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XVI.
MAKING EBU3326/SIP COMPATIBLE CONNECTIONS
Comrex codecs (and many other brands) have a set of protocols that allow easy IP connections between units. In
general, when connecting between Comrex hardware, it’s best to use these proprietary modes to take the most
advantage of the features of the product.
However, many users are concerned about getting “locked in” to a certain codec brand. Because of this, an
international committee was formed by the European Broadcast Union called N/ACIP to hammer out a common
protocol to interconnect codec brands. This committee resulted in the establishment of
EBU3326
, a technical
document describing how best to achieve this goal.
EBU3326 by and large establishes a set of features each codec should support, and then leaves most of the heavy
lifting to other, previously established standards like SIP (IETF RFC 3261). Topics not covered (yet) by EBU3326
include things like carrying ancillary data, contact closures from end-to-end, codec remote control, monitoring, and
complex NAT traversal—which at this point are still left to the individual manufacturer’s discretion. If these topics
are important to a user’s application, it’s best to stick to a single codec vendor and their proprietary protocols.
More about ebu3326
The Tech 3326 document defines several mandatory encoding algorithms, and the transport layer that could be
used on them for compatibility. But the most complex part of the standard was the decision on how to arrange
Session Initialization, which is the handshake that takes place at the start of an IP codec call. The most commonly
used protocol is called
SIP
, which is used extensively by VoIP phones and therefore was a logical choice. SIP carries
the advantage of making BRIC-Link compatible with a range of other non-broadcast products, like VoIP hardware,
software, and even mobile phone apps.
ebu3326 In brIC-LInk
BRIC-Link does not fully comply with EBU3326, as it does not feature the mandatory MPEG Layer II codec. Aside
from this, BRIC-Link has been tested to be compatible with several other manufacturer’s devices using encoders
supported by both products. When using
EBU3326/SIP Compatible
mode (how the user interface describes
EBU3326), ancillary data, contact closures, Switchboard TS, Multistreaming and Multicasting are not supported.
Outgoing call profiles built with the EBU3326/SIP channel may lack some advanced options, and cannot be set for
different encoders in each direction (i.e., EBU3326/SIP calls are always symmetrical).
Summary of Contents for BRIC-Link
Page 1: ...Product Manual ...
