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Jumbo frames with Nexus switches

neteng2323
Level 1
Level 1

As I understand it, jumbo frames are implemented differently between Nexus 5K, 9K, and 7K...

 

What is the difference between the system jumbomtu command on these switches and the policy-map?  You can't change the MTU per interface on the 5k but can on the 9K, and 7K even though system jumbomtu 9216 is set globally.  

 

So question are...

1.  Difference between 5k and 7k, 9k in regards to enabling Jumbo frames?

2. A show interface command shows Jumbo packets being transmitted on our 9k but MTU size still states 1500 bytes, what gives?

3.  Our 7k is set with the same global command but no interface is showing jumbo packets being sent or received? 

1 Accepted Solution

Accepted Solutions

Ganesh Hariharan
VIP Alumni
VIP Alumni
As I understand it, jumbo frames are implemented differently between Nexus 5K, 9K, and 7K...


What is the difference between the system jumbomtu command on these switches and the policy-map?  You can't change the MTU per interface on the 5k but can on the 9K, and 7K even though system jumbomtu 9216 is set globally.  


So question are...

1.  Difference between 5k and 7k, 9k in regards to enabling Jumbo frames?

2. A show interface command shows Jumbo packets being transmitted on our 9k but MTU size still states 1500 bytes, what gives?

3.  Our 7k is set with the same global command but no interface is showing jumbo packets being sent or received? 

Hi,

System Jumbo MTU command is configured to sets an upper limit for Jumbo MTU which is 9216 by default and to set the  jumbo frame support in switches to support use policy-map pattern is used.

Hope that Helps..

-GI

Rate if it Helps

View solution in original post

2 Replies 2

Ganesh Hariharan
VIP Alumni
VIP Alumni
As I understand it, jumbo frames are implemented differently between Nexus 5K, 9K, and 7K...


What is the difference between the system jumbomtu command on these switches and the policy-map?  You can't change the MTU per interface on the 5k but can on the 9K, and 7K even though system jumbomtu 9216 is set globally.  


So question are...

1.  Difference between 5k and 7k, 9k in regards to enabling Jumbo frames?

2. A show interface command shows Jumbo packets being transmitted on our 9k but MTU size still states 1500 bytes, what gives?

3.  Our 7k is set with the same global command but no interface is showing jumbo packets being sent or received? 

Hi,

System Jumbo MTU command is configured to sets an upper limit for Jumbo MTU which is 9216 by default and to set the  jumbo frame support in switches to support use policy-map pattern is used.

Hope that Helps..

-GI

Rate if it Helps

Joshua Schroth
Level 1
Level 1

I hate to necro such an old thread, but I don't feel like all of your questions were completely answered. I have the same thing going on with #2:

 

"2. A show interface command shows Jumbo packets being transmitted on our 9k but MTU size still states 1500 bytes, what gives?"

 

Our 93180YC-EX shows jumbo packets being TX/RX on the trunk ports to the ESXI Hosts, but the interfaces are using MTU 1500. If we actually set those trunk ports to mtu 9216 it breaks the hosts. What's going on here?

 

# show inv
NAME: "Chassis", DESCR: "Nexus9000 93180YC-EX chassis"

 

#show run all

interface port-channel113
description To VxRack SIO Host (ESXi)

switchport
switchport mode trunk
no switchport monitor
no switchport dot1q ethertype
no switchport priority extend
switchport access vlan 1
switchport trunk native vlan 132
switchport trunk allow-multi-tag
no switchport vlan mapping enable
priority-flow-control mode auto
priority-flow-control watch-dog-interval off
spanning-tree port-priority 128
spanning-tree cost auto
spanning-tree link-type auto
spanning-tree port type edge trunk
no spanning-tree bpduguard
no spanning-tree bpdufilter
logging event port link-status default
logging event port trunk-status default
flowcontrol receive off
flowcontrol send off
delay 1
snmp trap link-status
mtu 1500
speed 25000
duplex auto
no port-type fabric
negotiate auto
storm-control broadcast level 100.00
storm-control multicast level 100.00
storm-control unicast level 100.00
no storm-control action
bandwidth 25000000
no bandwidth inherit
load-interval counter 1 30
load-interval counter 2 300
no load-interval counter 3
no switchport virtual-ethernet-bridge
no switchport block multicast
no switchport block unicast
no shutdown lan
lacp graceful-convergence
lacp suspend-individual
lacp min-links 1
lacp max-bundle 32
no port-channel port load-defer
lacp fast-select-hot-standby
no port-channel port hash-distribution
no lacp mode delay
no port-channel bfd track-member-link
no port-channel bfd start
no lacp vpc-convergence
vpc 113
no shutdown
no switchport autostate exclude

