Posted on August 9, 2018 4:04 am
 |  Asked by Bryan Holloway
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We ran into an interesting problem today. While migrating from a Cisco L3 switch to an Arista 7050, we installed three BiDi transceivers. While link would come up, we never see any MAC addresses on the interface. However, if we plug the same transceivers into the Cisco, the MAC address table populates and everything works fine. Is there perhaps a known issue with Arista switches and BiDi transceivers? We are mocking this up in the lab before opening a TAC case, but I thought I’d ask the forum if anyone has seen this before or had any prior experience with this setup. Thank you … – bryan

Posted by Harsha Kalsi
Answered on August 9, 2018 5:04 am

Hi Bryan,
Considering you are using a 40GBASE-SRBD transceiver. There is no extra config required to make this work, just make sure that the port is speed forced to 40G as this particular transceiver only operates at 40G speed. You can check the interface supported speed using “show interfaces capabilities”.
For example,
Switch(config)#show int et50/1 capabilities
Model: DCS-7050SX-64
Speed/Duplex: 40G/full(default)
Flowcontrol: rx-(off,on),tx-(off,on)

Hi — thanks for the response … I should’ve been more clear. These are 1G transceivers. Under “sh int stat” they appear as “1000BASE-BX10-D”.

(Bryan Holloway at August 9, 2018 7:22 pm)

More info:

#show int et10 capabilities
Model: DCS-7050SX-64
Type: 1000BASE-BX10-D
Speed/Duplex: 1G/full,auto(default)
Flowcontrol: rx-(off,on,desired),tx-(off,on,desired)

(Bryan Holloway at August 9, 2018 7:24 pm)
Posted by Harsha Kalsi
Answered on August 9, 2018 5:36 am

For mac learning issue, I would suggest contacting Arista support as there are several parameters (EOS, Transiceiver model, logs) to consider before we could conclude the problem seen.

Understood — that makes sense. We are going to attempt to reproduce the problem in the lab before pursuing this further. Thank you for the response(s)!

(Bryan Holloway at August 9, 2018 7:23 pm)
Posted by Teobaldo Leal
Answered on August 19, 2018 5:19 am

We perform a Brocade L3 migration to a 7280 Arista Router, some 1GE links in Arista didnt work as your case, we force speed in the other side of the link (in the switches that receive the link), some worked other didnt because cli on those switches doesnt support 1GE speed forced. For BIDI SFP, we use media converter (UTP to SFP) and we resolved the problem, please share solution in TAC, we didnt opened a case

Posted by Joanna Deng
Answered on August 20, 2018 10:47 am

Hi Bryan,
The Arista 7050 supports 10G/40G, but your BIDI transceiver is 1G. It can’t be supported. Maybe you can try to use 10G/40G BIDI transceiver to check it.

Posted by Nehemiah Hernandez
Answered on December 3, 2018 6:31 pm

We’re using 10G bidi optics without issue on 7280s. Haven’t tested with 1G however.

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