Руководство По Проектированию для Cisco Cisco Nexus 5010 Switch
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service-policy type network-qos jumbo
Starting from Cisco NX-OS 4.2(1)N1(1), the semantics of the MTU configuration have changed. Prior to this
release, the MTU specified the full frame size (the maximum payload size plus Ethernet headers). Starting from
Cisco NX-OS 4.2(1)N1(1), the MTU size specified in the configuration refers to the Ethernet payload only. The
release notes state the following:
“The meaning of MTU configuration has changed from pre-4.2(1)N1(1) releases to 4.2(1)N1(1) release. In pre-
4.2(1)N1(1) releases, the configured MTU included the Ethernet payload and Ethernet headers. In 4.2(1)N1(1)
release, the configured MTU includes only the Ethernet payload and not the Ethernet headers. When
upgrading/downgrading between pre-4.2(1)N1(1) and 4.2(1)N1(1) releases, NX-OS will automatically convert the
configuration to address this semantic change by adding/subtracting 38 to the MTU to address the Ethernet header
size.”
size.”
For the full release notes, see the following link:
The show queuing interface command displays the frame size that is allowed on a given interface as a result of
the MTU configuration command.
Per-Interface Jumbo Frames Configuration on Cisco Nexus 5000 Series Interfaces
Besides defining jumbo frames globally, you may need to define jumbo frames for specific interfaces. The policy
map type network cannot be mapped for an interface; it can be applied only systemwide. To work around this
restriction, you can define the type network policy map at the system level and then apply the policy map type qos
at the interface level. By using this approach, you can make sure that only selected interfaces are associated with
the QoS group that is used for jumbo frames.
Here is an example of how to implement this configuration. This example shows how to enable jumbo frames on
interfaces eth1/1 and 1/2.
IP access-list IP_traffic
Permit ip any any
Permit ip any any
Class-map type qos Class_jumbo
Match ip access-group name IP_traffic
Policy-map type qos Policy_Jumbo
Class type qos Class_jumbo
Set qos-group 5
Class-map type network-qos Class_jumbo
Match qos-group 5
Policy-map type network Policy_NQ_Jumbo
Class type network-qos Class_jumbo
Mtu 9000
System qos
Service-policy type network-qos Policy_NQ_Jumbo
Interface eth1/1-2
Service-policy type qos input Policy_Jumbo