2800 Series Router and WIC-1T

[Daniel Smith]

I have noticed that with a 2811 router and the older WIC-1T, that a 'clock rate 2000000' command appears in the configuration. No matter what I try, the command remains. I must be missing something here. Any suggestions would be great.

[lgijssel]

The port showing the command is probably a DCE?

Please check if you have set clock source to internal for this interface. If not you should be able to remove it using the no-form of the command.

http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_command_reference_chapter09186a00800880c2.html#1019126

Regards,

Leo

[Daniel Smith]

Unfortunately, the only 'clock' command that is available deals with the clock rate itself. Entering 'dte' in interface config mode results in 'invert txclock' on the interface.

[glbeach]

The code referenced in the link is 11 code. The router is a 2800. The 'no' version of this command has not been supported for a long time now for this implimentation. In my experience even when the option was available it wouldnt function in these scenerios.

A little anicdotal history, the DTE used to be the default setting for serial interfaces. This was a long time ago though. I think back in 10.0 code.

[glbeach]

The serial interface of a router will 'default' to a DCE interface until it detects a DTE cable type. Becuase the default is DCE, and a DCE interface MUST provide clock to the DTE side the clockrate shows up in config. This is also why you are unable to remove the clock command. The clock command will go away once a DTE cable has been detected (You can verify what the interface sees with the 'show controller serial interface [#]).

Not too worry though, if this is how you experience the issue, this is expected behavior. Holler if it is otherwise.

Glen

[sanyaolu]

Glen,

I have two 1841 Series Router with built-in CSU/DSU

Ref. your statement "The clock command will go away once a DTE cable has been detected (You can verify what the interface sees with the 'show controller serial interface [#]).

"

How will i know if an interface is DTE or DCE i could not find the line that identify that. See below;

#sho service-module serial 0/0/0

Module type is T1/fractional

Hardware revision is 0.49, Software revision is 20051025,

Image checksum is 0x3EFB7B, Protocol revision is 0.1

Receiver has no alarms.

Framing is ESF, Line Code is B8ZS, Current clock source is internal,

Fraction has 24 timeslots (64 Kbits/sec each), Net bandwidth is 1536 Kbits/sec.

Last user loopback performed:

remote loopback

duration 00:01:21

Last module self-test (done at startup): Passed

Last clearing of alarm counters 3d20h

loss of signal : 0,

loss of frame : 24, last occurred 2d20h

AIS alarm : 20, last occurred 2d20h

Remote alarm : 1, last occurred 2d20h

Module access errors : 0,

Total Data (last 96 15 minute intervals):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Data in current interval (70 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

============

#sho controllers serial 0/0/0

Interface Serial0/1/0

Hardware is GT96K with Integrated FT1 CSU/DSU module

TX and RX clocks detected.

idb at 0x62A42F10, driver data structure at 0x62A4A6D4

wic_info 0x62A4ACD0

Physical Port 1, SCC Num 1

[glbeach]

Hi Adeolu,

The DTE and DCE relationship with serial interfaces deals specificaly with 'Serial type' interfaces. The DTE and DCE clocking relationship relates to Layer 1 "serial communication". This comminication occurs between the Router 'Serial Type" interface and an external DCE type device, usualy a CSU/DSU or Modem or other device. The serial interface type of a WIC-1T and WIC-2T are DB-25 serial interfaces. The serial communcation occurs across usualy V.35 there are other cable types though.

I preface with this to explain the following. The WIC-1DSU-T1 interface is a T1 card that has an internal CSU/DSU. Since the CSU/DSU is internal there is no 'Physical Serial' Level of communication occuring here. This step of the topology is eliminated by this card. Therfore there is no DTE or DCE interface and therfore no 'serial' clock rate command.

There is clocking though on the WIC-1DSU-T1 but this is 'Physical Layer T1 clocking'. The speed of the interface is determined by the amound of SDO's configured in the service-module timeslots and the speed assigned to the DSO's. The clock internal or line are the T1 clocking settings available on this card.

Hope this helps explain this better.

GB

http://www.cisco.com/en/US/customer/products/hw/modules/ps3129/products_tech_note09186a0080093d70.shtml

http://www.cisco.com/en/US/customer/products/sw/iosswrel/ps5012/products_feature_guide09186a0080194a32.html