Subject: Re: [GROW] [Idr] RFC7854: EoR

From: "Tim Evens (tievens)" <[email-masked]>
Date: Fri, 23 Sep 2022 00:02:49 +0000

When I wrote route-refresh, that was from the router/sender side, not BMP receiver sending a route-refresh. BMP is still write-only.

There are use-cases for re-syncing the RIB to the BMP receiver.  Some of the methods today are to clear the peer, request a route-refresh in, or to reset the BMP feed. This is a bit intrusive to the router (sender) and BMP receiver. Having to go to the router to request a refresh to the BMP server, IMO, is still okay.  The problem is that control knobs for refresh are at the BGP peer level, not BMP.  For Adj-RIB-In Pre-Policy, it makes sense to do that on the peer, but for Post-Policy, Adj-RIB-Out and Local-RIB, it doesn’t really make sense.  Having a knob to initiate BMP side refresh would be very nice and hopefully less intrusive.

Regardless of the BMP server needing a refresh, a BMP server does not know when someone has requested route-refresh IN at the peer level (maybe it was requested for policy change, …) Instead, the BMP receiver, blindly, receives a boat load of updates with no awareness that it was a new RIB dump or controlled refresh. In this case, it would appear to be churn.  IMO, there is value in having a message to signal the receiver that a refresh is coming, followed by an EoR.  A PEER_UP could be used for this, but that is intrusive and misuse of PEER_UP.

--Tim

On 9/22/22, 11:03 AM, "Jeffrey Haas" <[email-masked]> wrote:

> On Sep 21, 2022, at 7:42 AM, Zhuangshunwan <zhuangshunwan=[email-masked]> wrote:
>
> Hi Tim and All,
>
> I think the idea of a "BMP route refresh" would be appreciated,  it will helps keep the information synchronized between the BMP Server and the BMP Client.

Would someone clarify what they mean by a bmp route refresh?

The BMP protocol was intentionally designed as write-only.

-- Jeff