* DiffServ uses the 6-bit Differentiated services Field (DS field) in the IP header for packet classification purposes.

* In the Diffserv model, the marker marks a packet with a value that reflects a forwarding behavior. Marking is the process of placing a value in the packet's header to indicate how to forward the packet to the network. IPQoS contains two marker modules:

/ dscpmk – Marks the DS field in an IP packet header with a numeric value that is called the Differentiated Services codepoint, or DSCP. A Diffserv-aware router can then use the DS codepoint to apply the appropriate forwarding behavior to the packet.

/ dlcosmk – Marks the virtual local area network (VLAN) tag of an Ethernet frame header with a numeric value that is called the user priority. The user priority indicates the class of service (CoS), which defines the appropriate forwarding behavior to be applied to the datagram.

Note:

* Differentiated services or DiffServ is a computer networking architecture that specifies a simple, scalable and coarse-grained mechanism for classifying and managing network traffic and providing quality of service (QoS) on modern IP networks. DiffServ can, for example, be used to provide low-latency to critical network traffic such as voice or streaming media while providing simple best-effort service to non-critical services such as web traffic or file transfers.

* IPQoS, included in Solaris, includes the following modules, which are part of the Differentiated Services (Diffserv) architecture that is defined in RFC 2475:

Classifier

Meter

Marker

IPQoS adds the following enhancements to the Diffserv model:

Flow-accounting module

802.1D datagram marker