Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp-based-ani-00.txt

Liyizhou <liyizhou@huawei.com> Thu, 28 October 2021 06:58 UTC

From: Liyizhou <liyizhou@huawei.com>
To: Michael Richardson <mcr+ietf@sandelman.ca>, Anima WG <anima@ietf.org>
Thread-Topic: [Anima] I-D Action: draft-yizhou-anima-l2-acp-based-ani-00.txt
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Date: Thu, 28 Oct 2021 06:58:10 +0000
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Subject: Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp-based-ani-00.txt
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Hi Michael,

Please see inlines with [yz]. Thanks.

Yizhou

-----Original Message-----
From: Anima [mailto:anima-bounces@ietf.org] On Behalf Of Michael Richardson
Sent: Wednesday, October 27, 2021 2:09 AM
To: Anima WG <anima@ietf.org>
Subject: Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp-based-ani-00.txt

Liyizhou <liyizhou@huawei.com> wrote:
    > A campus network may contain the different types of equipment, L2
    > switches,

unmanaged L2 switches?
Or managed L2 switches with L3 addresses for their control plane?

[yz] Right, also corrected in another email. It refers to something like "the interface cannot or is not configured to automatically get IP address without any external exchange."  

    > L3 routers, hybrid L2/L3 switches. To make things easy, it is
    > quite common that all the nodes are enrolled as layer 2 to form a layer
    > 2 topology.

Yes. It's a regular disaster when loops form and the STP turns off the wrong port, and then the network breaks.

[yz] Yes. We normally want to turn on STP on access ports and turn them off on trunk ports. Before getting plugged, it may not be so clear which ports will be used as trunk ports. So when turning off STP, there is a risk of loop though we basically trust network admin can do correct cabling.
The ambition is to form a L2 ACP without requiring STP and without requiring IP reachability first in the management plane. Too ambitious? 

    > Then a collection of the physical connection/topology would
    > be required to check to see if the cabling is correctly made.

SNMP/YANG collection of LLDP adjacency data would seem to be the correct process here.

[yz] It can be done in this way. But again, it requires IP reachability first. 

    > That is
    > to say, assuming using link-local unicast and multicast address to
    > reach each L2 port brings extra requirements to L2 devices as L2 ports
    > may never use those IP addresses for their real data plane forwarding.

That seems like the wrong way to do things.

--
Michael Richardson <mcr+IETF@sandelman.ca>   . o O ( IPv6 IøT consulting )
           Sandelman Software Works Inc, Ottawa and Worldwide

Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp… Brian E Carpenter
Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp… Liyizhou
Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp… duzongpeng@foxmail.com
Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp… Michael Richardson
Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp… Michael Richardson
Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp… Liyizhou
Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp… Liyizhou
Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp… Liyizhou
Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp… Brian E Carpenter
Re: [Anima] I-D Action: draft-yizhou-anima-l2-acp… Michael Richardson