IEEE 802.1p
IEEE 802.1p was an IEEE working group that was supposed to re-regulate the transport of data of different priorities in computer networks . The resulting IEEE 802.1Q standard works on the 2nd level of the OSI reference model . The transmitted frames are divided into priority classes from 0 to 7. The 0 is used for frames that are not assigned a specific priority. The standard only specifies that the priority is coded with a number from 0 to 7, but does not make any further statements about how the frames should be treated in detail. The priorities are determined by the priority code point(PCP) field of the Tag Control Information (TCI) field encoded in an additional VLAN tag (see IEEE 802.3 Tagged MAC Frame ).
The prioritization of the frames is necessary in order to guarantee low latency or high data security in heavily used networks. Applications such as Voice over IP are given a high priority to keep latency and jitter low, while other applications with lower requirements are given lower priorities.
The IEEE never published a document under the name IEEE 802.1p. The contents of the working group have been incorporated into IEEE 802.1Q .
Prioritization level
The prioritization levels are divided into 8 levels by the 3-bit PCP field as follows:
| PCP | Network priority | Abbreviation | Traffic properties |
|---|---|---|---|
| 1 | 0 (lowest) | BK | Background |
| 0 | 1 | BE | Best effort |
| 2 | 2 | EE | Excellent effort |
| 3 | 3 | CA | Critical Applications |
| 4th | 4th | VI | Video, <100 ms delay |
| 5 | 5 | VO | Voice, <10 ms delay |
| 6th | 6th | IC | Internetwork Control |
| 7th | 7 (highest) | NC | Network Control |
The above recommendations have been revised in IEEE 802.1Q-2005 and differ from the original recommendations in IEEE 802.1D-2004.
See also
- Class of Service (CoS)
- Ethernet
- IEEE 802
- Differentiated Services (DiffServ)
Individual evidence
- ↑ IEEE Std. 802.1Q-2011, IEEE Standard for Local and metropolitan area networks - Bridges and Bridged Networks ( en , PDF; 12.7 MiB). ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. Table I-2 - Traffic type acronyms.
