Packet Filtering; Rate Limiting On Ports - H3C S7500 Series Operation Manual

Operation Manual – QoS
H3C S7500 Series Ethernet Switches

1.1.6 Packet Filtering

Packet filter means filtering the service traffic. For example, in the operation of dropping
packets, the service traffic matching the traffic classification rule is dropped and the
other traffic is permitted. Ethernet switches adopt complicated traffic classification rules
to filter the packets based on much information and to drop these useless, unreliable,
and doubtful packets. Therefore, the network security is enhanced.
The two critical steps in the packet filtering operation are:
Step1: Classify the inbound packets of the port by the specific classification rules.
Step 2: Filter and drop the classified packets.
The packet filtering feature can be implemented by applying ACL rules to a port. Refer
to the description in the ACL module for detailed configurations.

1.1.7 Rate Limiting on Ports

Rate limiting on ports is port-based rate limiting. It limits the total rate of outbound
packets on a port.
1.1.8 TP
The network will be made more congested by plenty of continuous burst packets if the
traffic of each user is not limited. The traffic of each user must be limited in order to
make better use of the limited network resources and provide better service for more
users. For example, if each traffic can only get its committed resources in an interval,
network congestion caused by excess bursts can be avoided.
Traffic policing (TP) is a kind of traffic control policy to limit the traffic and its resource
usage by supervising the traffic specification. The traffic control policy is implemented
according to the evaluation results on the premise of knowing whether the traffic
exceeds the specification. The token bucket is generally adopted in the evaluation of
traffic specification.
I. Traffic evaluation and the token bucket
The token bucket can be considered as a container with a certain capacity to hold
tokens. The system puts tokens into the bucket at the set rate. When the token bucket
is full, the extra tokens will overflow and the number of tokens in the bucket stops
increasing.
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Chapter 1 QoS Configuration