Network Router User Manual

Chapter 12: BGP Configuration Guide
126 SmartSwitch Router User Reference Manual
The SSR BGP Implementation
The SSR routing protocol implementation is based on GateD 4.0.3 code
(http://www.gated.org). GateD is a modular software program consisting of core
services, a routing database, and protocol modules supporting multiple routing protocols
(RIP versions 1 and 2, OSPF version 2, BGP version 2 through 4, and Integrated IS-IS).
Since the SSR IP routing code is based upon GateD, BGP can also be configured using a
GateD configuration file (gated.conf) instead of the SSR Command Line Interface (CLI).
Additionally, even if the SSR is configured using the CLI, the gated.conf equivalent can be
displayed by entering the ip-router show configuration-file command at the SSR Enable
prompt.
VLANs, interfaces, ACLs, and many other SSR configurable entities and functionality can
only be configured using the SSR CLI. Therefore, a gated.conf file is dependent upon some
SSR CLI configuration.
Basic BGP Tasks
This section describes the basic tasks necessary to configure BGP on the SSR. Due to the
abstract nature of BGP, many BGP designs can be extremely complex. For any one BGP
design challenge, there may only be one solution out of many that is relevant to common
practice.
When designing a BGP configuration, it may be prudent to refer to information in RFCs,
Internet drafts, and books about BGP. Some BGP designs may also require the aid of an
experienced BGP network consultant.
Basic BGP configuration involves the following tasks:
• Setting the autonomous system number
• Setting the router ID
• Creating a BGP peer group
• Adding and removing a BGP peer host
• Starting BGP
• Using AS path regular expressions
• Using AS path prepend