Re: [Tsv-art] Tsvart last call review of draft-ietf-softwire-mesh-multicast-22

[Joe Touch <touch@xxxxxxxxxxxxxx>]

Hi, Shu,

On Jun 2, 2019, at 8:31 AM, 杨术 <yangshu@xxxxxxxxxx> wrote:

Dear Joseph,

Thank you for your comments.

About fragmentation, we modified this part as following:

The encapsulation performed by an upstream AFBR will increase the
   size of packets.  As a result, the outgoing I-IP link MTU may not
   accommodate the larger packet size.  It is not always possible for
   core operators to increase the MTU of every link, thus fragmentation

it might be useful to be specific - “source fragmentation” rather than “fragmentation”.

   after encapsulation and reassembling of encapsulated packets MUST be
   supported by AFBRs [RFC5565].  PMTUD [RFC8201] SHOULD be enabled and

   that ICMPv6 packets must not be filtered in the I-IP network.  Using

“ICMPv6 packets MUST NOT be filtered in the …”

(i.e., delete “that” and capitalize MUST NOT.

   tunnel will reduce the effective MTU of the datagram.  When the

This repeats the same idea - it isn’t needed.

   original packet size exceeds the effective MTU, fragmentation MUST
   happen after encapsulation on the upstream AFBR, and reassembly MUST
   happen before decapsulation on the downstream AFBR.  Fragmentation
   and tunnel configuration considerations are provided in [RFC5565] and
   [I-D.ietf-intarea-tunnels].  The detailed procedure can be referred
   in Section 7.2 of [RFC2473].

I would suggest the following, which includes the suggestions above:

   The encapsulation performed by an upstream AFBR will increase the

   size of packets.  As a result, the outgoing I-IP link MTU may not

   accommodate the larger packet size.  It is not always possible for

   core operators to increase the MTU of every link, thus source fragmentation

  after encapsulation and reassembling of encapsulated packets MUST be

   supported by AFBRs [RFC5565].  PMTUD [RFC8201] SHOULD be enabled and

   ICMPv6 packets MUST NOT be filtered in the I-IP network.   Fragmentation
   and tunnel configuration considerations are provided in [RFC5565

   and [I-D.ietf-intarea-tunnels].  The detailed procedure can be referred

   in Section 7.2 of [RFC2473].

Joe