North American Network Operators Group

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Re: Dialup congestion and winter weather (fwd)

  • From: Jeff Mcadams
  • Date: Thu Dec 28 00:10:01 2000

Also sprach [email protected]
>An important question to ask people reporting this   type of problem is
>are they getitng a normal busy (all modems busy) or a fast busy (telco
>out of circuits).  Two very different problems.  An ISP can work on
>fixing the first, but the second is a telco with a shortage of circuits
>between the customer and the isp.

Maybe, maybe not.  In the pretty common case of an ISP fed by ISDN PRI,
its been our experience that once all of the channels on all of the
available PRI to the ISP are in use, the telco will generate an all
circuits busy type of response as the PRI are trunk-side, so the
switches typically treat them as inter-switch trunks being filled, not
end lines to the ISP being full.

The end result being that an end-user can't always tell if a fast-busy
indicates a telco problem or a capacity problem at the ISP.

The work-around available to the ISP is to set the last line/channel
(assuming you're using a first-available type of hunt rather than a
circular or something else) to reject calls with a cause code of 17
(User busy) which will generate a normal user busy signal when the rest
of the trunks are full.  How you do this on your RAS equipment is
implementation independant of course.  If anyone is interested, I can
give pointers to do this on 3Com Total Control chassis.

>> It seems like a lot of people are at home, dialing into the Internet
>> today.  There is a major ice storm in the middle of the country, and
>> its pretty much a holiday week elsewhere.  Traffic seems to be moving
>> on the major backbones, but some folks in the midwest report some
>> problems dialing in from home.

We've, for a long time, tried to add whatever extra service we could
right before bad winter weather approached.  I remember one time,
several years ago, I added a tenth again of our then-current hunt-group
size of modems to our hunt group in anticipation of snow that night.  We
filled those lines that night when we had not be filling the lines
before that capacity was added.

So...winter weather spikes in usage have been around for a while...and
it makes've got greater difficulty getting out and about, so
many people take the path of least resistance and play about online.
Jeff McAdams                            Email: [email protected]
Head Network Administrator              Voice: (502) 966-3848
IgLou Internet Services                        (800) 436-4456