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Need Some Help? Problem w/Fiber Uplinks.

Need Some Help? Problem w/Fiber Uplinks.

Need Some Help? Problem w/Fiber Uplinks.

I need some help and I am hoping someone can help. I have some older switches uplinked via fiber. They have older SX modules uplinked w/multi-mode with SC connectors. They work fine when they are uplinked to each other. However, I need to replace one of the switches with a newer switch which only has a newer SFP module with LC connector. So I bought the SFP connectors and I also bought a SC to LC adapter. So on the one switch I still have the older SX connected connected to the switch with the SC connector and then on the other end of the fiber I have SC connectors plugged into the SC to LC adapter which is connected to the new SFX SX adapter on the new switch. The problem is that I cannot get an uplink and I am not sure why. I did a direct patch between two new SFP ports on the new switch with a multi-mode cable w/SC connectors just to ensure that the adapters and the new SFPs worked and I can get an uplink fine. I just cannot get an uplink between the old and new switch.

The old switch is an old Avaya switch using an X330S2 (SX) module connected w/multi-mode to another Avaya switch - works.

The old switch, old Avaya switch using an X330S2 (SX) module, trying to connect w/multi-mode to new switch with a SMC SFP 550mm LC SFP adapter using a LC-M to SC-F adapter - does not work?

Any ideas? I am at a loss. To me, it seems if I can get an ST to ST to work on the old switches, I should be able to get this to work. I know the adapters work.

What the hang am I missing?


RE: Need Some Help? Problem w/Fiber Uplinks.

They must be the same speed. You can't usually link a gig GBIC to a 100meg GBIC. Also, you must cross transmit and receive. My transmit goes to your receive. And they must both be multimode or both single mode. Can't mix and match.

RE: Need Some Help? Problem w/Fiber Uplinks.

I try reversing the connections to ensure that I wasn't mixing up the cross and receive - neither combo worked. I am pretty sure the older Avaya modules were gig as well, but I will confirm that. Thanks. I really appreciate the response.

RE: Need Some Help? Problem w/Fiber Uplinks.

The Avaya X330S1 Expansion sub-module provides one 1000Base-SX port, the Avaya X330S2 Expansion sub-module provides two 1000Base-Sx ports.

RE: Need Some Help? Problem w/Fiber Uplinks.

The new switch may need some configuration. Assign speed for the GBIC port, etc. Loop new switch to itself and see if you get link light.

RE: Need Some Help? Problem w/Fiber Uplinks.

I did loop the new switch to itself and get an uplink - that rules out my SFPs or the adapter. However, I did not try forcing the port to Gig on the new switch - I had it just set to auto. I will have to give that a try. Is there any chance that my older SX modules just will not work with a newer SX module? They are both SX and should be compatible right? Thanks.

RE: Need Some Help? Problem w/Fiber Uplinks.

The forced uplink was the trick! Thanks.

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