Cisco Systems 4500 Configuring CoS Mutation

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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 37 Configuring Quality of Service
Configuring QoS on Supervisor Engine 6-E, Supervisor Engine 6L-E, Catalyst 4900M, and Catalyst 4948E
– If there is an egress queuing policy on the port, the queue is selected based on the classification
criteria applicable to the packet.
As per CSCtf40934, beginning with Cisco IOS Release 12.2(54)SG, locally generated HI
priority packets are handled as follows:
In the absence of a QoS policy, HI priority packets are enqueued into an internal priority queue.
In the presence of a policy, HI priority packets are enqueued into a priority queue if one is
defined. If none is defined, classification criteria determines the queue. HI priority packets are
never subjected to egress QoS marking. Locally generated packets that are not HI priority are
treated like any other packet. For example, QoS policy is used to determine any marking and
queueing action.
Low Priority Packets
Packets that are not considered high priority (as described previously) are considered unimportant. These
include locally sourced pings, Telnet, and other protocol packets. They receive the same treatment as any
other packet that is transmitting the given transmit port including egress classification, marking, and
queuing.
Configuring CoS Mutation
CoS reflection and CoS mutation are supported on Supervisor E ngine 6-E and Catalyst 4900M. Below
is an example of how to apply CoS reflection.
Let us say that traffic arrives on interface gigabit 2/5 with VLAN 10 and COS 1, 2, .... We want traffic
to egress interface gigabit 2/6 with outer tag VLAN 11 and CoS copied from C-tag, where C-tag is
VLAN 10 and COS 1, 2, ...
class-map match-all c2
match cos 2
class-map match-all c1
match cos 1
!
policy-map my
class c1
set cos 1
class c2
set cos 2
interface GigabitEthernet2/5
switchport mode trunk
switchport vlan mapping 10 dot1q-tunnel 11
spanning-tree bpdufilter enable