Hi Jeffrey,
Please see Yubao2> below.
Thanks,
Yubao
原始邮件
发件人：Jeffrey(Zhaohui)Zhang
收件人：王玉保10045807;draft-rabadan-bess-evpn-inter-domain-op...@ietf.org;draft-ietf-bess-evpn-virtual-...@ietf.org;jorge.raba...@nokia.com;
抄送人：bess@ietf.org;
日 期 ：2023年05月15日 22:18
主 题 ：RE: [bess] Discussion on draft-rabadan-bess-evpn-inter-domain-opt-b and
draft-ietf-bess-evpn-virtual-hub.
Hi Yubao,
Please see zzh> below.
From: BESS <bess-boun...@ietf.org> On Behalf Of wang.yub...@zte.com.cn
Sent: Thursday, May 11, 2023 3:32 AM
To: draft-rabadan-bess-evpn-inter-domain-op...@ietf.org;
draft-ietf-bess-evpn-virtual-...@ietf.org; jorge.raba...@nokia.com
Cc: bess@ietf.org
Subject: [bess] Discussion on draft-rabadan-bess-evpn-inter-domain-opt-b and
draft-ietf-bess-evpn-virtual-hub.
[External Email. Be cautious of content]
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. "
zzh> It is the same label allocated by the V-hub to identify the source
V-spoke. When IR is used to receive traffic from the source V-spoke, it is
downstream/receiver-allocated (from the sending V-spoke point of view); when
P2MP is used to relay traffic from the source V-spoke to others, it is
upstream/sender-allocated (from the receiving PE point of view). But it is the
same label allocated by the V-hub. From the V-hub point of view, it is from the
regular (down-stream allocation) label space.
Yubao2> But old odinary upstream-assigned VPN/EVPN labels are allocated in an
independent label space, thus them may be assigned with the same value as a
ordinary downstream-assigned label of another service. When there are both
ordinary upstream-assigned VPN/EVPN labels and PED labels and both of them
should be allocated by the same PE, will these two types of upstream-assigned
labels be allocated in the same label space? Will an odinary upstream-assigned
VPN/EVPN label (e.g. a mVPN label) and a PED label are assigned with the same
value?
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?
Zzh> As explained above, it is from the same label space of the allocator.
Yubao2> When both above two types of upstream-assigned labels and ordinary
downstream-assigned labels (from the same originating PE) are rewritten by the
same inter-domain option-b node, will these three types of VPN/EVPN labels are
allocated in the same label-space of that inter-domain option-b node?
Zzh> The questions below are a bit complicated; we can continue if the above
explanation does not resolve them.
Yubao2> I understand that PED labels can allocated in the downstream-assigned
label space on the originating PE. But I am not sure whether they will be
re-allocated in the downstream-assigned label space on the inter-domain
option-b node. As far as I know, there is only one downstream-assigned label
space on the the inter-domain option-b node. Whether a PED label and an
ordinary upstream-assigned label can share the same P2MP LSP whose root is an
inter-domain option-b node or not? if they can, they should not be assigned
with the same value. But the ordinary upstream-assigned labels are allocated in
a independent label space for now, their values are independent of any
downstream-assigned labels.
Zzh> Thanks.
Zzh> Jeffrey
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
Juniper Business Use Only
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