BGP path selection during high latency

[Chhabi Thapa]

Hello everyone,

is there any way to route the traffic via secondary link if the latency through primary link reach >50ms ? In this scenario i'm using ebgp,ibgp and hsrp.

[Jon Marshall]

Might help if you indicated where you are using BGP and HSRP.

Jon

[Chhabi Thapa]

I'm using HSRP in LAN 192.168.1.0/24.R1 will be active and R2 will be standby mode.

ibgp is between R1 and R2 and eBGP is with Primary and Secondary service provider  from R1 and R2 respectively and R3 also.

[Jon Marshall]

As Reza says you could use IP SLA for latency and then tie that with EEM to shut the BGP session on the primary which would then mean R1 would use R2 to send traffic out.

There may be an easier solution but nothing springs to mind at the moment.

Jon

[Reza Sharifi]

You can setup IP SlAs with tracking.

see link:

http://packetpushers.net/using-ip-sla-delay-feature-to-safely-monitor-lossy-links/

https://supportforums.cisco.com/document/32186/dual-internet-links-nating-pbr-and-ip-sla

HTH

[Reza Sharifi]

Hi,

>50ms to what destination?

If the latency is on the Internet, you can set up SLAs with multiple providers.

HTH

[Chhabi Thapa]

Ok both links will be 1Mbps L3VPN MPLS link and destination will be 172.16.1.0/24 network from 192.168.1.0/24.

Is there any other solution apart from SLA ?

[Jon Marshall]

Something has to monitor the latency and BGP can't do that.

You could, I suppose, just include everything in an EEM script ie. do your own latency monitoring.

Jon

[Joseph W. Doherty]

Possibly PfR.