Cisco BGP

Border Gateway Protocol (RFC 4271) är ett path vector routing protokoll. Det kommunicerar på TCP port 179 så routing måste vara på plats, man kan nästan se det som ett L4-protokoll.

States

TCP

Idle State

ConnectRetry timer 120 sekunder

Active State

BGP speaker försöker nå peer med TCP

Connect State

TCP session established

BGP

OpenSent State

BGP version, AS number, hold time, BGP ID
Börja skicka keepalives

OpenConfirm State

Response recieved

Established State

Skicka uppdateringar
Neighbor up

Konfiguration

router bgp [ASN]
no auto-summary

iBGP eller eBGP

neighbor [ip-address] remote-as [ASN]

Loopback

neighbor [ip-address] update-source [interface]

eBGP om det ej är directly connected, t.ex. loopback

neighbor [ip-address] ebgp-multihop 2
neighbor [ip-address] next-hop-self

MD5

neighbor [ip-address] password cisco 

network [ip-address] mask [subnet-mask]

bgp default local-preference 100
no synchronization

Timers

tim bg 10 30 20

Show

show ip bgp summary
show ip bgp neighbor

Reset

clear ip bgp *