How to set "CRC 16" on serial E1 WIC interface?

[hummer3331973]

Hi-

I have a 1721 with an E1 WIC and I'm trying to match my provider's setting. Their router facing mine is using this:

MTU 1500 bytes, BW 1984 Kbit, DLY 20000 usec, rely 246/255, load 1/255
Encapsulation HDLC, crc 16, loopback not set

I was able to copy this setting except for the "CRC 16". How do you add/change this? Here's my current setting:

Serial0:0 is up, line protocol is up
  Hardware is DSX1
  Internet address is 
  MTU 1500 bytes, BW 1984 Kbit/sec, DLY 20000 usec,
     reliability 255/255, txload 11/255, rxload 1/255
  Encapsulation HDLC, loopback not set
  Keepalive set (10 sec)

 

[NetRx]

I believe that is the default setting for a serial interface although that IOS won't show it under 'show int'. You might be able to do this to verify:

Router(config)#interface s0:0
Router(config-if)#crc ?
Router(config-if)#crc 16 (if possible)
Router(config-if)#end
Router#show run (to verify)

If there is no value for 'crc 16' under the interface after the show run then that is the default setting. You might be able to find something in 'show tech'.

I would be more concerned with this if you weren't already:

rely 246/255,

Might be an anomaly but if you start seeing packet loss/connectivity issues that might be why.

 

[hummer3331973]

Thanks NetRx. Do I have to match "rely 246/255" as well?

 

[NetRx]

No, in fact that value is dynamic. It basically means that over the last five minutes, 246/255, or 96% of the time, the line was available.

That value should never drop below 255. It should always be 255/255. Anything below 255 is usually indicative of a physical layer problem (line noise, bad run, etc.) It is important to note that the problem is on the ISP's interface, not yours.

I was advising you to follow-up with your provider and ask them if it is something you should be concerned with. If you start having quality issues across that link then that is the first thing to check.

 

[burtsbees]

To follow up on the network doc...

the Telco LOVES to blame customer equipment, like 80% of the time, and 90% of that the problem actually is the Telco's equipment. They are usually too lazy to do intrusive/aggressive testing, like the last mile, to the LEC, etc. They'll do a loopback to the smartjack and say, "Your WIC card is faulty.".

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!