CDP-SW1-4-DUPLEX_MISMATCH:

[JOSE RIVERA]

We recently migrated to Cisco 6800 from 6500.

We are using 10 G fiber WAN links.

When we  enable netflow in the  6800 we start getting these syslog messages:

 %CDP-SW1-4-DUPLEX_MISMATCH: duplex mismatch discovered on TenGigabitEthernet2/1/1 (not half duplex), with KECK-VSS6807-1                                              -7-Core NDE_0 (half duplex).

if we disable Netflow, the problem goes away.

or

If we disable CDP in the interface where netflow was enabled the problem also goes away.

Question:

Is there a way to suppress these alerts without disabling netflow or CDP in the intrefaces?

Thanks!

Jose Rivera

[Julio E. Moisa]

Hi Jose,

Have you tried configuring both interfaces with

duplex full manually?

[JOSE RIVERA]

Julio,

thanks,

it is not a layer1/layer2 issue with duplex, otherwise the fiber link would not come up.

When Netflow is enabled it creates and NDE interface, which is the one that has the "CDP duplex mismatch".

I don't know how to set the NDE to full duplex.

I guess I should explain that this problem is a "cosmetic problem" , everything is working properly, except that my syslog gets full of these messages and we lose any important information that might have been logged.

Like I said if Netflow is disabled or we disable CDP in the interface that has Netflow, the problem goes away, but we want to have cdp and netflow running at the same time .

Thanks!

Jose

[Julio E. Moisa]

Thank you Jose

and is it is a clear channel? do we sure there are not ISP's devices in the middle, not lost packets, right? Otherwise it could be a bug. 

Please let me try to find any information related.

[Julio E. Moisa]

Please check this links and the bugs mentioned:

https://supportforums.cisco.com/document/21331/cisco-discovery-protocol-displays-cdp-4-duplexmismatch-error-message-catalyst-fixed

[JOSE RIVERA]

Julio,

thanks,

I did see that link, but I think our problem is similar but not the same.

when we  show CDP this is what we get:

VIE-VSS6807-6-7-Core#show cdp neighbors tenGigabitEthernet 2/1/1
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
                  D - Remote, C - CVTA, M - Two-port Mac Relay

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
KECK-VSS6807-1-7-Core
                 Ten 2/1/1         159             R S I  C6807-XL  NDE_0
KECK-VSS6807-1-7-Core
                 Ten 2/1/1         179             R S I  C6807-XL  Ten 1/1/1

Total cdp entries displayed : 2

the entry  for NDE_0 is created when you enable Netflow v9 ( at least that is the version  we are using).

if we remove Netflow, that entry goes away and the problem goes away ( the NDE_0 interface goes away).

We want to have CDP enable.....

Is there anyway to just suppress a message?

Thanks!

Jose

[paul driver]

Hello

we want to have cdp and netflow running at the same time .

Have you tried enabling LLDP instead

res
Paul

[JOSE RIVERA]

Paul,

thanks, we have not tried that, but all of our monitoring systems rely on CDP to run some scripts and compare data.

Jose

[paul driver]

Hello

no worries the log discriptor is a very good way to suppress the msgs showing in console or syslog 

I am very aware of this feature having used it numerous times .

I misinterpreted your request as I thought you wanted to negate the msgs not suppress them and still required a discovery protocol 

glad to hear your sorted 

res

paul

[JOSE RIVERA]

this is an Ethernet circuit, we have verified that we are not losing any data in the Carrier portion of the circuit.

Our SE does think this is a bug, however we have Quad Sup redundancy in our VSS, and it would not be a simple upgrade, hence we were trying to see if there is a way to suppress these messages, as everything is working as it should ( other than this message).

Thanks!

Jose

[Rolf Fischer]

Jose,

as a workaround you could configure a CDP TLV List which allows all TLVs except for Duplex and apply this list to TenG2/1/1.

Switch(config-tlv-list)#?
  address              Select address TLV
  capability           Select capability TLV
  cos                  Select cos TLV
  default              Set a command to its defaults
  duplex               Select duplex TLV
  exit                 Exit from tlv-list mode
  ext-port-id          Select external port id TLV
  hello-protocol       Select hello-protocol TLV
  ip-prefix            Select ip-prefix TLV
  mgmt-address         Select management address TLV
  native-vlan          Select native-vlan TLV
  no                   Negate a command or set its defaults
  platform             Select platform TLV
  port-id              Select port id TLV
  power-available      Select power-available TLV
  powernet             Select powernet-event TLV
  spare-pair-poe       Select spair pair poe TLV
  trust                Select trust TLV
  unidirectional-mode  Select unidirectional-mode TLV
  version              Select version TLV
  vtp-mgmt-domain      Select vtp mgmt domain TLV
  vvid                 Select vvid TLV

I've never tried this but I think it should do the trick.

HTH

Rolf

[JOSE RIVERA]

Rolf,

Thanks,

I tried it and it did not work ... I added the following:

cdp tlv-list test
 duplex
cdp filter-tlv-list test

!
interface TenGigabitEthernet2/1/1

 cdp filter-tlv-list test
end

and I still received the alerts:

May  3 2017 10:57:50: %CDP-SW1-4-DUPLEX_MISMATCH: duplex mismatch discovered on TenGigabitEthernet2/1/1 (not half duplex), with KECK-VSS6807-1-7-Core NDE_0 (half duplex).

thanks

Jose

[Rolf Fischer · Accepted solution]

Jose,

glad to hear that you found a solution.

I should have been more precise: The TLV filter-list filters outgoing CDP messages.

So in order to get rid of the syslog messages on the local switch, you need to configure the list on the remote switch. A quick test on a pair of lab switches worked as desired.

HTH
Rolf

[JOSE RIVERA]

Rolf,

Thanks, that did the job.

I guess I did it right the first time, I just did not know the far end would be the one not getting the alert, Once you clear that point, we tested again and that alert is no longer logged.

thank you very much, as I knew my solutions was not the correct solution.

Jose

[JOSE RIVERA]

We found something that worked ...

This solution may not be for everyone !!!!

This issue seems to be a cosmetic issue, when Netflow created the interface it comes up as 1/2 duplex, so we knew there was nothing wrong, all we wanted was to make the alert go away.

the alert was:

May  3 2017 10:57:50: %CDP-SW1-4-DUPLEX_MISMATCH: duplex mismatch discovered on TenGigabitEthernet2/1/1 (not half duplex), with KECK-VSS6807-1-7-Core NDE_0 (half duplex).

we used contents of that alert to suppress it via logging commands as follows:

logging discriminator NDE_0 msg-body drops NDE_0
logging buffered discriminator NDE_0
logging console discriminator NDE_0

This did the job, we still get other alerts, but this alert is being dropped.

I guess the downfall would be if something would go wrong with the NDE_0 interface if would also get dropped, but at least we are not getting 1440 alerts everyday on all of our devices ( one a minute).