[12517] in North American Network Operators' Group
Re: Routing without source information and Traffic self-similari
daemon@ATHENA.MIT.EDU (DAVE NORDLUND)
Thu Sep 18 19:35:45 1997
Date: Thu, 18 Sep 1997 18:17:57 CST-600
From: DAVE NORDLUND <nordlund@ccstaff.cc.ukans.edu>
In-reply-to: <199709182103.RAA04706@jacana.lcs.mit.edu>
To: nanog@merit.edu, nbreslow@mit.edu
Reply-to: d-nordlund@ukans.edu
> Date: Thu, 18 Sep 1997 17:03:26 -0400
> From: Nathan Boyd <boydn@jacana.lcs.mit.edu>
> Subject: Re: Routing without source information and Traffic self-similarity
> To: falcon@labyrinth.org
> Cc: nanog@merit.edu, nbreslow@mit.edu
>
> > Okay... I'll bite...
>
> Thanks! ;>
>
> > Maybe I am just naive but if the IP header did not contain a source
> > address, how would TCP acknowledgement, windowing, or re-transmission take
> > place?
> >
> > How would a request for data be serviced? Would responses always be in
> > the form of a all-nets/all-hosts broadcast? How else would the response
> > get back to the originating host?
>
> The point is that the source address is not explicitly *required* in the
> *header*. Thus, a source and destination could "setup" an IP session by
> negotiating a "session ID" or something - the first packet from source to
> destination would include the source's address in the *payload* along with
> information to start the negotiation process. I am describing, in other words,
> something like an ATM transport layer that would live below IP.
SLIP and PPP header compression do this now. All the "fixed" data is left
out and replaced by the receiving station by the information in the table
created by the first packet or two. This, however only works on a path
that does NOT require routing.
>
> > [snip]
> >
> > Routing Protocols.... we need source addressing so we know, at the IP
> > layer, who our sources of information are, and then, who can we accept
> > information from and who we should refuse information from. In addition,
> > access-lists, route-filters, and other types of security would be
> > non-functional without source addresses.
>
> Now you're addressing (so to speak ;) the kind of issues that I am concerned
> with: without mandating source information in the header, how can the
> destination make decisions about rejecting/accepting traffic? alternatively,
> how can middle agents (e.g., routers) do filtering, etc.? how can we
> possibly prevent spoofing?
>
> > Lastly, how would you accomplish a traceroute on a network with no source
> > addressing? Where would the ICMP ttl expired messages be directed if
> > there was no source address in the packet?
>
> I don't know! You tell me! Do we make each intermediate router "aware" of
> the negotiated session ID? Doesn't sound tractable to me.
>
> I hope this clarifies this - I don't think it is so strivial as my initial
> email led you to believe.
>
> Cheers,
>
> Nate
>
>
>
Dave Nordlund d-nordlund@ukans.edu
University of Kansas 913/864-0450
Computing Services FAX 913/864-0485
Lawrence, KS 66045 KANREN
