Mastering BGP Configuration on Cisco® Routers

1. Introduction to BGP

• What is BGP?
• Basic protocol operation.
• Comparison with other routing protocols.
• BGP terminology: AS, peer, route and other terms.
• BGP architecture: IBGP and EBGP. 

2. Configuring a network as a transit AS

• The autonomous system concept.
• AS roles: stub, multihomed and transit.
• Configuring BGP sessions between autonomous systems.
• Configuring border routers.

3. Configuring policy-based route selection

• Route maps:
  • basic syntax;
  • attribute manipulation: set, match and other operations;
  • common examples: filtering, prefix lists and more.
• BGP communities:
  • community types: standard, extended, route target and others;
  • community propagation within a network;
  • using communities for route filtering and distribution.
• Other control mechanisms:
  • AS path filters;
  • local preference;
  • MED (Multi-Exit Discriminator);
  • atomic aggregate.

4. Configuring attribute-based route selection

• BGP attributes: AS path, origin, MED, local preference and others.
• How attributes affect route selection.
• Configuring attributes.

5. Configuring customer–provider connectivity

• Basic configuration of customer–provider BGP sessions.
• Network advertisement.
• Route filtering.
• Resolving common problems.

6. Scaling service provider networks

• BGP scalability issues.
• Scaling techniques: confederations, route reflectors and others.
• Implementation and configuration.

7. Optimising BGP scalability

• Optimising routing tables.
• Reducing BGP traffic.
• Using route reflection.
• Other optimisation techniques.

Practical labs:

• Establish BGP sessions between two routers.
• Advertise IP networks through BGP.
• Verify BGP convergence and route propagation.
• Understand administrative distance and its impact on route selection.
• Configure administrative distance for different routing protocols.
• Use prefix filters to control advertised routes.
• Configure route maps to filter and modify BGP attributes.
• Manipulate BGP attributes — weight, local preference, AS path, MED and communities — to influence route selection.
• Configure specific attribute values to achieve the desired routing behaviour.
• Deploy a route reflector to reduce IBGP session counts in a large network.
• Configure route reflector clients.
• Limit the number of routes a router learns to avoid performance issues.
• Group BGP neighbours to simplify management and configuration.
• Implement TTL security checks to prevent redirection attacks.
• Configure a fully meshed IBGP network and understand its implications.
• Analyse route propagation in a multihop BGP network.