Subject: [netlmm] PMIPv6-Multihome support by MAG

From: "Magesh Shanmugam" <[email-masked]>
Date: Fri, 28 Nov 2008 17:05:50 +0530

Sri
 
When Mobile Node(MN) present in the PMIPv6 domain is having multiple
interfaces (Interface # 1 and # 2), mobility session will be created 
for each interface.  For the multi-home case, Mobile Node Link Layer
Identifier should be a mandatory option, while we send PBU message 
to LMA, since when LMA processes the PBU message, it does the Binding Cache
Entry lookup procedure (as mentioned in section 5.4.1).  
If there exist a Binding Cache entry for Interface # 1(1st PBU sent without
MN-Link Layer Option and ALL_ZERO HNP), 
then how will LMA decide that the 2nd PBU (sent without MN-Link Layer and
ALL_ZERO HNP) received for Interface #2 of MN is 
for Initial (New) Registration.
 
Thanks
S Magesh
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From: Sri Gundavelli <[email-masked]>
Date: Fri, 28 Nov 2008 18:59:41 -0800 (PST)

Hi Magesh,

> for Initial (New) Registration.

The handoff hint for the second PBU should indicate that its a new
attachment and then the LMA will create a new session.

As we always said, LMA requires some identifiers to identify the session.
Without these basic identifiers, there is nothing much the LMA can do.
There is no magic behind, simple identifiers are required and without
this the LMA has to fall back to some guessing game. If the MAG keeps
passing no prefix, no link-layer id, no handoff hint, there is no way
to lookup the session and when we have to assume multi-homed host.
Instead, the MAG should always try to provide the proper handoff hint,
link-layer id (generated or real) and prefixes where ever possible. This
will bring some predictability into the lookup logic.

Regards
Sri

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From: "Magesh Shanmugam" <[email-masked]>
Date: Mon, 1 Dec 2008 11:03:08 +0530

Sri

My comments inline...

Thanks
S Magesh 

-----Original Message-----
From: Sri Gundavelli [mailto:[email-masked]] 
Sent: Saturday, November 29, 2008 8:30 AM
To: Magesh Shanmugam
Cc: [email-masked]
Subject: Re: PMIPv6-Multihome support by MAG

Hi Magesh,

On Fri, 28 Nov 2008, Magesh Shanmugam wrote:

> Identifier should be a mandatory option, while we send PBU message to 
> LMA, since when LMA processes the PBU message, it does the Binding 
> Cache Entry lookup procedure (as mentioned in section 5.4.1).
> If there exist a Binding Cache entry for Interface # 1(1st PBU sent 
> without MN-Link Layer Option and ALL_ZERO HNP), then how will LMA 
> decide that the 2nd PBU (sent without MN-Link Layer and ALL_ZERO HNP) 
> received for Interface #2 of MN is for Initial (New) Registration.
>

As we always said, LMA requires some identifiers to identify the session.
Without these basic identifiers, there is nothing much the LMA can do.
There is no magic behind, simple identifiers are required and without this
the LMA has to fall back to some guessing game. If the MAG keeps passing no
prefix, no link-layer id, no handoff hint, there is no way to lookup the
session and when we have to assume multi-homed host.
Instead, the MAG should always try to provide the proper handoff hint,
link-layer id (generated or real) and prefixes where ever possible. This
will bring some predictability into the lookup logic.

[Magesh] Yes, I agree to your statement.  PBU's sent by MAG for different
interfaces on the same MN has proper Handoff Indicator (i.e. Attachment over
new interface), but it doesn't carry HNP and Link Layer Identifier.  My
point here is that, for more clarity in the multi-homed scenario (RFC), it
is better to mention that the Link Layer Identifier option be mandatory or
conditional, rather than optional.

Regards
Sri

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From: Sri Gundavelli <[email-masked]>
Date: Sun, 30 Nov 2008 22:19:24 -0800 (PST)

Magesh,

> conditional, rather than optional.

We could not mandate the presence of link-layer id, as it is not present
in all wireless systems (Ex: LTE) and so we had to make it optional. If
that is present, in systems where this protocol is used, it should be
mandated in those specific architectures.

Regards
Sri