Ken, What I was getting at was that the SRB part of the SRT bridge is still acting as a SRB bridge for those nodes on that side of the network. Therefore when end hosts on that network try to find a route through this bridge to other end hosts on the SRB side of the network the RIF field will be manipulated (for spanning and explorer packets). So to make the sweeping statement that RIF fields will never change on SRT bridges is very misleading to the newbie, (me in this instance).
I conclude that it is safe to say that RIF will never be manipulated on 'Transparent only' Bridges since they don't exist. Thx for the replies, Ken. Phil. --- "Sexton, Ken" wrote: > Phil, > > Can I therefore conclude that in a 'Source Route > Transparent' Bridge the RIF field will indeed change > ? > Contrary to the whitepaper. > > On the above - In SRT mode, you are allowing the > router to source route > traffic and transparently bridge traffic on the same > device (router), but > any hosts on either bridging environment can not > communicate amongst > themselves. (i.e. a host on an SRB network cannot > sent traffic destined for > a host on the transparent side of the network). The > SRT Bridge will never > add or remove RIF information from a frame in order > for the two technologies > to communicate. This is where Source-route > Translation bridging (SR/TLB) > comes in. > > Now your above question needs some consideration. > The router will now act as > a "RIF end station", where a RIF table will be built > for end stations on the > SRB side, and a forwarding table for the transparent > side. By creating a > virtual ring within the router, all the token to > ethernet frame conversion > will take place (i.e MTU, bit ordering, etc) before > the frame is sent on its > way. It makes no sense to set the RII bit to a "1" > when sending the traffic > to a transparent end host, as it will not understand > what to do with it > anyway. > > Hope this helps > > Ken Sexton > Data Network Engineering > ICG Communications > [EMAIL PROTECTED] > > > > > -----Original Message----- > From: Phil Barker > [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, March 06, 2002 9:02 AM > To: [EMAIL PROTECTED] > Subject: RE: certificationZone Bridging White paper > ! [7:37393] > > > 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 > > > > __________________________________________________ > > 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 > [EMAIL PROTECTED] > > __________________________________________________ > 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 > > > > === message truncated === __________________________________________________ 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 Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=37567&t=37393 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
