What is BGP, When do I use it

• Routing protocol of the Internet, the only external gateway protocol currently in use
• Management of trust and untrust
• Routing through autonomous systems instead of routers
• The slowest routing protocol by design
• Primarily service provider, but also in the enterprise
• Reliable updates, TCP-Based, port 179
• Triggered Updates only (5 seconds internal, 30 seconds external)
• Complicated Metric for finding the best route
• All neighbors are manually set up
• Complex filters are typically used

When not to run BGP

• You're only connected to one external AS (ISP)
• You don’t have enough bandwidth to receive updates
• You don’t have powerful routers, minimum of 512MB RAM per peer for the complete table
• You don’t fully understand BGP

When to use BGP

• You need high availability through multiple ISPs
• You are a service provider
• Extremely large networks with demarc points to other divisions or partners

Golden Rule of BGP (RFC 1771)

BGP does not enable one AS to send traffic to a neighbor AS intending that the traffic take a different route from that taken by traffic orginating in the neighbor AS

You can’t tell someone else what to do with their traffic, you only have control over your AS.