Re: [multimob] Direct Multicast Routing & the Deployment of PIM-SM(Juan Liu)

["Thomas C. Schmidt" <[e-mail]>]

Hi Juan Liu,

please see inline.

On 01.08.2012 19:27, [e-mail] wrote:

>> Message: 1
>> Date: Wed, 01 Aug 2012 16:01:56 -0700
>> From: "Thomas C. Schmidt" <[e-mail]>
>> To: "[e-mail]" <[e-mail]>
>> Subject: [multimob] Direct Multicast Routing & the Deployment  of
>>    PIM-SM
>> Message-ID: <[e-mail]>
>> Content-Type: text/plain; charset=ISO-8859-15; format=flowed
>>
>> Hi all,
>>
>> after Monday's presentation of PIM deployment options
>> (draft-ietf-multimob-pmipv6-source), there was the discussion on further
>> optimization options. In detail, the idea was raised to reach MNs  not
>> via their (permanent) HNP advertisements at the LMA, but directly  at
>> their current MAGs. The latter would require a dynamic unicast routing
>> protocol in the access network.

> In order that multicast traffic reach MNs directly via MAG-MAG tunnel not
> via LMA-MAG tunnel,MRIB can be constructed using route from the tunnel
> between MAGs(draft-liu-multimob-pmipv6-multicast-ro).

The scenario of your draft is a completely different one: If I
understood correctly, you distribute traffic in an overlay. (construct a
mesh of tunnels between MAGs, inquire routes to MNs via an LMA-based
on-demand search and then select the proper tunnel for forwarding).

This is different from what we refer to by the term "direct (or
localized) routing".

>>
>> I promised to talk to Sri about this (underlying unicast) approach.  As
>> expected, Sri emphasized that the PMIP WGs intentionally do *not*
>> consider this a working option. The reason is that node mobility
>> typically is more intense and faster than unicast routing dynamics.
>> Advertising MN's HNPs throughout the access network would cause route
>> pollution and convergence problems and quickly lead to inconsistencies.
>> For the unicast case, this is the equivalent of pushing multicast
>> mobility management into multicast routing, which we equally avoid.

> About the working option you talk with Sri,does it refer to direct 
> routing via MAGs,
> which in PMIP WG unicast routing through MAG-MAG tunnel is an acceptable 
> optimization
> options for PMIPv6 routing. Hope i'm not wrong about this.

We didn't talk about overlay solutions. We just addressed the
straight-forward deployment of dynamic unicast routing protocols like
iBGP or OSPF. So nothing was said about your draft.

Best regards,

Thomas

-- 

Prof. Dr. Thomas C. Schmidt
° Hamburg University of Applied Sciences                   Berliner Tor 7 °
° Dept. Informatik, Internet Technologies Group    20099 Hamburg, Germany °
° http://www.haw-hamburg.de/inet                   Fon: [phone] °
° http://www.informatik.haw-hamburg.de/~schmidt    Fax: [phone] °