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Technology Stocks : Frank Coluccio Technology Forum - ASAP -- Ignore unavailable to you. Want to Upgrade?

To: ahhaha who wrote (451)	11/24/1999 5:14:00 PM
From: Frank A. Coluccio	Read Replies (2) \| Respond to of 1782

Conceptually what you are saying is sound, but there are graded differences to consider between the two models (i.e., the differences between the 'net and the PSTN). Under normal conditions in the PSTN, and in end offices specifically, "blocking" at the end-office switch level is actually "engineered" to take place in fewer than 1% to 2% of all attempts to complete a call. At least that was the case prior to the advent of Internet modem access requirements. Such "blocking factors" are derived from some rather tedious traffic analyses and some rather arcane (IMO) Erlang_B formulae. However, during central office equipment failures and cable outages, this number soars upwards from the <1% bogie proportionally to the degree of the outage's effect. But this would constitute an "abnormal" condition. Somewhere in between normal and abnormal conditions you have other phenomena which are directly related to abnormal calling patterns, as would be the case during severe weather conditons (storms and earthquakes), or other incidents of national interest. On the Internet, conversely, there are continuously unpredictable and variable conditions which exist which require a constant on the fly assessment of congestion conditions at any point in time. QoS, in this case, is required to take from the poor and give to the rich, in normal times and abnormal, alike, and in good times and in bad. Or, at least that is the theory promoted by QoSists. Among bandwidthists, there is disagreement on this, however, but here I am prone to digress off the central point. In POTS terms, we usually discuss these issues in terms of "normal" conditions, and we would not normally expect to see noticeable QoS gradients during normal times in the POTS world. It's usually a matter of it's either there, or it isn't there (as in the <1% of the times that you cannot get through), normally. Exceptions to this might be when there is a sudden surge in traffic, such as during the national events I cited above, when a given section becomes overwhelmed to the point where traffic exceeds the assumptions that were used to determine blocking factors. Here's when you get those fast busy signals at 120 interrupts per second. All lines are busy. This also happens when a wireless pcn company like Sprint promotes a special offering in a given area, and doesn't do enough provisioning or buildout to support the onslaught of new services that ensue. In those cases, such as I'm experiencing now, you wind up going into "fast busy" conditions, which usually means that all central office or wireless path resources are busy, so please try again. ======= BTW, here's another clip from the NANOG List concerning that CO DCS/DACS outage which took place yesterday: "Ah, I see my friends at the FCC are reading this list. "The Bell Atlantic FCC outage report for the Nov 23 New Jersey outage has been scanned, and is online at the FCC web site." fcc.gov