Comtech EF Data MDX420 SkyWire Manual - Manual (Page 112)

MDX420 SkyWire™ Satellite Network Gateway SkyWire QoS
MN-MDX420 Revision 6 C–2
By making use of the information inherent in the data stream, SkyWire offers Quality of Service
when no other QOS source is available. While at the same time, providing transparent operation
that won't interfere when external equipment is used for traffic shaping. The following paragraphs
provide additional detail on the various types of QOS information available in the data stream and
how SkyWire uses them to route the data to the appropriate queue.
C.2.1 IEEE Tagged Packets
When a packet contains an optional IEEE tag, SkyWire uses the priority information contained in
the tag to determine the appropriate queue. The IEEE tag supports 8 priorities with 7 being the
highest and 0 being the lowest. The following diagrams illustrate the format of the IEEE tag and
the mapping of the various priorities to the four available queues.
IEEE Tag Format
Second Octet
0x00
Priority
3 bits
CFI
1 bit
VID (start)
4 bits
VID (continued)
8 bits
First Octet
0x81
Network Queue
Priority 6 and 7
Critical Queue
Priority 4 and 5
Immediate Queue
Priority 2 and 3
Routine Queue
Priority 0 and 1
Queue
Manager
Packets Out
IEEE Tag Prioritized Traffic Flow
Packets In