Maybe I misunderstood where the RII resides, but in some
whitepapers/websites they say that the RII is the first bit of the Source
Address (I believe it's the source MAC in this case)? So if this bit is set
to one, then the MAC address has been changed and the destination will see
it as a different MAC address... I am understanding this wrong?
Thanks.
-----Original Message-----
From: Omar Baceski [mailto:[EMAIL PROTECTED]]
Sent: Monday, September 18, 2000 12:55 PM
To: Scoles, Damian
Subject: RE: Source Route Bridging
TB is okay (it's the same as an ethernet switch)
SRB is wrong. if the RII is set to 0, we have a frame for the local ring, so
the bridge does nothing with the frame.
in the other cases, the mac addresses are never changed. the bridges work
only with the rif.
the translational stuff is okay, it is the only case in wich the router
must change the macaddress format between canonical and noncanonical formats
to translate from token to ether or viceversa
RSRB is okay
if we talk about DLSW, well, it is very similar to RSRB in the way the
bridge manages traffic. I mean, the router must create a virtual ring and
the rif is terminated at the origin ring. again, the mac address is never
changed
> -----Mensaje original-----
> De: Scoles, Damian [SMTP:[EMAIL PROTECTED]]
> Enviado el: Monday, September 18, 2000 12:39 PM
> Para: Groupstudy (E-mail)
> Asunto: Source Route Bridging
>
> I just wanted to see if there was anyone who could clear a few things up
> for
> me about Source Route Bridging and its many variations.
>
> What I am mainly trying to clear up is MAC addresses that are transmitted
> to
> the destination over these networks. Here we go:
>
>
> Transparent Bridging [TB]
> MAC Address is NEVER changed from end to end. The destination sees
> the original source MAC address when the packet arrives.
>
> Source Route Bridging [SRB]
> If the RII is set to 0, then the destination sees the original
> source MAC address when the packet arrives.
> If, however, the RII is set to 1, then the first bit of the original
> source address is modified and the destination sees this modified
> version of the original source's MAC address.
> Example.
> Original MAC Address (HEX) 00-50-DA-84-4B-E1
> (Binary) 0000
> 0000........
> Modified MAC Address (HEX) 80-50-DA-84-4B-E1
> (Binary) 1000
> 0000........
>
> Source Route Transparent Bridging [SRT]
> Ethernet hosts/Non Source Route Capable Hosts
> MAC is NEVER modified. Destination sees the original source
> MAC Address.
> Token Ring/Source Route Bridge hosts
> Same as the SRB example about with RII 0 or 1.
>
> Source Route Translational Bridging [SR/TLB]
> Token Ring to Token Ring (Source Route Capable)
> Same as the SRB example about with RII 0 or 1.
> Ethernet to Ethernet
> MAC is NEVER modified. Destination sees the original source
> MAC Address.
> Token Ring to Ethernet OR Ethernet to Token Ring
> MAC Address is converted to the correct version for each
> side:
> Example
> Token Ring MAC (Hex) 0 0
> 5 0 D A 8 4 4 B E 1
> Token Ring MAC (Binary) 0000 0000 - 0101
> 0000 - 1101 1010 - 1000 0100 - 0100 1011 - 1110 0001
>
> Ethernet MAC (Hex) 0 0
> 0 A 5 B 2 1 D 2 8 7
> Ethernet MAC (Binary) 0000 0000 - 0000
> 1010 - 0101 1011 - 0010 0001 - 1101 0010 - 1000 0111
>
> Remote Source Route Bridging [RSRB]
> Same as SRB with the RII set to 0 or 1 issue.
>
> Data Link Switching + [DLSw+]
> This is where I have the most confusion. If the RIF is regenerated
> at each step, I am not sure if the source and destination in the packets
> are
> modified. If the MAC's are modified then the MAC at the destination is
> for
> the last interface of the last router that touched the packet. If these
> devices act like normal bridges, the only thing you would have to worry
> about is the RII bit as with SRB.
>
>
>
> That's it, I hope this was clear and someone can straighten up anything I
> might have screwed up. Thanks!
>
>
>
>
>
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