Enterprise QoS Solution Reference Network Design Guide

Chapter 2 Campus QoS Design
Version 3.3
Catalyst 2950—QoS Considerations and Design
In the example below, the ACEs being referenced by QoS policies are using IP protocol masks, including
(TCP/UDP) source ports.
Example 2-6 Show MLS Masks QoS Verification of an Untrusted Multi-Application Server Model
CAT2950#show mls masks qos
Mask1
Type : qos
Fields : ip-proto, src-port
Policymap : UNTRUSTED-SERVER
Interfaces : Fa0/1
CAT2950#
Catalyst 2950—Conditionally-Trusted IP Phone + PC with Scavenger-Class QoS
(Basic) Model
Configuration
This section includes the following topics:
Configuration
Catalyst MLS QoS Verification Commands
When configuring an access-switch to trust/conditionally-trust CoS, then the default mapping for CoS 5
should be adjusted to point to DSCP EF (46), instead of DSCP CS5 (40). This modification is shown
below.
Example 2-7 Catalyst 2950—CoS-to-DSCP Marking Modification for Voice
CAT2950(config)#mls qos map cos-dscp 0 8 16 24 32 46 48 56 ! Maps CoS 5 to EF
CAT2950(config)#
Note Adjusting the default CoS-to-DSCP mapping for call signaling (which formerly was mapped from CoS
3 to DSCP AF31/26) is no longer required. This is because the default mapping of CoS 3 points to DSCP
CS3 (24), which is the call signaling marking that all Cisco IP Telephony devices markings will migrate
to.
Catalyst MLS QoS Verification Commands
The show mls qos map [cos-dscp | dscp-cos] verification command returns the DSCP-to-CoS and
CoS-to-DSCP mappings. These mappings may be either the default mappings or manually configured
overrides.
In the example below, the default mapping for CoS 5 (DSCP CS5) has been modified to point to DSCP
EF instead.
Example 2-8 Show MLS QoS Map Verification for a Catalyst 2950 Switch
CAT2950#show mls qos map
Dscp-cos map:
dscp: 0 8 10 16 18 24 26 32 34 40 46 48 56
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Enterprise QoS Solution Reference Network Design Guide
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