Comtech EF Data DMD-2050E - Manual (Page 285)

DMD2050E Universal Satellite Modem Ethernet Data Interface Setup
MN-DMD2050E Revision 2 H–3
When Port 4 is selected for Daisy Chain, any data received on Port 4 (JS4) is forwarded to of the
other LAN side ports (Ports 1 - 3) and is not transmitted over the satellite. This is extremely
useful in a point-to -multipoint configuration as illustrated in Figure H-1.
H.1.3 Ethernet QOS Type
When Normal QOS is selected, the interface determines a packets priority based on the
following:
• IEEE 803.3ac Tag when present
• IPv4 Type of Service / Differentiated Services Field
• Ipv6 Traffic Class
When Port Based QOS is selected, the interface determines the priority of a packed based upon
the port on which it arrived.
• Port 1 (JS1) has the highest priority
• Port 2 (JS2) has the second highest priority
• Port 3 (JS3) has the second lowest priority
• Port 4 (JS4) has the lowest priority
H.1.4 Ethernet QOS Queue
When Fair Weighted queuing is selected, the interface transmits packets at a rate of 8, 4, 2, and
1 from the highest priority queue to the lowest respectively. With fair weighted queuing, all
queues with data in them are guaranteed to receive some bandwidth.
When Strict Priority is selected, the interface transmits packets from the highest priority queue
until it is empty. It then begins transmitting data from the next highest priority queue. If higher
priority data arrives, the interface finishes the current packet and then goes back to transmitting
packets from the higher priority queue until it is again empty. Care must be taken when selecting
Strict Priority, as it is entirely possible for the lower priority queues to be stalled indefinitely.