How to Configure Jumbo Frame on Nexus 7000 to UCS / Fabric interconnect

williammanurung · ‎09-22-2018

Hii all,

I want to ask about jumbo frame, this my topology:

So, in agg1 and agg2 have port-channel 20 with vpc 20, connect to fabric interconnect.

when ucs blade set qos jumbo frame to 9216, and i configure jumbo frame on interface po20 on agg1, but interface po20 down.

what want to know is:

1. Can UCS set jumbo frame on 9216?

2. why the interface po20 down on agg1? is it because i am not configure jumbo frame on po20 on agg2? if i configure on both side (agg1 and agg2), is it any down time?

3. On vpc tolopogy, is it must configure on both side?

4. can i configure jumbo frame 9216 on agg1 and agg2, but on UCS blade I set 8900?

5. How can i set jumbo frame on nexus 7000? only set on interface or must set system qos like N5K?

6. can you explain how to configurin jumbo frame on nexus 7000 connect to UCS? step by step.

Thanks everyone.

cassiolange · ‎09-22-2018

Hello William,

1) On UCS side you must configure two things:

vNIC or vNIC template set MTU to 9000
LAN -> QOS System Class -> Best effort -> Set MTU to 9216

2) MTU must be identical on both side of vPC. Check the link below.

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus7000/sw/interfaces/config/cisco_nexus7000_interfaces_config_guide_8x/config-vpcs.html#concept_E56AEA7C0D824EBC952C052197D01C8C

3) Yes

4) You could do this configuration, but in some cases you will fragment the frame. Configure same MTU on both side.

5) Set system jumbo MTU to 9216. Configure interface set MTU to 9216.

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus7000/sw/interfaces/config/cisco_nexus7000_interfaces_config_guide_8x/config-basic-interface-parameters.html#concept_4B42C21732554FF995E5C5C90E62AF1E

6) Configure N7K on both side.

System MTU
Interface MTU

Configure UCS

QOS System Class -> Best effort
vNIC or vNIC Template

Ask to the server guys to configure the OS to accomodate new MTU.

Good luck.

Regards

williammanurung · ‎09-22-2018

Hi cassiolange,

Thanks for your detail answer.

But, i have another question:

1) On UCS side you must configure two things:

vNIC or vNIC template set MTU to 9000
LAN -> QOS System Class -> Best effort -> Set MTU to 9216

vNIC or vNIC template just set to 9000? not 9216? have we configure MTU 9216 on Fabric interconnect?

2) MTU must be identical on both side of vPC. Check the link below.

because i am only configure on one side, so the vpc comes to suspend right? So, It make down time if we configure MTU on VPC?

5) Set system jumbo MTU to 9216. Configure interface set MTU to 9216.

so, where vdc i set the system jumbo 9216? vdc admin or vdc context? can i verify with command : show interface x/y?

6)Ask to the server guys to configure the OS to accomodate new MTU.

For information, on ucs blade we have there VM that need jumbo frame connection to AGG1 and AGG2.So, we must configure mtu 9216 on there VM Server too? or just QOS System Class and vNIC/vNIC Template?

Do you have link set MTU on UCS?

Thanks for your support cassiolange :)

cassiolange · ‎09-23-2018

Hello William,

1)

vNIC doesn't support MTU 9216. The maximum transmission unit, or packet size, is 9000.

https://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/ucs-manager/GUI-User-Guides/Network-Mgmt/4-0/b_UCSM_Network_Mgmt_Guide_4_0/b_UCSM_Network_Mgmt_Guide_4_0_chapter_01010.html

2) When you configure just one side vPC will suspend one side. You must ensure that all interfaces in the vPC have the identical operational and configuration parameters. You will need schedule a maintenance windows.

3) On context VDC. To verify show interface x/y.

!
system jumbomtu 9216
!
int eth 3/1
 mtu 9216

4) You need instruct the server OS tu generate frames with 9000. In case of VMware you will need set the VMware vSwitch to accomodate larger MTU, and configure the VM the generate larger MTU frames.

All path needs support jumbo MTU.

Good luck,

Regards.

williammanurung · ‎09-24-2018

Hi cassiolange,

Ok thanks for your answer, I will update to you if work.

Thanks a lot.