Cisco Nexus 5000 Series Switches

Nexus 5000 Series Switch Interfaces and HP Pass-Thru Modules Interoperability Error

Document ID: 116254

Updated: Jul 19, 2013

Contributed by Prashanth Krishnappa, Cisco TAC Engineer.



This document describes the interoperability problem seen with Hewlett-Packard (HP) Pass-Thru modules and Cisco Nexus 5000 Series switches and also provides a solution to the problem.


There is a problem encountered after the Nexus 5000 with 2232 (woodside Fabric Extender (FEX)) is upgraded to Release 5.2. When the 2232 interfaces connect to 10Gb HP Pass-Thru modules, they flap continually and eventually error disable:

NDCD29ACCSW1# show int brief | inc linkFlap
Eth152/1/1 2 eth trunk down linkFlapErrDisabled 10G(D) 1001
Eth152/1/2 2 eth trunk down linkFlapErrDisabled 10G(D) 1002
Eth152/1/3 2 eth trunk down linkFlapErrDisabled 10G(D) 1003
Eth152/1/4 2 eth trunk down linkFlapErrDisabled 10G(D) 1004
Eth152/1/5 2 eth trunk down linkFlapErrDisabled 10G(D) 1005
Eth152/1/9 2 eth trunk down linkFlapErrDisabled 10G(D) 1009

There is a known HP 10Gb Pass-Thru module link flap issue documented on the HP website, and they recommend that customers upgrade to version So far in all of the cases, the HP 10Gb Pass-Thru firmware is

Note: The Pass-Thru module firmware is independent of the HP Onboard Adminstrator (OBA) version.

In order to determine the Pass-Thru module firmware, enter the show interconnect info 11 command:

1. Ethernet 
Product Name: HP 10GbE Pass-Thru Module
Width: Single
URL to Management interface:
In-Band IPv4 Address:
User Assigned Name:
Part Number: 538113-B21
Spare Part Number: 504624-001
Serial Number: MY31104WWTTemperature Sensor: Present
JS2 Connector: Absent
Internal Ethernet Interface to OA: Absent
Internal Ethernet Route to OA: Enabled
Internal Serial Interface to OA: Present
Internal Serial Route to OA: Enabled
Serial Port Baud Rate: 9600
External Serial Port Interface: Present
External Ethernet Interface: Absent
Manufacturer: HP

Then, enter the connect interconnect 1 command in order to view this output:

NOTICE: This pass-thru connection to the integrated I/O console
is provided for convenience and does not supply additional access
control.  For security reasons, use the password features of the
integrated switch.
Connecting to integrated switch 1 at 9600,N81...
Escape character is '<Ctrl>_' (Control + Shift + Underscore)

Press Enter in order to display the switch console:

Command: D)isconnect, C)hange settings, send B)reak, E)xit command mode X)modem send > C
Change settings for: L)ocal Session, R)emote Port [I/O Bay 1], E)xit
Change settings for: L)ocal Session, R)emote Port [I/O Bay 1], E)xit R
Settings: B)audrate; flow control: N)one H)ardware S)oftware; E)xit > N
Connected to integrated switch 1 at 9600,N81.
Escape character is '<Ctrl>_' (Control + Shift + Underscore)

Enter the 10GbE Pass-Thru# /system command in order to view the HP Pass-Thru module version number:

[System Menu]
    info     -  System Information Display                                     
    config   -  Set Active or Factory Default Config                           
    dumpconfig -  Dump Saved Config                                              
    xmodem   -  Download new image using XMODEM                                
    reset    -  Reset The Switch                                               
System# info
System:                  HP 10Gbe Pass-Thru
Board: HP 10GbE Pass-Thru Module
Serial:                  MY31104WWT      

As shown, the system runs HP Pass-Thru module version HP mentions that this version is not meant to be shipped to customers and is not published on their website. Their Pass-Thru module vendor shipped a few modules with this version in error. Once HP discovered the link flap issue, they released a patch which resolves this issue. Version was requested from HP in order to further test the issue, but HP does not have the version.

Note: The reason why this issue is only apparent with Release 5.2, and not older releases, is that there might be more tolerance with improper HP modules in older Nexus operating systems.


If customers open service requests with similar symptoms, check the HP Pass-Thru module firmware and have them upgrade to version

Related Information

Updated: Jul 19, 2013
Document ID: 116254