Nexus 5020's & 2k ToR setup with Jumbo Frames

Answered Question
May 25th, 2010
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Hello everyone.


I currently upgraded my nexus 5020's to the new version of NX-OS 4.2(1)N1.1.   Everything upgraded pretty well as far as I can see. 


Now i've been asked to set up Jumbo Frames on the two 5k's.   Keep in mind the two 5020's are not running a VPC setup.   There is no

connection directly from one 5020 to the other.   They both head to dual 6509's running VSS.    My question is, in order to set up Jumbo frames

switch wide...do i need to do this by entering the following?


switch(config)# policy-map type network-qos jumbo<br/>switch(config-pmap-nq)# class type network-qos class-default<br/>switch(config-pmap-c-nq)# mtu 9216<br/>switch(config-pmap-c-nq)# exit<br/>switch(config-pmap-nq)# exit<br/>switch(config)# system qos<br/>switch(config-sys-qos)# service-policy type network-qos jumbo</code></p><p style="text-align: left;"><code><span style="font-family: arial,helvetica,sans-serif;">Also, I would assume this would take care of setting all interfaces to allow Jumbo frames, but when I look at </span>

<span style="font-family: arial,helvetica,sans-serif;">MTU size when doing sho interfaces, it's still showing 1500.   I was just curious, since this is policy based </span>

<span style="font-family: arial,helvetica,sans-serif;">will it show the new MTU size?</span>

</code></p><p style="text-align: left;"><code><span style="font-family: arial,helvetica,sans-serif;">In addition, will I have to do anything in order to allow Jumbo frames on my nexus 2k top of rack switches? </span>

<span style="font-family: arial,helvetica,sans-serif;">Since these are controlled by the 5k's, will my above commands take care of that for the 2k's?</span>

</code></p><p style="text-align: left;"><code><span style="font-family: arial,helvetica,sans-serif;">Thanks in advance,</span>

Correct Answer by Lucien Avramov about 7 years 3 days ago

Enable jumbo you have it right:




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


show interface ethernet x/y will display under the jumbo counters the information about jumbo packets.



Nothing to do for the N2K, this command enables it globally.



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Correct Answer
Lucien Avramov Tue, 05/25/2010 - 15:37
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Enable jumbo you have it right:




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


show interface ethernet x/y will display under the jumbo counters the information about jumbo packets.



Nothing to do for the N2K, this command enables it globally.



----

Please support CSC Helps Haiti


https://supportforums.cisco.com/docs/DOC-8895

https://supportforums.cisco.com

jonesl1 Wed, 05/26/2010 - 04:30
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Thank you Lucien for the help.   It's nice to be able receive confirmation on a subject that I dont know a lot about. 


Thanks again.

schrothxx Thu, 01/20/2011 - 13:08
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What if I want to enable jumbo frame per interface?  On my Nexus 5020, I only want use 10 ports with jumbo frames and the rest with a regular 1500 MTU size.  Will a global enable like this impact the 1500 MTU frames on the interfaces not using the larger 9216 MTU size?

Lucien Avramov Mon, 01/24/2011 - 12:13
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Jumbo is only global on N5K at this time.

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