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Receive VoIP & IP Telephony related news, articles, and product information directly to your inbox! CLICK HERE!
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SIPconnect™
The SIPconnect Recommendation: An Industry Accepted Approach to Direct IP Peering for IP PBX and VoIP Service Provider Communications |
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| by SIP Forum |
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As enterprises and service providers migrate services to VoIP, a new demand has emerged for IP peering, or an end-to-end VoIP connection,
between enterprises and services providers. Today's Voice over IP (VoIP) communications systems offer customers a wealth of advanced features, as well as the ability to easily add new capabilities as requirements change and evolve. IP PBXs in particular have gained strong traction in the marketplace, and by most accounts IP PBX deployments have now overtaken traditional TDM-based PBX deployments. Moreover, service providers are rapidly evolving their networks using VoIP technology to improve efficiency and deploy new services.
To that end, a new method of connecting VoIP networks to other companies and service providers is needed. Companies are running into the limitations of using traditional
TDM technology (such as trunking gateways) to make their links. When PRI or analog connections are used to connect to service provider networks, the features that can be supported between the networks are limited to the least common denominator of features that can be supported on the PRI or analog line connecting them to each other. The quality of the media connection is also diminished as traffic is converted from VoIP to TDM and back again between networks.
Equipment manufacturers and service providers
have largely reached a consensus that the Session Initiation Protocol (SIP) is the best protocol choice to use in the interconnection
outlined above. However, choosing SIP alone is not enough. As a large family of IETF RFCs, support of SIP rarely implies support of all RFCs or even all functionality
of a particular RFC. Further, there are often multiple ways of accomplishing the same technical task in SIP, which can complicate interoperability with "extra" choices. Finally, the interconnection of VoIP networks encompasses issues beyond signaling, such as media and security, which also need to be addressed to define a predictable
interface model.
The SIP Forum's SIPconnect Technical Recommendation
has been developed to address these problems. Organized and maintained by the SIP Forum, SIPconnect defines a method for enabling direct peering between a SIP-enabled service provider network and a SIP-enabled enterprise network. SIPconnect specifies a reference architecture, a minimal set of IETF and ITU-T standards that must be supported, provides precise guidance in the areas where the standards leave multiple implementation options, and specifies a minimal set of capabilities
that should be supported by the service provider and enterprise networks.
What is SIPconnect?
The SIPconnect Interface Specification defines a common set of implementation rules for those who desire to interface a SIP-enabled IP PBX with a SIP-enabled VoIP service provider. It specifies which VoIP protocols must be supported, provides
guidance in the areas where the protocols leave too many options, and identifies a baseline set of features that should be supported by PBXs and service providers. It is important to note that SIPconnect is not intended to be a new protocol; rather, it is presented as a recommended
set of interoperability guidelines for the interconnection of a SIP-enabled IP PBX to a service provider's SIP-enabled VoIP infrastructure.
In June 2006, the SIPconnect Technical Recommendation achieved "Proposed Recommendation" status, meaning the specification is complete and awaits validation
through actual implementations. The SIP Forum is now also officially charged with organizing and maintaining the SIPconnect
specification, and is responsible for the evolution of the initiative.
SIPconnect Reference Architecture
The following reference diagram (Figure 3) outlines the common functional elements required to support the SIPconnect Interface Specification. It is important to note that SIPconnect treats the network elements in the diagram as separate physical components
for the purposes of illustration only. It is perfectly acceptable for an equipment manufacturer to combine one or more of these functions in a single physical device.
For example, a manufacturer many choose to integrate the SIP Proxy Server function with the IP PBX function, while another manufacturer many choose to integrate the SIP Proxy Server, IP PBX and Firewall functions. Both implementations (as well as other combinations) are considered to be conformant as long as they fully adhere to the individual rules governing each of the integrated functions.
Key Benefits of Implementing SIPconnect
SIPconnect establishes norms for connectivity well beyond the simple population of SIP headers, and offers the following key benefits:
- Universal Approach. SIPconnect fills a current void in the industry by providing clear instructions for IP peering between IP PBX and VoIP service providers. This will accelerate adoption and reduce development
costs for PBX developers and service providers.
- Customer Cost Savings. Direct IP peering makes VoIP gateways unnecessary,
and extends the benefits and savings of VoIP communication systems (i.e. DID and conferencing) into the network and beyond to compliant destinations.
- Transparent Feature Transport. Individual
end-user information is passed from the IP PBX to the network intact (and with application layer security intact) rather than being lumped into one account. This enables important information for presence and other user-based applications to travel through the network to terminating IP PBXs without being stripped out.
- Quality of Service. Important transport layer issues are defined, including: QoS configuration, echo cancellation, method for DTMF relay, packetization rates, codec support, and dealing with fax and modem traffic.
- Security. Requirement for Transport Layer Security along with defined approaches to identity and authentication
provide a secure model of IP PBX to Service Provider peering.
Conclusion
Next-generation network solutions that utilize
gateways and other equipment to enable IP networks to interface with TDM networks have been essential in the evolution of VoIP and enhanced IP communications. These bridging solutions between legacy networks and new IP networks have contributed to the growing deployment of IP PBXs and other next-gen communication solutions.
Now that VoIP-based communications solutions
like IP PBXs are being deployed to customers at breakthrough rates, and VARs, Interconnects and VoIP service providers are increasingly looking for more efficient and cost effective ways to serve their customers, a better method of interfacing IP PBXs with service provider networks is necessary.
In fact, the ability to transport the intelligent
end-user information associated with enhanced features from a customer premises through the network and beyond to another customer is vital for the overall growth of the IP telephony marketplace. Direct IP peering enables this next generation interconnection
and the SIPconnect Interface Specification offers a revolutionary starting point for equipment manufacturers, service providers, and VARs and Interconnects.
Indeed, the ability of an IP PBX to directly peer with a VoIP service provider offers VARs and Interconnects and other channel partners immediate relief from the need to troubleshoot quality of service issues, and allows a number of important security-
related functions to be handled by the VoIP service provider network, including NAT traversal for seamless SIP connectivity through network firewalls. |
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