Connect three connections on router 1841 (just two ethernet interfaces)

[Bruno Silva]

Hi,

I've an issue with a 1841 router. It have only two ethernet interfaces and i want three connections: WIMAX, LAN and Satellite. 

My initial configuration, and it works, is only with WIMAX and LAN:

"
interface FastEthernet0/0
ip dhcp client client-id ascii M7-ROU-01
ip address dhcp
ip access-group 150 out
ip pim sparse-mode
speed 100
full-duplex
!
interface FastEthernet0/0.807
description outsideWIMAX
encapsulation dot1Q 807
ip address 10.1.145.25 255.255.255.252
!
interface FastEthernet0/1
no ip address
ip pim sparse-mode
duplex auto
speed auto
!
interface FastEthernet0/1.607
description insideLAN
encapsulation dot1Q 607
ip address 192.168.150.1 255.255.255.0
ip pim sparse-mode
ip nat inside
ip virtual-reassembly in

"

A few notes:

- The inside network have a 3650 switch for entire site;

- The wimax network needs this command "ip dhcp client client-id ascii M7-ROU-01" because it can connect to a different sites and get a specific IP according to each site.

So.... what i want is add another satellite connection (internet connection with DHCP) to make a VPN to my central site making redundancy of the wimax.

any ideas!?

Thanks a lot for your support!

[shaps · Accepted solution]

If you have a switch in front of the router then you can use vlans to separate the wimax and satellite traffic,  the outside router interface will use sub interfaces to connect to the relevant vlans you've used on the switchports.  

[Joseph W. Doherty]

As Shaps has mentioned, you can use an external switch, perhaps your 3650?  On the router, you use subinterfaces, as also described by Shaps.  You define a trunk on the switch and VLANs.  (Minimally, you would likely need 3 switch ports.  One for the trunk to the router.  Two, one each, for what would have been your two router links.)

Another option, if available for your 1941, is to acquire one or more Ethernet ports for it.  Normally, in a case like yours, you would want routed ports.

[Bruno Silva]

YEs!

thanks! it was the solution! indeed, i had this idea... and i implemented, but somehow it didn´t work.. i tried once again and tcharan :)

Ups, but now, i've got another problem...

Now i've got: Wimax connection, LAN connection, satellite connection, and i didn´t mentioned befored, i've also cellular connection (3G card).

Most of time... there is no wimax connection, but i've got internet by 3G(ICPC) or satellite (DHCP).

To achieve my other vpn site (specific IP), the 1841 router do not now where to go, if by cellular connection on satellite connection.

I now i can specify prioryties in routes. for example (with both interfaces no shutdown):

ip route host x.x.x.x fastethernet 0/1.406 110 (satellite)

ip route host x.x.x.x cellular 0/0/0 220 (3G)

the problem is, if i lost satellite internet connection, it no assume cellular internet connection because the interface f0/1.406 continues no shutdown, and it have IP address...

How can i solve this?