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BigIron RX Series Configuration Guide
487
53-1002253-01
Determining packet drop priority using WRED
18
Determining packet drop priority using WRED
You can configure a
device
to monitor traffic congestion and drop packets according to a WRED
(Weighted Random Early Detection) algorithm. This algorithm enables the system to detect the
onset of congestion and take corrective action. In practice, WRED causes a Switch to start dropping
packets as traffic in the switch starts to back up. WRED provides various control points that can be
configured to change a system's reaction to congestion. The following variables are used when
calculating whether to drop or forward packets:
•
Statistical Average-Q-Size – The statistical average size of the queue calculated over time on
the switch.
•
Current-Q-Size – The current size of the queue as calculated on the switch.
•
Wq – This variable specifies the weights that should be given to the current queue size and the
statistical average-q-size when calculating the size for WRED calculations.
•
Max-Instantaneous-Q-Size – The maximum size up to which a queue is allowed to grow.
Packets that cause the queue to grow beyond this point are unconditionally dropped. This
variable is user configured.
•
Min-Average-Q-Size – The average queue size below which all packets are accepted. This
variable is user configured.
•
Max-Average-Q-Size – The average queue size above which all packets are dropped. This
variable is user configured.
•
Pmax – The maximum drop probability when queue-size is at Max-Average-Q-Size. This variable
is user configured.
•
Pkt-Size-Max – The packet size to which the current packet's size is compared as shown in the
algorithm below. This variable is user configured.
Mark
The marking type enabled on the interface. The marking type can be
any of the following:
•
COS – CoS marking is enabled.
•
DSCP – DSCP marking is enabled.
•
No – Marking is not enabled.
Trust-Level
The trust level enabled on the interface. The trust level can be one of
the following:
•
DSCP
•
L2 CoS
CoS-DSCP map
COS
The CoS (802.1p) values.
dscp
The DSCP values to which the device maps the CoS values above.
DSCP-priority map
d1 and d2
The DSCP -> forwarding priority mappings that are currently in effect.
DSCP-DSCP map
d1 and d2
The DSCP -> DSCP mappings that are currently in effect.
CoS-priority map
The CoS (802.1p) forwarding priority mapping that is currently in effect.
TABLE 95
ToS-based QoS configuration information (Continued)
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Содержание BigIron RX Series
Страница 100: ...24 BigIron RX Series Configuration Guide 53 1002253 01 Logging on through the Web Management Interface 2 ...
Страница 192: ...116 BigIron RX Series Configuration Guide 53 1002253 01 Configuring authentication method lists 4 ...
Страница 228: ...152 BigIron RX Series Configuration Guide 53 1002253 01 Enabling WAN PHY mode support 6 ...
Страница 312: ...236 BigIron RX Series Configuration Guide 53 1002253 01 Displaying IP information 7 ...
Страница 356: ...280 BigIron RX Series Configuration Guide 53 1002253 01 Resetting LLDP statistics 9 ...
Страница 402: ...326 BigIron RX Series Configuration Guide 53 1002253 01 Transparent firewall mode 11 ...
Страница 432: ...356 BigIron RX Series Configuration Guide 53 1002253 01 SuperSpan 12 ...
Страница 500: ...424 BigIron RX Series Configuration Guide 53 1002253 01 MRP CLI example 14 ...
Страница 580: ...504 BigIron RX Series Configuration Guide 53 1002253 01 Configuring multicast traffic engineering 18 ...
Страница 591: ...BigIron RX Series Configuration Guide 515 53 1002253 01 Displaying traffic reduction 19 ...
Страница 592: ...516 BigIron RX Series Configuration Guide 53 1002253 01 Displaying traffic reduction 19 ...
Страница 598: ...522 BigIron RX Series Configuration Guide 53 1002253 01 Viewing Layer 2 ACLs 20 ...
Страница 656: ...580 BigIron RX Series Configuration Guide 53 1002253 01 Trunk formation 22 ...
Страница 754: ...678 BigIron RX Series Configuration Guide 53 1002253 01 Displaying RIP filters 24 ...
Страница 814: ...738 BigIron RX Series Configuration Guide 53 1002253 01 Displaying OSPF information 25 ...
Страница 932: ...856 BigIron RX Series Configuration Guide 53 1002253 01 Generalized TTL security mechanism support 26 ...
Страница 980: ...904 BigIron RX Series Configuration Guide 53 1002253 01 Clearing IS IS information 28 ...
Страница 1000: ...924 BigIron RX Series Configuration Guide 53 1002253 01 Using secure copy 30 ...
Страница 1088: ...1012 BigIron RX Series Configuration Guide 53 1002253 01 IP source guard 35 ...
Страница 1108: ...1032 BigIron RX Series Configuration Guide 53 1002253 01 Reading CDP packets 37 ...
Страница 1126: ...1050 BigIron RX Series Configuration Guide 53 1002253 01 Clearing sFlow statistics 39 ...
Страница 1140: ...1064 BigIron RX Series Configuration Guide 53 1002253 01 802 1s Multiple Spanning Tree Protocol 40 ...
Страница 1324: ...1248 BigIron RX Series Configuration Guide 53 1002253 01 Displaying OSPFv3 information 48 ...
Страница 1363: ...BigIron RX Series Configuration Guide 1287 53 1002253 01 Continuous System Monitor 51 ...
Страница 1364: ...1288 BigIron RX Series Configuration Guide 53 1002253 01 Continuous System Monitor 51 ...
Страница 1404: ...1328 BigIron RX Series Configuration Guide 53 1002253 01 Commands That Require a Reload D ...
Страница 1458: ...1382 BigIron RX Series Configuration Guide 53 1002253 01 VSRP E ...