3com WXR100 3CRWXR10095A User Manual

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ONFIGURING

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ERVICE

MSS performs classification on ingress to determine a packet’s CoS value. 
This CoS value is used to mark the packet at the egress interface.

The classification and marking performed by the switch depend on 
whether the ingress interface has an 802.1p or DSCP value other than 0, 
and whether the egress interface is tagged or is an IP tunnel.

The mappings between DSCP and CoS values are configurable. (See 
“Changing CoS Mappings” on page 344.) 802.1p and CoS values map 
directly and are not configurable. DSCP 0 of the DSCP-to-CoS map is 
reserved. 802.1p determines CoS for packets with DSCP 0. CoS 0 of the 
CoS-to-DSCP map is also reserved. CoS 0 packets are marked with DSCP 0.

Table 27 shows how WMM priority information is mapped across the 
network. When WMM is enabled, 3Com switches and MAPs perform 
these mappings automatically.

You can use static CoS to assign the same CoS value to all packets for a 
specific SSID. The static CoS value is assigned on the MAP, in both traffic 
directions (from the client to the WX and from the WX to the client). (For 
information, see “Configuring Static CoS” on page 343.)

Table 27   WMM Priority Mappings

0

0

0

0

0

0

Background

3

3

0x60

24

3

3

1

1

0x20

8

1

1

Best Effort

2

2

0x40

16

2

2

4

4

0x80

32

4

4

Video

5

5

0xa0

40

5

5

6

6

0xc0

48

6

6

Voice

7

7

0xe0

56

7

7