S300, S500, S2700, S5700 and S6700 V200R024C00 Configuration Guide - QoS
This document describes the configurations of QoS functions, including MQC, priority mapping, traffic policing, traffic shaping, interface-based rate limiting, congestion avoidance, congestion management, packet filtering, redirection, traffic statistics, ACL-based simplified traffic policy, HQoS, and SAC.
This document describes the configurations of QoS functions, including MQC, priority mapping, traffic policing, traffic shaping, interface-based rate limiting, congestion avoidance, congestion management, packet filtering, redirection, traffic statistics, ACL-based simplified traffic policy, HQoS, and SAC.
Example for Configuring DSCP Priority Mapping
Networking Requirements
The network provides voice, video, and data services, with priorities in descending order. When flows of different services are transmitted on the network, devices must identify priorities of these services to provide differentiated services.
The precedence field in a packet depends on the network type. For example, packets on a Layer 3 network carry the DSCP field. As shown in Figure 3-8, the DSCP priorities of data, voice, and video packets are 16, 46, and 32, respectively. When service flows reach the Switch, the Switch places them into different queues for scheduling based on their priorities. Specifically, voice packets with DSCP priority 46 are placed into queue 5, video packets with DSCP priority 32 into queue 6, and data packets with DSCP priority 16 into queue 7.
On a switch, queues are mapped to PHBs. As such, DSCP priorities of packets can be mapped to PHBs so that packets are placed into corresponding queues based on their DSCP priorities. The PHBs of queues 5, 6, and 7 are EF, CS6, and CS7, respectively. For details about the mapping between PHBs and queues, see Mapping Between CoS Values and Interface Queue Indexes.
Configuration Roadmap
- Configure routes and interfaces to ensure Layer 3 network connectivity. In this example, the Layer 3 network has been configured.
- Create a DiffServ domain and map DSCP priorities to PHBs.
- Bind the DiffServ domain to the inbound interface GE0/0/1 on the Switch.
Only the S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S2730S-S, S5735-L-I, S5735-L1, S300, S5735-L, S5735S-L1, S5735-S, S500, S5735-S-I, S6735-S, S6730-H, S6730S-H, S6730-S, and S6730S-S support the ip-dscp-inbound command. Therefore, this example is applicable only to these models.
Procedure
- Create and configure a DiffServ domain.
# Create DiffServ domain ds on the Switch and map DSCP priorities to PHBs.
[Switch] diffserv domain ds [Switch-dsdomain-ds] ip-dscp-inbound 46 phb ef [Switch-dsdomain-ds] ip-dscp-inbound 32 phb cs6 [Switch-dsdomain-ds] ip-dscp-inbound 16 phb cs7 [Switch-dsdomain-ds] quit
- Bind the DiffServ domain to an interface.
# Bind DiffServ domain ds to GE0/0/1.
[Switch] interface gigabitethernet 0/0/1 [Switch-GigabitEthernet0/0/1] trust upstream ds [Switch-GigabitEthernet0/0/1] quit
- Verify the configuration.
# Send IP packets with DSCP priority 46 to GE0/0/1, and then run the display qos queue statistics interface GE0/0/1 command to check queue-based traffic statistics on the interface. If queue 5 has packet statistics, DSCP priority mapping is successfully configured.