7-3
called the 802.1p priority, because its use is defined in IEEE 802.1p. Table 7-3 presents the values for
802.1p priority.
Figure 7-3 802.1Q tag header
1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 Priority VLAN ID
TPID (Tag protocol identifier) TCI (Tag control information)
Byte 1 Byte 2
0
Byte 3 Byte 4
CFI
7 5432107 5432106 6 7 5432107 54321066
Table 7-3 Description on 802.1p priority
802.1p priority (decimal) 802.1p priority (binary) Description
0 000 best-effort
1 001 background
2 010 spare
3 011 excellent-effort
4 100 controlled-load
5 101 video
6 110 voice
7 111 network-management
802.11e Priority
To provide QoS services on WLAN, the 802.11e standard was developed. IEEE 802.11e is a MAC-layer
enhancement to IEEE 802.11. IEEE 802.11e adds a 2-byte QoS Control field to the 802.11e MAC frame
header. Three bits of the QoS control field represents the 802.11e priority, which ranges from 0 to 7.
Figure 7-4 802.11e frame structure
Priority Mapping Overview
Introduction to Priority Mapping
When a packet enters an AP, the AP assigns a set of QoS priority parameters to the packet based on a
certain priority field carried in the packet and sometimes may modify its priority, according to certain
To Next Page
Loading...
Need help?
General
