Comments to latest draft version 7 of the Frame Relay DTE MIB
Alan Bartky <alan@xylan.com> Thu, 04 April 1996 21:30 UTC
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Date: Thu, 04 Apr 1996 12:21:10 -0800
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From: Alan Bartky <alan@xylan.com>
Message-Id: <9604042021.AA07448@irvine.xylan.com>
To: iplpdn@CNRI.Reston.VA.US
Subject: Comments to latest draft version 7 of the Frame Relay DTE MIB
Fellow Frame Relay Mibbers and Mibbettes - This email is to comment on the latest draft to further the effort in bringing the MIB work to closure. I have some minor editorial comments, and comments on the latest proposal from James at Newbridge on the ifIndex issue I raised previously. As far as the ifIndex issues, it is my humble opinion that the current MIB text and objects are fine and that the discussions on protocol multiplexing and ifIndex can be worked on in the future (if need be) and need not and should not affect releasing the current draft MIB as an RFC. ******************* Editorial comments: ******************* 1) I think it would be a good idea to add a reference to RFC 1604 (Frame Relay DCE MIB) since it has if nothing else good descriptions on a lot of the Frame Relay functions, variables, and protocol issues and how they are handled. 2) The second paragraph of section 4.1 is the first time the evolution MIB is mentioned. It needs a reference [xx] added: With the extention of the interfaces MIB, it is possible to configure frame relay DLCs as individual interfaces and create ifTable entries for each. This is not recommended and is not directly supported by this MIB. Additionally, in the presence of demand circuits creation of individual ifEntries for each is not possible. 3) The text for section 4.1 is kind of a mixture between an operation model (as the title says) and how Frame Relay relates to and gives guidelines for operation of/with RFC 1573. At minimum you might want to have at least an introductory sentence or two before the ifTable implementations guidlines table. 4) There are some places in the document that do not conform to 80 column spacing and cause printing errors such as line wrapping (or difficult reading on some text editors) to occur, or have other "formatting" errors The examples I found are: ifHCInOctets Only required when ifSpeed >= 155 Mbits/s. See details for ifInOctets. ifHCOutOctets Only required when ifSpeed >= 155 Mbits/s. See details for ifInOctets. frErrType OBJECT-TYPE SYNTAX INTEGER { unknownError(1), receiveShort(2), receiveLong(3), illegalAddress(4), unknownAddress(5), dlcmiProtoErr(6), dlcmiUnknownIE(7), dlcmiSequenceErr(8), dlcmiUnknownRpt(9), noErrorSinceReset(10) } MAX-ACCESS read-only STATUS current DESCRIPTION "The type of error that was last seen on this interface: receiveShort: frame was not long enough to allow demultiplexing - the address field was incomplete, or for virtual circuits using Multiprotocol over Frame Relay, the protocol identifier was missing or incomplete. receiveLong: frame exceeded maximum length configured for this interface. illegalAddress: address field did not match configured format. unknownAddress: frame received on a virtual circuit which was not active or administratively disabled. dlcmiProtoErr: unspecified error occurred when attempting to interpret link maintenance frame. dlcmiUnknownIE: link maintenance frame contained an Information Element type which is not valid for the configured link maintenance protocol. dlcmiSequenceErr: link maintenance frame contained a sequence number Brown & Baker [Page 27] Draft Frame Relay DTE MIB April 1995 number other than the expected value. dlcmiUnknownRpt: link maintenance frame contained a Report Type Information Element whose value was not valid for the configured link maintenance protocol. noErrorSinceReset: no errors have been detected since the last cold start or warm start." ::= { frErrEntry 2 } ************************* Comments on James' text: ************************* > It seems to me that the only reasonable way to solve this is by layering. > Frankly, I think that anyone who configures their box as he describes is > worthy of their fate; they're better off with a completely point to point > configuration in the case. But *if* they want to do this, the way to do it > is by using the RFC 1573 stack table. > I have seen this case when I was working at Sync Research. There are cases where a customer has a large star network with Frame Relay T1 running to multiple remote sites with different network protocols at the different sites (i.e. complex networks with hundreds of PVCs). I agree that the correct solution for this involves use of the RFC 1573 stack table. > Install the IP, IPX, and Bridged interfaces on generic ifEntries, associate > other ifEntries with the DLCIs, and stack the first set on the second as > desired. > > > | | | | > | IPX | IP | Bridge | > +-----||-----+----||-----+---||------+ > > ifIndex.27 ifIndex.28 ifIndex.29 > > |\ /| / | > | \ / | / | > | \/ | / | Stack Table Entries > | /\ | / | ifStackEntry.27.10 etc. > | / \ | / | > |/ \|/ | > > ifIndex.10= ifIndex.11= ifIndex.12= > DLCI 40 DLCI 41 DLCI 42 I can see a couple of things that still need to be worked out with this model (although it appears to be heading in the right direction). Let's add RS-232 to the picture (it gets more complex if you are running Frame Relay over ISDN, so let's keep the example simple for now). | | | | | IPX | IP | Bridge | +-----||-----+----||-----+---||------+ ifIndex.27 ifIndex.28 ifIndex.29 |\ /| / | | \ / | / | | \/ | / | Stack Table Entries | /\ | / | ifStackEntry.27.10 etc. | / \ | / | |/ \|/ | ifIndex.10= ifIndex.11= ifIndex.12= DLCI 40 DLCI 41 DLCI 42 \ | / \ | / \ | / \ | / \ | / \|/ ifIndex.1= rs-232 The issues I see with this are: 1) There is no "generic" ifIndex type. There is other, proprietary or Frame Relay. In the above example, 27, 28 and 29 could I guess be proprietary multiplexing type or other (since this is not really proprietary, but a use of RFC1490, but there is no RFC1490 Multiprotocol MIB for this). 2) At some point we need an ifIndex for the Frame Relay Management. I guess again that one of them could be used and the others could use the Logical ifIndex in the circuit table. > > And we don't have to change the Frame Relay MIB to do that - nor do we have > to change the ATM MIB when they decide to do the same thing with ATM. > We (at Xylan) would obviously concur with figuring this out so that it also would work with ATM. > Can you imagine this with SVCs? yikes! > Or combined with ISDN B channels, bonding, multilink, Channelized T1, etc., etc., etc. The good news is this complexity keeps people like us employed ;-) !! Regards, Alan ********************************************************** Alan K. Bartky Email:alan@xylan.com Principal Software Engineer XYLAN Corporation Voice:(714) 597-8042 15707 ROCKFIELD BLVD STE 155F FAX: (714) 597-8342 IRVINE CA 92718-2830 **********************************************************