BGP4 Case Studies/Tutorial

Author: Sam Halabi-cisco Systems
Date: 1/25/1996
Rev: A1.2

The purpose of this paper is to introduce the reader to the latest in BGP4 terminology and design issues. It is targeted to the novice as well as the experienced user. For any clarification or comments please send e-mail to shalabi@cisco.com.

Index

Section 1:

• Introduction
• How does BGP work
• What are peers (neighbors)
• Information exchange between peers
• EBGP and IBGP
• Enabling BGP routing
• BGP Neighbors/Peers
• BGP and Loopback interfaces
• EBGP Multihop
• EBGP Multihop (Load Balancing)
• Route Maps
• Network command
• Redistribution
• Static routes and redistribution
• Internal BGP
• The BGP decision algorithm

Section 2:

• As_path Attribute
• Origin Attribute
• BGP Nexthop Attribute
• BGP Nexthop (Multiaccess Networks)
• BGP Nexthop (NBMA)
• Nexthopself
• BGP Backdoor
• Synchronization
• Disabling synchronization
• Weight Attribute
• Local Preference Attribute
• Metric Attribute
• Community Attribute

Section 3:

• BGP Filtering
• Route Filtering
• Path Filtering
• AS-Regular Expression
• BGP Community Filtering
• BGP Neighbors and Route maps
• Use of set as-path prepend
• BGP Peer Groups

Section 4:

• CIDR and Aggregate Addresses
• Aggregate Commands
• CIDR example1
• CIDR example2 (as-set)
• BGP Confederation
• Route Reflectors
• Multiple RRs within a cluster
• RR and conventional BGP speakers
• Avoiding looping of routing information
• Route Flap Dampening
• How BGP selects a Path

Section 5:

• Practical design example:

Copyright 1995 Cisco Systems Inc.