Enabling Jumbo Frame in Nexus 5596, IOS Ver : 5.1(3)N1(1)

[Amartya_ghosh]

I have a requirement to enable Jumbo frames in my network for some DB servers. The connectivity goes as follows,

DB Server:1 -->> Nexus 2232 ->>Nexus5596-->>Nexus7010-->>Nexus5596-->>Nexus2232-->>DB Server:2

Going through some Cisco documents it seems that on 7K we can enable Jumbo frames on interface level but not on 5K.

It would be great if someone can answer few queries those are going through my mind before I can decide to enable Jumbo Frames,

1) Is it possible to enable jumbo frames (9216) on interface level in 5K

2) Is there any impact of enabling jumbo frame globally in 5K

3) If I need to enable Jumbo frame end to end that involves 7K, then I have to enable it on uplinks from the access switches (5K) as well. Will this impact on traffic from other servers (except the DB servers) traffic comming through this same links to core (7K).

[Reza Sharifi]

1) Is it possible to enable jumbo frames (9216) on interface level in 5K

On the 5Ks, it can only be enabled globally.

2) Is there any impact of enabling jumbo frame globally in 5K

All interface will be supporting Jumbo frames

3) If I need to enable Jumbo frame end to end that involves 7K, then I  have to enable it on uplinks from the access switches (5K) as well. Will this impact on traffic from other servers (except the DB  servers) traffic comming through this same links to core (7K).

That is correct.  You need to enable it on the 7Ks (per interface). It will not imapact other servers using the same switch, but you may want to do all of these in on outage window just in case.

http://www.cisco.com/en/US/products/ps9670/products_configuration_example09186a0080b44116.shtml

HTH

[sajid_m123]

I think, JF are enabled under service policy and it is enabled only for the class referenced. It is enabled for all the traffic if default class is used. Please correct if wrong?

My only concern is that for any non-tcp traffic some device in the path would have to do fragmentations and how it would be handled?

Thanks!

[David Goldsmith]

Amartya,

Did you ever get an answer to this or figure out how to enable Jumbo Frames on both the 5596 switch and the 2232 FEX?  We've got a similar setup with needing jumbo frames for our SAN.

[Amartya_ghosh]

David,

Actually I did implement it in my setup and it worked. Though I dont think it can be configured explicitly on FEX level. As per my understanding you need to enable it on 5596 and it work for the FEX ports as well.

You can refer below links for configurations commands.

http://www.cisco.com/en/US/products/ps9670/products_configuration_example09186a0080b44116.shtml

http://blog.scottlowe.org/2009/11/09/enabling-jumbo-frames-on-a-nexus-5000/

[Iker Santamaria Molla]

Hi Amartya,

you're right about "Jumbo Frame" on Nexus 5000. The only way to "activate" is via "QoS" configuration.

Here is the minimum configuration necessary:

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

On Nexus 7000, it's possible to configure per interface or for entire switch:

switch(config)#system jumbomtu 9216

switch(config)#interface ethernet x/x
switch(config-if)#switchport
switch(config-if)#mtu 9216
switch(config-if)#exit

Regards.

[wes_ward]

If you are running fiber channel you will want to do it this way, as the posts above will cause you to lose your FC.

policy-map type network-qos fcoe-jumbo

  class type network-qos class-fcoe

   pause no-drop

   mtu 2158

  class type network-qos class-default

   mtu 9216

   multicast-optimize

system qos

  service-policy type network-qos fcoe-jumbo