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Showing posts from May, 2017

Jumbo frames in Nexus 5000

When we connect storage devices or some special requirements we need to change port MTU size. In Cisco 4500 and Cisco 6500 we have a option to enable MTU size per interface basis. But in Nexus 5000 it is only enable on full switch. This means all ports will be effected by MTU size. I don't know why this advance Nexus 5000 doesn't have option to change MTU per interface basis. There are simple commands to activate the same :
In this below configuration we are changing MTU size to 9216 :

switch(config)#policy-map type network-qos jumbo switch(config-pmap-nq)#class type network-qos class-default switch(config-pmap-c-nq)#mtu 9216 switch(config-pmap-c-nq)#exit switch(config-pmap-nq)#exit switch(config)#system qos switch(config-sys-qos)#service-policy type network-qos jumbo


We need to create QOS policy which can filter MTU with size 9216. After you apply this policy, All ports will use 9216 MTU. You doesn't need to restart the switch. There is one catch in it :
switch# show inter…

Flexible Netflow on the Cisco 4500 Switch

Netflow is the very basic need which is required when troubleshooting Network slowness problems. Unfortunately Cisco 4500 switch does not have General/Traditional Netflow which we configure on Cisco Routers and Cisco 6500 switches etc. Cisco 4500 only supports Flexible Netflow which is basically Netflow V9. In this post I will guide you to configure Flexible Netflow in Cisco 4500 switch.
There are 4 steps to configure Flexible Netflow in Cisco 4500 switch:

Create a flow record
Create a flow exporter
Create a flow monitor
Apply the monitor to an interface
Step 1 : Create Flow record :
The flow record defines the fields that will be used to group traffic into unique flows. In my example, I used the following configuration:

flow record IPV4-FLOW-RECORD match ipv4 tos match ipv4 protocol match ipv4 source address match ipv4 destination address match transport source-port match transport destination-port collect interface input collect interface output colle…