Инструкции По Установке для 3com S7906E

 

13-11 

0 000000 

be 

(default) 

 

802.1p priority lies in Layer 2 packet headers and is applicable to occasions where Layer 3 header 

analysis is not needed and QoS must be assured at Layer 2. 

Figure 13-2 An Ethernet frame with an 802.1Q tag header 

 

 

As shown in 

, the 4-byte 802.1Q tag header consists of the tag protocol identifier (TPID, two 

bytes in length), whose value is 0x8100, and the tag control information (TCI, two bytes in length). 

 presents the format of the 802.1Q tag header. The Priority field in the 802.1Q tag header is 

called the 802.1p priority, because its use is defined in IEEE 802.1p. 

 presents the values 

for 802.1p priority.  

Figure 13-3 802.1Q tag header 

 

 

Table 13-22 Description on 802.1p priority 

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