port hot standby down in nexus 7k vpc port channel

Unanswered Question
Jun 4th, 2012

Hi all,

we have ucs fabric interconnect which connect to vPC domain (2 nexus 7ks), each fabric interconnect has 8 uplinks to 7k paris (4 uplinks for each 7k)

those 2 Nexus7k are running on the same firmware and ucs fabric interconnect connect to the same module and port of two 7k.

So basically, everything is same on two 7k.

On 7k-2, all ports in vpc port channel from ucs fabric interconnect are up.

But on 7k-1, we have 2 ports down which shows "hot standby in bundle"

7k-1# show int e9/6

Ethernet9/6 is down (Hot standby in bundle)

Dedicated Interface

  Belongs to Po202

  Hardware: 10000 Ethernet, address: 1cdf.0fd2.0edd (bia 1cdf.0fd2.0edd)

  Description: Connection to fi-A : eth 1/36

  MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec

  reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ARPA

  Port mode is trunk

  auto-duplex, 10 Gb/s, media type is 10G

  Beacon is turned off

  Auto-Negotiation is turned off

  Input flow-control is off, output flow-control is off

  Rate mode is shared

  Switchport monitor is off

  EtherType is 0x8100

  Last link flapped 4d17h

  Last clearing of "show interface" counters never

  3 interface resets

  30 seconds input rate 3192 bits/sec, 1 packets/sec

  30 seconds output rate 3160 bits/sec, 1 packets/sec

  Load-Interval #2: 5 minute (300 seconds)

    input rate 3.01 Kbps, 2 pps; output rate 3.08 Kbps, 2 pps

Interface 9/6 config as below:

interface Ethernet9/6

  description Connection to fi-a : eth 1/36

  switchport

  switchport mode trunk

  switchport trunk allowed vlan 100,200,300-400

  channel-group 202 mode active

  no shutdown

----------------------------------------

7k-1# show port-channel summary

Flags:  D - Down        P - Up in port-channel (members)

        I - Individual  H - Hot-standby (LACP only)

        s - Suspended   r - Module-removed

        S - Switched    R - Routed

        U - Up (port-channel)

        M - Not in use. Min-links not met

--------------------------------------------------------------------------------

Group Port-       Type     Protocol  Member Ports

      Channel

--------------------------------------------------------------------------------

1     Po1(SU)     Eth      LACP      Eth3/1(P)    Eth3/2(P)    Eth4/1(P)

                                     Eth4/2(P)

2     Po2(SU)     Eth      LACP      Eth3/18(P)   Eth4/26(P)

202   Po202(SU)   Eth      LACP      Eth8/5(P)    Eth8/6(P)    Eth9/5(P)

                                     Eth9/6(H)

203   Po203(SU)   Eth      LACP      Eth8/7(P)    Eth8/8(P)    Eth9/7(P)

                                     Eth9/8(H)

7k-2# show running-config | inc lacp
feature lacp
7k-2# show port-channel summary
Flags:  D - Down        P - Up in port-channel (members)
        I - Individual  H - Hot-standby (LACP only)
        s - Suspended   r - Module-removed
        S - Switched    R - Routed
        U - Up (port-channel)
        M - Not in use. Min-links not met
--------------------------------------------------------------------------------
Group Port-       Type     Protocol  Member Ports
      Channel
--------------------------------------------------------------------------------
1     Po1(SU)     Eth      LACP      Eth3/1(P)    Eth3/2(P)    Eth4/1(P)
                                     Eth4/2(P)
2     Po2(SU)     Eth      LACP      Eth3/18(P)   Eth4/26(P)
202   Po202(SU)   Eth      LACP      Eth8/5(P)    Eth8/6(P)    Eth9/5(P)
                                     Eth9/6(P)
203   Po203(SU)   Eth      LACP      Eth8/7(P)    Eth8/8(P)    Eth9/7(P)
                                     Eth9/8(P)

7k firmware version

# sh ver
Cisco Nexus Operating System (NX-OS) Software
TAC support: http://www.cisco.com/tac
Documents: http://www.cisco.com/en/US/products/ps9372/tsd_products_support_series_home.html
Copyright (c) 2002-2012, Cisco Systems, Inc. All rights reserved.
The copyrights to certain works contained in this software are
owned by other third parties and used and distributed under
license. Certain components of this software are licensed under
the GNU General Public License (GPL) version 2.0 or the GNU
Lesser General Public License (LGPL) Version 2.1. A copy of each
such license is available at
http://www.opensource.org/licenses/gpl-2.0.php and
http://www.opensource.org/licenses/lgpl-2.1.php

Software
  BIOS:      version 3.22.0
  kickstart: version 5.2(4)
  system:    version 5.2(4)
  BIOS compile time:       02/20/10
  kickstart image file is: bootflash:///n7000-s1-kickstart.5.2.4.bin
  kickstart compile time:  12/25/2020 12:00:00 [03/08/2012 14:58:13]
  system image file is:    bootflash:///n7000-s1-dk9.5.2.4.bin
  system compile time:     1/28/2012 23:00:00 [03/08/2012 15:59:07]


Hardware
  cisco Nexus7000 C7010 (10 Slot) Chassis ("Supervisor module-1X")
  Intel(R) Xeon(R) CPU         with 4109560 kB of memory.
  Processor Board ID JAF1446BCER

  Device name: AC2004-PISR2-EPS
  bootflash:    2029608 kB
  slot0:              0 kB (expansion flash)

Kernel uptime is 39 day(s), 2 hour(s), 33 minute(s), 3 second(s)

Last reset
  Reason: Unknown
  System version: 5.2(3)
  Service:

plugin
  Core Plugin, Ethernet Plugin

we have not define MaxBundle (the maximum number of bundled ports allowed in a LACP port channel)

any idea about this?

I have this problem too.
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bill.greenwood Tue, 06/05/2012 - 14:58

You can use show cdp neighbor on the interfaces. You should get the 6K name and serial number. You can use this to ensure the devices are cabled as you believe. I suspect you have a cabling problem.

Bill

Sent from Cisco Technical Support iPad App

krun_shah Tue, 06/05/2012 - 19:54

Issue seems to be with LACP port priority,

LACP Port Priority

Each port that is configured to use LACP has an LACP port priority. You  can accept the default value of 32768 for the LACP port priority, or you  can configure a value between 1 and 65535. LACP uses the port priority  with the port number to form the port identifier.

LACP uses the port priority to decide which ports should be put in  standby mode when there is a limitation that prevents all compatible  ports from aggregating and which ports should be put into active mode. A  higher port priority value means a lower priority for LACP. You can  configure the port priority so that specified ports have a lower  priority for LACP and are most likely to be chosen as active links,  rather than hot-standby links.

I understand you do not have any LACP port-priority configured under  interface it could be some software bug preventing this port to be in  active bundled in port-channel. Have you seen issue after ISSU upgrade from 5.2(3) to 5.2(4)??

Try this :

Do show run all and make sure all ports in port-channel 202 has same priority.

Manually configure lacp port-priority on all ports to same value between 0-65535 on all member ports

if nothing works then collect show tech lacp and post it here.

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Posted June 4, 2012 at 10:41 PM
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