Is a 3845 G0/0 slot in SFP mode for HIMI only?

[j.england]

This was brought up in a meeting when we were debating on how to terminate an optical WAN handoff.  I guess I just assumed that the G0/0 slot in the 3845 would act as any other gig port with an SFP, but someone stated they thought it might be for HIMI only.  I haven't found any documentation to say one way or another, so I thought I'd throw it out to the community:  Is the G0/0 slot in SFP mode for HIMI only? 

By the by, we have no etherswitch modules in this router.

Thanks!

Justin

[Leo Laohoo]

If memory serves me correct the 3845 has ONE (1) dual-personality port:  It can be RJ-45 or SFP.  By default it's set to RJ-45 and if you want to use SFP then you have to go into the interface-level and enter the command "media SFP".

[j.england]

You are correct, sir.  There is only the single dual-personality port and one other gig interface.  There is a concern that when in SFP mode, G0/0 can only be used for HIMI, and not for connecting whatever optical device for whichever purpose we please.  I'm fairly certain that in SFP mode it will function just the same as any gigabit optical interface.  Any thoughts on that? 

And thanks for the reply!

[Leo Laohoo]

Excuse my ignorance but what is "HIMI"?

The Dual-Personality port is a Layer 3 port.  The only difference between the RJ-45 and the SFP port is just that.  You can connect your router using the SFP port, configure it as a Layer 3 and connect it to another SFP port. 

[j.england]

From http://www.cisco.com/en/US/docs/ios/12_4/12_4_mainline/srdescn1.html

The HIMI feature provides the capability to establish a connection between two enhanced network modules (NME) or between the onboard small-form-factor pluggable (SFP) Gigabit Ethernet module and an NME on the Cisco 3825 and Cisco 3845 routers. Currently, Cisco EtherSwitch service modules are the only NMEs that support HIMI.

Ah yeah that's what I figured.  Just wanted to confirm since the seed of doubt was planted.  Thanks!

[Leo Laohoo · Accepted solution]

The reason why I asked because when I was using the 3845 router I connected this router to another using SFP because we had a dark fibre.

The HIMI, if I understand the Cisco document, will allow a switch blade module an uplink using this port.

The Gi0/0 SFP port is not a HIMI-only port (that'll be silly).  It can be used any which way you want PLUS act as a HIMI port.

[j.england]

Perfect, that's exactly what I thought.  Just wanted to confirm.  I appreciate it!

[Leo Laohoo]

Thanks for the rating.