Lab 142 - BGP Timers

Lab 142 - BGP Timers
Di Posting Oleh : Simple Learning
Kategori : BGP Core Technologies Routing

Prerequisites: CCNP level skills.

Note!
Configuration from Lab 140.

Topology

Pic. 1 - Topology Diagram.

Icons designed by: Andrzej Szoblik - http://www.newo.pl

Task 1
The BGP policy stipulates that the R5's timer to send BGP advertisements should be set to 10 seconds (default: iBGP=5 seconds, eBGP=30 seconds). Also BGP peer loss should be detected in 15 seconds (default=180 seconds). Also improve the BGP scanner operation by decreasing the default value of 60 seconds to 20 seconds.

Solution

Task 1

The BGP policy stipulates that the R5's timer to send BGP advertisements should be set to 10 seconds (default: iBGP=5 seconds, eBGP=30 seconds). Also BGP peer loss should be detected in 15 seconds (default=180 seconds). Also improve the BGP scanner operation by decreasing the default value of 60 seconds to 20 seconds.

R5 Configuration:

!

router bgp 50
 no synchronization
 bgp router-id 172.16.105.5
 bgp log-neighbor-changes
 bgp scan-time 20
 network 172.16.105.0 mask 255.255.255.0
 timers bgp 5 15
 neighbor 10.1.35.3 remote-as 100
 neighbor 10.1.35.3 advertisement-interval 10
 no auto-summary

!

Note!
Hello timer is set to 5 seconds following the rule 3 x keepalive = holdtime.

BGP Processes:

• BGP Open - responsible for BGP session establishment.
• BGP I/O - handles queuing and processing updates and keepalive packets.
• BGP Scanner - responsible for conditional route advertisements, route dampening, import and export of routes into VRF (MPLS), and confirms the reachability to the NEXT_HOP (the last one is handled now by BGP next-hop tracking).
• BGP Router - calculates the best path, establishes peers, sends and receives routes and interacts with RIB.

Source:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00809d16f0.shtml#understandbgp

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