BGPSIM(8)

NAME

bgpsim - BGP4 routing environment simulator

DESCRIPTION

Usage: bgpsim [-i router_id] [-p port] [-f file] [-v] [-o output]

BGPsim simulates complex BGP4 routing environments with possibly high levels of routing instability/change.

BGPsim includes a perl program, BGPsim.pl, which is used to generate ASCII descriptions of BGP traffic for use with route_btoa and sbgp. (The BGPsim Perl code is still quite rough.)

Synopsis

BGPsim [-f configuration_file] [-l routing table] [-v] [-s] [-m]

Options

-f configuration_file

Read the specified configuration file. By default, bgpsim

tries

to read ./bgpsim.conf.

-v

Turn on verbose logging to standard output. This is useful to turn on logging before the debug commands are read in the
configuration file.

-s

By default, BGPSim does not set mandatory BGP attributes,
including origin, nexthop and ASPath. If this flag is used,
BGPsim will add these attributes and prepend the local AS to the ASPath.

-m

Use a new dump format.

Description

By default, BGPsim looks for "./bgpsim.conf". The format of the configuration file is described below. BGPsim also has an interactive (Cisco Systems router-like) interface: telnet to port 5674 on the machine running BGPsim.

NOTE:

BGPsim does not include mandatory attributes by default. You will need to explicitly include a nexthop, origin, and apsath attribute in your BGPsim configuration. Also note that BGPSim does not prepend its own AS by default.

Sample Configuration File

A sample BGPsim configuration file is shown below.

network-list 1 range 10.0.0.0/8 11.0.0.0 stability 10 jitter 4 map 1 ! route-map 1 set nexthop 198.108.60.8 set aspath 185 123 23 23 12 set origin igp !

network-list 2 range 192.32.0.0/24 192.32.255.0 stability 9 jitter 3 change 12 jitter 4 route-map 2 3 ! route-map 2 set next-hop 198.108.60.244 set as-path 185 123 23 23 12 set origin igp set community 56:123 set dpa as 56 121 set local-preference 23 ! route-map 3 set as-path 185 100 10 102 set origin igp set community 100:345 set dpa as 3 23 set local-preference 83 ! router bgp 185

neighbor 198.108.60.244 remote-as 65
neighbor 198.108.60.112 remote-as 165

This file describes two simulation processes, as defined by
network-list 1 and 2, which changes routes to two BGP peers (AS 65

and

AS165).

The first simulation process, network-list 1, changes routes
(10.0.0.0/8 and 11.0.0.0/8) as defined in range every 10 seconds.

This

simulates an announcement of the routes first, and then a withdrawal after 10 seconds. Ten seconds after the withdraw, the next
announcement is propagated. Thus the announcements and withdraws are repeated every 10 seconds. These routes have attributes defined in
route-map 1: nexthop is 198.108.60.8 and aspath is a sequence of 123 23 23 12.

The second network list describes simulation of the range of routes from 192.32.0.0/24 to 192.32.255.0/24 (i.e. 192.32.1.0/24,
192.32.2.0/24, etc.) All of these routes have an initial aspath of
(123 23 23 12), a next-hop of 198.108.60.244, and others as defined

in

route-map 2. These attributes change every 12 seconds among route

maps

2 and 3.

The peers (AS 65 and AS165) receive routing updates originated by
these two simulation processes.

Configuration Commands

For information about the uii, debug, and access-list configuration commands, see Chapter 2, "Getting Started." In addition to the MRTd configuration commands, the following are available in BGPsim to
simulate routing changes:

network-list
Defines a network-list with . This definition behaves like a routing

process which generates routing changes within a range defined

by

range subcommand by an interval defined by stability subcommand, changing route attributes as specified by change and route-map
subcommands.

Options include:

range

Defines a range to announce and withdraw, starting with up to

(inclusive). The range is along classful boundaries.

stability
[jitter ]

Defines an interval in second to change routes. Routes are
announced first and then withdrawn after the interval. Thus,

with

the interval, announce and withdraw repeat. Jitter adds/sub

tracts

a random number of seconds between 0 and <jitter number> to the interval.

change
[jitter ]

Defines an interval in second to change attributes of routes

being

announced. route-map subcommand defines a sequence. Jitter
adds/subtracts a random <number> of seconds from the timer.

map ...

Defines a sequence of route-maps to be used. The next route-mapis

adopted after the interval defined in change subcommand. At the end of list, the first route-map is adopted as a next. The first route-map behaves as a default, that is, this is always adopted before adopting other route-maps.

file ...

Loads routes from routing table dump file rather than using a range

of

addresses.

BGPSim also adds several commands to bgp router commands:

neighbor stability

Define stability for TCP peering session with this peer.

Interactive Interface Commands

The BGPsim interactive interface supports the following commands in addition to MRTd interactive interface commands:

show simulation

stop simulation

start simulation

You can find more documentation in /usr/share/doc/mrt/html/

Debian/GNU Linux October 2002 BGPSIM(8)