Hi Mukul,
That's a helpful clarification, thank you.
It's good to be reminded that F flag lives in the shared Peer Header rather
than being RM-specific, so it's structurally available to Stats messages too.
Looking at the current adj-ribs-filtered-00 text again with that in mind, I
think it actually pins down exactly the gap:
* Section 4 says "In Stats messages, counts MUST reflect the filtered RIB
numbers and not the original RIB ones," but it stops short of stating that the
F flag itself be set consistently in the Stats message's Peer Header for that
same session.
*
So as written, an implementation could arguably satisfy the letter of the text
by adjusting the counts while leaving F unset (or inconsistent) on the Stats
side
*
This is exactly the inconsistency you flagged as unhelpful for correlation.
Would it make sense to tighten this into an explicit MUST, something like:
* "The Peer F Flag MUST be set consistently across all BMP message types
that share this Peer Header for the lifetime of the session (Route Monitoring,
Stats Report, Route Mirroring).
*
An implementation MUST NOT report F=1 in one message type while reporting F=0
(or omitting the equivalent filtered-count adjustment) in another, for the same
peer."
Since you're already a co-author on adj-ribs-filtered, that
operational-consideration addition (Section 5, or as a normative bullet in
Section 4) seems like the cleanest, lowest-overhead fix and no new TLV needed
for the RIB/Stats side at all.
That said, it doesn't fully close Reshad/Nan's original question:
adj-ribs-filtered-00 only talks about Adj-RIB-In/Out and Stats messages and
says nothing about routing-event messages
(draft-geng-grow-bmp-rel-enhancement's actual subject). On that note, would it
make sense for rel-enhancement to explicitly say event messages reuse this same
Peer F Flag bit (with the same cross-message consistency rule above), rather
than defining a separate mechanism?
*
That would give collectors one consistent signal to check across RM, Stats, and
event messages, with a single small text addition on each side rather than a
new generic flag.
Your thoughts Nan, Reshad, Mukul on this ?
Happy to help draft the exact text for either document if useful.
Thanks,
Saumya
From: Srivastava, Mukul <[email protected]>
Date: Saturday, 25 July 2026 at 8:50 PM
To: Dikshit, Saumya <[email protected]>; gengnan <[email protected]>;
Reshad Rahman <[email protected]>
Cc: Grow <[email protected]>
Subject: Re: [GROW] Re: Question on draft-geng-grow-bmp-rel-enhancement
Hello Saumya
>>>>>> If a router locally rate-limits or drops events (per the mitigation text
>>>>>> in draft-geng-grow-bmp-rel-enhancement) and separately reports gauges
>>>>>> such as the ones in
*
draft-ietf-grow-bmp-bgp-rib-stats (RFC 9972) or
*
the policy-driven counters in draft-smc-grow-bmp-route-change-stats,
a collector has no way to know that an observed gauge delta might not be fully
explained by the event stream it received it may look like an unexplained jump.
—
[MS] - The BMP stats messages have BMP peer header. The filter flag is part of
the BMP peer header. If the filter flag is not set in stats message, while
the other msg had filter flag set, then the collector should use caution and
know that the data it received was filtered while the stats count is not
filtered.
I would assume for ideal operation, the router should have flag set/unset for
all events/data/stats message for a session. Inconsistency in this flag state
between different messages, will not help in meaningful correlation at
collector.
I think we should add this in the operational consideration for filtered
drafts, if it isn’t present already.
Thanks
Mukul
From: Dikshit, Saumya <[email protected]>
Date: Saturday, July 25, 2026 at 2:37 AM
To: gengnan <[email protected]>; Reshad Rahman
<[email protected]>
Cc: Grow <[email protected]>
Subject: [GROW] Re: Question on draft-geng-grow-bmp-rel-enhancement
Hi Nan, Reshad,
I was going through the draft and couldn’t help bringing up another angle,
(though not-unrelated) to the email chain discussion :
The same blind spot effects statistics consumers, not just event-log consumers.
If a router locally rate-limits or drops events (per the mitigation text in
draft-geng-grow-bmp-rel-enhancement) and separately reports gauges such as the
ones in
*
draft-ietf-grow-bmp-bgp-rib-stats (RFC 9972) or
*
the policy-driven counters in draft-smc-grow-bmp-route-change-stats,
a collector has no way to know that an observed gauge delta might not be fully
explained by the event stream it received it may look like an unexplained jump.
Rather than defining filtering-indication independently for events (in this
draft) and for RIB streams (bmp-adj-ribs-filtered), would it make sense to
define one small, generic TLV/flag, that any BMP consumer event, RM, or SR
message can check? This would definitely help in achieving "telemetry
completeness"
More than happy and willing to sketch this as a short contribution if there's
appetite, as we hit a related need while defining the per-peer gauges in
draft-smc-grow-bmp-route-change-stats.
Thanks,
Saumya.
From: gengnan <[email protected]>
Date: Thursday, 23 July 2026 at 3:39 PM
To: Reshad Rahman <[email protected]>
Cc: Grow <[email protected]>
Subject: [GROW] Re: Question on draft-geng-grow-bmp-rel-enhancement
Hi Reshad,
As stated in Section 3 of draft-ietf-grow-bmp-adj-ribs-filtered:
> ... be informative to the rest of the system that they should not make
> decisions assuming that this stream is transmitting all the information about
> it.
The same logic seems to apply to event reporting. If critical events are
filtered locally without any signal to the collector, monitoring systems may
draw incorrect conclusions based on incomplete data. It would therefore be
valuable to consider a mechanism to convey this filtering state for events.
Best,
Nan
From: Reshad Rahman <[email protected]>
Sent: Thursday, July 23, 2026 1:43 AM
To: Grow <[email protected]>
Subject: [GROW] Question on draft-geng-grow-bmp-rel-enhancement
Hi,
Appropriate caution SHOULD be taken when picking routing events to
report, as next-hop related updates may produce heavy message loads
during network instability. Mitigation measures SHOULD be deployed
on both reporting and receiving sides. For example, local endpoints
can apply event filtering controls, while receivers maintain
corresponding processing mechanisms to handle potential high-volume
event bursts gracefully.
During the meeting today the text above was highlighted by Nan (based on
feedback from Prasad). I have no issue with the feedback and text, but is there
any indication of filtering sent to the collector?
draft-ietf-grow-bmp-adj-ribs-filtered which was presented earlier adds a Peer F
flag for Adj-Rib-In/Out, IIUC that doesn't cover events in
draft-geng-grow-bmp-rel-enhancement? IMO we want indication of filtering for
"critical" events.
Regards,
Reshad.
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