re: single attach doc
Fazil Osman <xlnt!jake!fazil@ucsd.edu> Mon, 04 March 1991 22:05 UTC
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Date: Mon, 04 Mar 1991 13:16:58 -0800
From: Fazil Osman <xlnt!jake!fazil@ucsd.edu>
Message-Id: <9103042116.AA09971@jake.>
To: fddi@merit.edu
Subject: re: single attach doc
Status: O
I have read Richard Fox's document "Definition of a Proxy IP Bridge for an FDDI Network". I have a lot of concern about this document. Here are some initial ones: 1. The FDDI commitee has not really resolved how dual MAC stations communicate with each other. As an example, FDDI Station Management (SMT) uses frames to inform other nodes of their neighbor, etc. In a network where some stations have their MAC attached to one ring and other stations have their MACs attached to the second ring, SMT cannot communicate this information between the two rings. The spirit of the commitee was that they would not preclude using the second ring for data transmission, and when any user decides to do that, they would configure their ring in a sensible manner. Such comments as "mandating that all single attached stations must be put on the primary ring only, isn't enough to solve the IP integrity problem, since a twisted ring may end up with single attached stations on both rings " ignore the fact that the FDDI commitee accepted the fact that A-A and B-B connections would occur because of miswiring and that these would be corrected ASAP. Adding more protocols is not the solution. Better configuration control is. 2. This proposal requires that anyone building a FDDI to FDDI bridge has to have the ability to look inside an FDDI frame at the EARP field, in order to determine whether it is forwarding a frame. An FDDI to FDDI bridge has to be able to filter 400,000 packets/sec. on each port. Adding this extra complexity will kill its performance. Is the problem being solved in the right place? Will a FDDI to FDDI bridge also have to solve the same problem for DECNET and ISO, etc. ? Once again, solve the problem in the right place, i.e. at the FDDI commitee. Either control the configurations or have the commitee come up with solutions that will work for ALL protocols. 3. I do not understand the first paragraph on page 7 "Providing ..". What are those advantages that are being compromised? I do not understand the comment about EARP frames being forwarded during learning. Is this a problem with EARP ( a protocol that is being proposed to solve the same problem as this Proxy IP bridging) or is the problem with IP? During wrap, users expect a perturbations but these will be limited to fractions of a second. Our concern is that this proposal is something that will affect ALL FDDI implementors in order to solve the requirements of a small set of users. There is no question that their requirements should be addressed. But before we invent new protocols, we should explore the things that should be done differently on that small set of machines to interoperate with the standard implementations. fazil osman xdi 15010 avenue of science, suite 100 san diego, ca 92128 fazil@xlnt.com
- single attach doc Richard Fox
- single attach doc Richard Fox
- re: single attach doc Fazil Osman
- re: single attach doc Fazil Osman