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Cisco Bug: CSCuj39168 - FEX drops jumbo frames

Last Modified

Feb 22, 2018

Products (7)

  • Cisco Nexus 7000 Series Switches
  • Cisco Nexus 7000 10-Slot Switch
  • Cisco Nexus 7000 4-Slot Switch
  • Cisco Nexus 7700 18-Slot Switch
  • Cisco Nexus 7000 18-Slot Switch
  • Cisco Nexus 7700 10-Slot Switch
  • Cisco Nexus 7000 9-Slot Switch

Known Affected Releases


Description (partial)

FEX doesn't forward jumbo frames even though the interfaces' MTU have been increased.
This has been observed on a N7K running 6.2(2).

Related Community Discussions

<key>CSCuj39168</key> - FEX drops jumbo frames
a fix to this could be adding policy-map type network-qos jumbo-nq-8e-policy class type network-qos c-nq-8e    congestion-control tail-drop    mtu 9000 system qos service-policy type network-qos jumbo-nq-8e-policy to verify whether the fex now passes jumbos, attach to the fex and  observe whether TX/RX_PKT_{largesize} counters increment e.g., fex# show platform software woodside rmon 0 hi7 | TX_PKT_2048          |                   100|  | TX_PKT_4096          |                   100|  
Latest activity: Jun 19, 2014
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