The SBC is defined by the IMS architecture for bridging VoIP traffic between two IP-based networks. The SBC is typically designed with two parallel paths – one for the signaling plane, and the other for the media.

Though both sides of the SBC are all-IP networks, there is still a significant amount of media processing required, as codecs on both sides of the SBC might be different. This is especially true when one network is a wireline network, while the other is a mobile network.

Primary challenges found in the media path include:
 

• Transcoding narrowband and wideband voice. For example, transcoding from the newly created wideband G.711.1 codec into narrowband G.711, or transcoding from the wideband-AMR mobile codec into the AAC codec used by some fixed video phones.
   
• Manipulating video – transcoding, resizing, etc. Required, for example, when bridging between wireline video at VGA resolutions and mobile video at QVGA resolutions.
   
• Packet frame-size modifications (also known in the SBC segment as transrating). Required when bridging between a network that natively works with a VoIP packet size of 10ms, for example, and a secondary network with a native VoIP pack size of 20ms.
   
• Bridging IPv4 in one network to IPv6 in the other network.
   
• Bridging between an unsecured VoIP network, and a network utilizing encryption in the form of Secure RTP (SRTP with AES encryption).

All these operations are supported by the SURF Engine, making it the ideal engine for driving your next generation SBC.