Flow-Based Traffic Accounting; Burst - H3C S3100-52P Operation Manual

Operation Manual – QoS-QoS Profile
H3C S3100-52P Ethernet Switch
packets of multiple TCP connections simultaneously, the TCP connections will turn to
the state of congestion avoidance and slow startup for the traffics to be regulated. The
traffic peak will then occur in a certain future time. Consequently, the network traffic
jitters all the time.
II. WRED
You can use weighted random early detection (WRED) to avoid global TCP session
synchronization.
In WRED algorithm, an upper limit and a lower limit are set for each queue, and the
packets in a queue are processed as follows.
When the current queue length is smaller than the lower limit, no packet is
dropped;
When the queue length exceeds the upper limit, all the newly received packets are
dropped;
When the queue length is between the lower limit and the upper limit, the newly
received packets are dropped at random. The longer the queue, the more likely
the newly received packets may be dropped. However, a maximum drop
probability exists.
In WRED, random numbers are generated to determine the packets to be dropped. As
the dropping policy is determined by IP precedence, packets with lower precedence are
more likely to be dropped.
WRED prevents global TCP session synchronization. It enables other TCP sessions to
be free of a TCP session slowed down because of its packets being dropped. In this
way, TCP sessions can operate in different rates in any case and the link bandwidth can
be fully utilized.

1.3.11 Flow-based Traffic Accounting

The function of flow-based traffic accounting is to use ACL rules in traffic classification
and perform traffic accounting on the packets matching the ACL rules. You can get the
statistics of the packets you are interested in through this function.

1.3.12 Burst

The Burst function can provide better packet cache function and traffic forwarding
performance. It is suitable for networks where
Large amount of broadcast/multicast packets and large burst traffic exist.
Packets of high-rate links are forwarded to low-rate links or packets of multiple
links with the equal rates are forwarded to a single link that is of the same rate as
that of the incoming links.
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Chapter 1 QoS Configuration