Vivotek CC8371-HV, Руководство пользователя

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User's Manual - 91
QoS/DSCP (the DiffServ model)
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 Codepoint). 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, queueing 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 to reserve for it.
Below are the setting options of DSCP (DiffServ Codepoint). Specify the DSCP value for each
application (0~63).
Note that different vendors of network devices might have different methodologies and unique
implementations. Shown below is a sample corresponding information from a Cisco switch. You
should enter a DSCP tag value according to the information provided by the network devices.
32
QoS Baseline/Technical Marketing Classification and Marking Recommendations
Application Layer3 Classification Layer 2 CoS/MPLS EXP
IPP PHB DSCP
IP Routing 6 CS6 48 6
Voice 5 EF 46 5
Interactive Video 4 AF41 34 4 QoS B
Streaming-Video 4 CS4 32 4
Locally-defined Mission-
Critical Data
3 - 25 3
Call-signaling 3 AF31/CS3 26/24 3
Transactional Data 2 AF21 18 2
Network Management 2 CS2 16 2
Bulk Data 1 AF11 10 1