Subject: Re: [Seamoby] Security Requirments for CAR Discovery

From: "Govind Krishnamurthi" <[email-masked]>
Date: Wed, 13 Mar 2002 17:49:42 -0500

Hi James,
Just to add to Hemant's comments, reachability of GAARs according to CAR 
discovery is in the view of the current MN in question. Two GAARs may be
reachable for an MN but not for a different MN. In the IP sense, two GAARs 
are always reachable somehow through the Internet (of course I am not 
considering private addresses here. But even in that case it may be 
reachable indirectly through a border router). In summary,
I share Hemant's concern about why you are going linking routing and CAR 
discovery.  I don't know whether I am  missing something.

Regards,
Govind.

>
>Hi James:
>
>Please see coments below marked as [HC]
>
>--------------------------snip---------------------------------------
>> > >on
>> > >     the security of routing information distribution.
>> >
>> > I do not agree with this part. What is the relation between routing
>>and CAR
>> > requirements? The first part of your requirement covers all the IETF
>> > security policies and protocols, and that should be enough in my
>>opinion.
>> >
>>
>>CAR discovery involves sending information about the reachability and
>>capabilities of one router to another, possibly via a host.
>
>[HC] CAR discovery is not about spreading reachability information of one
>router to another. That is the job of routing protocols. It is about
>capability exchange between GAARs.
>
>Routing
>>information distribution involves sending information about the
>>reachability and capabilities of one router to another, usually not via
>>a host. The only thing the two don't have in common is that one could
>>possibly use a host while the other doesn't.
>
>[HC] I think there is little commanality between routing protocols and CAR
>discovery. Let me explain. There are two main parts of CAR discovery: GAAR
>discovery and capability exchange. I will come to GAAR discovery later. As
>far as the capability exchange between the GAARs is considered, once the 
>two
>GAARs have decided to exchange capabilities they can do so by opening 
>simply
>a peer-to-peer connection such as TCP between them or use open loop
>messaging like UDP and ICMP. I see no involvment of routing protocols here
>(beyond the point that they will help route the packets containing these
>messages). To give an analogy, if two routers need to do FTP between them
>they simply do it using TCP. FTP is however not deemed to be related to
>routing. If capabilities are exchanged via MN instead, the same logic still
>applies. Only, there is extra node between them.
>
>Now coming to GAAR discovery part, I struggle to see how a routing protocol
>are related to GAAR discovery. The problem statement clearly points hout 
>how
>GAAR discovery (Geospace) is different from logical neighborhood discovery
>(Cyberspace) on which routing protocols are built.
>
>In either case, the routing
>>fabric has to be able to trust the information it gets.
>
>[HC] Why CAR discovery needs to inject any information in routing fabric? 
>As
>I have explained above, it is about peer to peer information exchange
>between GAARs.
>
>Thus, the
>>security on the information distribution needs to be the same. Note that
>>this is *not* to say that, a priori, CAR discovery and routing
>>information distribution should be solved by the same protocol, just
>>that they involve the same kind of security problem.
>>
>>For an example of the problems it might cause if security on CAR
>>discovery were any less than that on routing information distribution,
>>consider security on MIP binding updates. The newly decided upon
>>protocol, return routability, depends critically upon the security of
>>the routing fabric. If the security on CAR discovery causes the security
>>of the routing fabric to be compromised, then MIP RR security on BU
>>updates is compromised.
>>
>>             jak
>>
>
>[HC] I am not denying that the security problem may exist. But then, we 
>need
>to point it out more directly and precisely rather than saying that the
>security problem is something like the one involved in routing. I think the
>problem is that "why will the two GAARs involve in capability exchange in
>the first place, unless they are assured about the validity of each other".
>Now we do have to come up with a solution to that. But, it is difficult to
>see how this problem alone can draw relation between CAR discovery and
>routing protocols.
>
>Regards,
>Hemant
>
>
>
>
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---

From: "James Kempf" <[email-masked]>
Date: Wed, 13 Mar 2002 16:57:07 -0800

> discovery.  I don't know whether I am  missing something.

I don't think there's any contradiction. Routing means getting packets
to hosts. Whether they go one way for one host and another for another
doesn't not make it routing.

BTW, I'm wondering if you and Hemant aren't confusing "routing" *the
problem* with "routing" *the protocols*? I never meant to imply that CAR
discovery protocols and routing information distribution protocols are
the same. We are still talking requirements, that would be solution
space.

            jak

---

From: "James Kempf" <[email-masked]>
Date: Wed, 13 Mar 2002 16:57:07 -0800

jak