 

#show int po113
port-channel113 is up
admin state is up,
vPC Status: Up, vPC number: 113
Hardware: Port-Channel, address: 
Description: To VxRack SIO Host (ESXi)
MTU 1500 bytes, BW 25000000 Kbit, DLY 10 usec

reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, medium is broadcast
Port mode is trunk
full-duplex, 25 Gb/s
Input flow-control is off, output flow-control is off
Auto-mdix is turned off
Switchport monitor is off
EtherType is 0x8100
Members in this channel: Eth1/5
Last clearing of "show interface" counters 1d23h
0 interface resets
Load-Interval #1: 30 seconds
30 seconds input rate 453288 bits/sec, 97 packets/sec
30 seconds output rate 122304 bits/sec, 72 packets/sec
input rate 453.29 Kbps, 97 pps; output rate 122.30 Kbps, 72 pps
Load-Interval #2: 5 minute (300 seconds)
300 seconds input rate 1568008 bits/sec, 149 packets/sec
300 seconds output rate 185272 bits/sec, 45 packets/sec
input rate 1.57 Mbps, 149 pps; output rate 185.27 Kbps, 45 pps
RX
198705886 unicast packets 10591 multicast packets 8729 broadcast packets
198725206 input packets 222877192968 bytes
134243819 jumbo packets 0 storm suppression bytes
0 runts 0 giants 0 CRC 0 no buffer
0 input error 0 short frame 0 overrun 0 underrun 0 ignored
0 watchdog 0 bad etype drop 0 bad proto drop 0 if down drop
0 input with dribble 0 input discard
0 Rx pause
TX
30717728 unicast packets 861191 multicast packets 225113 broadcast packets
31804032 output packets 19067272038 bytes
1240382 jumbo packets
0 output error 0 collision 0 deferred 0 late collision
0 lost carrier 0 no carrier 0 babble 0 output discard
0 Tx pause

 

#show int e1/5
Ethernet1/5 is up
admin state is up, Dedicated Interface
Belongs to Po113
Hardware: 100/1000/10000/25000 Ethernet, address: 
Description: To R640 10-Drive 1-3-02:01 (ESXi)
MTU 1500 bytes, BW 25000000 Kbit, DLY 10 usec
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, medium is broadcast
Port mode is trunk
full-duplex, 25 Gb/s, media type is 25G
Beacon is turned off
Auto-Negotiation is turned off FEC mode is Auto
Input flow-control is off, output flow-control is off
Auto-mdix is turned off
Rate mode is dedicated
Switchport monitor is off
EtherType is 0x8100
EEE (efficient-ethernet) : n/a
Last link flapped 61week(s) 2day(s)
Last clearing of "show interface" counters 1d23h
0 interface resets
Load-Interval #1: 30 seconds
30 seconds input rate 281016 bits/sec, 101 packets/sec
30 seconds output rate 216984 bits/sec, 102 packets/sec
input rate 281.02 Kbps, 101 pps; output rate 216.98 Kbps, 102 pps
Load-Interval #2: 5 minute (300 seconds)
300 seconds input rate 4864272 bits/sec, 520 packets/sec
300 seconds output rate 531696 bits/sec, 91 packets/sec
input rate 4.86 Mbps, 520 pps; output rate 531.70 Kbps, 91 pps
RX
198812957 unicast packets 10604 multicast packets 8733 broadcast packets
198832294 input packets 222994865219 bytes
134309896 jumbo packets 0 storm suppression bytes
0 runts 0 giants 0 CRC 0 no buffer
0 input error 0 short frame 0 overrun 0 underrun 0 ignored
0 watchdog 0 bad etype drop 0 bad proto drop 0 if down drop
0 input with dribble 0 input discard
0 Rx pause
TX
30739796 unicast packets 861717 multicast packets 225251 broadcast packets
31826764 output packets 19080114435 bytes
1240454 jumbo packets
0 output error 0 collision 0 deferred 0 late collision
0 lost carrier 0 no carrier 0 babble 0 output discard

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