no BFD support for the BGP peering with ISP. Any suggestions?

[paheeradan.nagulan]

We have a DIA(Internet) circuit with our ISP at the Nexus 9k EDGE switch. We are doing BGP(Learning default route and advertising our public network to the internet) with them. The ISP mentioned that they don't support BFD(I was planning to use it with BGP. So the router will bring down the BGP process in case there is a link failure).  What are the recommendations that we can deploy to reduce the network convergence(Changing the BGP hold-down timer to a lower value etc).

[MHM Cisco World]

are
EEM + IP SLA for BGP
is OK for you ?

[paheeradan.nagulan]

That's a good suggestion. I was thinking along the ways of changing BGP attributes such as bgp timers. Do you think that will help in this case?

[Harold Ritter]

Hi @paheeradan.nagulan ,

Reducing the bgp timers will certainly help. At the the end it all depends what convergence time you are expecting.

Regards,

[David Ruess]

Hello,

I cant remember (and cant test at the moment) But BFD echo mode might work. I am not sure if BFD needs to be enabled on the remote interface but echo mode is basically echo my BFD packet back to me (so I would assume only 1 side is needed). This is done to reduce the overhead of actually processing the packet bidirectionally. Maybe try configuring echo mode on your interface and see if it registers the protocol and can be used. 

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus9000/sw/6-x/interfaces/configuration/guide/b_Cisco_Nexus_9000_Series_NX-OS_Interfaces_Configuration_Guide/b_Cisco_Nexus_9000_Series_NX-OS_Interfaces_Configuration_Guide_chapter_0101.html#...

Hope that helps

-David

[Harold Ritter]

Hi @David Ruess ,

BFD needs to be configured on both ends. Once it is configured on both end, you might then decide to configure the echo mode on one side only (asynchronous). 

Regards,

[David Ruess]

Yeah I tried to skim the documentation for it but couldn't find it. Thank you for the clarification.

[paheeradan.nagulan]

Thanks for the suggestion!

[MHM Cisco World]

check my below Lab and comment 

[paheeradan.nagulan]

Hi @MHM Cisco World,

Thank you for the detailed lab. Highly appreciate it. Yes, it makes sense to use BFD echo. But in my case, the ISP mentioned that they won't support BFD. My understand is to run BFD echo on my side, I need to configure BFD neighborship on both ends which is not possible in my case. So I was trying to find other means of speeding up the BGP convergence? Also there will be a L2 in between us and the ISP.

[MHM Cisco World]

I will share case2 after 1 hr.

[MHM Cisco World]

check my below lab and comments

[paheeradan.nagulan]

Hi @MHM Cisco World ,

Thanks for the detailed analysis. Appreciate it. My case is similar to Case A(A- one side is run BFD echo and other DO NOT run bfd). So are you thinking that running bfd ONLY ON my side(ISP won't support BFD) will be sufficient to detect the peer reachability?

[Harold Ritter]

Hi @paheeradan.nagulan ,

> My understand is to run BFD echo on my side, I need to configure BFD neighborship on

> both ends

Your understanding is correct. If the other side is not configured for BFD, configuring BFD echo on you side will not work.

Regards,

[paheeradan.nagulan]

Thanks @Harold Ritter for confirming it.