![background image](http://html.mh-extra.com/html/d-link/dcs-3010/dcs-3010_user-manual_77595050.webp)
50
D-Link DCS-3010 User Manual
Configuration
QoS/DSCP
DSCP-ECN defines QoS at Layer 3 (Network Layer). The Differentiated Services (DiffServ) model is based on packet marking and
router queuing disciplines. The marking is done by adding a field to the IP header, called the DSCP (Differentiated Services Code
Point). This is a 6-bit field that provides 64 different class IDs. It gives an indication of how a given packet is to be forwarded, known
as the Per Hop Behavior (PHB). The PHB describes a particular service level in terms of bandwidth, queuing theory, and dropping
(discarding the packet) decisions. Routers at each network node classify packets according to their DSCP value and give them a
particular forwarding treatment. For example, how much bandwidth should be reserved.
Quality of Service refers to a resource reservation control mechanism, which guarantees a certain quality to different services on the
network. Quality of service guarantees are important if the network capacity is insufficient, especially for real-time streaming multimedia
applications. Quality can be defined as, for instance, a maintained level of bit rate, low latency, no packet dropping, etc.