[ovs-discuss] BFD with 'option : remote_ip = flow'

Vivek Srivastava V vivek.v.srivastava at ericsson.com
Wed Aug 16 10:54:58 UTC 2017

Hi Ben,

Thanks for your response. Please see below inline.


-----Original Message-----
From: Ben Pfaff [mailto:blp at ovn.org] 
Sent: Friday, August 11, 2017 9:24 PM
To: Vivek Srivastava V
Cc: ovs-discuss at openvswitch.org
Subject: Re: [ovs-discuss] BFD with 'option : remote_ip = flow'

On Fri, Aug 11, 2017 at 08:48:20AM +0000, Vivek Srivastava V wrote:
> 1.  Is there any way to configure/manage BFD sessions to destinations, 
> independent of the tunnel port/interface created?

Not currently.  If you have a good idea for how to extend the OVS BFD support to be more flexible, we'd accept patches.

[Viveks] We are planning to create a separate table/schema for maintaining independent BFD sessions. An entry in this BFD table can be identified by a session ID generated/configured and will have same columns as we have for BFD in interface table. In future we can choose to remove the BFD related fields from interface table and  use a reference (session_id) from the BFD table. WDYT? 

> 2.       Does OVS support multi-hop BFD? In roadmap?

No.  I hadn't heard of multi-hop BFD before, so I looked around a bit and found RFC 5883.  That RFC, though, doesn't really provide a specification for how to do this.  Is there a detailed specification somewhere else?

[Viveks] Unfortunately I also couldn't find any implementation specific details about multihop BFD, other than RFC 5883 and some configuration related info available on the net. What I could gather is that it is mostly same as onehop BFD, with some additional considerations- 
1. uses different UDP destination port 4784 (MUST)
2. suggests session authentication  (SHOULD)
3. De-multiplexing (applicable only in case of multiple BFD sessions between same pair of TEPs)
So I think we should be good with supporting the first item initially.

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