nanog mailing list archives
Re: IPv6 news
From: Andre Oppermann <nanog-list () nrg4u com>
Date: Tue, 18 Oct 2005 17:48:42 +0200
Paul Jakma wrote:
On Tue, 18 Oct 2005, Andre Oppermann wrote:SS7 over IP is quite popular these days. However call routing != SS7 message routing.By call-routing you mean the actual circuit switching of each call? I don't mean that, I mean the number routing, which SS7 /does/ do - you referred to it as being more analogous to DNS iirc in operation.
>
Nope, it's not. Can you name a phone prefix routing protocol?Ehm, SS7 ;).You might call it DNS-like because it's request based, but it still provides routing information.
SS7 is not a routing protocol. SS7 is a transport stack like what we refer commonly to as TCP/IP. There are a number of protocols that run atop the basic SS7 transport network. Some protocols are datagram oriented and some are session oriented. For call handling ISUP or derivates are used. The main difference to the IP world is the limited scope in the PSTN. A PSTN switch consults its (static) number routing table for the trunk to forward the call on. Then it contacts the switch at the other end of the tunk and hands over further forwarding to it. If that doesn't work out the circuit gets shut down backward switch to switch. For special numbers like 800 and 900 there is another protocol called IN (Intelligent Network) which is nothing else than DNS. Each special number has a 'real' number in its shadow. The originating switch requests the real number through IN and then the normal call forward happens. IN may deliver different numbers based on the location of the orginating switch or daytime or any other criteria you may think of. A little bit like Akamai if you wish. However there is nothing akin BGP or OSPF in the SS7 suite of protocols. All the forwarding/trunk tables are computed offline for each switch and then stored on the switches by some bulk data transfer. Variantions are emerging with extended IN platforms where you have one more central databases of forwarding information but that is just a large geographically distributed switch then. -- Andre
Current thread:
- Re: IPv6 news, (continued)
- Re: IPv6 news Paul Jakma (Oct 18)
- Re: IPv6 news Andre Oppermann (Oct 18)
- Re: IPv6 news Paul Jakma (Oct 18)
- Re: IPv6 news Andre Oppermann (Oct 18)
- Re: IPv6 news Paul Jakma (Oct 18)
- Re: IPv6 news Andre Oppermann (Oct 18)
- Re: IPv6 news Paul Jakma (Oct 18)
- Re: IPv6 news Paul Jakma (Oct 18)
- Re: IPv6 news Andre Oppermann (Oct 18)
- Re: IPv6 news Paul Jakma (Oct 18)
- Re: IPv6 news Andre Oppermann (Oct 18)
- Re: IPv6 news Michael . Dillon (Oct 18)
- Re: IPv6 news Andre Oppermann (Oct 18)
- Re: IPv6 news Michael . Dillon (Oct 19)
- Re: IPv6 news Todd Vierling (Oct 19)
- Re: IPv6 news Michael . Dillon (Oct 19)
- Re: IPv6 news Tom Vest (Oct 19)
- Re: IPv6 news John Dupuy (Oct 18)
- Re: IPv6 news Michael . Dillon (Oct 18)
- Re: IPv6 news Jeroen Massar (Oct 17)
- Re: IPv6 news Michael . Dillon (Oct 17)