03-09-2010 07:55 AM - edited 03-06-2019 10:04 AM
Based on the Cisco documentation I added these lines into the config of the switch:
policy-map jumbo
class class-default
mtu 9216
system qos
service-policy jumbo
When I run a show int though I'm still seeing the MTU set as 1500. Any ideas? Is there more to it than this?
switch# show int e1/2
Ethernet1/2 is up
Hardware is 1000/10000 Ethernet, address is 000d.ecd3.2dc9 (bia 000d.ecd3.2dc9
)
MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA
Port mode is access
full-duplex, 10 Gb/s, media type is 10g
Input flow-control is off, output flow-control is off
Auto-mdix is turned on
Rate mode is dedicated
Switchport monitor is off
Last clearing of "show interface" counters never
5 minute input rate 27 bytes/sec, 0 packets/sec
5 minute output rate 0 bytes/sec, 0 packets/sec
Rx
105549568 input packets 104585363 unicast packets 944820 multicast packets
19385 broadcast packets 0 jumbo packets 0 storm suppression packets
80312619994 bytes
0 No buffer 0 runt 0 Overrun
0 crc 0 Ignored 0 Bad etype drop
0 Bad proto drop
03-09-2010 11:15 AM
What version of software are you using ?
There are known issues with some versions of the software showing the incorrect MTU on the physical interface.
Jon
03-09-2010 11:43 AM
Right now it's 4.0(1a)N1(1) but I'm getting ready to upgrade to the newest code. I also opened a case with the TAC; they sent me a link to documentation with a different (slightly) set of commands
Thanks for the reply.
03-09-2010 08:40 PM
Based on the Cisco documentation I added these lines into the config of the switch:
policy-map jumbo
class class-default
mtu 9216
system qos
service-policy jumboWhen I run a show int though I'm still seeing the MTU set as 1500. Any ideas? Is there more to it than this?
switch# show int e1/2
Ethernet1/2 is up
Hardware is 1000/10000 Ethernet, address is 000d.ecd3.2dc9 (bia 000d.ecd3.2dc9
)
MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA
Port mode is access
full-duplex, 10 Gb/s, media type is 10g
Input flow-control is off, output flow-control is off
Auto-mdix is turned on
Rate mode is dedicated
Switchport monitor is off
Last clearing of "show interface" counters never
5 minute input rate 27 bytes/sec, 0 packets/sec
5 minute output rate 0 bytes/sec, 0 packets/sec
Rx
105549568 input packets 104585363 unicast packets 944820 multicast packets
19385 broadcast packets 0 jumbo packets 0 storm suppression packets
80312619994 bytes
0 No buffer 0 runt 0 Overrun
0 crc 0 Ignored 0 Bad etype drop
0 Bad proto drop
Hi,
As per the below link from cisco in open caveteis section they have bug id with your MTU case and some of the resolved caveteas also mentioned in version 4.0(1a)N1(1).
CSCsl21529
Symptom: An incorrect MTU value is displayed in the show interface command output. The Nexus 5000 Series switch only supports class-based MTU. Per-interface level MTU configuration is not supported. The switch supports jumbo frames by default. However, the show interface command output currently displays an incorrect MTU value of 1500 bytes.
Workaround: None.
Remember to rate the helpful post
Ganesh.H
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