The Romantic Language of SIP Trunking

Romance languages (Italian, French, Rumanian, Catalan and over thirty others) are somewhat similar. They all derive from Latin and this common origin means knowing one gives you a leg-up in learning another (or so they claim). Over the past month, I’ve been putting this hypothesis to the test, and while it would have been really cool to say I speak a more obscure language like Galician, Picard or Norman, I’ve settled for the more broadly used Portuguese.

The way I see it, given Level 3’s deep South American presence (courtesy of the recent Global Crossing acquisition), it might actually come in handy someday. As a native Spanish speaker, I find some things do come easier (many words and grammatical rules are similar) but pronunciation is tricky and there is always a temptation to borrow from Spanish when I don’t know (or have forgotten) the right word. Sometimes it works, sometimes it doesn’t. Sometimes the borrowed word has an altogether different meaning in Portuguese. I may intend to speak of a pregnant woman (embarazada) but folks hear of a confused woman (embaraçada) or write of sorrow (pena) and readers imagine a feather (also pena). There have even been a couple of truly embarrassing examples which I cannot repeat for this audience.

Something similar happens when it comes to SIP Trunking. Many folks assume that since SIP is a standard protocol (defined by RFCs), SIP Trunking must therefore be a common product (a single language, if you will). The truth is there are many nuances which make SIP Trunking more akin to a language family. There are many practical and philosophical reasons why these differences exist.

On one hand, you have differences in the way the carrier implements SIP which include supported cross-protocol interactions (TCP, UDP,RTP, RTCP, etc), settings for packet size, codecs supported, redirect and re-invite implementations -not to mention the fact hardware manufacturers often have different interpretations of the SIP standard itself. These nuances are often the result of trade-offs made between quality, security and cost and a lack of consensus as to the best approach.

On the other hand, you also have differences in the carrier services grouped under the SIP Trunking moniker. I’ve heard everything from PRI replacement (centralized or otherwise with each carrier’s footprint limitations), toll-free, contact center and dedicated long distance go by this name. There is no shared definition – if it uses SIP and it connects you to the PSTN, someone is likely to call it SIP Trunking. In fact, Global Crossing used the term to refer to all their VoIP products whereas Level 3 used it specifically in reference to the centralized two-way local PRI replacement (even though we offer all of these services using SIP).

I am by no means suggesting there is anarchy in the SIP world. Each carrier’s offering has consistent rules and generally works the same way for all customers using the same equipment (dialect, if you will). All I’m suggesting is it’s helpful to be aware of the nuances that exist between carriers. When you hear “SIP Trunking”, think “language family” and find out what language in that family your equipment is actually expected to know. Perhaps you’d like to share an experience? And the next time you hear me say “Oi!” I may be saying hello in Portuguese, on the other hand I may just be jamming to AC/DC’s TNT.