Router 2811 and C2960 Switch Trunking Problem

[sunriderhk]

Hi all

I got an problem with a trunking problem between Router 2811 and C2960 switch

In router 2811 - I created f0/0.1 10.65.20.1 (VLAN 1) and f0/0.48 10.65.23.1 (VLAN 48)

In C2960 - Vlan 1 10.65.20.30 , VLAN 48 10.65.23.30

Finally I can only ping VLAN 1 IP but fail to ping VLAN 48 IP, can help me how to troubleshoot it?

Hugo

Router 2811 Configuration:

interface FastEthernet0/0.1
 encapsulation dot1Q 1 native
 ip address 10.65.20.1 255.255.255.0
!
interface FastEthernet0/0.48
 encapsulation dot1Q 48
 ip address 10.65.23.1 255.255.255.0

C2960 Configuration:

interface FastEthernet0/24
 switchport mode trunk

[sunriderhk]

I can ping when int vlan 48 shutdown, why?

2960_24(config)#int vlan 48
2960_24(config-if)#sh
2960_24(config-if)#shutdown 
2960_24(config-if)#end
2960_24#ping 10.65.23.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.65.23.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/9 ms

I cannot ping others vlan 48 devices once I shutdown int vlan 48 on switch

[Jon Marshall]

The 2960 is a L2 switch so it acts like an PC does ie. it has an IP address and it has a default gateway.

So it should only have one vlan interface up at any one time because that is all it needs.

But you had two vlan interfaces up at the same time which is what caused the problems,

It does work with a L3 switch ie. on those you can have multiple L3 vlan interfaces and it will route between them.

When you say you cannot ping other vlan 48 devices do you mean from the switch ?

If so make sure the clients have the IP address 10.65.23.1 as their default gateway.

Clients in both vlans need to use the IP address of the corresponding IP on the router subinterfaces.

Jon

[sunriderhk]

We have a similar network design while the router is C3825 but it works for me. and also vlan 48 is Voice VLAN for us, it must be up

[Jon Marshall]

I'm not sure what you are referring to ?

It's not the vlan that isn't active it's the L3 interface for that vlan.

You can still use the vlan for end clients but the default gateway is on the router.

I can't really help if you just say you have a network design and the vlan must be up because I don't know what you mean.

Jon

[sunriderhk]

I resolved the solution by using the same environment

[Jon Marshall]

Perhaps you could explain how you resolved it so others can benefit.

We try our best to help people out and we all do this in our own free time voluntarily.

We don't necessarily expect thanks but it would help other people if they read this thread in future if you could take a bit of time to say exactly what you did to make it all work.

Jon

[sunriderhk]

2960_24#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
2960_24(config)#int vlan 48
2960_24(config-if)#shutdown 
2960_24(config-if)#no shutdown 
2960_24(config-if)#end
2960_24#ping 10.65.23.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.65.23.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
2960_24#ping 10.65.23.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.65.23.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

[Jon Marshall]

Sorry I don't understand.

I asked you to shutdown the interface but you did then brought it straight back up.

I mean shut it down and leave it shutdown.

Jon

[sunriderhk]

I can ping when int vlan 48 shutdown, why?

2960_24(config)#int vlan 48
2960_24(config-if)#sh
2960_24(config-if)#shutdown 
2960_24(config-if)#end
2960_24#ping 10.65.23.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.65.23.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/9 ms

[sunriderhk]

I cannot ping others vlan 48 devices once I shutdown int vlan 48 on switch

[Reza Sharifi]

Hi,

Can you delete "native" from interface FastEthernet0/0.1

encapsulation dot1Q 1

and test again?

HTH