Subject: [MOBILE-IP] Is this list alive

From: Sharad Joshi <[email-masked]>
Date: Thu, 16 Sep 1999 17:39:39 +0530

Hi,

Just wanted to know about this mailing list. Is this list alive? I could
find no archive for this list.

Since i've taken up some bandwidth, i'll utilize it fully. My ques
follows.... sorry for the long mail.

Rfc2002 in section 3.6.1.1, 4th paragraph (Sending registration requests
-- ip fields) says:

       (if the mobile)...does not know the IP address of its home agent,
       the mobile node may use dynamic home agent address resolution
       to automatically determine the IP address of its home agent
       (Section 3.6.1.2).  In this case, the IP destination address is
       set to the subnet-directed broadcast address of the mobile node's
       home network.  This address MUST NOT be used as the destination
       IP address if the mobile node is registering via a foreign agent,
       although it MAY be used as the Home Agent address in the body of
       the Registration Request when registering via a foreign agent.

question:

In the "dynamic home agent address resolution" thing that the rfc talks
about, the registration request home agent field is subnet-directed
broadcast address of the home network. But what will be the destination IP
address in the datagram (acc. to above lines, this MUST NOT be broadcast
address). If it is the foreign agent's address, whom does the FA send the
registration requests to? And how is the Mobile Home Authentication valid
in this case (all requests must include this authentication, no?)

Sharad.

P.S. I am not subscribed to this list, please Cc me.

---

From: Sharad Joshi <[email-masked]>
Date: Fri, 17 Sep 1999 12:40:35 +0530

Thanks for the reply John,

On Fri, 17 Sep 1999, John Williams Floroiu wrote:

+ > Rfc2002 in section 3.6.1.1, 4th paragraph (Sending registration requests
+ > -- ip fields) says:

[snip]

+ > question:
+ >
+ > In the "dynamic home agent address resolution" thing that the rfc talks
+ > about, the registration request home agent field is subnet-directed
+ > broadcast address of the home network. But what will be the destination IP
+ > address in the datagram (acc. to above lines, this MUST NOT be broadcast
+ > address). If it is the foreign agent's address, whom does the FA send the
+ > registration requests to? And how is the Mobile Home Authentication valid
+ > in this case (all requests must include this authentication, no?)
+
+ To its own home IP address, for instance. Such a datagram will be routed to
+ HNet. However, a potential HA in HNet cannot attract such a datagram, since
+ it has no binding with that MN at that moment. Consequently, a good idea
+ would be to have the HA set in promiscuous mode.
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^
Isn't that an overhead on the part of HA? I thought Agents were always
configured to know who they serve as HAs to. Isn't that so? Or am i
missing something? In that case, yeah, dest add. 'may' (or 'should') be
home ip add. of the MN.

+ A second possibility would be to use the "All Mobility Agents" multicast
+ address.

But that MUST have a TTL of 1, no? Is it assumed that the mobile wont be
farther than 2 hops from the HA?

Sharad.

---

From: John Williams Floroiu <[email-masked]>
Date: Fri, 17 Sep 1999 08:35:47 +0200

Hi Sharad,

> in this case (all requests must include this authentication, no?)

To its own home IP address, for instance. Such a datagram will be routed to
HNet. However, a potential HA in HNet cannot attract such a datagram, since
it has no binding with that MN at that moment. Consequently, a good idea
would be to have the HA set in promiscuous mode.
A second possibility would be to use the "All Mobility Agents" multicast
address.

John.