Subject: Re: [multimob] Comment on draft-asaeda-multimob-pmip6-extension-07

From: seil jeon <[email-masked]>
Date: Mon, 12 Dec 2011 17:42:43 +0900

Hi Hitoshi and all,

I moved the issue discussion to other title.

Regarding on the issue of Hitoshi's idea, we better use this title.

Please see below.

2011/12/12 Hitoshi Asaeda <[email-masked]>

> Hi Seil,
>
> > This discussion has been continuing repeatedly.
>
> It'd be better to move on more fundamental discussion, though..
>
> > When the MAG is connected with other PIM-SM router not over LMA, there's
> no
> > problem. PIM-SM establishes multicast routing path using RPF algorithm
> > through reflecting MAG's RIB.
>
> Whether routing "over LMA" or not is not precise.
>
> > But when the MAG is connected with several LMAs including PIM-SM, MRIB
> > SHOULD get information from PMIP routing table but "MAG's RIB doesn't
> > reflect PMIP routing" (Thomas and Hitoshi agreed it).
>
> Not very precise.
> PIM-SM does not need to use PMIP policy routing at all.
> Some MRIB entries are copied from MAG's RIB, other MRIB entries are
> separately configured if needed. The MRIB entries may use M-Tunnel
> established between MAG and LMA.
>
> Regards,
> --
> Hitoshi Asaeda
>

O.K. If my understainding is correct, your PIM-SM idea is based on not
"PMIP tunnel" but "M-Tunnel" between MAG and LMA to choose one LMA using
RPF algorithm.
And "M-Tunnel" information is in MAG's RIB.

And if then, the upstream router of MAG has nothing to be an LMA, it can be
another dedicated server for multicast support because it does not use PMIP
tunnel. So, your idea appear to me as one of specific PIM-SM application
method over dedicated multicast architecture.

---

From: Hitoshi Asaeda <[email-masked]>
Date: Mon, 12 Dec 2011 18:26:51 +0900 (JST)

Hi Seil,

> "PMIP tunnel" but "M-Tunnel" between MAG and LMA to choose one LMA using

If LMA is not an upstream router in MAG's RIB but if it should be in
MAG's MRIB, M-Tunnel is used to attach.

> And "M-Tunnel" information is in MAG's RIB.

Precisely, "M-Tunnel information is in MAG's MRIB".

> method over dedicated multicast architecture.

I don't understand what "dedicated server" and "dedicated multicast
architecture" mean.

Let's see the case of direct routing.
If operator thinks streams for some group (or source) prefixes do not
need to go through LMA (as they are direct routing), MAG enabling
PIM-SM simply forwards PIM join messages to its adjacent multicast
router without M-Tunnel and can get the streams natively.

Regards,
--
Hitoshi Asaeda

---

From: seil jeon <[email-masked]>
Date: Mon, 12 Dec 2011 20:12:54 +0900

Hi Hitoshi,

Please see inline.

> I don't understand what "dedicated server" and "dedicated multicast
=> The multicast replicator, as it is, to deliver the multicast packets to
all attached MAGs (e.g. MTMA named in draft-zuniga-multimob-pmipv6-ropt).

> router without M-Tunnel and can get the streams natively.
=> The issue is not the use of PIM-SM based direct routing. In my sense,
the issue was raised because you has been calling the entity, establishing
"M-Tunnel" with an MAG, an LMA. As I told you before, the entity cannot be
an LMA but may be closely to a sort of multicast replicator server
deliverying multicast packets to attached MAGs.

---

From: Hitoshi Asaeda <[email-masked]>
Date: Mon, 12 Dec 2011 23:17:02 +0900 (JST)

> I don't understand what "dedicated server" and "dedicated multicast
 
=> The multicast replicator, as it is, to deliver the multicast
   packets to all attached MAGs (e.g. MTMA named in
   draft-zuniga-multimob-pmipv6-ropt).

We don't need to assume to have such special entity.

> router without M-Tunnel and can get the streams natively.

=> The issue is not the use of PIM-SM based direct routing. In my
   sense, the issue was raised because you has been calling the
   entity, establishing "M-Tunnel" with an MAG, an LMA. As I told you
   before, the entity cannot be an LMA but may be closely to a sort of
   multicast replicator server deliverying multicast packets to
   attached MAGs.

There is no issue as you said.
MAG enabling PIM-SM communicates with neighbor PIM-SM routers. The
neighbor PIM-SM router may be the LMA enabling PIM-SM, may be an
adjacent PIM-SM router, etc. No difference from the ordinal PIM-SM
routing behavior.

M-Tunnel is used to configure an upstream (neighbor) router when a
multicast route for some group/source prefixes should be distinguished
from the corresponding route in RIB. This is also same as of the
regular situation (while dedicate M-Tunnel is a new definition of
specific GRE tunnel).

Regards,
--
Hitoshi Asaeda