TRIP deployment?

I'm not sure if this is the right mailing list for this question: how widely is TRIP (Telephone Routing over IP [RFC3219]) deployed / used in current networks? is the big ENUM provider, I think that's the method
that has gained popularity for VoIP Peering on the signaling end. TRIP
sounds like it would be useful for finding QoS routes for media streams.

Hi, Jeremy, Cayle, All --

I am regularly involved with SIP interconnect. There are a number of providers of similar Federated/All-call-query-ENUM Multilateral Islands, but they do not befit the bilateral interconnect model which most people involved with voice interconnect need to follow, so that they can manage quality and the commercial properties of individual prefixes. *Some* of the island methods I have seen, perform signaling arbitration and media transcoding so that all parties on the island can communicate with all other parties, which is worrying to me as one of the benefits of end-to-end VoIP is the preservation of wideband audio codecs and new signaling features across the call path, compared with lowest-common-denominator call routing (just like TDM paths in the middle).

I discussed this with Richard Shockey last year and proposed to him an out-of-band, trip-like gateway protocol that could express prefixes along with all relevant technical and commercial properties between telecoms peers. If the commercial and technical properties fit the requirements of the peer, then the prefix is appended to the dialplan of the peer (be it via a local ENUM zone or some other prefix/call routing method). The point is that the protocol to communicate prefixes and attributes needs to be call routing agnostic. I did some work on this protocol, but don't feel ready to take the document to the relevant working groups at this stage, but would welcome feedback on it from anyone here who is involved with voice interconnect.

This is a bit layer 7ish, so the thread is possibly reaching a conclusion on list, but I really hope it continues off-list.

best wishes

[sorry for late reply - .us Thanksgiving plus LIFO mailing list reading creates posting latency]

I'm not sure if this is the right mailing list for this question: how widely is TRIP (Telephone Routing over IP [RFC3219]) deployed / used in current networks?

There was a reference stack made in the Vovida package for TRIP, but in my experiments with it a number of years ago I was unable to implement it in any satisfactory way, and the code was far from complete. There was a TRIP commercial implementation in the Acme Packet SBC (Session Border Controller) equipment, and one in the Jasomi SBC IIRC, but I don't know what the status of those two stacks is today or if anyone uses them.

I've never seen TRIP offered as a peering method in any exchange of any sort, so the short answer to your question as far as I know is "There is no significant use of TRIP today." This is a shame, since it seems like it would be useful. My belief is that there are significant economic dis-incentives for E.164 interconnection that are easily implemented and which create fluid, low-cost (or zero-cost) marketplaces for minutes, and I will not discuss the obvious opponents to such marketplaces. E.164-based ENUM is another casualty of that economic structure as it is inextricably linked to political decisions. There are additional problems with large-scale distributed routing of E.164 numbers as the trust model for number ownership is difficult to manage (the root cause of so many problems) and routing failures are much more operationally painful and difficult to resolve during unexpected failures. I'd be happy to be proven wrong on my assumption that TRIP is not used - does anyone have evidence of TRIP being used in readily-joinable federations, either in conjunction with geographic layer 3 peering fabrics or otherwise?

Despite the failure of TRIP to catch on, there was some use that has come out of RFC3219 (TRIP). The ITAD concept, which defines an IANA-allocated unique identifier to telephony entities in other use cases. An ITAD is much like an ASN, except 32 bits, and currently zero-cost. The project uses ITADs as part of a lookup mechanism based on ENUM-like DNS methods, in effect creating a phone keypad-friendly, IP communications-focused alternative to the normal E.164 phone numbers that are the standard for PSTN dialing. This moves quickly out of typical NANOG charter areas, but is worth mentioning as ITAD resources are being used to uniquely identify worldwide telephony networks that are layered on top of existing IP networks. As of 2008-12-03, the ITAD number space of the next assignment block will cross into the four-digit range. (full disclosure: I manage the Freenum project, so I'll be biased and suggest that anyone who manages any sort of IP-based telephony system with public inbound SIP capability should examine this - it's trivial to set up.)

Other routing or routing-like protocols for telephony you might find interesting include OSP (Open Settlement Protocol), DUNDI (Distributed Universal Number DIscovery), and ENUM (ENUM). Each protocol has niche areas in which they are used for different purposes, but none have been overwhelmingly successful in a public setting, though ENUM has been very successful in "private" interconnects and mildly successful in some locations which have enlightened and technically educated national regulators. North America is not implementing ENUM in any public manner at this time to my knowledge.

   Telephony Routing over IP (TRIP) Parameters (death via Cisco?)
   DUNDi - VoIP-Info
   ENUM - The bridge between the switched telephony network and the Internet - VoIP-Info