Selling SIP: You Can't Sell What You Don't Know

By Tom Cross

Technology Columnist

 

 

 

 

The panelists on the session Selling SIP Trunking at the Channel Partners Conference in Las Vegas missed the mark in helping the SRO audience get to square one for selling SIP Trunking. Without going into all the issues they could have and should have addressed, here are three tips.

 

What is SIP? Make sure you know what SIP means. It means Session Initiation Protocol (News - Alert), not anything else. Basically, SIP provides signaling, like car traffic lights, in order that SIP devices can call other SIP devices over a symmetrical broadband internet connection (no ADSL). If you want to know more about the working of SIP protocol, get involved in technical discussions or your product interoperability compliant, go to the SIP Forum (News - Alert), a nonprofit industry interoperability organization at www.sipforum.org. The SIP Forum will help you understand the industry, players, protocols such as RTP (Realtime Transport Protocol), SDP (Session Description Protocol) and others as well as RFC (Request For Comments) that are the basis for all SIP development.

 

SIP devices can be hard phones, wireless phones, softphones (software) and other devices such as soda machines and in the future nearly every other device. SIP moves the “intelligence” from the PBX (News - Alert)/CO into the device. That is, SIP devices communicate directly with one another without the need for a PBX or CO (Central Office) switching system. This is just like the way your PC communicates directly with a Web site. This means the features are in the SIP device, not PBX. Practically speaking, this means I can use my laptop with softphone software as a telephone and can take it anywhere and plug in to an Internet connection and begin making outgoing or receiving incoming calls from other SIP devices without a PBX. If I need to call outside my SIP network or receive a call, my SIP gateway provider gives me a PSTN number, which you can call and no matter where I am you can call me. Features such as voice mail, transfer, conference, etc. can be added through software from the SIP system or SIP gateway provider.

 

Bandwidth planning is paramount. SIP devices use a CODEC (coder-decoder, compression-decompression), a technical term for computer chip, to process calls into international standard voice formats. One major CODEC, G.711 provides for high-performance “toll-quality” calls and uses 64 KBPS per call. A low-performance CODEC (much like cellular service) for low-bandwidth voice calls of 8 KBPS is G.729. There are other CODECS supported by various manufacturers. Check specific companies for details.

 

The most important point is that in planning for SIP implementations allocate 80–100 KBPS per call for G.711 and around 30 KBPS per call for G.729. That is, while G.711 uses 64KBPS of voice it needs more bandwidth because of the packetizing (RTP-TCP/UDP (News - Alert)-IP overhead) for an Internet protocol network. Here’s an easy rule of thumb, for G.711 take the total number of simultaneous (concurrent) calls times 100 KBPS and that is the bandwidth the customer needs for peak “busy hour” times. In addition, SIP trunking providers will limit the number of voice calls based on the CODECS they support. One SIP trunking provider supports 11 calls using G.711 and 42 calls with G.729. However, the customer benefit when users are not on the telephone with the bandwidth is automatically or “dynamically” available for their data needs. In other words, check with your SIP trunking provider, media gateway manufacturer and other “parts” in the network. That is, YMMV (your mileage may vary).

 

There are seven other critical concepts such as security, interoperability, pre-installation planning, data systems integration and others you need to be “SIP smart” in selling SIP that are included in OCS-101 and SIP Essentials 2.0c available in the onsite and online courses.

 

The online version is $299 for SIP 2.0c and $499 for OCS-101 Office Communications Server per person (volume and site license discounts available). Discounts are also available to members of the SIP Forum and MS Partners for $99 per student during May.

 

For customizing, special discounts, Web site animations, technical/sales training, technical writing and other services, go to http://www.techtionary.com or please call Tom Cross (News - Alert) at 303-594-1694 or [email protected].

 

*Courses are free to channel partners – see terms and conditions at http://www.techtionary.com/techu/.

 

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