operators can manipulate BGP communities attribute based on their network policy. BGP communities attribute is defined in RFC1997 - BGP Communities Attribute and RFC1998 - An Application of the BGP Community Attribute in Multi-home Routing. It is an optional transitive attribute, therefore local policy can travel through different autonomous system.

Communities attribute is a set of communities values. Each communities value is 4 octet long. The following format is used to define communities value.

AS:VAL

This format represents 4 octet communities value. AS is high order 2 octet in digit format. VAL is low order 2 octet in digit format. This format is useful to define AS oriented policy value. For example, 7675:80 can be used when AS 7675 wants to pass local policy value 80 to neighboring peer.

internet

internet represents well-known communities value 0.

no-export

no-export represents well-known communities value NO_EXPORT
(0xFFFFFF01). All routes carry this value must not be advertised to outside a BGP confederation boundary. If neighboring BGP peer is part of BGP confederation, the peer is considered as inside a BGP confederation boundary, so the route will be announced to the peer.

no-advertise

no-advertise represents well-known communities value NO_ADVERTISE
(0xFFFFFF02). All routes carry this value must not be advertise to other BGP peers.

local-AS

local-AS represents well-known communities value NO_EXPORT_SUBCONFED (0xFFFFFF03). All routes carry this value must not be advertised to external BGP peers. Even if the neighboring router is part of confederation, it is considered as external BGP peer, so the route will not be announced to the peer.

When BGP communities attribute is received, duplicated communities value in the communities attribute is ignored and each communities values are sorted in numerical order.

9.8.1 BGP Community Lists
9.8.2 Numbered BGP Community Lists
9.8.3 BGP Community in Route Map
9.8.4 Display BGP Routes by Community
9.8.5 Using BGP Communities Attribute

9.8.1 BGP Community Lists

BGP community list is a user defined BGP communites attribute list. BGP community list can be used for matching or manipulating BGP communities attribute in updates.

There are two types of community list. One is standard community list and another is expanded community list. Standard community list defines communities attribute. Expanded community list defines communities attribute string with regular expression. Standard community list is compiled into binary format when user define it. Standard community list will be directly compared to BGP communities attribute in BGP updates. Therefore the comparison is faster than expanded community list.

Command: ip community-list standard name {permit|deny} community {}

This command defines a new standard community list. community is communities value. The community is compiled into community structure. We can define multiple community list under same name. In that case match will happen user defined order. Once the community list matches to communities attribute in BGP updates it return permit or deny by the community list definition. When there is no matched entry, deny will be returned. When community is empty it matches to any routes.

Command: ip community-list expanded name {permit|deny} line {}

This command defines a new expanded community list. line is a string expression of communities attribute. line can include regular expression to match communities attribute in BGP updates.

Command: no ip community-list name {}

Command: no ip community-list standard name {}

Command: no ip community-list expanded name {}

These commands delete community lists specified by name. All of community lists shares a single name space. So community lists can be removed simpley specifying community lists name.

Command: show ip community-list {}

Command: show ip community-list name {}

This command display current community list information. When name is specified the specified community list's information is shown.

# show ip community-list Named Community standard list CLIST permit 7675:80 7675:100 no-export deny internet Named Community expanded list EXPAND permit : # show ip community-list CLIST Named Community standard list CLIST permit 7675:80 7675:100 no-export deny internet

9.8.2 Numbered BGP Community Lists

When number is used for BGP community list name, the number has special meanings. Community list number in the range from 1 and 99 is standard community list. Community list number in the range from 100 to 199 is expanded community list. These community lists are called as numbered community lists. On the other hand normal community lists is called as named community lists.

Command: ip community-list <1-99> {permit|deny} community {}

This command defines a new community list. <1-99> is standard community list number. Community list name within this range defines standard community list. When community is empty it matches to any routes.

Command: ip community-list <100-199> {permit|deny} community {}

This command defines a new community list. <100-199> is expanded community list number. Community list name within this range defines expanded community list.

Command: ip community-list name {permit|deny} community {}

When community list type is not specifed, the community list type is automatically detected. If community can be compiled into communities attribute, the community list is defined as a standard community list. Otherwise it is defined as an expanded community list. This feature is left for backward compability. Use of this feature is not recommended.

9.8.3 BGP Community in Route Map

In Route Map (see section 12. Route Map), we can match or set BGP communities attribute. Using this feature network operator can implement their network policy based on BGP communities attribute.

Following commands can be used in Route Map.

