Subject: [Mip4] Detecting presence of a Foreign Agent

From: Darshan Purohit <[email-masked]>
Date: Thu, 16 Jun 2005 15:49:34 -0700

I am a bit unsure about detecting whether a foriegn agent is being used or not.
and what could be the possible Foreign Agent Address

The way I thought about it is  ...

If D bit is not set ,        FADDR = Care-of Address
                                          (Source address could be NAT
Translated)
If D bit is set
        If no UDP Tunnel Request Extension
                    FADDR = source address , if source != care-of address
                     else NO Foreign Agent
         else
                    ?????

Now, in the last else, a UDP Tunnel request extension is present   and
 MN is using
a co-located care-of Address.   If there is  an   FA-HA Auth Extension,   how 
do we look for the Foreign Agent Security Association.    The source address
could have been NAT Translated and the care-of address belongs to the MN.

Am I missing something here ?

Thanks
Darshan.

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---

From: Sri Gundavelli <[email-masked]>
Date: Thu, 16 Jun 2005 16:10:37 -0700 (PDT)

>                     FADDR = source address , if source != care-of address

If the UDP Tunnel request extension is before MHAE, the extension is added
by the MN and the tunnel will terminate at the MN, or if the "D" bit is
set. The "R" bit in the UDP Tunnel request extension will indicate if the
FA is in the control path and so the special keep alive message for
bringing up the tunnel to fix the NAT mappings for the data traffic.

> could have been NAT Translated and the care-of address belongs to the MN.

Please read issue#45, I've created this for the RFC3344bis. This is still
unresolved and Pete plans to toss a coin in Paris. We will fix these
issues in 3519bis anyways.

Sri