%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet1/43

[hemadri37]

Dear Members,

I am getting follwoing errors continuously in ths switch.

Gi 1/43 and gi 1/42 is uplink access ports for vlan 101 and vlan 111

config is follow

interface GigabitEthernet1/42
description Uplink VLAN101
switchport access vlan 101
switchport mode access
logging event link-status
logging event trunk-status
storm-control broadcast level 1.00
storm-control action trap
end

interface GigabitEthernet1/43
description Uplink VLAN111
switchport access vlan 111
switchport mode access
logging event link-status
logging event trunk-status
storm-control broadcast level 1.00
storm-control action trap

can anyone advise on this please

Regards

Hemadri

[Mark Malone]

Hi

that alert is warning of the far end device cdp vlan config miss-match whats connected to g1/43 and whats the port config on the far end device the 4948 ?

[hemadri37]

Hi,

Far end device is also cisco 4948

interface GigabitEthernet1/42
description Uplink VLAN101
switchport access vlan 101
switchport mode access
logging event link-status
logging event trunk-status
storm-control broadcast level 1.00
storm-control action trap
end

interface GigabitEthernet1/43
description Uplink VLAN111
switchport access vlan 111
switchport mode access
logging event link-status
logging event trunk-status
storm-control broadcast level 1.00
storm-control action trap

Also we found Duplicate if alias value configured n different indexes, - Ignoring if Alias on the following if indexes: 2, 3, 4, 5 this alarm in switch. is it related to this in anyway.

Regards

Hemadri

[Mark Malone]

have you got the native vlan command configured on either switches or any other local LAN connected switches to these 4948s on any trunk interface ? , that alert has to becoming from one of the switches

•Use the show interfaces trunk command to check whether the local and peer native VLANs match. If the native VLAN does not match on both sides, VLAN leaking occurs.

[hemadri37]

Hi,

Sure will check and update.

Also we observed this error in switch.

Duplicate if alias value configured n different indexes, - Ignoring if Alias on the following if indexes: 2, 3, 4, 5

What it exactly indicates any idea about this.

Regards

Hemadri

[Mark Malone]

Not sure what that is but the native vlan is a common alert to do with vlans being miss configured as natives on trunk links connected together between switches

That new alert is there anything else with it in logs ? it my be software related , is it continuous or once off in logging

[hemadri37]

I didnot find any other info in logs apart from this. Also it is not continuos.

It is not coming very frequently, but it comes in late intervals but not daily.

Regards

Hemadri

[Mark Malone]

Ok is the CDP log continuous when was the last one , just trying to establish if its still an issue ? this will keep occurring if there is native vlan miss matches between switches but if its stopped the issue isn't relevant anymore

Honestly looking around the tech docs I cant see anything for the 2nd alert that matches may just be cosmetic on the software , I don't believe there related though as I have seen cdp native issue few times over the years and many times on this forum

[hemadri37]

Hi Mark,

Yes the CDP log is continuos. it is coming now also.

will check the status as you advised.

[Mark Malone]

Yes then the native issue is there somewhere , unless I can see your configs I cant really assist further , it has to be stated somewhere to be seen in logs like that and if its continuous the switches are definitely seeing it somewhere , there's no hub's or any unmanaged switches in between these 4948s that could cause it too if there not set same as your local ports

[chrihussey]

Just curious, what does the output of "show cdp neighbor" look like in both these switches?

Thanks

[hemadri37]

Hi,

I have this problem in switcn HSBU_AGG1B1

HSBU_AGG1B1#show cdp nei
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
HSBU_AGG1A1.HSBU Gig 1/1 150 R S I WS-C4948 Gig 1/1
HSBU_AGG1A1.HSBU Gig 1/4 150 R S I WS-C4948 Gig 1/4
HSBU_AGG1A1.HSBU Gig 1/3 150 R S I WS-C4948 Gig 1/3
HSBU_AGG1A1.HSBU Gig 1/2 150 R S I WS-C4948 Gig 1/2
HSBU_AGG1B1.HSBU Gig 1/43 158 R S I WS-C4948 Gig 1/42
HSBU_AGG1B1.HSBU Gig 1/42 158 R S I WS-C4948 Gig 1/43

in other Switch

HSBU_AGG1A1#show cdp nei
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
HSBU_AGG1B1.HSBU Gig 1/1 169 R S I WS-C4948 Gig 1/1
HSBU_AGG1B1.HSBU Gig 1/4 169 R S I WS-C4948 Gig 1/4
HSBU_AGG1B1.HSBU Gig 1/3 169 R S I WS-C4948 Gig 1/3
HSBU_AGG1B1.HSBU Gig 1/2 169 R S I WS-C4948 Gig 1/2

[chrihussey]

So doesn't CDP neighbor show that you have the interfaces crossed? That would be the issue.

[Mark Malone]

hmm something doesnt look right there with these 2

HSBU_AGG1B1.HSBU Gig 1/43 158 R S I WS-C4948 Gig 1/42
HSBU_AGG1B1.HSBU Gig 1/42 158 R S I WS-C4948 Gig 1/43

why doesnt switch 2 show the return cdp paths for these 2 if there all directly connected ?

[hemadri37]

Hi,

Both switches are directly connected on gi 1/1, 1/2, 1/3 & 1/4 interfaces only.

Interface gi 1/42 and i/43 are not directly connected between these switches.

this two ports are uplinks for vlan 101 and vlan 111