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New Member

CRC/Input errors increasing on DS3 link

I have a DS3 unframed connection between Tokyo and HK. At tokyo end it is a Cisco 7200 (PA T3 + card) and at HK it is Cisco 3845 (NM-1T3/E3 card). I am having CRC / input errors on the serial interface on Tokyo side. No patterns, just burst of errors. Checked the settings on both sides all match. Clock source is internal at Tokyo and line at HK end. The cable length though is 180 feet at Tokyo end (can this be a problem ???) Howevere did loop tests from Tokyo end even to the mux at far end. NO errors when using tester for ds3 but errors pop up when router is connected, even on the loop. Line coding is B3ZS, and also "framing c-bit' is given at both side router (SP says this is not an issue as they dnt really look at this etting on router in an unframed ckt case --- Is this true or does the router setting need a change for framing to unframed? There are few ADMs and MUxs between the routers, but all seem to be synced in terms of setting. Any troublehsooting steps or advise to correct this issue is welcome. Any previous experience with such scenarios is also welcome.




Re: CRC/Input errors increasing on DS3 link


hope this link may help u out in ur troubleshooting process...


New Member

Re: CRC/Input errors increasing on DS3 link

In b/w is there anyway to know what are the elctric level (Dbm) for this PA T3 ds3 card ?

New Member

Re: CRC/Input errors increasing on DS3 link

Rx measured from HX in front of CPE (including coax cable) is around -4.5 dBm. Wanted to know whether this falls under Cisco's acceptable range for a PA-T3+ DS3 adapter ....

New Member

Re: CRC/Input errors increasing on DS3 link

few things to check

1. Framing change c-bit

2. DSU bandwith...should match with the network DSU bandwidth define

3. Disable scrabling

4. Check local cable

example config

interface Serial2/0

description 44210

bandwidth 44210

ip address a.b.c.d.

no ip redirects

no ip proxy-arp

max-reserved-bandwidth 100

encapsulation ppp

no peer neighbor-route

dsu bandwidth 44210

framing c-bit

cablelength 180

serial restart-delay 0

no cdp enable