Hi authors,
I noticed that draft-rabadan-bess-evpn-inter-domain-opt-b tries to summarize
the impact of the Inter-Domain Option-B connectivity in the EVPN procedures.
And I noticed that, when there is an inter-domain option-b node between virtual
hub nodes and virtual spoke nodes, how should the PED label attribute ( section
7.1 of draft-ietf-bess-evpn-virtual-hub ) be rewritten has not been clearly
defined yet.
" ... ... Notice that an "upstream-assigned" label used by a V-hub to send
traffic with on a P2MP tunnel to identify the source V-spoke is the
same "downstream-assigned" label used by the V-hub to receive traffic
on the IR tunnel from the V-spoke. "
As described in section 7.1 of draft-ietf-bess-evpn-virutal-hub, the PED label
is both "upstream-assigned" and "downstream-assigned". In such case, when an
inter-domain option-b nodes decides to rewrite the PED labels, how can it find
a common label value which is unused both in the "upstream-assigned" label
space and "downstream-assigned" label space?
PE1------------------ABR-----------------PE2
When the ABR propagate EVPN routes to PE3, should the PED labels from PE2 be
rewritten in the same "upstream-assigned" label space as the PED labels from
PE1?
Especially when there are multiple types of EVPN services over P2MP LSP between
PE1 and PE2. e.g. only half of these services of is EVPN VH/VS over P2MP LSP,
the other half of these services is normal EVPN VPLS over P2MP LSP. The ABR
above is the common inter-domain option-b node of both the two halves of these
services.Should the EVPN labels of those normal EVPN VPLS over P2MP LSP
services also be allocated in the same "upstream-assigned" label space as the
PED labels?
If there is also a normal L3VPN/EVPN over MP2P/P2P LSP service between PE1 and
PE2, from the viewpoint of ABR node, should the EVPN label of such normal
L3VPN/EVPN service also be allocated in the same "downstream-assigned" label
space as the PED labels? Will the label rewritting procedures for these normal
L3VPN/EVPN over MP2P/P2P services be affected by the PED label rewritting
procedures?
Will this use case be considered by any of these two drafts?
Thanks,
Yubao
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