cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
1566
Views
5
Helpful
2
Replies

Nexus 5596UP - Jumbo frames TX even though jumbo frames not enabled?

LA-Engineer
Level 1
Level 1

Could someone tell me why this port is sending Jumbo Packets even though jumbo frames are not enabled on the switch?  I'm trying to trouble shoot an issue with a server not being able to transfer at wire speed.

 

Ethernet1/35 is up
 Dedicated Interface
  Belongs to Po751
  Hardware: 1000/10000 Ethernet, address: 547f.eeb0.1baa (bia 547f.eeb0.1baa)
  Description: x
  MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec
  reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA
  Port mode is trunk
  full-duplex, 10 Gb/s, media type is 10G
  Beacon is turned off
  Input flow-control is off, output flow-control is off
  Rate mode is dedicated
  Switchport monitor is off
  EtherType is 0x8100
  Last link flapped 33week(s) 2day(s)
  Last clearing of "show interface" counters never
  1 interface resets
  30 seconds input rate 221920 bits/sec, 71 packets/sec
  30 seconds output rate 216968 bits/sec, 177 packets/sec
  Load-Interval #2: 5 minute (300 seconds)
    input rate 419.02 Kbps, 57 pps; output rate 570.33 Kbps, 192 pps
  RX
    19339643291 unicast packets  22999366 multicast packets  2241049 broadcast packets
    19364883706 input packets  8219619292920 bytes
    1440124319 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
    19419081143 unicast packets  632675822 multicast packets  553773489 broadcast packets
    20605530454 output packets  9077525431634 bytes
    2145386732 jumbo packets
    0 output errors  0 collision  0 deferred  0 late collision
    0 lost carrier  0 no carrier  0 babble 0 output discard
    0 Tx pause

 

 

2 Replies 2

LA-Engineer
Level 1
Level 1

Opened a ticket with Cisco and this is what they pointed me to.  I just wanted to update this post with the solution.

http://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/troubleshooting/guide/N5K_Troubleshooting_Guide/n5K_ts_l2.html#wp1029593

 

Nickolus Looper
Level 1
Level 1

Note that the command

sh hardware internal carmel port ethernet 1/1 counters rx
breaks down counters for a port by many different frame sizes.
 
At one point TAC mentioned to me that a frame could be 1518 bytes when it leaves a host, but when a dot1q tag is inserted, that can push the total frame size just over 1518.  The switch could then count it as a jumbo even if it truly isn't jumbo.
 
If anyone has more info on this notion, I would be very interested in hearing it.
 
Thanks
Review Cisco Networking for a $25 gift card