3Com 3C13618 Command Reference Manual page 287

3Com Router Command Reference Guide — V1.00
Parameter
de: Discard the Frame Relay packets whose the discard eligible (DE) bit is 1 if there is
congestion.
ecn: Process the BECN and FECN flag bits in the Frame Relay packets if there is
congestion.
queue-percentage: Network congestion threshold, the utilization rate of PVC queue. It
equals to the percentage that the current PVC queue length ocuppies in the total queue
length, ranging from 0 to 100.
Description
Using the congestion-threshold command, you can enable the congestion
management on a Frame Relay PVC. Using the undo congestion-threshold
command, you can disable the congestion management on the Frame Relay PVC.
If the percentage that the current PVC queue length ocuppies the total queue length is
greater than queue-percentage divided by 100, the router will assume that congestion
occurs on the PVC, and will begin to implement congestion processing on the packets
on the PVC.
Once congestion occurs, the router will adopt the following two measures:
Discard all the Frame Relay packets that are marked with the DE and are
transmitted on the PVC.
Process the BECN and FECN flag bits in the Frame Relay packets transmitted on
the PVC. As for the forward packets to be forwarded, the router will set the FECN
flag bit in the Frame Relay packet headers to 1. As for the backward packets on
the same PVC, the router will set the BECN flag bit in the Frame Relay packet
headers to 1. If there is no backward packets to be forwarded after a certain period,
the router will automatically transmit the Q922A Test Reponse packets with the
BECN flag bit 1 to the calling DTE.
Note:
Only when the Frame Relay traffic shaping is enabled on the interface where the PVC is located, can the
congestion management take effect on the PVC.
For related commands, see fr congestion-threshold.
Example
# Set the Frame Relay PVC to discard the Frame Relay packets that are marked with
DE bit when the current queueing length exceeds 80% of the total queueing length.
[3Com-fr-class-one]congestion-threshold de 80
94