On 07/22/2015 04:23 PM, Paul Heitkemper wrote:
I hope this is apropos for this listserv. Is there a good source somewhere
which describes (with examples) the messaging inherent in making a trunk?
What does it mean "to be a trunk"?
SIP "trunking" is, to borrow a phrase from Patai & Koertge, an
"accordion concept": when it's expanded and contracted, much marketing
music comes out.
"Trunking" is not an especially intelligible concept outside the
circuit-switched world. About the only common--but by no means essential
or universal!--features of a "SIP trunk" are:
- Policy permits passing calling and called party identity freely.
- Designed as an inter-machine peering arrangement, i.e. based on IP
trust between industrial network elements that don't necessarily support
digest challenge authentication.
- Typically end-to-end, without NAT interceding.
That said, there are plenty of retail "SIP trunking providers" for whose
offerings none of these things are true.
Bottom line: it's little more than a marketing concept designed to make
SIP access products understandable to traditional telephony folks,
having no basis whatsoever in SIP semantics. It's rather akin to how
mid-2000s WiMax providers used to market "wireless DSL".
-- Alex
--
Alex Balashov | Principal | Evariste Systems LLC
303 Perimeter Center North, Suite 300
Atlanta, GA 30346
United States
Tel: +1-800-250-5920 (toll-free) / +1-678-954-0671 (direct)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
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