VTP between ROUTER and SWITCH does not work

[Didier1966]

Hello,

Sorry for my newbie question, but to prepare myself for some CCNA courses in October I made a small setup to try a router on a stick ,this work as expected but ....

In the CISCO 1841 (router) , you can setup VLANS and VPT as SERVER and in my CISCO 2950 (switch) as client:

I expected that if both are on the same domain with the same password and everithing that it will work , I mean by work , when I setup the VLAN DATABASE in the ROUTER that he will send it to the switch , but unfortunatly this does not work.

Just for the fun I created in a other switch a VLAN DATABASE (has a SERVER) and this was dumped directly in the CISCO 2950 , so I know that the CISCO 2950 is workin and able to receive VPT.

Any idea why it does not work from the router ?

It is not urgent , it is just for my personal knowledge

Best Regards,

Didier

Router#sh run
Building configuration...
Current configuration : 2303 bytes
!
version 15.1
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot system flash c1841-advsecurityk9-mz.151-3.T2.bin
boot-end-marker
!
!
!
no aaa new-model
!
dot11 syslog
ip source-route
!
!
no ip dhcp use vrf connected
ip dhcp excluded-address 192.168.1.1
ip dhcp excluded-address 192.168.10.1
ip dhcp excluded-address 192.168.20.1
ip dhcp excluded-address 192.168.30.1
ip dhcp excluded-address 192.168.40.1
!
ip dhcp pool VLAN1
   import all
   network 192.168.1.0 255.255.255.0
   default-router 192.168.1.1
!
ip dhcp pool VLAN10
   import all
   network 192.168.10.0 255.255.255.0
   default-router 192.168.10.1
!
ip dhcp pool VLAN20
   import all
   network 192.168.20.0 255.255.255.0
   default-router 192.168.20.1
!
ip dhcp pool VLAN30
   import all
   network 192.168.30.0 255.255.255.0
   default-router 192.168.30.1
!
ip dhcp pool VLAN40
   import all
   network 192.168.40.0 255.255.255.0
   default-router 192.168.40.1
!
!
!
ip cef
!
multilink bundle-name authenticated
!
crypto pki token default removal timeout 0
!
!
!
!
license udi pid CISCO1841 sn FCZ1217905C
archive
 log config
  hidekeys
!
redundancy
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
 no ip address
 duplex auto
 speed auto
!
interface FastEthernet0/0.1
 encapsulation dot1Q 1 native
 ip address 192.168.1.1 255.255.255.0
!
interface FastEthernet0/0.10
 encapsulation dot1Q 10
 ip address 192.168.10.1 255.255.255.0
!
interface FastEthernet0/0.20
 encapsulation dot1Q 20
 ip address 192.168.20.1 255.255.255.0
!
interface FastEthernet0/0.30
 encapsulation dot1Q 30
 ip address 192.168.30.1 255.255.255.0
!
interface FastEthernet0/0.40
 encapsulation dot1Q 40
 ip address 192.168.40.1 255.255.255.0
!
interface FastEthernet0/1
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface Serial0/0/0
 no ip address
 shutdown
 clock rate 2000000
!
interface Serial0/0/1
 no ip address
 shutdown
 clock rate 2000000
!
interface Serial0/1/0
 no ip address
 shutdown
 clock rate 2000000
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
logging esm config
!
!
!
!
!
control-plane
!
!
!
line con 0
 speed 115200
line aux 0
line vty 0 4
 login
 transport input all
!
scheduler allocate 20000 1000
end
Router#
Router#
Router#
Router#

Switch#sh run
Building configuration...
Current configuration : 1152 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname Switch
!
!
ip subnet-zero
!
no ip domain-lookup
ip host R1 192.168.1.1
!
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!
!
!
!
interface FastEthernet0/1
 switchport access vlan 10
 switchport mode access
 spanning-tree portfast
!
interface FastEthernet0/2
 switchport access vlan 20
 switchport mode access
 spanning-tree portfast
!
interface FastEthernet0/3
 switchport access vlan 30
 switchport mode access
 spanning-tree portfast
!
interface FastEthernet0/4
!
interface FastEthernet0/5
!
interface FastEthernet0/6
!
interface FastEthernet0/7
!
interface FastEthernet0/8
!
interface FastEthernet0/9
!
interface FastEthernet0/10
!
interface FastEthernet0/11
 switchport mode trunk
!
interface FastEthernet0/12
 switchport mode trunk
!
interface Vlan1
 ip address 192.168.1.254 255.255.255.0
 no ip route-cache
!
ip http server
!
line con 0
 password cisco
 login
 speed 115200
line vty 0 4
 privilege level 15
 password cisco
 login
line vty 5 15
 login
!
!
end
Switch#
Switch#
Switch#

[Peter Paluch · Accepted solution]

Hello Didier,

While the 1841 router supports VTP commands, they are effective only if you install a switching module (such as HWIC-4ESW) into the router's WIC slots, and they apply only to switchports on this switching module. Routers do not speak VTP on their routed onboard ports - because for VLANs on these routed ports, you create subinterfaces directly. That is why the VTP does not seem to work between your router and the 2950 switch.

Best regards,

Peter

[Didier1966]

Hello Peter,

Thank You for your prompt reply.

How can I learn this kind of tricks , when you use VPT , CISCO or the IOS do not tell you this , maybe in a next release we will have a message

Thank You Again.

Best Regards,

Didier

[Peter Paluch]

Hello Didier,

Thank you! About learning these tricks... well, it's simply practice. I've been working with Cisco devices since 2001. Don't worry, you will learn these things soon enough, and in the meantime, these forums are exactly what should save you the hard try-and-fail way of doing things. Feel always welcome to come and discuss any topic you might have!

Best regards,

Peter

[Gabor Torok]

5 years later cisco has got a same issue...

I'm still interested how possibe to pass trough the VTP information between router and switch.
e.g. router 2901 has got 3 Gi port, 1 internet, another 2 1-1 switch eg 3560 without hard-wiring together the 2 switch.

may VPN? or tunnelling?