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Cisco Bug: CSCuo39308 - An LLDP frame with length of 0 in an optional TLV is discarded

Last Modified

May 08, 2020

Products (8)

  • Cisco Nexus 7000 Series Switches
  • Cisco Nexus 7000 10-Slot Switch
  • Cisco Nexus 7000 4-Slot Switch
  • Cisco Nexus 7700 6-Slot Switch
  • Cisco Nexus 7700 18-Slot Switch
  • Cisco Nexus 7000 18-Slot Switch
  • Cisco Nexus 7000 9-Slot Switch
  • Cisco Nexus 7700 10-Slot Switch

Known Affected Releases

6.2(6)

Description (partial)

Symptom:
The following syslog message is seen on an NX-OS device:

2014 Apr  1 16:31:13.550 N7K_1 LLDP-3-INVALID_LLDP_RECEIVED Received an invalid LLDP on Eth4/31

1.This bug will be seen in N7K 6.2.8 and all the N7K releases before that
2.This bug has been resolved and will not be seen in 6.2.10 and onwards.

Conditions:
An LLDP peer of an NXOS device is including an optional TLV in the LLDP frame with a length of 0.  This particular optional TLV does not have a specified minimum length per the LLDP standard (802.1AB)

Also, the logging level for lldp has been increased from its default of '2' to 3 or higher:

N7K_1# show logging level lldp
Facility        Default Severity        Current Session Severity
--------        ----------------        ------------------------
lldp                    2                       5 <<<<<<<<<<<<<<<<<<<<<<<

0(emergencies)          1(alerts)       2(critical)
3(errors)               4(warnings)     5(notifications)
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