Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!aramis.rutgers.edu!athos.rutgers.edu!hedrick From: hedrick@athos.rutgers.edu (Charles Hedrick) Newsgroups: comp.dcom.lans Subject: Re: What about "brouters"? Message-ID: Date: 6 Oct 88 22:49:43 GMT References: <281@fed.FRB.GOV> <25255@bu-cs.BU.EDU> Organization: Rutgers Univ., New Brunswick, N.J. Lines: 71 >Dr. Hedrick, what is your opinion? Just so we're clear on what is and isn't implemented where with the cisco Hybridge: - the MCI card actually has 4 interfaces, not 2. Up to 2 Ethernets and 2 serial lines (each of which will go to at least T1, and I think I heard 4Mbit/sec mentioned). There will also be a version later that has 4 serial lines only. - much of the work of packet forwarding for both bridge and router is done in the MCI card. However in the current incarnation there is some processing done on the 68020 for packets that are routed. (Note the distinction between protocols that the Hybridge handles as a router and those that it handles as a bridge.) How much can be done by the MCI for protocols that are routed depends upon the protocol and the route. In the release of the software that I've seen, the very high-speed router performance happens only for IP, and only when going between interfaces on the same MCI card. However long term plans are to add fast-switch support for other protocols and for switching between interfaces on different MCI cards. I'm not the right one to announce future cisco products, but we expect to see DECnet and inter-MCI fast switching very soon. Testing the performance of such a thing is harder than it sounds. How many of you have things that can generate or monitor 12Kpps? We actually do (we have the same equipment cisco uses: a pair of HP Lanalyzers), but I'm more interested in trying something with real traffic. I've made some preliminary attempts, but don't have anything to report yet. I agree that this approach helps defuse the router/bridge controversy. It may not completely end it, though. - the technology for high performance bridges and routers is essentially identical. That's why the Hybridge is possible. However if you don't need 12Kpps (and practically speaking, you probably don't), you may still find less expensive bridges and routers whose technology isn't the same. - Administrators still have to decide how to configure them. This should be done on network architectural grounds, just as the decision always was done. Of course it's now easier to change your mind, and mixed strategies are available that weren't before. I didn't mention the Hybridge in my reply to the guy at the FRB for two reasons: - Although my preference for routers over bridges is well known, my guess was that simply replacing his bridges with routers, brouters, or anything else, would probably not help him with his traffic problem, unless he's having problems with excessive broadcasts. It might be better for general architectural reasons, of course. - If I were doing a network for a Federal Reserve Bank, I probably would wait until these products had been out for a few months before buying one. Personally, I'm trying to get up enough money to get a bunch of MCI cards for Rutgers. But then if my gateway hangs because of some crazy thing our network does that cisco has never seen before, I don't have half the banks in the U.S. go bankrupt. This is not specific advice based on experience with the MCI (my policy is not to comment on the reliability of beta test systems), but on general experience in the industry.