Switch 7700 Configuration Guide, v2

QoS Overview 195
such as MAC address, IP protocol, source IP address, destination IP address, and
the port number of application can be used for traffic classification. Generally, the
classification standards are encapsulated in the header of the packets. The packet
content is seldom used as the classification standard.
Packet Filter
Packet filters filter network traffic. For example, the deny operation discards the
traffic that is matched with a traffic classification rule, while allowing other traffic
to pass through. With the complex traffic classification rules, Ethernet switches
enable the filtering of information carried in Layer 2 traffic to discard the useless,
unreliable or doubtful traffic, to enhance network security.
To filter packets:
1 Classify the incoming traffic according to the classification rule.
2 Filter the classified traffic.
Traffic Policing
To deliver better service with limited network resources, QoS monitors the traffic
of the specific user on the incoming traffic, so it can make better use of the
assigned resource.
Bandwidth Assurance
Through the traffic reservation, a minimum bandwidth is reserved for specified
traffic flow. Even when the network congestion occurs, the QoS requirements
such as packet dropping ratio, delay, and jitter can also be satisfied.
Port Rate Limit
The port rate limit is the port-based rate limit used for limiting the general speed
of packet output on the port.
Traffic Priority
The Switch 7700 can deliver priority tag service for special packets. The tags
include TOS, DSCP and 802.1p, etc., which can be used and defined in different
QoS modules.
Select Output Queue for the Packets
The Ethernet switch can select corresponding output queues for special packets.
Queue Scheduling
When congestion occurs, packets compete for resources. Strict-Priority Queue (SP)
algorithms overcome the problem.