I apologize for the delay in answering this message.
On 12/21/2017 4:22 AM, Xiejingrong wrote:
I have a comment on draft-ietf-bess-mvpn-expl-track-03.
The chap 5.3 of this document said:
Furthermore, if the PTA specifies "no tunnel info", the LIR and LIR-pF
flags in the PTA MUST be passed along unchanged.
This will ensure that an egress ABR/ASBR only sends a Leaf A-D route
in response to a "match for tracking" if it is on the path to an
egress PE for the flow(s) identified in the corresponding S-PMSI A-D
route.
The issue is as follow:
In a [IngressPE--EgressABR--EgressPE] topology, IngressPE send a
Wildcard S-PMSI(*,*) route with PTA(flag<LIR+LIR-pF>), whose NLRI is
donated as SPMSI(type<0/1/2>RD,*,*,IngressPE). This SPMSI route will
be relayed by EgressABR to EgressPE with PTA flag untouched. Then
EgressPE will generate ONE LeafAD route with
NLRI(type<0/1/2>RD,*,*,IngressPE,EgressPE) and RT<EgressABR> and
N(N>=0) LeafAD routes with
NLRI(type<16/17/18>RD,S,G,IngressPE,EgressPE) and RT<EgressABR>. All
according to chap 5.2 of this document.
Then according to chap 5.3 of this document:
IngressABR will only send a Leaf A-D route, It should be the ONE of
LeafAD(type<0/1/2RD,*,*,IngressPE,EgressABR) with RT<IngressABR>.
In the example above, there is an "EgressABR" but not an "IngressABR".
So I'm not completely sure that I understand your question.
Then how should IngressABR deal with the the N(N>=0) LeafAD routes
with NLRI(type<16/17/18>RD,S,G,IngressPE,EgressPE) and RT<EgressABR> ?
It is not clarified in RFC7524 either. See chap 7.1 of RFC7524, which
only clarify LeafAD route with type<0/1/2>RD.
Should such LeafAD route with type<16/17/18>RD be accepted and
installed by EgressABR, and then ‘relay’ back to IngressPE, and thus
enable IngressPE explicit tracking inside the ingress “segmentation
domain” ?
The intention is the following. Suppose an egress ABR/ASBR satisfies
the following two conditions:
1. It has installed an S-PMSI A-D route with the following properties:
- its NLRI has wildcards for S and G,
- its NLRI specifies PE1 as the ingress PE,
- its PTA specifies "no tunnel info" and has LIR-pF set.
2. It has installed one or more Leaf A-D routes whose NLRI specifies
(S,G) with PE1 as ingress PE
Then the ABR/ASBR should originate a Leaf A-D route (with RD type
16/17/18) specifying (S,G) with ingress PE1.
The Leaf A-D route would be withdrawn when one of these conditions no
longer holds.
Does this answer your question?
_______________________________________________
BESS mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/bess
