Trouble with 1841 and 4ESW Switch

VeeDub a écrit :

You need to configure bridge-groups between Fa0/0.101, Fa0/0/0 and Fa0/0/1 (for VLAN 101), between Fa0/0.102 and Fa0/0/2 (for VLAN 102) and between Fa0/0.103 and Fa0/0/3 (for VLAN 103).

Thanks for your response. I have looked for a guide to setting up bridge groups but cannot find anything specific. Can anyone povide a link to a good doco?

A couple of things here

1. Are you using a Crossover cable? Since you're going from switch to switch, instead of router to switch, you will need a Crossover cable.
2. Generally, if you have a trunk port on 1 side, you need a trunk port on the other side. You've hard coded your switchports on the

1841 to be access ports, and your 2950 port to be a trunk port. Given that one side will be sending dot1q tags and the other side won't be able to read them, this will not likely work very well

What I would suggest is the following:

On the 1841:

interface range fa0/0/0 - 3 switchport mode trunk switchport trunk encapsulation dot1q switchport trunk allowed vlan none switchport trunk allowed vlan add 101,102,103

On the other side, these VLANs should be configured to match, so do the following on the 2950

Assuming your VLANs aren't yet configured on the 2950:

conf t

vlan 101 exit vlan 102 exit vlan 103 exit

int f0/1 switchport trunk encap dot1q switchport mode trunk switchport trunk allowed vlan none switchport trunk allowed vlan 101,102,103

If you make sure to use a Crossover cable, that should work.

It should be noted that you will have to configure 4 ports in total on the 2950 to connect to 4 ports on the switch card if you want bandwidth over 100 mbps.

Hope that helps

Thanks Mike for your input,

I am actually using the router port though to connect to the external switch hence I do not need a cross-over cable. The trunk to the external switch is working absolutely fine as I can access and route between the different access ports assigned to the vlans on the 2950. The issue is that I want to do the same with the 4-ESW. However I need to bind the different switch ports (fa0/0/0-fa0/0/3) to the same vlans the sub-interfaces on fa0/0 and this is the issue.

Essentially, I want the following Layer 2 VLANs on the 1841 and the listed interfaces members of these VLANs

VLAN 101 fa0/0.101, fa0/0/0, fa0/0/1 VLAN 102 fa0/0.102, fa0/0/2 VLAN 103 fa0/0.103, fa0/0/3

I then want to be able to route betwen these VLANs using the L3 interfaces on each VLAN (fa0/0.101, fa0/0.102, fa0/0.103) for both the ports on the 4ESW and on the external 2950. As I mentioned, I am routing fine on the 2950 as this is straight forward. It is the routing between the 4ESW ports which is the issue. I also dont think what you are suggesting about configuring a trunk on the 4ESW ports will work as they are just Layer 2 interfaces, not Layer 3.

If you can assist withe creating he bridge groups to be able to put the 4ESW switchports on the same VLANs as the appropriate sub- interfaces on fa0/0 i would be appreciative.

Thanks

How long ago did you purchase this 1841? You probably have support on it. Call the TAC and they will help your or pretty much do it for you.

It was bought second hand, so I have no support for it.

Thanks

Good day

If I have this right, you have 2 objectives with this test that you're doing.

1. You want to create a trunked connection between the 1st 10/100 fixed router port on the Cisco 1841 to a trunk port on the Cisco

2950. You have thus configured 3 sub-interfaces on the 1841 for the Fa0/0 port, each representing 1 VLAN, and you have configured the trunk port on the switch to carry the 3 VLANs to the Cisco router

1. You want to create 3 VLANs on the 1841 for the 4 port switch, and relate 1 VLAN per port, all of whom will be configured in access mode

If you want to do this, you will still need to create 3 layer 3 VLAN virtual interfaces on the router. The fact that you have 3 trunked sub-interface ports does not mean that the layer 3 VLAN interfaces have yet been created. Here's what I suggest you add to the configuration:

interface vlan 101 ip address 10.100.101.2 255.255.255.0

interface vlan 102 ip address 10.100.102.2 255.255.255.0

interface vlan 103 ip address 10.100.103.2 255.255.255.0

What you could also do, in order to simplify everything is simply plug the trunk port on the 2950 into a trunk port on the hwic-4esw and carry the 3 vlans across.

To be honest, I've never tried doing this before. I do not, however, as mentioned, believe that the VLANs will carry over as layer 3 VLAN interfaces for the switchports, which are a separate module on the router, if you create sub-interfaces. The sub-interfaces will treat the VLANs as local to that connection, I believe

If anyone has any ideas on this, I wouldn't mind hearing them, as I'm not absolutely positive on what I'm saying here.

However, please give it a shot with what I suggested, as I suspect that should work

< snipped >

! I tink you will need this:- [maybe:-)]

! Clearly you may choose briigde group 101, 102, 103 ! but I though it woud be clearer to avoid that in the example.

! UNTESTED

bridge irb

bridge 1 protocol ieee bridge 1 route ip

bridge 2 protocol ieee bridge 2 route ip

bridge 3 protocol ieee bridge 3 route ip

interface FastEthernet0/0 no ip address duplex auto speed auto description Link to 2950 fa0/1 ! interface FastEthernet0/0.101 encapsulation dot1Q 101 bridge-group 1 ! interface FastEthernet0/0.102 encapsulation dot1Q 102 bridge-group 2 ! interface FastEthernet0/0.103 encapsulation dot1Q 103 bridge-group 3 ! ! interface FastEthernet0/0/0 switchport access vlan 101 ! interface FastEthernet0/0/1 switchport access vlan 101 ! interface FastEthernet0/0/2 switchport access vlan 102 ! interface FastEthernet0/0/3 switchport access vlan 103

int bvi1 ip address 10.100.101.1 255.255.255.0

int bvi2 ip address 10.100.102.1 255.255.255.0 int bvi3 ip address 10.100.103.1 255.255.255.0

! various "no shuts" if required

There may be a way to have the IP addresses on the .xxx sub interfaces instead but I can't get that picture right now.

On review, I don't think that is any good now. Sorry.