March 11, 2010

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The introduction of SIP brings the challenge of protecting the network from an untrusted network, and the opportunity to manage the routing of calls to a degree not possible with traditional telephony. This installment of our continuing Knowledge Base will review how an Ingate Enterprise Session Border Controller (E-SBC) can address both the challenges and opportunities.


Diagnosing and Troubleshooting


SIP trunks can deliver excellent voice quality and reliability.  However, employing tools for diagnosing, isolating and troubleshooting problems with the VoIP media stream helps avoid potential issues, including QoS problems.    


Gather Information at the Network Edge

The metrics that can be gathered at the point of entry to an enterprise network are valuable in identifying and diagnosing problems that could degrade voice quality.  Enterprise Session Border Controllers (E-SBCs) like the Ingate Firewall and SIParator and the IX78 E-SBC are located at the right place in the network.

For carriers, the demarcation point between their network and an enterprise network can also serve as the first line of defense.  The Ingate Firewall/SIParator can sit on the edge of the enterprise network and serve as this demarcation point, gathering the statistics necessary to monitor service delivery to maintain QoS.  This allows carriers to see the primary statistics for determining the quality of the call through the network and diagnose whether problems are caused on the public or private side.


Diagnostic Tools

Ingate has extensive diagnostic tools to ensure maximum voice quality, QoS and reliability in all VoIP deployments, including SIP trunking.  One such tool is media quality scoring.  With the Ingate as demarcation point, it can monitor the RTP stream and compute statistics for the number of packets sent, bytes sent, jitter, number of missing packets and maximum number of consecutive missing packets.  This information can be gathered as separate data for each direction and reported individually.  It can also be used to compute a Mean Opinion Score (MOS).

The Ingate can also be placed in front of an existing firewall, allowing the Ingate to employ QoS rules with the introduction of SIP.  The Ingate will enable the use of SIP, leave an existing SIP-unaware network firewall in place and still provide the bandwidth management necessary to ensure that voice receives priority, and therefore does not suffer from conflicts with data packets which can stand delay, where voice cannot.


Voice quality and reliability are competitive differentiators for carriers and enterprises alike.  Taking the right steps to diagnose and troubleshoot issues before they become serious makes smart business sense.



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SIP Trunking Benefits and Best Practises - Whitepaper

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