Native VLAN Mismatch 1

[ronnyserrano]

I'm a newbie so forgive me if this is a dumb question. I'm getting a Native vlan mismatch. I have a 4507 as my core switch. The config for the port that is an issue on the 4507:

interface GigabitEthernet4/45
switchport access vlan 21
switchport mode access
service-policy output ETHERNET
qos trust cos
tx-queue 3
priority high
shape percent 33

We've connect a 2960G to this port. It is only supposed to act as a dumb switch. No trunking, don't even care if it is VLAN'd in any special way. The native VLAN on the 4507 is setup as
vlan 999
name NATIVE_VLAN

Config on 2960G is: (I took out the password lines)

Current configuration : 1384 bytes
!
version 12.2
service config
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname HOF-SECURITY-SWITCH
!
no aaa new-model
system mtu routing 1500
ip subnet-zero
!
no file verify auto
spanning-tree mode pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
interface GigabitEthernet0/1
interface GigabitEthernet0/2
interface GigabitEthernet0/3
interface GigabitEthernet0/4
interface GigabitEthernet0/5
interface GigabitEthernet0/6
interface GigabitEthernet0/7
interface GigabitEthernet0/8
interface GigabitEthernet0/9
interface GigabitEthernet0/10
interface GigabitEthernet0/11
interface GigabitEthernet0/12
interface GigabitEthernet0/13
interface GigabitEthernet0/14
interface GigabitEthernet0/15
interface GigabitEthernet0/16
interface GigabitEthernet0/17
interface GigabitEthernet0/18
interface GigabitEthernet0/19
interface GigabitEthernet0/20
interface GigabitEthernet0/21
interface GigabitEthernet0/22
interface GigabitEthernet0/23
interface GigabitEthernet0/24
!
interface Vlan1
no ip address
no ip route-cache
shutdown
!
ip http server
!
control-plane
!


!
end

The exact error message is:
2w4d: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEth
ernet0/21 (1), with HOF-CORE-1.HEARTSONFIRE.COM GigabitEthernet4/45 (21).

I know I can shut off CDP, but thatdoesn't seem to be the right answer. Can anyone point me in the right direction.

thanks
RS

 

[jeter]

why not just make the port interface GigabitEthernet 4/45
a trunk port?



Spc NVARNG
Tek-TIP Member 19,650

 

[ronnyserrano]

I suppose I could.. but what's the benefit? I wanted to just put a plan old Dell powerconnect switch in here... someone spec'd a Cisco switch because it cost more . I'm not even assigning the ports on the 2960 to a VLAN.. if I make it a trunk port then I have to worry about things like VLAN tagging.. don't I?

There will only be one subnet on this switch and 90% of the traffic is self contained on this switch.

 

[ADB100]

In your config you said the Native VLAN is 999, however the configuration of the interface is

interface GigabitEthernet4/45
 switchport access vlan 21
 switchport mode access

This makes the port an access port in VLAN 21, there is nothing to do with Native VLAN 999 anywhere on the port, plus it isn't a trunk so the Native VLAN is irrelevant. What you are seeing is an error message generated because you have VLAN 1 on the 2960 end and VLAN 21 on the 4500 end. This is because CDP is advertising the VLAN ID and the switches see it as an error as they don't tie-up.
Best way to solve it is add this to the 2960:

vlan 21
 exit
interface range GigabitEthernet0/1 - 24
 switchport access vlan 21
 switchport mode access

That will fix it.

Andy

 

[vipergg]

The message does not hurt anything , just copnnect it up . If it really bugs you then you have to fix the vlans on each end so they match up . On the 2960 create vlan 21 and then put the ports in vlan 21 , message will dissappear.

 

[burtsbees]

If it were OpenVMS, you'd type
SYS$SYSTEM:reply/disable

lol

Burt

 

[ronnyserrano]

Andy & Everyone,

I used your piece of code and fixed it. I'm always amazed at how quickly people get back to you on tek-tips and how good the answers are. Not only did I fix it, I now understand the stupid message better. Everywhere I looked regarding that error message on the net it talked about trunking. It never talked about mismatched vlan IDs.

Thanks again everyone!
RS