This is a draft cheat sheet. It is a work in progress and is not finished yet.
BGP Operation
Phase 1 - TCP |
Phase 2 - BGP Capbalities Exchange |
Both BGP routers attempt a TCP session on port 179. |
After the TCP Session is established - BGP Speakers exchange messages. |
FSM
Phase |
State Name |
Next Successfull State |
TCP |
Idle(Start) |
Connect |
TCP |
Connect |
OpenSent |
TCP |
Active(If TCP fails) |
OpenSent |
BGP |
OpenSent |
OpenConfirm |
BGP |
OpenConfirm |
Established! |
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BGP Messages
Open - Initial request for a BGP session |
Update - Exchange NLRI between peers |
Notification - Indicate an error and closes session |
KeepAlive - Response to Open Messages & Maintains TCP session |
RouteRefresh - Requests a BGP peer resend the routes it advertised at session establishement. |
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BGP Timers
Connect Retry |
120 seconds |
Hold Time |
90 seconds |
Keep Alive |
30 seconds |
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Attributes
Well-Known Mandatory |
Must be present in every BGP Update |
Well-Known Discretionary |
Recognized by all BGP implementations, but may or may not be present in the Update message |
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