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C
HAPTER
11
| Class of Service
Layer 3/4 Priority Settings
– 242 –
L
AYER
3/4 P
RIORITY
S
ETTINGS
M
APPING
L
AYER
3/4
P
RIORITIES
TO
C
O
S
V
ALUES
The switch supports several common methods of prioritizing layer 3/4
traffic to meet application requirements. Traffic priorities can be specified in
the IP header of a frame, using the priority bits in the Type of Service (ToS)
octet, or the number of the TCP/UDP port. If priority bits are used, the ToS
octet may contain three bits for IP Precedence or six bits for Differentiated
Services Code Point (DSCP) service. When these services are enabled, the
priorities are mapped to a Class of Service value by the switch, and the
traffic then sent to the corresponding output queue.
Because different priority information may be contained in the traffic, this
switch maps priority values to the output queues in the following manner –
The precedence for priority mapping is DSCP Priority and then Default Port
Priority.
N
OTE
:
The default settings used for mapping priority values from ingress
traffic to internal DSCP values are used to determine the hardware queues
used for egress traffic, not to replace the priority values. These defaults are
designed to optimize priority services for the majority of network
applications. It should not be necessary to modify any of the default
settings, unless a queuing problem occurs with a particular application.
S
ETTING
P
RIORITY
P
ROCESSING
TO
DSCP
OR
C
O
S
The switch allows a choice between using DSCP or CoS priority processing
methods. Use the Priority > Trust Mode page to select the required
processing method.
CLI R
EFERENCES
"qos map trust-mode" on page 938
C
OMMAND
U
SAGE
If the QoS mapping mode is set to DSCP, and the ingress packet type is
IPv4, then priority processing will be based on the DSCP value in the
ingress packet.
If the QoS mapping mode is set to DSCP, and a non-IP packet is
received, the packet’s CoS and CFI (Canonical Format Indicator) values
are used for priority processing if the packet is tagged. For an untagged
packet, the default port priority (see
) is used for priority
processing.
If the QoS mapping mode is set to CoS, and the ingress packet type is
IPv4, then priority processing will be based on the CoS and CFI values
in the ingress packet.
For an untagged packet, the default port priority (see
) is used
for priority processing.
Содержание DG-FS4526E
Страница 4: ...ABOUT THIS GUIDE 4...
Страница 34: ...CONTENTS 34...
Страница 50: ...TABLES 50...
Страница 52: ...SECTION I Getting Started 52...
Страница 62: ...CHAPTER 1 Introduction System Defaults 62...
Страница 80: ...CHAPTER 2 Initial Switch Configuration Managing System Files 80...
Страница 82: ...SECTION II Web Configuration 82...
Страница 100: ...CHAPTER 3 Using the Web Interface Navigating the Web Browser Interface 100...
Страница 128: ...CHAPTER 4 Basic Management Tasks Resetting the System 128...
Страница 166: ...CHAPTER 5 Interface Configuration VLAN Trunking 166...
Страница 198: ...CHAPTER 6 VLAN Configuration Configuring VLAN Mirroring 198...
Страница 516: ...CHAPTER 17 IP Services Displaying the DNS Cache 516...
Страница 562: ...CHAPTER 19 Using the Command Line Interface CLI Command Groups 562...
Страница 652: ...CHAPTER 22 SNMP Commands 652...
Страница 660: ...CHAPTER 23 Remote Monitoring Commands 660...
Страница 714: ...CHAPTER 24 Authentication Commands Management IP Filter 714...
Страница 802: ...CHAPTER 27 Interface Commands 802...
Страница 824: ...CHAPTER 29 Port Mirroring Commands RSPAN Mirroring Commands 824...
Страница 846: ...CHAPTER 32 Address Table Commands 846...
Страница 874: ...CHAPTER 33 Spanning Tree Commands 874...
Страница 886: ...CHAPTER 34 ERPS Commands 886...
Страница 928: ...CHAPTER 35 VLAN Commands Configuring Voice VLANs 928...
Страница 942: ...CHAPTER 36 Class of Service Commands Priority Commands Layer 3 and 4 942...
Страница 998: ...CHAPTER 38 Multicast Filtering Commands Multicast VLAN Registration 998...
Страница 1022: ...CHAPTER 39 LLDP Commands 1022...
Страница 1064: ...CHAPTER 40 CFM Commands 1064...
Страница 1084: ...CHAPTER 42 Domain Name Service Commands 1084...
Страница 1090: ...CHAPTER 43 DHCP Commands DHCP Client 1090...
Страница 1122: ...CHAPTER 44 IP Interface Commands IPv6 Interface 1122...
Страница 1124: ...SECTION IV Appendices 1124...
Страница 1129: ...APPENDIX A Software Specifications Management Information Bases 1129 Trap RFC 1215 UDP MIB RFC 2013...
Страница 1130: ...APPENDIX A Software Specifications Management Information Bases 1130...
Страница 1152: ...COMMAND LIST 1152...
Страница 1161: ......
Страница 1162: ...DG FS4526E 042012 HW R01...