Serial Carriers on Channel Group

[derwylie]

Hi,

I am running IOS Version 12.2(27)SBA4 on a 7206vxr. I have the following cards:

PA-MC-2E1-120 Channelized E1 (balanced) Port adapter, 2 ports

PA-4T+= Mx serial Port adapter, 4 ports

When I run 'show interfaces' for a physical interface configured on the latter, the output contains states for each carrier (DCD, DSR, DTR, RTS and CTS).

When I run 'show interfaces' for a channel group configured on the channelized card, the only carrier information displayed is "2 carrier transitions". There is no detail on DCD, DSR, DTR, RTS or CTS state.

I would like to understand why this is. Are carrier states relevant here? Is there another command I can use to get this information?

Thanks,

Derek.

[pkhatri]

Hi Derek,

The DCD, DSR, DTR, RTS and CTS are specific to serial interfaces, not E1 interfaces. That is why you don't see those for your E1 interfaces. There is no such command that will allow you to see it for an E1 interface because these parameters are not relevant to E1 interfaces.

Hope that helps,

Paresh

[pkhatri]

A bit more info, Derek.

The Cisco serial interfaces support a number of serial protocols (V.35, X.21, RS-232, RS-449, RS-530) depending on the cable used...

All of these have support for DCD, DSR, RTS, CTS and so on... Here's a link to the specific cabling for each:

http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a00801f5d8e.shtml

The E1 interface uses a G.703 electrical interface which does not support any of the above.

Hope that helps - pls rate the post if it does.

Paresh

[derwylie]

Hi Paresh,

thanks for your reply. This is useful information. However, I am still slightly confused. The show interfaces output for a channel group includes the line "2 carrier transitions" but does not detail which carriers. Can you explain?

Thanks,

Derek.

[ankurbhasin]

Hi Derek,

Carrier transitions appear in the output of the show interfaces serial exec command whenever there is an interruption in the carrier signal (such as an interface reset at the remote end of a link).

The following problems can result in this symptom:

•Line interruptions due to an external source (such as physical separation of cabling, red or yellow T1 alarms, or lightning striking somewhere along the network)

•Faulty switch, DSU, or router hardware

Check this link for more details

http://www.cisco.com/en/US/products/hw/routers/ps352/module_installation_and_configuration_guides_chapter09186a008040b5c6.html#wp1040730

HTH, if yes please rate the post.

Ankur