Route Map: match community word {}

Route Map: match community word exact-match {}

This command perform match to BGP updates using community list word. When the one of BGP communities value match to the one of communities value in community list, it is match. When exact-match keyword is spcified, match happen only when BGP updates have completely same communities value specified in the community list.

Route Map: set community none {}

Route Map: set community community {}

Route Map: set community community additive {}

This command manipulate communities value in BGP updates. When none is specified as communities value, it removes entire communities attribute from BGP updates. When community is not none, specified communities value is set to BGP updates. If BGP updates already has BGP communities value, the existing BGP communities value is replaced with specified community value. When additive keyword is specified, community is appended to the existing communities value.

Route Map: set comm-list word delete {}

This command remove communities value from BGP communities attribute. The word is community list name. When BGP route's communities value matches to the community list word, the communities value is removed. When all of communities value is removed eventually, the BGP update's communities attribute is completely removed.

9.8.4 Display BGP Routes by Community

To show BGP routes which has specific BGP communities attribute, show ip bgp command can be used. The community value and community list can be used for show ip bgp command.

Command: show ip bgp community {}

Command: show ip bgp community community {}

Command: show ip bgp community community exact-match {}

show ip bgp community displays BGP routes which has communities attribute. When community is specified, BGP routes that matches community value is displayed. For this command, internet keyword can't be used for community value. When exact-match is specified, it display only routes that have an exact match.

Command: show ip bgp community-list word {}

Command: show ip bgp community-list word exact-match {}

This commands display BGP routes that matches community list word. When exact-match is specified, display only routes that have an exact match.

9.8.5 Using BGP Communities Attribute

Following configuration is the most typical usage of BGP communities attribute. AS 7675 provides upstream Internet connection to AS 100. When following configuration exists in AS 7675, AS 100 networks operator can set local preference in AS 7675 network by setting BGP communities attribute to the updates.

router bgp 7675
 neighbor 192.168.0.1 remote-as 100
 neighbor 192.168.0.1 route-map RMAP in
!
ip community-list 70 permit 7675:70
ip community-list 70 deny
ip community-list 80 permit 7675:80
ip community-list 80 deny
ip community-list 90 permit 7675:90
ip community-list 90 deny
!
route-map RMAP permit 10
 match community 70
 set local-preference 70
!
route-map RMAP permit 20
 match community 80
 set local-preference 80
!
route-map RMAP permit 30
 match community 90
 set local-preference 90

Following configuration announce 10.0.0.0/8 from AS 100 to AS 7675. The route has communities value 7675:80 so when above configuration exists in AS 7675, announced route's local preference will be set to value 80.

router bgp 100
 network 10.0.0.0/8
 neighbor 192.168.0.2 remote-as 7675
 neighbor 192.168.0.2 route-map RMAP out
!
ip prefix-list PLIST permit 10.0.0.0/8
!
route-map RMAP permit 10
 match ip address prefix-list PLIST
 set community 7675:80

Following configuration is an example of BGP route filtering using communities attribute. This configuration only permit BGP routes which has BGP communities value 0:80 or 0:90. Network operator can put special internal communities value at BGP border router, then limit the BGP routes announcement into the internal network.

router bgp 7675
 neighbor 192.168.0.1 remote-as 100
 neighbor 192.168.0.1 route-map RMAP in
!
ip community-list 1 permit 0:80 0:90
!
route-map RMAP permit in
 match community 1

Following exmaple filter BGP routes which has communities value 1:1. When there is no match community-list returns deny. To avoid filtering all of routes, we need to define permit any at last.

router bgp 7675
 neighbor 192.168.0.1 remote-as 100
 neighbor 192.168.0.1 route-map RMAP in
!
ip community-list standard FILTER deny 1:1
ip community-list standard FILTER permit
!
route-map RMAP permit 10
 match community FILTER

Communities value keyword internet has special meanings in standard community lists. In below example internet act as match any. It matches all of BGP routes even if the route does not have communities attribute at all. So community list INTERNET is same as above example's FILTER.

ip community-list standard INTERNET deny 1:1
ip community-list standard INTERNET permit internet

Following configuration is an example of communities value deletion. With this configuration communities value 100:1 and 100:2 is removed from BGP updates. For communities value deletion, only permit community-list is used. deny community-list is ignored.

router bgp 7675
 neighbor 192.168.0.1 remote-as 100
 neighbor 192.168.0.1 route-map RMAP in
!
ip community-list standard DEL permit 100:1 100:2
!
route-map RMAP permit 10
 set comm-list DEL delete