We have an existing 10 G p2p link between our Datacenter ( DC) and Corporate Office ( HQ )with a service provider, Lets call A

When A did our install they have used a Cienna box on HQ side , I guess it is a fiber type converter ( SM to MM fiber ), so we ended up using MM fiber with a 10G-SR transceiver to our 4500 swicth on HQ side .

On the DC side we still ended up using MM fiber with 10G-SR module .

This circuit was up and running with out issues.

Now we are swicthing to a different Service provide . lets say B.

B says that the hand off will be a SM type , and they are not providing with any Cienna box .

So should we have to use SM fiber with 10G-LR type transceiver to connect to our 4500 on HQ side and also SM fiber with 10G-R type connector on the DC side ?

Is there any way we could reuse the existing MM fiber and 10G-SR modules ??

I am trying to understand how the Service providers run a p2p connection in this case 10G-ELAN , when there are differnt segments involved . ( in this case .. they have multiple gateways between the circuit from HQ---- gateway1 -- gateway 2 -- DC) and what connector types and fiber types need to be used on each end of the segment .

Please help !!

2 Answers 2


You don't need to be concerned with how any ISP runs their network. All that matters to you is what they hand-off. ISP A gave you MM/10G-SR; ISP B is giving you SM/10G-LR. You will need new fiber drops and new interface modules.

While the existing MM fiber might carry the new signal, passing SM over MM is problematic at the best of times -- and only works over a few meters. The SR modules you have absolutely will not work. They operate at 850nm, while LR operates at 1310nm.


Since ISP A AND ISP B have different cable types, it's clear that you should choose the right fiber type and interface modules provided by ISP B, that is single-mode fiber with single-mode 10G SFP+ transceivers, say SFP-10G-LR.

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