Subject: RE: [midcom] policy & duration

From: John LaCour <[email-masked]>
Date: Thu, 9 Aug 2001 08:32:25 -0700

> Directionality is
> implicit in the source and destination addresses in the packet
> header and a middlebox with more than one interface already
> knows how to route.
> 
> Melinda

I disagree.  Well, sort of.  What we are concerned about is
directionality in the context of security policy.  We don't
want to say that routing policy is the equivalent security policy
with regards to direction.

For example, if all of my SIP phones are behind one interface
and my Gateway behind another, if someone or something screws 
up my routing table, I don't want to my VoIP traffic to be 
sent out to the Internet. 

That said, I don't want to try to express complex network
topologies, interfaces, directions, etc. in MIDCOM.  I'm in favor
of being to able give the logical middlebox and path a name in
the protocol.

-John

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From: Jiri Kuthan <[email-masked]>
Date: Fri, 10 Aug 2001 01:07:39 +0200

John,

Let me assume:
a) it is desirable that a middlebox knows through which 
   interfaces a packet is expected to go (which is what I call
   direction) 
b) the flow 5-tuple is known to SIP proxy (which is not necessarily 
   the case with SIP but let us ignore it for now)

Do you expect the SIP proxy to know direction/interfaces 
(even if expressed very abstractly) better than a middlebox? 
If so, I will certainly want to have it in the protocol. 
I am not sure otherwise.

-Jiri

--
Jiri Kuthan            http://iptel.org/~jiri