Comments on: Speeding Upstream – Part I http://volpefirm.com/docsis/speeding-upstream-part-i/ A Technical Communications Company Wed, 16 May 2012 06:51:01 +0000 hourly 1 http://wordpress.org/?v=3.3.2 By: Brady http://volpefirm.com/docsis/speeding-upstream-part-i/#comment-220 Brady Wed, 08 Dec 2010 13:10:02 +0000 http://bradyvolpe.com/?p=318#comment-220 Helmut, If this is isolated to just one CM and you have others like it, it is likely one of two things. 1) It is a bad CM or 2) the CM is on a bad leg/tap. It could be suffering from too much loss, micro-reflections, group delay, impulse noise, etc. It is really difficult to tell. Statistically only a small percentage of modems go bad (single digits). So you could start with replacing the modem, but I recommend you don't assume that solves the problem. There may be other issues at hand. -Brady Helmut,

If this is isolated to just one CM and you have others like it, it is likely one of two things. 1) It is a bad CM or 2) the CM is on a bad leg/tap. It could be suffering from too much loss, micro-reflections, group delay, impulse noise, etc. It is really difficult to tell.

Statistically only a small percentage of modems go bad (single digits). So you could start with replacing the modem, but I recommend you don’t assume that solves the problem. There may be other issues at hand.

-Brady

]]> By: Helmut Normann http://volpefirm.com/docsis/speeding-upstream-part-i/#comment-219 Helmut Normann Thu, 02 Dec 2010 21:15:32 +0000 http://bradyvolpe.com/?p=318#comment-219 Thank you gentlemen for the very excellent series of articles that I will study closely during the upcoming holidays. Today I heard from a cable operator of following problem of his Docsis 3.0 system: Upstream bonding is configured on a uBR10k, one upstream only, all working fine. All of the sudden there is a load of 26Mbit/sec on upstream while all CMs are configured to only 6 Mbit/sec. The load is coming from 1 CM. Rebooting this CM and everything is OK again. Is it caused by the configuration of CMTS or of the CM? Please advise. Thank you gentlemen for the very excellent series of articles that I will study closely during the upcoming holidays. Today I heard from a cable operator of following problem of his Docsis 3.0 system:
Upstream bonding is configured on a uBR10k, one upstream only, all working fine. All of the sudden there is a load of 26Mbit/sec on upstream while all CMs are configured to only 6 Mbit/sec. The load is coming from 1 CM. Rebooting this CM and everything is OK again. Is it caused by the configuration of CMTS or of the CM? Please advise.

]]> By: Brady http://volpefirm.com/docsis/speeding-upstream-part-i/#comment-218 Brady Mon, 26 Oct 2009 11:28:24 +0000 http://bradyvolpe.com/?p=318#comment-218 Stewart, A response from J. Downey: <em>"If the modem is getting insertion flaps, it could be offline continuously to the end customer. Still a good indication to the cable operator of something suspicious and needing investigation."</em> Regards, -Brady Stewart,

A response from J. Downey:

“If the modem is getting insertion flaps, it could be offline continuously to the end customer. Still a good indication to the cable operator of something suspicious and needing investigation.”

Regards,
-Brady

]]> By: stewart http://volpefirm.com/docsis/speeding-upstream-part-i/#comment-217 stewart Fri, 09 Oct 2009 20:53:49 +0000 http://bradyvolpe.com/?p=318#comment-217 Chaps, Another excellent article-one question: "If the CM sends initial ranging two or more times within two minutes, the flap count increments by one. This does not necessarily mean a modem going offline and online. It could be a modem that goes through “init” states many times." If the modem is in an init state, then surely it wont be passing customer data so in that sense does an insertion count not mean that the device is effectively offline in the customer's eyes? cheers Stew Chaps,
Another excellent article-one question:

“If the CM sends initial ranging two or more times within two minutes, the flap count increments by one. This does not necessarily mean a modem going offline and online. It could be a modem that goes through “init” states many times.”

If the modem is in an init state, then surely it wont be passing customer data so in that sense does an insertion count not mean that the device is effectively offline in the customer’s eyes?

cheers

Stew

]]>