rate-limit
Establishes the egress rate limit in the port. The value is set in Mbps.
map
Configures the translation table for some COS values. The map command estab-
lishes which packets, with certain COS values, are re-tagged and transmitted by
the switch with a different COS value. Re-tagging is executed at entry, so the com-
mand must specify which port the packets you want re-tagged must enter through.
So that the packets being transmitted are re-tagged, configure the tag-insertion
option in the
feature vlan
menu for all ports where the re-tagged packets are trans-
mitted.
override-cos
Establishes the COS value that all packets received through this port are going to
be transmitted with. So that packets being transmitted are re-tagged, configure the
tag-insertion option in the
feature vlan
menu for all the ports where re-tagged
packets are transmitted.
priority
Establishes the egress queues service discipline for said port. Allowable values
are as follows:
strict
: The queues are served with strict discipline. This means packets from a
queue are not transmitted if there are packets awaiting transmission in higher-pri-
ority queues. E.g. packets in the low queue are not transmitted while there are
packets to be transmitted in any of the other three queues. This discipline requires
careful configuration as it can lead to situations where some queues are never
served.
urgent-strict
: The urgent queue takes strict priority while the other three are served
in accordance with the Weighted Round Robin system. This means that packets
from the other queues are not transmitted if there are packets in the urgent queue.
This discipline also requires caution as it can lead to situations where only urgent
queue packets are served.
wrr
: All the queues are served in accordance with the Weighted Round Robin sys-
tem. A weighted table determines how many times the scheduler has polled every
queue in each cycle and packets are sent accordingly. This is the switch default
operating mode.
trust
Establishes which field is used to prioritize the packets in a port.
Allowable values are as follows:
none
: Prioritizes depending on the port's default COS value.
cos
: Prioritizes depending on the value of the packet 802.1Q tag COS field. De-
fault is COS.
dscp
: Prioritizes depending on the IP packet DSCP value.
Note
Some switches may vary from others, depending on the trust option. When the packet does not have
COS, some switches use the DSCP value to prioritize and others do not prioritize said packet. In the
same way, if you select the dscp trust option and the packet does not have DSCP, some switches use
COS to prioritize packets and others don't.
The priority option is not available in all switches. For some, priority is globally configured.
Example 1:
Setting switch port 3 output rate to 20 Mbps.
ethernet0/0 switch config>port 3 qos rate-limit 20
Example 2:
Configuring COS re-tagging in two different ways in two switch ports:
(1)
All packets in port 14 are re-tagged by default to COS 5, regardless of the COS value they had on arrival.
(2)
All packets entering port 15 with a COS 6 value are re-tagged to COS 5.
ethernet0/0 switch config>port 14 qos override-cos 5
ethernet0/0 switch config>port 15 map cos 6 to cos 5
ethernet0/0 switch config>exit
ethernet0/0 config>>exit
Config>feature vlan
Teldat SA
7 Switch Configuration
LAN Interfaces
53
