[mpls] MPLS-RT review of draft-kompella-mpls-lart

Yingzhen Qu <yingzhen.ietf@gmail.com> Sun, 05 December 2021 03:08 UTC

From: Yingzhen Qu <yingzhen.ietf@gmail.com>
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Date: Sat, 04 Dec 2021 19:08:01 -0800
Cc: mpls-chairs@ietf.org
To: mpls@ietf.org, draft-kompella-mpls-larp@ietf.org
Archived-At: <https://mailarchive.ietf.org/arch/msg/mpls/K5RQs_Cfv5FstrnCOiz2Ph6L-fU>
Subject: [mpls] MPLS-RT review of draft-kompella-mpls-lart
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Hi,

I have reviewed the draft and here are my thoughts and comments.

The document is technically sound. L-ARP is defined to advertise label bindings for IP host addresses, and the draft covers both control plane and data plane. One general comment is that it will be helpful if the authors add some explanations about how the protocol is used/deployed.

Detailed comments (line numbers are generated using idnits):
15 Distribution of labels via ARP enables simple plug-and-play operation
16 of MPLS, which is key to deploying MPLS in data centers and
17 enterprises.
[major] The motivation of this proposal is to easy the deployment of MPLS in data centers and enterprises using “MPLS Fabric”. More details/clarifications are needed, especially how it’s different from traditional service provider MPLS networks.

166 L-ARP server. Within the MPLS Fabric, the usual MPLS protocols (IGP,
167 LDP, RSVP-TE) are run.
[nit] s/are run/are running

169 the overlay virtual network technology). H1 might also want to talk
170 to a member of the MPLS Fabric, say T.
[minor] Please elaborate why H1 might want to talk to T? A use case example would help.

201 label into the MPLS Fabric. This can be triggered by configuration
202 on T3, or when T3 first receives an L-ARP request from H3 (indicating
203 that H3 wants MPLS connectivity), or via some other protocol.
[minor] my understanding is that the kind of advertisement sent from T3 to H3 either triggered by configuration or request depends on the configuration on T3, so it could be a node SID or LDP message etc. Please correct me if my understanding is wrong.

238 3. sends a (proxy) L-ARP reply to H1 with the Source Hardware
239 Address (SHA) set to (L, M), where M is T1's metric to H3.
[nit] I assume the L here means a label to reach T3 from T1?
244 To send a packet to H3 over an MPLS tunnel, H1 pushes L1 onto the
245 packet, sets the destination MAC address to M1 and sends it to T1.
246 On receiving this packet, T1 swaps the top label with the label(s)
247 for its MPLS tunnel to H3.
[minor] Please clarify L1 and M1 here.

Section 3.4
It would be helpful if the forwarding table of H1 is shown here.

Thanks,
Yingzhen

[mpls] MPLS-RT review of draft-kompella-mpls-lart Yingzhen Qu
Re: [mpls] MPLS-RT review of draft-kompella-mpls-… Erik Auerswald