For all circuit emulation channels except those with differential clock sources, RTP headers in absolute mode can be optionally enabled (disabled by default). For circuit emulation channels that use differential clock sources, this configuration is blocked. All channel groups on a specific DS1 or E1 can be configured for the same mode of operation.
When enabled for absolute mode operation, an RTP header is inserted. On transmit, the CES IWF inserts an incrementing (by 1 for each packet) timestamp into the packets. All other fields are set to zero. The RTP header is ignored on receipt. This mode is enabled for interoperability purposes only for devices that require an RTP header to be present.