ISR 4321 Physical Interfaces

[ZK916]

Hello,

We have an ISR4321 router and currently using the two onboard RJ-45 Copper ports. There is an SFP port that's currently not being used. We need to use third third SFP port; however, the specs in the datasheet(see below and scroll down to ISR4321) show that this SFP port having the same physical port ID as the G0/0/0 copper port. I am unclear as to why this SFP having the same port ID. 

I am hoping someone could shed some light into this mystery for me! 

https://www.cisco.com/c/en/us/td/docs/routers/access/4400/hardware/installation/guide4400-4300/C4400_isr/Overview.html#99991

Thanks in advance. 

• best, |zK

[M02@rt37]

@ZK916 

It is called "combo" port.

You choose to use G0/0/0/0 as RJ45 port or SFP port.

[ZK916]

So, it is either or. Meaning, if the copper port is used then the SFP port can't be used and vice versa. Correct? 

[M02@rt37]

Yes that's it @ZK916 

[ZK916]

Thank you, M02@rt37 

I was just curious if there were any Cisco document that explains that and specifically a document related to the ISR 4000 platforms.

Much appreciated. 

[Joseph W. Doherty]

Good question about documentation.

Possibly might be documented in the hardware documentation for the device.  Have you looked there?

I will note, dual ports being just one port have been in use for decades, including on non-Cisco devices.  I recall possibly my first encounter with such might have been two copper Ethernet ports, side-by-side, on a small dumb L2 switch, one wired as MDI the other as MDI-X.  (Are you some what new to networking?  Reason I ask, unfortunately, it's not uncommon documentation might be "skimpy" on things "everyone" [in a particular industry] "knows".)

[M02@rt37 · Accepted solution]

@ZK916 

ISR 4000 datasheet 

https://www.cisco.com/c/en/us/products/collateral/routers/4000-series-integrated-services-routers-isr/data_sheet-c78-732542.html

And this document: https://content.cisco.com/chapter.sjs?uri=/searchable/chapter/www.cisco.com/content/en/us/td/docs/routers/access/4400/hardware/installation/guide4400-4300/C4400_isr/Overview.html.xml

[ZK916]

Thank you so much!