Difference between revisions of "Cisco BGP"

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Line 37: Line 37:
 
MD5
 
MD5
 
  neighbor [ip-address] password cisco  
 
  neighbor [ip-address] password cisco  
 
+
Granne
 
  network [ip-address] mask [subnet-mask]
 
  network [ip-address] mask [subnet-mask]
 
+
Preference
 
  bgp default local-preference 100
 
  bgp default local-preference 100
 
Synchronization is enabled by default in Cisco IOS Software Release prior to 12.2(8)T.  
 
Synchronization is enabled by default in Cisco IOS Software Release prior to 12.2(8)T.  
Line 45: Line 45:
 
Timers
 
Timers
 
  tim bg 10 30 20
 
  tim bg 10 30 20
 +
För att byta från NLRI-format till AFI-format i konfigurationen
 +
bgp upgrade-cli
  
 
===Dampening===
 
===Dampening===
Line 52: Line 54:
 
  router bgp [ASN]
 
  router bgp [ASN]
 
  bgp dampening route-map selective_dampening
 
  bgp dampening route-map selective_dampening
 
+
Route flap
 
  show ip bgp flap-statistics
 
  show ip bgp flap-statistics
  

Revision as of 10:42, 5 November 2015

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. BGP kan få många vägar till samma destination. Bästa vägen väljs utifrån en algoritm. http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13753-25.html

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 

Granne

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

Preference

bgp default local-preference 100

Synchronization is enabled by default in Cisco IOS Software Release prior to 12.2(8)T.

no synchronization

Timers

tim bg 10 30 20

För att byta från NLRI-format till AFI-format i konfigurationen

bgp upgrade-cli

Dampening

route-map selective_dampening permit 10
set dampening 5 1900 2000 10

5=half-life, 1900=reuse-limit, 2000=suppress-limit, 10 max-suppress-limit

router bgp [ASN]
bgp dampening route-map selective_dampening

Route flap

show ip bgp flap-statistics

Show

show ip bgp summary
show ip bgp neighbor
show ip bgp rib-failure

Reset

clear ip bgp *
clear ip bgp <address> soft