Connect electrical gigabits ports with optical ports

[lfelipeph132]

Hello,

I have a question regarding optical and electrical ports.  Is it possible to connect them together in two Cisco 7200 or CIsco 7600? Do they need any special configuration?

Thank you very much in advance.

Kind regards

[pwwiddicombe · Accepted solution]

How do you mean "connect them together"?  Are you referring to bundling (i.e. to get twice the throughput by having 2 links), or simply connecting them?

Assuming it's connecting them, then you can't do it directly.  You need to have the correct media and speeds to do it.  Typically with fiber you have an SFP (or GBIC) to plug in and adapt to multimode or single mode fiber.  If the other end of the link is copper, then you need a copper SFP or GBIC.

If it's 2 copper ports, you probably need a Gigabit crossover cable between the 2.  Fiber cables are normally manufactured as crossover cables, so you can easily connect them - but make sure you are consistent - all single mode or all multimode components.  Don't use SX (multimode) adapters with single mode fiber cables.

[lfelipeph132]

Thanks for your answer pwwiddicombe. Yes, I meant connecting them, not bundling them.

So, if both ends are 1Gigabit port (one electrical and the other one optical) and using an adapter in the optical port, then it would be possible no? Is it necessary to put any special configuration to make them work (like autonegotiation or something else)?

Regards

[pwwiddicombe]

By electrical, I assume you mean the standard 8-Pin Gigabit copper RJ45 port.  It is possible your electrical interface is really an SFP slot with nothing plugged into it?  The SFP slot looks similar on the outside, but is about 2" deep to allow for the size of the SFP.

The optical one - is it directly ON the expansion card, or is it an optical interface (i.e. an SFP) plugged into the expansion slot (or a slot in the router)?  If it's a plug-in SFP, you could remove it and get the RJ45 equivalent, in which case you could use copper, if that's all your other side supports.

SOME cisco platforms have a dual-capability (i.e. port Gi 0/0 refers to both an RJ45 and an SFP port side by side), and on these you can only use one at a time, and may have to specify "media-type RJ45" on these. 

If you're really unlucky or on a tight budget, it could be cheaper to get an external media converter; but it needs power and you then have another source of failure - but it can be done.  They can be finicky to get duplex right; and restart properly after a power outage.  Getting internal modules tends to be much more reliable (i.e. proper SFP's or router interfaces).

[Leo Laohoo]

Bundling together, like Etherchannel?  The answer is yes, however, there are prerequisite requirements to Etherchannel (read this: Understanding EtherChannels).

Due to stability reason, it's better to use either all optical or all copper point-to-point links.  Having an optical link on one side and a media converter on the other side "may" work but there are more "points of failure".