Thanks Ken,

>>> SNIP2

The first SRB enabled bridge in the path (from
originator to 
destination)
will see that this is an explorer packet and add its
route designator 
(RD)
information to the RIF.

>>> END SNIP2

Can I therefore conclude that in a 'Source Route
Transparent' Bridge the RIF field will indeed change ?
Contrary to the whitepaper.

Phil.
 
 --- "Sexton, Ken"  wrote: >
Phil,
> The first bit within the Source Address Field is
> normally the I/G bit, to
> define if the source address is individual (unicast)
> or group (multicast)
> address. In an SRB bridged environment, this one bit
> is used to indicate if
> any Routing Information Field  (RIF) information is
> present in the Token
> frame following the SA field.
> 
> This bit will be set by hosts with the SRB
> environment and used by bridges
> to indicate the above. The hosts will keep a
> "forwarding table" on how to
> reach any required destination host.
> 
> If the host doesn't know how to get to a particular
> destination, it will
> send out an explorer frame (all routes explorer
> -ARE) or a Spanning tree
> explorer (SPE) frame to locate the destination. It
> will depending on your
> bridged environment which explorer frame is used.
> 
> The first SRB enabled bridge in the path (from
> originator to destination)
> will see that this is an explorer packet and add its
> route designator (RD)
> information to the RIF. The first bridge will add
> the first ring number,
> it's bridge number, and the ring number of the
> interface it going to send
> the explorer packet out of. 
> 
> When all said and done - the host will know how to
> reach that particular end
> host and include RIF information in the token frame.
> The RII, will tell the
> bridge that a RIF is present and forward the frame
> according to the RIF RC
> and RD fields.
> 
> Ken Sexton
> Data Network Engineering 
> ICG Communications
> [EMAIL PROTECTED]
> 
> 
> 
> 
> -----Original Message-----
> From: Phil Barker
> [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, March 06, 2002 6:35 AM
> To: [EMAIL PROTECTED]
> Subject: certificationZone Bridging White paper !
> [7:37393]
> 
> 
> 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
> !!! 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
> 
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