Comtech EF Data CME-5200 Manual - Manual (Page 51)

CME-5200 Digicast Media Router ASI Receiver Revision A
IP Routing Support MN/MRASIRCDC.IOM
Note that the upper 5 bits of the multicast IP address are ignored in the MAC so that 32
Multicast group IP addresses map to a single MAC address. This implies further filtering
is required at the end device.
B.3 Section Packing
Section packing is a technique to provide more optimal utilization of the MPEG-2
Transport Stream (TS) packet structure. When section packing is not used, each TS
packet (containing the MPE section) can carry no more than a single section. This often
results in wasted payload capacity when the sections are less than 184 bytes.
The section packing feature allows more than a single MPE section to be carried by an
MPEG-2 TS packet, thereby minimizing wasted payload capacity. In the case of a large
MPE section that spans multiple MPEG-2 packets, the ending of an MPE section may
occur in the middle of an MPEG-2 packet. In this instance, with section packing, a new
MPE section begins immediately after the first MPE section has finished without any
‘fill’ (wasted) bytes having to be inserted before the start of the next MPEG-2 packet.
Figure B-2. Section Packing
B-3