Subject: [MOBILE-IP] Cellular IP questions

From: Rohit Rakshe <[email-masked]>
Date: Sun, 19 Nov 2000 15:22:26 -0600

Hi,

I am a graduate student at University of Minnesota. I read cellular IP
draft and  have some questions  about it. (I  am assuming this  is the
correct mailing list  to discuss this. If not,  can someone please let
me know ?)

1. Cell-IP  updates   binding  caches  of   routers  on  the   way  to
gateway. Does this not mean that  the domain topology HAS to be a tree
structure.  Because if  it was  not a  tree, then  there could  be two
distinct paths from the mobile node  to the gateway. And then we could
not update binding caches of routers on the way.

Now, if such  restriction is indeed placed, it  limits the topology of
the domain severely (and we are losing robustness of IP).

2. If a mobile  node (A) is sending packets to  some other mobile node
(B) located very close in  the same cellular domain, the packets could
be routed straight  to (B) because mobile nodes  always use their home
IP addresses. But cell-IP says that all packets have to be routed thru
the gateway. This might not be the best thing to do.

Why can't  we just  send those  packets directly to  (B) and  then the
router  which intercepts the  packets on  the way  to gateway  send an
empty data  packet addressed to the  gateway on (A)'s  behalf (for the
purpose of updating  binding caches of the routers all  the way to the
gateway.).

I would  appreciate your  replies. I  am studying this  as part  of my
project.

Thanks,
Rohit