Hi Shunwan, Nan, Haibo,
Thanks for the quick and positive turnaround.
I am glad the Remote VRF Information TLV generalization is useful.
Below is a concrete proposal for the EVPN/IRB text and worked example we'd like
to contribute to -02.
1. Proposed addition:
New subsection under Section 2.1 (Remote VRF Information TLV), e.g., "2.1.4.
Applicability to EVPN Type-5/IRB Inter-VRF Route Leaking”.
The TLV as defined (Information Type/Length, Index, AFI, SAFI, Remote BGP ID,
Remote Route Distinguisher) already generalizes cleanly to EVPN (AFI=25,
SAFI=70) without any wire-format change, only an applicability statement and
example are needed.
Proposed text:
“"
The Remote VRF Information TLV defined in Section 2.1 applies equally to EVPN
Loc-RIB [RFC9069] reporting for EVPN Route Type 5 (IP Prefix Route) [RFC7432]
[RFC9135] routes that have been leaked between EVPN Instances (EVIs) via
Integrated Routing and Bridging (IRB), by setting AFI=25, SAFI=70 in the TLV.
This addresses the "dynamic inter-VRF route leaking (IVRL)” gap noted in
[I-D.saum-grow-bmp-afi-safi-evpn], which defines per-EVI counters (Stats
Type=1) that quantify how many routes were leaked into a given EVI, but does
not itself identify which remote EVI each leaked route came from. This
document's TLV supplies that missing "from which remote EVI" detail; the two
mechanisms are intended to be used together, not as alternatives.
“"
2. Proposed worked example (parallel to Figures 1-4/8-9, EVPN/IRB case):
PE1 hosts EVI11 (RD11, import RT1) with a symmetric-IRB L3VNI.
PE2 hosts EVI21 (RD21, export RT1), whose locally attached CE advertises IP
Prefix P1 as an EVPN Route Type 5.
PE1 imports P1 into EVI11 via IRB.
Today, PE1 reporting the Loc-RIB routing information in EVI11 to the BMP
server only shows:
Prefix: P1
Nexthop: <PE2 address>
Peer Distinguisher: RD11 --> The RD of EVI11 on PE1
Peer Address: 0.0.0.0
Peer BGP ID: <PE1 router-id> --> The router-id of EVI11
And, with no way for the collector to tell that P1 was leaked in from EVI21
on PE2 specifically (as opposed to being locally originate in EVI11, or leaked
from some other EVI sharing RT1). Using the Remote VRF Information TLV (AFI=25,
SAFI=70):
Prefix: P1
Nexthop: <PE2 address>
Peer Distinguisher: RD11 --> The RD of EVI11 on PE1
Peer Address: 0.0.0.0
Peer BGP ID: <PE1 router-id> --> The router-id of EVI11
Remote BGP ID: <PE2 address>
Remote Route Distinguisher: RD21 --> The RD of the remote EVI
A collector correlating this with the per-EVI leaked-route gauge
([I-D.saum-grow-bmp-afi-safi-evpn] Section 2.2, Stats Type=1, Subtype=5 for
Route Type 5) can now attribute both "how many routes were leaked into EVI11"
(the gauge) and "specifically which remote EVI they came from" (this TLV) from
a single, correlated BMP feed.
3. Registry note: our companion draft
[I-D.dikshit-grow-bmp-rd-scoped-rib-stats] already reserves Family value 1
("L3VPN (VPN-IPv4/VPN-IPv6 Loc-RIB)") in its RD-Scoped Statistics Family
registry as an offer for this document (or a companion) to adopt as a
statistics-side complement to the Remote VRF Information TLV, should you want a
gauge (e.g. "leaked routes from remote RD X") alongside the TLV rather than
only per-route TLV attachment. No action needed on your side unless useful ;
flagging it since it's directly relevant to the EVPN/IRB text above.
Would you prefer we send the above as a literal text diff against your -01
.txt/.xml source, or is a prose description like the above enough for you to
fold in yourselves for -02?
Thanks again. Looking forward to working on this together.
Best regards,
Saumya
(on behalf of Mukul Srivastava and Changwang Lin, co-authors of
[I-D.saum-grow-bmp-afi-safi-evpn] and
[I-D.dikshit-grow-bmp-rd-scoped-rib-stats])
From: Zhuangshunwan <[email protected]>
Date: Tuesday, 28 July 2026 at 11:59 AM
To: Dikshit, Saumya <[email protected]>; [email protected] <[email protected]>
Cc: [email protected]
<[email protected]>; Changwang Lin
<[email protected]>; Srivastava, Mukul <[email protected]>
Subject: RE: [GROW] Comments on
draft-zhuang-grow-bmp-enhancement-for-vrf-loc-rib-01 : applicability to
EVPN/IRB and inter-VRF leaking
Hi Saumya,
Greatly appreciate your positive feedback on the Remote VRF Information TLV
approach.
Please feel free to integrate your team's ideas and proposals into the -02
version. Let's collaborate to shape a comprehensive new version together.
Best regards,
Shunwan (on behalf of the co-authors of
draft-zhuang-grow-bmp-enhancement-for-vrf-loc-rib)
From: Dikshit, Saumya <[email protected]>
Sent: Sunday, July 26, 2026 6:50 PM
To: [email protected]
Cc: [email protected]; Changwang Lin
<[email protected]>; Srivastava, Mukul <[email protected]>
Subject: [GROW] Comments on
draft-zhuang-grow-bmp-enhancement-for-vrf-loc-rib-01 : applicability to
EVPN/IRB and inter-VRF leaking
Hi Shunwan, Nan, Haibo,
The Remote VRF Information TLV nicely closes the "which remote VPN instance did
this best-path come from" gap in RFC 9069 Loc-RIB reporting. I believe there's
a directly analogous problem on the EVPN side that this draft's mechanism could
cover with minor generalization:
* draft-saum-grow-bmp-afi-safi-evpn defines per-EVI EVPN RIB stats keyed by
RD (Section 2.2), and separately calls out "dynamic inter-VRF route leaking
(IVRL)" for EVPN Type-5/IRB routes as an area needing counters.
* Today your draft scopes the Remote VRF Information TLV to VPNv4/VPNv6
Loc-RIB only (Figure 1 example).
* Would you be open to extending the applicability statement to the EVPN
AFI/SAFI (25/70).
* Thus, single Remote VRF Information TLV mechanism covers both L3VPN
and EVPN-IRB inter-VRF leak visibility?
* If that's in scope for a -02, we'd like to contribute the EVPN-side text
and an example (analogous to your Figure 1) showing an EVPN Type-5 (prefix)
route leaked across VRFs with the Remote VRF Information TLV attached.
(Hi Nan, a separate topic from your rel-enhancement/filtering thread which I
was trying keep pace with. Just flagging in case both land in your inbox close
together.)
Let us know if a joint revision makes sense, happy to send a draft diff.
@Srivastava, Mukul<mailto:[email protected]> and @Changwang
Lin<mailto:[email protected]> are also co-author to
draft-saum-grow-bmp-afi-safi-evpn
Thanks ,
Saumya
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