In the instance where the RII indicator is a 1 the >frame will be 'source routed' if the frame is 'source >routed' then surely this implies that the RIF must be >manipulated in order to reflect the true Source Route
To comment of the above, the RII bit doesn't indicate whether the frame is a specific routed frame or whether it is a explorer frame. It only indicates whether the frame contains RIF information or not. The specifically routed frame indicator is within the RIF (first three bits of the RC field, known as the "type" or "broadcast" bits - 0xx = specifically routed frame, 10x = ARE frame, 11x = SPE frame). Maybe its the way its worded that may be the cause of confusion; I've never read it to verify. Ken Sexton Data Network Engineering ICG Communications [EMAIL PROTECTED] -----Original Message----- From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]] Sent: Wednesday, March 06, 2002 1:04 PM To: [EMAIL PROTECTED] Subject: Re: certificationZone Bridging White paper ! [7:37393] At 08:34 AM 3/6/02, Phil Barker wrote: >Just been re-reading this paper by David Wolfsener. >See SNIP below. > >In the instance where the RII indicator is a 1 the >frame will be 'source routed' if the frame is 'source >routed' then surely this implies that the RIF must be >manipulated in order to reflect the true Source Route The RIF is just referenced (not changed) in frames that are specifically routed. In other words, once the end station has found a route, it just puts it in the frame and the bridges just read it forwards or backwards and route accordingly. Could that be what he's getting at?? On the other hand, I agree with you that on an explorer, an SRT bridge changes the RIF. SRT simply implies a couple things: 1) If the RII is zero, just perform normal Ethernet-style transparent bridging 2) If the RII is one and redundant bridges exits, use the spanning tree to determine which way to forward explorer frames. By the way, SRT is the only form of source route bridging that the IEEE ever standardized. And you can get it for free! ;-) It's in Annex C of IEEE 802.1D, which you can get here: http://standards.ieee.org/getieee802/ Have fun with it! Priscilla >!!! I havn't got my 'Interconnections' with me so I >cannot confirm. > >Any ideas ? > >Phil. > > >>> SNIP > >Source Route Transparent Bridging (SRT) > >SRT works by analyzing the RII bit to determine if a >RIF is present. If the RII bit is 0, then a RIF is not >present and the frame is transparently bridged. If, >however, the RII bit is 1 and a RIF is present, then >the frame is source routed. Note that SRT bridges do >not add or remove RIFs to frames. By now, you ought to >wonder how to configure SRT. > > >>> END > >__________________________________________________ >Do You Yahoo!? >Everything you'll ever need on one web page >from News and Sport to Email and Music Charts >http://uk.my.yahoo.com ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=37476&t=37393 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
