AT-S80 Management Software User’s Guide
Section I: Using the Menus Interface
141
For example, a tagged packet with a priority tag of 6 is placed in the
egress port’s highest priority queue of 3, while a packet with a priority tag
of 1 is placed in the lowest priority queue.
Note
QoS is disabled by default on the switch.
You can customize these priority-to-queue assignments using the AT-S80
management software. The procedure for changing the default mappings
is found in “Mapping CoS Priorities to Egress Queues” on page 143. Note
that because all ports must use the same priority-to-egress queue
mappings, they are applied at the switch level. They cannot be set on a
per-port basis.
CoS primarily relates to tagged packets rather than untagged packets
because untagged packets do not contain a priority level. By default, all
untagged packets are temporarily assigned a priority level of 0 as they
enter a port and, at the default settings, are placed in a port’s Q0 egress
queue, the queue with the lowest priority. But you can override this by
assigning a different temporary priority level to a port so that all of the
untagged packets are stored in a different egress queue. The procedure
for this is explained in “Changing the Temporary Priority Level of Untagged
Traffic” on page 146.
One last thing to note is that the switch does not change the priority level in
a tagged packet. The packet leaves the switch with the same priority it had
when it entered. This is true even if you change the default priority-to-
egress queue mappings.
Table 2. Default Mappings of IEEE 802.1p Priority Levels
to Egress Port Priority Queues
IEEE 802.1p Traffic Class
AT-FS750 Switch
Egress Port Priority
Queue
0
0
1
0
2
0
3
1
4
2
5
2
6
3
7
3
Summary of Contents for AT-S80
Page 8: ...Contents 8 Appendix A AT S80 Software Default Settings 339 Index 343...
Page 12: ...Tables 12...
Page 24: ...24 Section I Using the Menus Interface...
Page 30: ...Chapter 2 Getting Started with the Menus Interface 30 Section I Using the Menus Interface...
Page 60: ...Chapter 4 Port Configuration 60 Section I Using the Menus Interface...
Page 78: ...Chapter 6 IGMP Snooping 78 Section I Using the Menus Interface...
Page 84: ...Chapter 7 Static Multicast Address 84 Section I Using the Menus Interface...
Page 90: ...Chapter 8 Port Mirroring 90 Section I Using the Menus Interface...
Page 96: ...Chapter 9 Dial in User Configuration 96 Section I Using the Menus Interface...
Page 118: ...Chapter 10 Virtual LANs 118 Section I Using the Menus Interface...
Page 170: ...Chapter 13 Rapid Spanning Tree Protocol RSTP 170 Section II Menus Interface...
Page 176: ...Chapter 14 Bandwidth Control 176 Section I Using the Menus Interface...
Page 206: ...Chapter 18 RADIUS Authentication Protocol 206 Section I Using the Menus Interface...
Page 212: ...212 Section II Using the Web Browser Interface...
Page 250: ...Chapter 23 Port Trunking 250 Section II Using the Web Browser Interface...
Page 254: ...Chapter 24 Port Mirroring 254 Section II Using the Web Browser Interface...
Page 260: ...Chapter 25 Static Multicast Address Table 260 Section II Using the Web Browser Interface...
Page 264: ...Chapter 26 IGMP Snooping 264 Section II Using the Web Browser Interface...
Page 272: ...Chapter 28 Bandwidth Control 272 Section II Using the Web Browser Interface...
Page 284: ...Chapter 29 Virtual LANs 284 Section II Using the Web Browser Interface...
Page 328: ...Chapter 36 Management Software Updates 328 Section II Using the Web Browser Interface...
Page 342: ...Appendix A AT S80 Software Default Settings 342...
Page 346: ...Index 346...