Re: [multimob] Comments on draft-deng-multimob-pmip6-requirement-01.txt

[Behcet Sarikaya <[e-mail]>]

Hi Thomas,



----- Original Message ----
From: Thomas C. Schmidt <[e-mail]>
To: Behcet Sarikaya <[e-mail]>
Cc: Hui Deng <[e-mail]>; [e-mail]
Sent: Thursday, October 23, 2008 3:16:10 AM
Subject: Re: [multimob] Comments on draft-deng-multimob-pmip6-requirement-01.txt

Hi Behcet,

Behcet Sarikaya wrote:

> It is not exactly clear why you state "Figure 2 depicts local routing
> as something totally different" ??? -
> what is expressed here: a content source local to the PMIP-domain - but
> not local to a particular MAP.
> 
> [behcet] In PMIP6 there is no MAP. You mean MAG here?

[thomas] Yes, sorry for the misprint.
> 
> And in consequence a (multicast) routing
>   within the PMIP domain without LMA-MAG tunneling. That's what the text
> says, as well.
> 
> [behcet] In PMIP6, the nodes between MAG and LMA do not matter because 
> all traffic is tunneled.

[thomas] except for the local routing option as described in section 
6.10.3 of RFC 5213. Here a local routing is foreseen between two unicast 
nodes on the same access link.

> Local routing in Fig. 2 would refer to a packet sent from MN1 to MN2 
> being routed by MAG1 locally without tunneling it to LMA1.
> If the packet MN1 sends is a multicast packet, RFC 5213 does not 
> describe how such a packet would be routed. Is this what you are trying 
> to address?
> 
[thomas] RFC5213 does not address multicast routing (that's why we are 
discussing it). The scenario described in fig 2 is *not* addressing 
mobile multicast senders, 

[behcet] Then I think the text and figure on the local routing is not needed because local routing in PMIPv6 refers to the routing of packets coming from the uplink and as you said this would be multicast sender situation which you left out in the requirements draft.

but a typical content distribution setting as 
for instance used in a provider-centric IPTV service. This means, a 
provider issues multicast streams from within his network domain, aiming 
at an efficient way to preserve (his own) network resources.

From the minimal perspective of RFC5213 (unicast routing) there is no 
efficient way to do this. That's why we are trying to identify protocol 
extensions that smoothly cooperate with RFC 5213.

[behcet] The situation you are talking about could become valid if route optimization is used with PMIPv6. In that case the content server in between MAG and LMA would send directly to MAG. If route optimization is not used then all traffic goes through LMA-MAG tunnel. Route optimization for PMIPv6 is some future work, there are drafts but we don't know if the standardization will go ahead.
Route optimization with multicasting is even more complicated problem. If you wish to state some requirements for this very complicated case please go ahead.
Best regards,

Behcet

Best regards,

Thomas


-- 

° Prof. Dr. Thomas C. Schmidt
° HAW Hamburg, Dept. Informatik
° University of Applied Sciences
° Berliner Tor 7, D 20099 Hamburg, Germany
° Fon: [phone], Fax: -8409
° http://www.informatik.haw-hamburg.de/~schmidt



      

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