All Rights Reserved © Alcatel-Lucent 2006, #####

Improved Register Procedure in PIM-

SM

draft-wen-pim-improved-register-00.txt

Haibo WEN

All Rights Reserved © Alcatel-Lucent 2006, #####2 | Presentation Title | Month 2006

Register procedure in current PIM-SM

1. Current procedureThe data-plane and control-plane are

not clearly separated in PIM-SM The sender sends MC data packets

once it wants to do, no control message exchange in control-plane.

At the DR, MC packets from sender trigger Register message (with encapsulation of MC data packets) in control plane.

The Register messages of this kind continue being sent until DR receives Register-Stop message. RP decapsulates the Register message and send the payload along the RP tree in the data plane.

Encapsulation and de-capsulation are relatively expensive operations for routers.

The arriving of native MC data packets in data-plane at RP will trigger Register-Stop message in control-plane.

2. Security issue Malicious user will use this feature

to attack the network by sending all kinds of MC data

Sender RP

Native MC data triggers the router to set SPTbit

When DR receives MC packets from sender, it will encapsulate MC packets in Register messages, and unicast them to the corresponding RP

When DR receives Join message from RP, ito sets the corresponding

PIM state and MC forwarding table

o MC data will not only natively flow along the Shortest Path Tree to RP, but also packets will continue be encapsulated in Register messages

DR

MC data in data-plane

Register messages containing MC data

JoinJoin

MC data in data-plane

MC dataMC data

RP decapsulates the Register message and delivers the MC data along the RP tree

Register message containing MC data

Register-Stop

RP receives multicast packets both from register message and from native multicast

Native multicast packet along SPT will trigger Register-Stop message

After receiving Register-Stop message, DR stops encapsulating MC packet in Register message

MC data in data-planeMC dataMC data

packets in data plane message in control plane

Figure 1: PIM registering procedure in current standard

All Rights Reserved © Alcatel-Lucent 2006, #####3 | Presentation Title | Month 2006

Improved PIM-SM register procedure (1/2)

Basic idea:DR will not forward/encapsulate MC until the delivery path has been established. Once the MC path from DR to RP has been established, the MC packets from the

sender will be forwarded.

Separate control plane and data plane completely Registering Process in the control-plane

– Sender management (logical messages. Two choices: (i) IGMP/MLD can be extended for this purpose; (ii) define new protocol))

– Sender-Request: request for sending MC data.

– DR-ACK: positive indication for allowing the sender to send MC data.

– DR-NAK: negative indication for not allowing the sender to send MC data.

– Sender-Alive: periodically sent by the sender to notify the DR that the sender is alive.

– Sender-Leave: the sender notifies the DR that it will not send MC data any more.

– DR’s register process (define 3 new messages except Join)– Register-Request: DR sends this message to RP to register.

– Join: to join the MC delivery tree

– SPT-OK: to notify the downstream routers on the SPT that the sender is alive, update the corresponding status in routers. Periodically sent from the root of SPT, either responded as a newly branch grafting this SPT.

– MC-Over: the sender will not send MC data, the SPT will be deleted (the corresponding status will be removed

MC data packets delivery in the data-plane

All Rights Reserved © Alcatel-Lucent 2006, #####4 | Presentation Title | Month 2006

Advantages:

Simplify the logic of registering procedure.

Clearly separate the control-plane and data-plane is good for speeding up data forwarding.

Authentication for MC sender can easily implemented in this procedure

No encapsulation and de-capsulation for MC data at the routers

SPT-OK along the SPT setting SPTbit removes the mechanism of MC data setting SPTbit, Keepalive timer

It’s good for fast forwarding.

Sender RP

SPT-OK message triggers the router to set SPTbit and update Keepalive timer

Once DR receives sender request, it will send Register message to the corresponding RP via unicast

When DR receives Join message from RP, ito sets the corresponding PIM state and MC

forwarding tableo sends SPT-OK message along the Shortest

Path Tree to RPo sends DR-ACK to sender

DR

Sender-Request

Register-Request

JoinJoin

DR-ACK

MC data in data-plane

SPT-OK SPT-OK

MC dataMC data

After getting positive confirm, sender can send MC data

Regi

ster

ing

proc

ess

Dat

a de

liver

y

RP delivers the MC data along the RP tree

Figure 2: new registering procedure with the separation of control plane and data plane (proposed in this patent)

packets in data plane message in control plane

Improved PIM-SM register procedure (2/2)

All Rights Reserved © Alcatel-Lucent 2006, #####

Thank you!