Replacing 2921 Router with 3745 Router that is Connected to ASA

[Israel Logan]

I have a 2921 router with two ports going into an ASA firewall.  Both ports are assigned to the same vlan and a vlan interface is created with an IP address.  This is working beautifully and we have no problems with this configuration.  

Now, it's time to update to a 3945 router and we are trying to do as seamless as possible a transition.  But the problem is that vlans just don't seem to work the same way on the 3945.  So everywhere I had vlan configuration in the 2921 it doesn't do anything in the 3945.  

Is there a workaround here where I won't have to make changes to the ASA?  Is there some way to make the 3945 ports cooperate like they do in the 2921?  

tia

[Tagir Temirgaliyev · Accepted solution]

I think you have HWIC-4ESW card installed in 2921

and you do not have so card in 3945

when configuring HWIC-4ESW card installed in 2921 you do something like this

interface FastEthernet0/0/0
 description ....
 switchport access vlan 20
!
interface FastEthernet0/0/1
 description ...
 switchport access vlan 30
!
interface FastEthernet0/0/2
 shutdown
!
interface FastEthernet0/0/3
  shutdown
!

!
interface Vlan30
 ...

and you can not configure

these interfaces in 3945 because this card is not installed inside

if you have not used port for example g0/0 you can configure it to connect to asa

share your configs and I will do it

[Israel Logan]

We are just going to get the hwic added to the new router.