Hi Jeffrey,
Thanks for your clearifications.
So the EVPN label reiceived from VH1 by a V-Spoke is not only an
upstream-assigned but also a downstream-assigned?
So, what value will the tunnel-type of PTA be assigned to? Ingress-Replication?
Assisted-Replication? P2MP?
The [EVPN-virtual-hub] has no referrence to [EVPN AR], so I don't think it will
be Assisted-Replication.
But when a PE receives a IR-PTA or P2MP-PTA, I think it is not the standard
behavior for it to install the EVPN label both as an incomming-label and as an
outgoing-label.
It should be explicitly described (like the PED labels). And I don't see such
descriptions.
Then I have other questions:
1) If the RRs(SPEs, to be precise) between the V-spokes and the V-Hub changed
the IMET route's nexthop to itself,
In what label space should the EVPN label be rewritten? In upstream-assigned
label space? or in downstream-assigned label space?
After the rewriting, can they still be the same value?
so it is not simply the recever V-spoke's viewpoint,
it is a domain-wide consensus.
The PED labels can be treated in such way just because they shouldn't be
rewritten by the transit-SPEs,
but the EVPN labels should be rewritten.
They are very different in the signalling and data plane behaviors.
The V-spokes can be placed in different geographical position (e.g. two
overseas branches of the same company), they may be in different ASes.
2) If the VS1 is an IPv4 node and VS2 is an IPv6 node,
How does the PED-labels-attribute carry the two PED labels?
Thanks,
Bob
原始邮件
发件人：Jeffrey(Zhaohui)Zhang <zzh...@juniper.net>
收件人：王玉保10045807;
抄送人：alexander.vainsht...@rbbn.com
<alexander.vainsht...@rbbn.com>;陈然00080434;张征00007940;bess@ietf.org
<bess@ietf.org>;
日 期 ：2020年08月24日 18:13
主 题 ：RE: Re:[bess] Hub-and-spoke support in
EVPN:RFC8317vs.draft-wang-bess-evpn-context-label-04
Hi Bob,
Whether a label is upstream-assigned or downstream assigned is from the view of
the receiving router. In this case, the labels are assigned by the v-hub, but
in case of IR traffic from the v-spokes, the labels are downstream-assigned from
the receiving v-hub point of view; in case of P2MP traffic from the v-hubs,
the labels are upstream-assigned from the receiving v-spokes point of view.
A better way to look at this is actually whether a label in *incoming data
packet* is from this receiving router’s own label space (notice that this
includes DCB/SRGB/SRLB labels) or from another router’s space. In the former
case
it is “downstream assigned” or “from own space”. In the latter case, it is
“upstream-assigned” or “from other spaces”. Notice that “from other spaces” is
more appropriate than “upstream-assigned” because the those labels are not
necessarily assigned from the
upstream/sending router’s space but could be from another router’s space.
An example of “other space” instead of “sender’s space” is in RFC 6513 (not
6514):
11.2.2.
Using PE Distinguisher Labels
If a given P-tunnel is to be used to carry packets traveling along a
bidirectional C-tree, then, EXCEPT for the case described in Sections
11.1 and 11.2.3, the packets that travel on that P-tunnel MUST carry
a PE Distinguisher Label (defined inSection 4), using the
encapsulation discussed inSection 12.3.
When a given PE transmits a given packet of a bidirectional C-group
to the P-tunnel, the packet will carry the PE Distinguisher Label
corresponding to the partition, for the C-group's C-RPA, that
contains the transmitting PE. This is the PE Distinguisher Label
that has been bound to the Upstream PE of that partition; it is not
necessarily the label that has been bound to the transmitting PE.
Jeffrey
Juniper Business Use Only
From: wang.yub...@zte.com.cn <wang.yub...@zte.com.cn>
Sent: Sunday, August 23, 2020 10:23 PM
To: Jeffrey (Zhaohui) Zhang <zzh...@juniper.net>
Cc: alexander.vainsht...@rbbn.com; chen....@zte.com.cn;
ext-zhang.zh...@zte.com.cn <zhang.zh...@zte.com.cn>; bess@ietf.org
Subject: Re:[bess] Hub-and-spoke support in EVPN:
RFC8317vs.draft-wang-bess-evpn-context-label-04
[External Email. Be cautious of content]
Hi Jeffrey,
In the following text:
… In case of IR with MPLS unicast tunnels, VH1 must advertise different
labels to different PEs, so that it can identify the sending PE based on the
label in the traffic from a V-spoke.
That “different labels o” should be changed to “different PE distinguisher
labels to”.
And the same EVPN label is advertised to different V-spokes,
Then I still have a question:
Whe VH1 use P2MP tunnel to broadcast BUM packets to all the V-Spokes,
Is that EVPN label a downstream-assigned label?
or it is an upstream-assigned label?
