Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Enabling Jumbo Frames on N7K VPC Peer Link

 

I have a 2 Nexus 5k's in a VPC environment. These 2 N5K's connect to the 2 upstream Catalyst 6500. Right now the the port-channels connecting from Nexus 5K's to Catalyst 6500 are enabled with jumbo frames(mtu 9216). As a part of migration work, i am migrating the uplinks from  Catalyst 6500 to Nexus 7000.So my new uplinks from Nexus 5000 will be connecting to Nexus 7000.When i migrate the uplinks to Nexus 7000, i will enable the jumbo frames on the VPC port-channel between Nexus 5000 to Nexus 7000. But my question here is: do i need to enable the jumbo frames(mtu 9216) on the peer link between Nexus 7k also. Please let me know if anyone has gone thruough this issue.

I have attached the diagram of my topology after i migrate to Nexus 7k.

5 REPLIES
Purple

   If you are going support

   If you are going support jumbo frames throughout your N7k's then yes I would enable it on the peer links.

Hello.Per my understanding,

Hello.

Per my understanding, jumbo frames are enabled on peer-link by default.

New Member

But when i do.... "sh run int

But when i do.... "sh run int po1 all"  i don't see mtu 9216 config over there. In my case, Port-channel 1 is a peer links between Nexus 7K. Could you please let me know how can i verify jumbo frames has been enabled on the peer link.

New Member

Saroj, I believe that mtu

Saroj,

 

I believe that mtu 9216 is on the VPC peer-link by default. I attempted to configure it in our lab and received an error when trying to apply it to the port-channel. I then did a show interface and noticed that the MTU was already at 9216.

 


interface port-channel10
  switchport mode trunk
  switchport trunk allowed vlan 1,810-813,820-823,900
  spanning-tree port type network
  vpc peer-link

N9k-1(config-if)# int p10
N9k-1(config-if)# mtu ?
  <1500-9216>  Enter MTU
N9k-1(config-if)# mtu 9216
ERROR: port-channel10: Cannot configure port MTU on Peer-Link.

 

N9k-1(config-if)# sho int p10
port-channel10 is up
admin state is up,
  Hardware: Port-Channel, address: f4cf.e237.a524 (bia f4cf.e237.a524)
  MTU 9216 bytes, BW 80000000 Kbit, DLY 10 usec
  reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, medium is broadcast

It is a relief to read that! 

It is a relief to read that!  I thought I was going to have to configure the peer-link MTU on-the-fly, with all the potential production impact that might have!  So thank you.

 

Kevin

 

945
Views
5
Helpful
5
Replies