Planet Networking & Communication WGSW-48000 User Manual page 115

The four TOS bits provide 15 different priority values, however only five values have a defined meaning.
DiffServ Code Point (DSCP) － is the traffic prioritization bits within an IP header that are encoded by certain applications
and/or devices to indicate the level of service required by the packet across a network. DSCP are defined in RFC2597 for
classifying traffic into different service classes. The Managed Switch extracts the codepoint value of the DS field from IPv4
packets and identifies the priority of the incoming IP packets based on the configured priority.
Destination
Preamble
Address
6 bytes
The DSCP is six bits wide, allowing coding for up to 64 different forwarding behaviors. The DSCP retains backward
compatibility with the three precedence bits so that non-DSCP compliant, TOS-enabled devices, will not conflict with the DSCP
mapping. Based on network policies, different kinds of traffic can be marked for different kinds of forwarding.
The page includes the following fields:
Object
• Mode
0 1 2
Precedence
IPv4 Packet Header Type of Service Octet
4 bit
VER=0100
VLAN
Source
TAG
Address
(Optional)
6 bytes 4 bytes
Figure 4-8-3: IPv4 frame format
Figure 4-8-4 DSCP configuration page screenshot
Description
Specifies the advanced QoS mode to be used.
• Disable
3 4 5 6
TOS
4 bit
Header Size
Ethernet Type
(0800)
2 bytes
Disables advanced QoS mode on the device.
115
User's Manual of WGSW-48000
7
MBZ
6 bit 2 bit
DiffServ RES
Data FCS
2 bytes 46-1517 bytes 4 bytes