I've posted a BGP and MULTI-HOMING tutorial I just wrote. It was going to be a Boardwatch column, but it turned out a bit too long and too advanced for that. Please take a look at http://www.netaxs.com/~freedman/bgp.html and share comments and thoughts... It's about 89k so I won't post it full-text to the list. Unfortunately it's just Part 1 of maybe 10 parts that can and probably will be written about routing in the next few months. Please keep comments redirected to inet-access and NOT to nanog. Here's a table of contents: BGP A WARNING PREREQUISITES BGP ROUTING: INTERNAL (INTERIOR) AND EXTERNAL SO WHY IS BGP INTERESTING? BEING "CONNECTED" TO THE INTERNET HARDWARE AND SOFTWARE FOR SPEAKING BGP PEERING SESSIONS AND ASNs: PART I WHAT DO YOU DO WITH BGP? PEERING SESSIONS eBGP vs. iBGP BGP AND THE SINGLE-HOMED AS-PATHS AS-PATH LENGTH AND BGP ROUTE SELECTION AS-PATH ACCESS LISTS (FILTERS) ENTERING, MODIFYING, AND DELETING as-path access-lists BGP METRICS (ATTRIBUTES) AND ROUTE SELECTION: INTRODUCTION BGP PATH SELECTION PROCESS ACCORDING TO CISCO BGP ATTRIBUTE TYPES EGP vs. IGP WHAT IS ROUTE FLAP AND WHY IS IT BAD? WHAT TO KEEP IN MIND WHEN CONFIGURING BGP BGP AND PEERING INTERNET CONNECTIVITY WITHOUT BGP BGP AND THE SINGLE-HOMED BGP AND THE MULTI-HOMED MULTI-HOMING AND LOAD-BALANCING HOW TO ANNOUNCE YOUR NETWORKS BEING ADVERTISED BY MULTIPLE PROVIDERS WITHOUT PI-SPACE CONTROLLING OUTGOING DATA FLOW: "FULL ROUTING" CONTROLLING OUTGOING DATA FLOW: "PARTIAL ROUTING": "CUSTOMER ROUTES ONLY" SO WHAT'S TO BE DONE? AS-PATH PADDING QUESTIONS AND COMMENTS THANKS TO TO BE DONE Sidebars Sidebar on Cisco BGP commands Sidebar on next-hop-self Sidebar on Outgoing Data Flow Control Without BGP Thanks, Avi