Subject: [MOBILE-IP] Too frequent Registration Request

From: kevin <[email-masked]>
Date: Thu, 6 Jan 2000 11:22:35 +0500

In RFC 2002 Section 3.6.3, it say:

The minimum time between Registration Requests MUST NOT be less than 1 second.

Should FA discard the second packet if FA receive the Registration Request from
the same MN within 1 second?

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HUAWEI (BANGALORE) BUSINESS OPERATION, BANGALORE, INDIA

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From: Steven Glass - Solaris Software <[email-masked]>
Date: Thu, 6 Jan 2000 11:56:38 -0500

>the same MN within 1 second?

    As I recall, from various places in the document, it says a couple of
related things; it's a loop-hole in the spec.  Sorry, I don't have the time to
reference them right now, but thanks for asking, as I meant to send this off to
Charlie a long time ago.

    According to 2002:

    If the FA rejects the registration request, it MUST NOT send a reply to the
MN more often than 1/s.

    Nothing is said in the case of the FA accepting the registration request; it
can simply forward it to the HA.  Nothing is said about how often it can do
this.  The implication, and I feel the spirit of 2002, though, is the FA should
reject any registrtaion request that is generated by a MN more often than 1/s.

    Nothing is said about the HA generating more than 1 reply/s.  This should be
allowed because a MN may be registering simultaneous bindings, or the FA could
have reset itself.

    The FA can then forward the HA's reply, of which there can be more than 1/s.

    I'm hoping this is resolved in 2002-bis, since a malicious node can pretend
to be a MN and flood two networks this way using FAs that behave to spec.  To
answer your question, though, I would say a responsible FA should should ignore
a second registration request appearing from the same MN within 1 second.

    Analogously, a HA that supports simultaneous bindings should be able to
ignore registration requests from the same MN through the same FA that arrive
more often than 1/second (network timing issues aside).  A HA that does not
support simultaneous bindings should be able to ignore registration requests
from the same MN regardless of FA that arrive more often the 1/second.

                              Cheers,
                                  Steve