At 10:40 AM +0100 2005-07-11, Michael.Dillon@btradianz.com wrote:
Some of the problems on the mobile networks were the result of a protocol to reserve mobile capabilities for the emergency services. The police have the authority to switch cells to emergency service and then people with specially registered SIM cards in their mobile can take priority. Presumably, some amount of capacity is also held in reserve for these people as well.
Yes, a certain amount of capacity can be placed on reserve for the holders of priority access SIMs. You only get those issued to you by the government. This can include critical emergency services personnel, selected government officials, important members of the financial services community, etc.... I don't know the specifics of how much capacity is reserved, but this sort of thing has been done on telecommunications networks for a long time. Back before cell phones existed, you could have "flash" traffic on the DDN or even the PSTN, and when placing a flash call the phone system would disconnect anyone that stood in your way of getting the connection you wanted. You had to be using special telephone equipment, or connected to a special operator with the right equipment, and you had damn well better be sure that your call was worthy of knocking anyone else off the network, but the capability was there. Even the President would normally make his calls at lower than "flash" priority. There were lower levels of priority that you could also use, but "flash" was the top one that I heard about.
I had moved the weekend before and my landline was not yet installed. Also, I live near a large hospital. I noticed that my mobile didn't function at all even late on Thursday unless I left home and travelled a kilometer or two from the hospital. Presumably, the cells in this suburban location had also been switched to emergency service.
Could be, but I'd be willing to bet it was more a matter of the cell just being overloaded. Traffic reservation for priority access SIMs is only going to take a small amount of the bandwidth available. The problem is that even normal heavy traffic can overload a cell, and what was seen during the time you're talking about was anything but "normal heavy". -- Brad Knowles, <brad@stop.mail-abuse.org> "Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety." -- Benjamin Franklin (1706-1790), reply of the Pennsylvania Assembly to the Governor, November 11, 1755 SAGE member since 1995. See <http://www.sage.org/> for more info.
Brad Knowles <brad@stop.mail-abuse.org> writes:
There were lower levels of priority that you could also use, but "flash" was the top one that I heard about.
The four buttons on the "1633" row of an AUTOVON telephone are labeled P, I, F, and FO for Priority, Immediate, Flash, and Flash-Override. The fifth (normal) level is of course routine, with no priority code attached. My understanding is that many (most?) phones could not issue the higher priority levels. Don't want some E-2 in a guard shack to misdial a number and knock off a four-star who's speaking with the Joint Chiefs. :) ---Rob
In message <87mzotpkm7.fsf@valhalla.seastrom.com>, "Robert E.Seastrom" writes:
Brad Knowles <brad@stop.mail-abuse.org> writes:
There were lower levels of priority that you could also use, but "flash" was the top one that I heard about.
The four buttons on the "1633" row of an AUTOVON telephone are labeled P, I, F, and FO for Priority, Immediate, Flash, and Flash-Override. The fifth (normal) level is of course routine, with no priority code attached.
And those levels appear as the TOS bits in RFC 791.... --Steven M. Bellovin, http://www.cs.columbia.edu/~smb
"Steven M. Bellovin" <smb@cs.columbia.edu> writes:
In message <87mzotpkm7.fsf@valhalla.seastrom.com>, "Robert E.Seastrom" writes:
Brad Knowles <brad@stop.mail-abuse.org> writes:
There were lower levels of priority that you could also use, but "flash" was the top one that I heard about.
The four buttons on the "1633" row of an AUTOVON telephone are labeled P, I, F, and FO for Priority, Immediate, Flash, and Flash-Override. The fifth (normal) level is of course routine, with no priority code attached.
And those levels appear as the TOS bits in RFC 791....
Yes, but nobody ever wrote a song about the TOS bits in Internet Protocol (this song dates to 1980): http://www.poppyfields.net/filks/00182.html ---Rob
On Mon, Jul 11, 2005 09:21:24AM -0400, Robert E. Seastrom allegedly wrote:
Yes, but nobody ever wrote a song about the TOS bits in Internet Protocol (this song dates to 1980):
If anyone has the words to "Mine Eyes Have Seen the Glory of the Architectural View", please let me know.
On Mon, Jul 11, 2005 at 12:16:34PM +0200, Brad Knowles wrote:
I don't know the specifics of how much capacity is reserved, but this sort of thing has been done on telecommunications networks for a long time. Back before cell phones existed, you could have "flash" traffic on the DDN or even the PSTN, and when placing a flash call the phone system would disconnect anyone that stood in your way of getting the connection you wanted.
You had to be using special telephone equipment, or connected to a special operator with the right equipment, and you had damn well better be sure that your call was worthy of knocking anyone else off the network, but the capability was there. Even the President would normally make his calls at lower than "flash" priority.
See also http://tsp.ncs.gov/ and http://wps.ncs.gov/ , as well as http://www.disa.mil/gs/dsn/tut_mlpp.html and http://www.disa.mil/gs/dsn/tut_precedence.html which explain those Fo, F, I and P keys on AutoVON 16-button WECo 2500s. Cheers, -- jra -- Jay R. Ashworth jra@baylink.com Designer +-Internetworking------+----------+ RFC 2100 Ashworth & Associates | Best Practices Wiki | | '87 e24 St Petersburg FL USA http://bestpractices.wikicities.com +1 727 647 1274 If you can read this... thank a system administrator. Or two. --me
participants (5)
-
Brad Knowles -
Jay R. Ashworth -
Robert E.Seastrom -
Scott W Brim -
Steven M. Bellovin