same VLANs on router's different interfaces

[s.souroutis]

Here is my problem. 1 router, 3 switches.

ROUTER fa1/0 -- SWITCH1

ROUTER fa1/1 -- SWITCH2

ROUTER fa2/0 -- SWITCH3

ROUTER

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SWITCH1 SWITCH2 SWITCH3

Every switch has 4 vlans configured. VLAN1, VLAN10, VLAN20 and VLAN30.

How can I configure the router to route between those VLANs?

I mean, if I use subinterfaces, I can configure interface fa1/0 ok.

interface fastethernet 1/0.1

encapsulation dot1Q 10

ip address 10.1.1.1 255.255.255.0

!

interface fastethernet 1/0.2

encapsulation dot1Q 20

ip address 20.1.1.1 255.255.255.0

!

interface fastethernet 1/0.3

encapsulation dot1Q 30

ip address 30.1.1.1 255.255.255.0

!

Then I go for interface fa1/1:

interface fastethernet 1/1.1

encapsulation dot1Q 10

ip address 10.1.1.2 255.255.255.0

% 10.1.1.0 overlaps with FastEthernet1/0.1

I thought about bridging, but is this the right way to do it?

Thank you for your help

[Cristian Matei]

Hi,

@Richard Burts It really depends on what the end goal. The configuration i provided, works for what he seems to try and achieve, which is a simple NAT overload, with no special requirements, get "internet access" (NAT in the end) via two different egress interfaces. With inside-outside NAT, this is gonna work, for simple PAT/overload. I agree it's not in a "recommended/best" configuration, and it does not take into account future possible NAT requirements which may force a reconfiguration of the existing NAT configuration. If the requirements were for policy NAT, or egress interface control combined with NAT, or extendable policy NAT, or ZBFW deployed, yes, route-maps would have been mandatory.

     At the same time, i agree that using route-maps from the start, it's better and safer, without actually loosing something (just some config time).

Regards,

Cristian Matei.