NETGEAR M4200 Software Administration Manual page 276

Weighted random early discard (WRED, also referred to as weighted random early detection)
considers packets for early discard only when the number of packets that are queued for
transmission on a port exceeds the relevant minimum WRED threshold. The green, yellow,
and red thresholds operate on TCP packets. A fourth threshold operates on non-TCP
packets.
If ECN is enabled and congestion occurs, ECN-capable TCP packets that are queued for
transmission and that are selected to be discarded by WRED are instead CE-marked and
transmitted. Packets that exceed the WRED upper threshold are also transmitted. If severe
congestion occurs on the switch (that is, no buffers are available), the packets are discarded.
On managed switches, ECN is implemented as part of the WRED configuration process. You
can configure any CoS queue to operate in ECN marking mode and you can configure
different discard thresholds for each color.
Client
1.1.1.1
Figure 29. WRED Explicit Congestion Notification configuration
To configure WRED Explicit Congestion Notification configuration:
1. Create class 1 and class 2.
(Netgear Switch) (Config)#class-map
(Netgear Switch) (Config)#class-map match-all class1
(Netgear Switch) (Config-classmap)#match srcip 1.1.1.1 255.255.255.255
(Netgear Switch) (Config-classmap)#exit
(Netgear Switch) (Config)#class-map match-all class2
(Netgear Switch) (Config-classmap)#match ip dscp 46
(Netgear Switch) (Config-classmap)#exit
2. Create a policy and configure the conform color for class 2.
(Netgear Switch) (Config)#policy-map p1 in
(Netgear Switch) (Config-policy-map)#class class1
(Netgear Switch) (Config-policy-classmap)#police-single-rate 1000000 128 128
conform-action transmit exceed-action transmit violate-action transmit
(Netgear Switch) (Config-policy-classmap)#conform-color class2
(Netgear Switch) (Config-policy-classmap)#exit
Managed Switches
1/0/25
Network
DiffServ
276
1/0/45
Switch
Server