Maybe I was confused by that "labels".
Thanks
Bob
原始邮件
发件人：Jeffrey(Zhaohui)Zhang <zzh...@juniper.net>
收件人：Alexander Vainshtein <alexander.vainsht...@rbbn.com>;王玉保10045807;
抄送人：陈然00080434;张征00007940;bess@ietf.org
<bess@ietf.org>;
日期：2020年08月24日
08:16
主题：RE: [bess] Hub-and-spoke support in EVPN:
RFC8317vs.draft-wang-bess-evpn-context-label-04
Hi Sasha, Bob,
In the following text:
… In case of IR with MPLS unicast tunnels, VH1 must advertise different
labels to different PEs, so that it can identify the sending PE based on the
label in the traffic from a V-spoke.
That “to” should be changed to “for”. Different labels are advertised in a PE
Distinguisher (PED) label attribute,
as explained in the third paragraph:
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. Therefore, the same PED Label attribute serves two
purposes.
Jeffrey
Juniper Business Use Only
From: Alexander Vainshtein <alexander.vainsht...@rbbn.com>
Sent: Sunday, August 23, 2020 12:37 PM
To: wang.yub...@zte.com.cn; Jeffrey (Zhaohui) Zhang <zzh...@juniper.net>
Cc: chen....@zte.com.cn; ext-zhang.zh...@zte.com.cn
<zhang.zh...@zte.com.cn>;bess@ietf.org
Subject: RE: [bess] Hub-and-spoke support in EVPN: RFC
8317vs.draft-wang-bess-evpn-context-label-04
[External Email. Be cautious of content]
Bob, Jeffrey and all,
Regarding the question “How does VH1 advertise many labels to a single RR with
the same NLRI?”
– my guess (FWIW) is that:
With IR each V-Spoke advertises its Type 3 EVPN route to V-Hub, so that V-Hub
is explicitly aware of each of its associated V-Spokes
V-Hub can then advertise the Unknown MAC Route (UMR) with the same MAC address
(00:00:00:00:00:00) but different IP addresses. in the Type 2 EVPN routes (and
different labels allocated per associated V-Spoke). As a consequence, these
routes would have different
NLRI and will all pass the RR.
One possibility is to use the IP address that identifies the specific V-Spoke
in the Type 3 EVPN route. In this case V-Spoke would receive all such routes
but select one that its own IP address
A better possibility would be for the V-Spoke to allocate a Route Import
Extended Community as defined in Section 7 of RFC 6514 and attach it to the
Type 3 EVPN route it advertises. In this case V-Hub would allocate a dummy IP
address (say from /127 subnet)
per each associated V-Spoke, use it in the UMR with the label for this V-Spoke
and attach the Route Import Extended Community advertised by the specific
V-Spoke to the UMR that is intended for this V-Spoke.
Neither of these options has been explicitly defined in theVirtual
Hub and Spoke in EVPN draft, and the draft has expired.
My 2c,
Sasha
Office: +972-39266302
Cell: +972-549266302
Email: alexander.vainsht...@ecitele.com
From: BESS <bess-boun...@ietf.org>On
Behalf Of wang.yub...@zte.com.cn
Sent: Saturday, August 22, 2020 6:39 AM
To: zzh...@juniper.net
Cc: chen....@zte.com.cn; zhang.zh...@zte.com.cn; bess@ietf.org
Subject: Re: [bess] Hub-and-spoke support in EVPN: RFC
8317vs.draft-wang-bess-evpn-context-label-04
Hi Jeffrey,
Maybe I was confused by the last mail.
Let's discuss it on the basis of the text of the [EVPN Virtual Hub] draft.
In section 7.1, it says that:
In case of IR with MPLS
unicast tunnels, VH1 must advertise different labels to different
PEs, so that it can identify the sending PE based on the label in the
traffic from a V-spoke.
I don't understand that sentence in the following questions:
1) How does VH1 advertise many labels to a single RR with the same NLRI?
2) How does the RR recognise that each (instead of only the recent one) of
these labels should be reflected?
3) Will the RR reflect all these labels to all V-Spokes?
4) Will each of the V-Spokes receive only the exact one (which is allocated for
that V-spoke by the VH1) of these labels from the same RR?
Thanks,
Bob
原始邮件
发件人：Jeffrey(Zhaohui)Zhang <zzh...@juniper.net>
收件人：王玉保10045807;bess@ietf.org <bess@ietf.org>;
抄送人：张征00007940;陈然00080434;
日期：2020年08月21日
23:33
主题：RE:
Re:Hub-and-spoke support in EVPN: RFC
8317vs.draft-wang-bess-evpn-context-label-04
Hi Bob,
*If* the AR REPLICATOR behaviors are removed from that draft,I think the
hub/spoke
scenario can't be well supported because that the RRs are widely used.
