Input & CRC Errors (New Cisco 1841 - WIC 1DSU-T1 V2)

[smartin]

For the past several months we have been testing a T1/MPLS connection at a remote site using a Cisco 1721 with a T1 DSU/CSU T1 (Model # WIC 1DSU T1). The test results have been great with access speeds & no errors.

This weekend I tried to replace the router with a new Cisco 1841 using a T1 DSU/CSU T1 (Model # WIC 1DSU-T1 V2).

When I installed the router I'm now seeing input & CRC errors (see image 1). I tried three different routers (all 1841 & DSU V2) and getting same results.

I believe this may be clock settings on the DSU (see image 2).

Can anyone help with this problem. Thanks.

[smartin]

Scadams, just wondering the results of your test. I'm starting to see errors on the WIC-1DSU-T1-V2 cards as well. How is Cisco going to correct this problem. I really don't want to make 50 or so patch cables.

Thanks...

[Scott Adams]

We tried a IOS patch from cisco that helped a little. But am pushing for a hardware fix on these cards.

[smartin]

What patch ? Can anyone download it ??

[amarch_harris]

No one has posted here in a while. Does anyone have an update to what the solution to this problem is? I am experiancing the same problem with a 1721 and a WIC-1DSU-T1-V2. Has anyone verified that using a modified cable with only pinouts for 1,2,4,5 will fix the problem?

Thanks!

[Scott Adams]

Cisco has released an IOS bug fix in 123-8T7, which can help some.. The card has been redisigned and Cisco is shipping us cards to replace the original V2 cards..I believe you need to open a TAC case with cisco in order to get replacement Cards..

[thisisshanky]

I had my customer's 1841 sitting 1/4 of a mile away from where the telco terminated the demarc, which was causing all these errors on the wic. We tested the router at the original demarc with the WIC-1DSU-T1-V2 and it worked without any errors.

[scottmac]

Category rated UTP (Cat 3,4,5,5e,& 6) are not spec for extended demarcs.

The correct cabling is "Premises Cable," which is a larger guage conductor, where the individual pair are shielded and enclosed in a shielded sheath (individualy shielded pair in a shielded jacket).

UTP is ~100ohm, Prem cable is ~150 ohm.

You can do a search in the catalog at www.anixter.com for "t1 cable" and get a couple pages of hits.

Prem cable is good for 655 feet (by spec). Cat-rated UTP would be doing well to make it the usual 100 meters (~328 feet). That would also assume that the cable spans are terminated correctly (to spec, by someone that *really* knows what they're doing).

Cat-rated cable is OK for shorter (relatively noise-free) runs ... and most manufacturers stuff can tolerate UTP ... but if things appear flaky, you gotta go with Prem cable.

FWIW

Scott

[lsharrah]

Cisco has stepped up and re-engineered their WIC-1DSU-T1-V2 wic card and suggested a new patched IOS as well for the 2800 series routers. Not sure about the 1700 series. Pls contact your Cisco representative for more details.

[amarch_harris]

"The special cable pin out is as followed

Pin 1 <--- twisted pair A ----> Pin 1

Pin 2 <--- twisted pair A ----> Pin 2

Pin 4 <--- twisted pair B -----> Pin 4

Pin 5 <--- twisted pair B ----> Pin 5"

Has anyone been able to get this special cable to resolve their issues? I tried it and I actually saw more errors on the line afterwards. I am wondering if the theory turned out not to be accurate after it was tested. I never saw any results from the test.

Thanks for everyone's input!