Comtech EF Data MDX420 SkyWire Manual - Manual (Page 114)

MDX420 SkyWire™ Satellite Network Gateway SkyWire QoS
MN-MDX420 Revision 6 C–4
C.2.3 IPv4 Packets with a Differentiated Services field (RFC 2474)
When a packet doesn't contain an IEEE tag, and it's an IPv4 packet with a Differentiated Services
field (DS), SkyWire uses the information contained in the Differentiated Services Code point field
to determine the appropriate queue. The Differentiated Services field is contained in the second
byte of the IPv4 header and supports 64 codepoints with 63 being the highest priority and 0 being
the lowest. The following diagrams illustrate the format of the IPv4 Differentiated Services
information and their mapping to the available queues. Please note, in IPv4 the Type of Service
field (discussed in the previous section) and Differentiated Services field occupy the same
location in the IP header, therefore, only one of these fields will be present in any particular IPv4
header.
IPv4 Differentiated Services Field
Differentiated Services Codepoint
6 bits
Reserved
2 bits
Network Queue
Codepoints 48 - 63
Critical Queue
Codepoints 32 - 47
Immediate Queue
Codepoints 16 - 31
Routine Queue
Codepoints 0 - 15
Queue
Manager
Packets Out
IPv4 Differentiated Services Traffic Flow
Packets In