The Many Flavors of SIP Trunking & SIP Applications

Like the many flavors of ice cream, there will be as many flavors of SIP-Session Initiation Protocol Trunk types and SIP applications. As we move forward I will continue to scour the universe for the more unique and interesting types. Shown in the animated tutorial is four of the many "flavors" of SIP trunks.
sip-trunk-4types-ipsec-mpls.swf

Here are the written explanations: - Public Internet - performance and security based on WAN connection - in this configuration performance is only as good as the upstream connection to the carrier, the bandwidth across the carrier's network and trunk connections to the PSTN or other carriers. In other words, you may have more than enough bandwidth to the carrier (provider), however the bandwidth "inside" the carrier's network is congested or insufficient. See Sidebar for more.
- Private MPLS-Multi-Protocol Label Switching - VPN-Virtual Private Network used for customers with several sites and not visible for other customers. MPLS is one of the most popular means for customer and carrier QoS and performance. In addition, pricing for MPLS is now, in many cases, the same as an IP circuit/connection. This suggests that customers with SIP trunking, PC or desktop video and other voice applications need to take an advantage of the many different levels or types (gold, silver, bronze) of MPLS for their applications. - Over IPSec VPNs for more security - requires more complex management using IPSec-IP Security implementation, real-time encryption & decryption, and potential multiple networks. IPSec and the following TLS will also be increasingly required for both real security and for corporate compliance tracking. IPSec adds encryption which may be enough but for those who need more, TLS and SRTP will be required. - With TLS-Transport Layer Security and SRTP-Secure Real-time Transport Protocol used for highly secure situations.
This is where Port Level Security or TLS-Transport Layer 4 Security takes place. That is, control access by the Port Number such as deny or access to Port 5060-5061 for SIP or access to any other function. This is called a Stateful Inspection for a firewall to check, alert or audit the status (state) of the TCP connection - SYN, SYN-ACK or FIN.
With elaborating on SPIT-SPAM over Internet Telephony, VOMIT-Voice Over Misconfigured Internet Telephony, call-jacking and a myriad of other voice attacks, they will be coming soon to a SIP device near you suggesting planning for complex SIP security processing now.

SIP SIDEBAR - First, sufficient bandwidth for SIP trunking and SIP applications will still be a limiting factor in its deployment. For example, I did a study for a major ILEC a few years ago in Atlanta and found vast capacities of optical fiber in certain parts of the CBD-Central Business District but a few blocks away, optical bandwidth was non-existent. Today, a colleague has found that in securing metro-optical ethernet that many of the buildings requested are not on any carrier's optical network. This has resulted in considerable delays on the part of the customer to expand their internal network for SIP, video and other applications.
Second, the SIP carrier may not have sufficient inbound or outbound PSTN trunk connections for peak demands by customers. Often called the "Mother's Day" syndrome where it all works fine until you have an overload on peak holidays.
Third, check with your carrier to In regard to peering with other SIP networks, this is the next "weak link" in the proliferation of SIP. One of the exciting features in OCS-Office Communications Server and other systems is the ability to create "federations" between companies. For example, there are more than 80,000 users using OCS IM-Instant Messaging between Intel and Microsoft. The concept of federations will grow exponentially as companies create IM bonds between each other. In addition, you can PC video conferences as easily as you do IM. I have done successfully on the bus using my AT&T broadband card. In other words, add SIP peering to your list of planning considerations.

This content is presented in detail in The SIP Planning Guide available in the onsite, online and via webseminars formats. Here is the schedule for the onsite course Portland - November 6-7. For more details, go to http://www.techtionary.com or directly at http://www.techtionary.com/sip/planning-guide/.

For more information and scheduling, please call Tom Cross at 303-594-1694 or cross@gocross.com