Reading the event log

[greencreeper]

I'm just wondering what these "critical" event log messages mean:

No Ranging Response received - T3 time-out
Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 timeout
DHCP WARNING - Non-critical field invalid in response
Started Unicast Maintenance Ranging - No Response received - T3 time-out

They can't be that critical because the modem works fine Is there a website that explains the messages, or some means of getting my paws on the manual?

[BBKing]

T3 and T4 are maintenance messages associated with DOCSIS - a quick read up on the protocol will tell you what they are - AFAIK if you miss too many the spec says the modem should try and re-connect, but missing the odd one is normal. The DHCP one is interesting, suggests the DHCP server is trying to set something on the modem that it doesn't recognise (there are all sorts of esoteric DHCP settings that mostly aren't used, and not all devices can understand all messages - for instance the DHCP server sets a lot of stuff on the STBs that a CM would find incomprehensible).

[greencreeper]

Originally Posted by BBKing

T3 and T4 are maintenance messages associated with DOCSIS - a quick read up on the protocol will tell you what they are - AFAIK if you miss too many the spec says the modem should try and re-connect, but missing the odd one is normal. The DHCP one is interesting, suggests the DHCP server is trying to set something on the modem that it doesn't recognise (there are all sorts of esoteric DHCP settings that mostly aren't used, and not all devices can understand all messages - for instance the DHCP server sets a lot of stuff on the STBs that a CM would find incomprehensible).

I never thought of that. God I'm getting old The RFCs - should have thought. Yeah. I've read the DHCP RFC I thought maybe the modem had asked something and got a reply it couldn't understand.

[Florence]

This is the log for my modem Ambit 200 the logs from July 8th seem weird as I didn't have it then. It was a replacment Modem Last Friday.

Index First Time Last Time Counts Level ID Text
1 Time Not Established Time Not Established 197 Critical (3) 82000200 No Ranging Response received - T3 time-out
2 THU JUL 08 10:07:19 2004 THU JUL 08 11:05:42 2004 19 Critical (3) 84000500 SYNC Timing Synchronization failure - Loss of Sync
3 THU JUL 08 10:07:34 2004 THU JUL 08 11:06:01 2004 19 Critical (3) 82000400 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 timeout
4 THU JUL 08 10:07:44 2004 THU JUL 08 11:06:11 2004 19 Critical (3) 85000100 No UCD's Received - Timeout
5 THU JUL 08 10:08:02 2004 THU JUL 08 11:23:24 2004 6 Critical (3) 82000300 Init RANGING Critical Ranging Request Retries exhausted
6 THU JUL 08 10:37:46 2004 THU JUL 08 11:27:04 2004 25 Critical (3) 68000100 DHCP FAILED - Discover sent, no offer received
7 THU JUL 08 10:40:16 2004 MON SEP 06 19:49:54 2004 7 Critical (3) 82000500 Started Unicast Maintenance Ranging - No Response received - T3 time-out
8 Time Not Established Time Not Established 7502 Notice (6) 84000100 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
9 Time Not Established Time Not Established 97 Notice (6) 84000200 SYNC Timing Synchronization failure - Failed to acquire FEC framing
10 Time Not Established Time Not Established 1 Notice (6) 84000400 SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period
11 Time Not Established Time Not Established 1 Critical (3) 68000300 DHCP WARNING - Non-critical field invalid in response.
12 SAT SEP 04 10:50:29 2004 SAT SEP 04 10:50:29 2004 1 Notice (6) 2454454273 coldStart
13 SAT SEP 04 10:50:29 2004 SAT SEP 04 10:50:29 2004 1 Notice (6) 2454454281 Link up--Ethernet interface
14 SAT SEP 04 10:50:29 2004 SAT SEP 04 10:50:29 2004 1 Notice (6) 2454454282 Link up--Cable interface
15 SAT SEP 04 10:50:29 2004 SAT SEP 04 10:50:29 2004 1 Notice (6) 2454454279 Link down--USB interface
16 SAT SEP 04 11:20:26 2004 SAT SEP 04 11:20:26 2004 1 Warning (5) 68010300 DHCP RENEW WARNING - Field invalid in response

Would like to have some understanding on this so its easier to understand...

[greencreeper]

Originally Posted by Kits

This is the log for my modem Ambit 200 the logs from July 8th seem weird as I didn't have it then. It was a replacment Modem Last Friday.

My modem is the same - has entries for last November. Three possibilities comes to mind: (1) factory testing; (2) engineer using the modem diagnostically at customer premises; and (3) it's secondhand (unlikely).


I did a Google for RFCs but they all seem to be memos or related protocols. It seems that the DOCSIS is a little different to how most Internet standards are developed in that it's a cable industry consortium that has created the specification:

Founded in 1988 by members of the cable television industry, Cable Television Laboratories, Inc. (CableLabs®) is a non-profit research and development consortium that is dedicated to pursuing new cable telecommunications technologies and to helping its cable operator members integrate those technical advancements into their business objectives [read: make heaps of cash].

http://www.cablelabs.com/about/

I had a look at the specifications They're very technical - everything you need to know to build a cable modem. All you need is coathanger, some tin foil, a 9v battery, and a loo roll middle Quite a bit of the spec went whistling over my head, and I still don't know what the messages mean because it seems that they're set by the manufacturer. Ambit's website is spartan to say the least. There might be something in the SNMP RFC but it's rather a lot to read.