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New Member

Different TrCRF numbers, but same ring number...possible?

I don't have a lab to try this, but is the following possible? 3 token ring switches are connected via ISL. The scenario would be to use 1 ring number for ease. In an undistributed TrCRF setup, ports belonging to a TrCRF can only be on the same physical switch. DRiP does not allow the TrCRF port assignments to go to another physical switch to protect the network from loops.

If switch A has TrCRF #40 with a defined ring number #5, can one create on switch B a TrCRF #41 with the same defined ring number #5 and switch C a TrCRF #42 also ring #5? I assume each TrCRF will be assigned a different TrBRF with different bridge numbers. I see this as possible since I believe DRiP looks at the TrCRF/VLAN number, not ring number.

Would a separate physical bridge be required to join all 3 TrBRFs somehow to create this 1 big token ring #5?

New Member

Re: Different TrCRF numbers, but same ring number...possible?


Can you describe what you are trying to accomplish? Do you want all 3 ISL connected switches to be connected to the same physical ring? If so, then your description of the problem and answer are correct. You will need to create 3 different BRF's (one for each switch) and create a CRF under each using the same ring number. The BRF's will need different bridge ID's to make the path unique. You will also need a Router/Bridge (external, RSM, etc) to connect the BRF's together. You will not be able to use the same BRF since you can not have multiple crf's under the same BRF with the same ring number.

If you would like to talk about the design in a little more detail, please email me at



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