Table Of Contents
Medianet Campus Cisco Catalyst 6500 QoS Design
Role in Medianet Campus Network
The Cisco Catalyst 6500 series switches are well-suited to the role of distribution- or core-layer switches in medianet campus networks. As such, these switches typically connect directly to other switches or routers, as shown in Figure 1.
To simplify design, this document assumes the use of WS-X6716-10GE linecards.
Figure 1 Cisco Catalyst 6500 Switches in a Medianet Campus Network
QoS Design Steps
There are four main steps to configure QoS on Cisco Catalyst 6500 series switches:
1. Enable QoS
2. Configure DSCP-Trust
3. Configure Ingress Queuing
4. Configure Egress Queuing
Step 1: Globally Enable QoS
QoS is globally enabled on the Cisco Catalyst 6500 with the mls qos command.
Step 2: Configure DSCP-Trust
DSCP trust is configured with the mls qos trust dscp interface-configuration command.
Switch ports that can be set to trust DSCP are shown as yellow circles in Figure 1.
Step 3: Configure Ingress Queuing
Three considerations need to be taken into account when determining if ingress queuing configuration is required on the Cisco Catalyst 6500 linecard:
•Is the linecard oversubscribed?
•Is the linecard operating in the distribution or core layers of the medianet campus network?
•Does the linecard support DSCP-to-Queue mapping?
Ingress queuing is only recommended when the answer to all three questions is Yes.
The medianet ingress queuing model for the Cisco Catalyst 6500 (with 6716 linecards) is shown in Figure 2.
Figure 2 Catalyst 6500 (6716) Ingress Queuing Model
Step 4: Configure Egress Queuing
The medianet egress queuing model for the Cisco Catalyst 6500 (with 6708 or 6716 linecards) is shown in Figure 3.
Figure 3 Catalyst 6500 (6716) Egress Queuing Model
Ingress QoS policies on the Cisco Catalyst 6500 are configured on the logical Port-Channel interface (typically these are simply to enable DSCP trust) , while egress QoS policies are configured on the physical port-member interfaces.
Cisco Validated Design (CVD)
The Cisco Validated Design for Cisco Catalyst 6500 series switches with WS-X6716-10GE linecards in the role of a distribution- or core-layer switch in a medianet campus network is presented on the reverse.
Note: Highlighted commands are global; otherwise these are interface specific.For more details, see Medianet Campus QoS Design 4.0: :http://www.cisco.com/en/US/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND_40/QoSCampus_40.html.