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- Path: sparky!uunet!ogicse!news.u.washington.edu!gray
- From: gray@cac.washington.edu (Terry Gray)
- Newsgroups: comp.dcom.cell-relay
- Subject: Re: Future of IP routers
- Message-ID: <1992Aug30.021454.29795@u.washington.edu>
- Date: 30 Aug 92 02:14:54 GMT
- Article-I.D.: u.1992Aug30.021454.29795
- References: <3445@ra.nrl.navy.mil> <1992Aug27.174448.28143@fokus.gmd.de> <1992Aug28.092320.17105@ccsun.strath.ac.uk>
- Sender: news@u.washington.edu (USENET News System)
- Organization: UW Networks and Distributed Computing
- Lines: 53
-
- In article <1992Aug28.092320.17105@ccsun.strath.ac.uk> craa85@ccsun.strath.ac.uk ( D.W.Stevenson) writes:
- >
- >In the future, it should be possible to open a data
- >connection from my workstation to another workstation
- >in another country directly over the ATM network,
- >without going near an IP (or OSI equivalent) router and
- >hence will the IP routing layer (or it's OSI equivalent)
- >really be necessary?
- >
- >To achieve interoperability
- >with other non ATM workstations it certainly will be, but
- >functionally, I suspect not. Studying the ISO
- >IP protocol I see "When the source and destination stations
- >are connected to the same network, an
- >internet protocol is not needed. In that case, the internet layer
- >is null and the (internet) header consists
- >of the single protocol identifier of 8 bits."
- >(taken from "Handbook of Computer Communications Standards"
- >Vol 1 by Stallings). Surely once I can open an ATM connection
- >from my workstation to your workstation,
- >passing across the world, through the global ATM network of switches,
- >we then become connected to the same network
- >and so no internet layer is needed and IP routers or equivalent
- >will no longer be required for data transfer over the ATM network.
- >
- >The original subject of this posting was whether IP routers would be
- >required in the future, or did I miss the point of the original posting?
-
- Dave,
- I think you may be forgetting the issue of layer 3 fault isolation.
- One of the key reasons we use IP routers is to provide firewalls for
- an important class of faults which do not stop at bridges or repeaters.
- I believe --somebody correct me if this is incorrect-- that the same
- issues will apply to ATM switches living in an IP environment. For example,
- if an ARP packet (or any other broadcast packet) appears at one port
- of an ATM switch, does it not appear on all other ports of the switch,
- assuming the appropriate AAL for handling the IP world?
-
- If so, you have a terrific opportunity for one department's broadcast
- storm to become *everyone's* broadcast storm.
-
- I too am just learning about ATM, so I hope to elicit expert comment on
- the above, but it sure seems to me that IP routers will continue to be
- essential ingredients for a campus network, if you place a premium on
- high availability. Unfortunately, the ATM router interfaces are likely
- to be *very* spendy...
-
-
-
- --
- Terry Gray
- University of Washington
- gray@cac.washington.edu
-