What do you mean by*if*in the above statement? It is the designed behavior with
hub and spoke scenario – with that do you still think there is a problem?
RR is only used for route distribution and should not make any difference.
Thanks.
Jeffrey
Juniper Business Use Only
From:wang.yub...@zte.com.cn <wang.yub...@zte.com.cn>
Sent: Thursday, August 20, 2020 9:52 PM
To: bess@ietf.org; Jeffrey (Zhaohui) Zhang
<zzh...@juniper.net>;alexander.vainsht...@rbbn.com
Cc:
alexander.vainsht...@rbbn.com;draft-wang-bess-evpn-context-la...@ietf.org;michael.gorokhov...@rbbn.com;ext-zhang.zh...@zte.com.cn
<zhang.zh...@zte.com.cn>;chen....@zte.com.cn
Subject: Re:Hub-and-spoke support in EVPN: RFC 8317
vs.draft-wang-bess-evpn-context-label-04
[External Email. Be cautious of content]
Hi Jeffrey and Sasha,
The flows of E-tree services typically are P2MP conections,
But the flows of hub/spoke services typically are MP2MP connections,
the spoke PEs can connect to each other under the assistance of the hub PE.
The hub/spoke services is actually a special pattern of VPLS, whose MP2MP
nature will be persisted.
So they are very different as what Jeffrey has pointed out.
But the hub/spoke secenario is very similar to the AR REPLICATOR/LEAF, IMHO.
And draft-ietf-bess-evpn-virtual-hub already applied a certain extent of AR
REPLICATOR behaviors to the hub PEs.
The only issues remained in draft-ietf-bess-evpn-virtual-hub is that when RRs
exists between hub-PE and spoke-PEs.
If the AR REPLICATOR behaviors are removed from that draft,
I think the hub/spoke scenario can't be well supported because that the RRs are
widely used.
and the AR REPLICATOR behaviors will still be required even if there are no RRs.
And I think the approaches discribed in draft-wang-bess-evpn-context-label-04
can solve the problems caused
by RR existence.
Best Regards,
Bob
原始邮件
发件人：Jeffrey(Zhaohui)Zhang <zzh...@juniper.net>
收件人：Alexander Vainshtein
<alexander.vainsht...@rbbn.com>;draft-wang-bess-evpn-context-la...@ietf.org
<draft-wang-bess-evpn-context-la...@ietf.org>;
抄送人：Michael Gorokhovsky <michael.gorokhov...@rbbn.com>;bess@ietf.org
<bess@ietf.org>;
日期：2020年08月20日
22:46
主题：RE: Hub-and-spoke support in EVPN: RFC 8317
vs.draft-wang-bess-evpn-context-label-04
Hub and spoke EVPN and E-tree are different.
However, draft-ietf-bess-evpn-virtual-hub should address the following two at
least:
* MPLS EVPN can't support hub/spoke usecase, where the spoke PEs can
only connect to each other through the hub PE. Especially when at
least two of the spoke PEs are connected to a common route
reflector.
* MPLS EVPN can't work as an AR-REPLICATOR. Because the AR-
REPLICATOR will apply replication for the ingress AR-LEAF too.
But a packet shoud not be sent back to the AR-LEAF where it is
received from.
Jeffrey
Juniper Business Use Only
From: BESS <bess-boun...@ietf.org>On
Behalf Of Alexander Vainshtein
Sent: Thursday, August 20, 2020 9:36 AM
To: draft-wang-bess-evpn-context-la...@ietf.org
Cc: Michael Gorokhovsky <michael.gorokhov...@rbbn.com>;bess@ietf.org
Subject: [bess] Hub-and-spoke support in EVPN: RFC 8317 vs.
draft-wang-bess-evpn-context-label-04
[External Email. Be cautious of content]
Dear authors of draft-wang-bess-evpn-context-label-04,
Section 2 “Problem Statement” of draft-wang-bess-evpn-context-label-04 states
that “MPLS EVPN can't support hub/spoke use
case, where the spoke PEs can only connect to each other through the hub PE.
Especially when at least two of the spoke PEs are connected to a common route
reflector”.
I have to admit that I do not understand why support of the generic E-Tree
functionality in EVPN defined inRFC
8317 is not sufficient for handling this use case.
In particular I do not see why connection of Spoke PEs to a common RR affects
the EVPN behavior (or L3vPN Hub-and-Spoke VPN behavior as defined inSection
4.3.5 of RFC 4364) in any way.
Regards, and lots of thanks in advance,
Sasha
Office: +972-39266302
Cell: +972-549266302
Email: alexander.vainsht...@ecitele.com
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