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| 8.2 |  | Quality of Service Mechanisms |
| 8.2.4 |  | Differentiated services model |

The Differentiated Services or DiffServ architecture is an emerging standard from the IETF. This architecture specifies that each packet is classified upon entry into the network. The classification is carried in the IP packet header, using either the IP precedence or the preferred Differential Services Code Point (DSCP). These are represented using the first three or six bits of the Type of Service (ToS) field. Classification can also be carried in the Layer 2 frame in the form of the Class of Service (CoS) field embodied in ISL and 802.1Q frames.

Once packets are classified at the edge by access layer switches or by border routers, the network uses the classification to determine how the traffic should be queued, shaped, and policed.

Unlike the IntServ model, DiffServ does not require network applications be QoS aware.