Figure 457 802.1Q tag header
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| TPID (Tag protocol identifier) |
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| TCI (Tag control information) |
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1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | Priority |
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7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Table 147 Description on 802.1p priority
802.1p priority (decimal) | 802.1p priority (binary) | Description |
0 | 000 | |
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1 | 001 | background |
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2 | 010 | spare |
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3 | 011 | |
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4 | 100 | |
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5 | 101 | video |
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6 | 110 | voice |
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7 | 111 | |
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Queue scheduling
In general, congestion management uses queuing technology. The system uses a certain queuing algorithm for traffic classification, and then uses a certain precedence algorithm to send the traffic. Each queuing algorithm handles a particular network traffic problem and has significant impacts on bandwidth resource assignment, delay, and jitter.
In this section, two common hardware queue scheduling algorithms Strict Priority (SP) queuing and Weighted Round Robin (WRR) queuing are introduced.
SP queuing
SP queuing is designed for
471