November 2006 IETF 67 San Diego 1

FMIPv6 Extension for Multicast Handover

Frank Xia

xiayangsong@huawei.com

November 2006 IETF 67 San Diego 2

Problem Statement -1

• A mobile node joins a multicast group via a local multicast router on the foreign link being visited.

• Mobile IPv6 does not provide mechanisms to enable local multicast session to survive hand-off

November 2006 IETF 67 San Diego 3

Problem Statement - 2

• Fast Handovers for Mobile IPv6 only deals with unicast traffic not multicast traffic

• Major application is in mobile IPTV deploymentSuch as every city has their own TV programs provided to users

November 2006 IETF 67 San Diego 4

Problem Statement - 3

• HoA based multicast membership – Requires HA tunnelling

• CoA based multicast membership– Local distribution hence improves

performance– Especially important in mobile IPTV

November 2006 IETF 67 San Diego 5

Proposed Solution

MN PAR NAR

RtSolPr

PrRtAdv

deliver packets (include multicast traffic)

FBU HI

HAck

FBackFBack

Disconnect

Connect

Forward packets (include multicast traffic)

FNA

1 FBU/HI convey an MN’s multicast information for an NAR to start building multicast delivery tree

2 PAR buffers multicast traffic during handover

3 NAR delivers the buffered traffic as soon as the MN attaches to the NAR

November 2006 IETF 67 San Diego 6

Mailing List Discussions-1• Building multicast delivery tree dynamically or statically?

Static configuration is limited and restricts mobility and not scalable.

We need dynamic configuration capability in the system which can be done with a small

extension to FMIP as the draft explains • How PAR knows when NAR has already constructed the multicast tree so

PAR can stop forwarding multicast data ?

Probably no need to have a special mechanism since even if MN had two copies of a packet, it would not be harmful to the upper layers

• How to maintain the tunnel for multicast traffic?

One tunnel is used not only for unicast traffic but also multicast stream. The tunnel is constructed and aged according to the standard FMIPv6. The lifetime in FBU message can be configured to a larger value to accommodate multicasting.

November 2006 IETF 67 San Diego 7

Mailing List Discussions-2

• Is it necessary to tunnel the multicast packets from PAR to NAR?

  Two purposes for tunneling multicast traffic:

1) buffering the multicast traffic during handover

2) making full use of the old multicast deliver tree in PAR before a new tree built in NAR

• Should FNA also get MGI option?

Yes, we will add this in the next revision

• Should we change the signaling?

Suggestion was NAR sends join to PAR upon handover and then sends prune after NAR joins the tree. Why? Join to PIM RP by NAR may take longer.

PAR is a leaf router for the multicast delivery, it is not proper to build multicast tree for NAR.

November 2006 IETF 67 San Diego 8

• Issue a revision based on the comments

• What does WG think about the problem?

Next Steps

November 2006 IETF 67 San Diego 9

Thank You.Questions?