Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have a Cisco 1841 router with 4 interfaces: FE 0/0 , FE0/1, AUX, CONSOLE. I have DSL line (WAN - PPP0E) which goes to FE0/1 & FE 0/0 goes to my LAN Switch.

Now we want to get another DSL line for the purpose of Load balncing/bonding/failover. I have some questions:

  1. Is it feasible to use two WAN interfaces for this purpose? I meant people are using this kind of scenario. Any opinions...
  2. Hardware: Do i need to buy Cisco WAN interface expansion card module or
  3. I just can buy Cisco etherswitch 4 port module (which can connect to my LAN switch)

I really appreciate any feedback for experts..

Thanks, Hemal

share|improve this question
up vote 1 down vote accepted

Is your LAN switch managed? In other words, is it VLAN capable?

If it's VLAN capable, you could have one VLAN on the switch for each DSL connection, and trunk them both back into Fa0/1, then split them back out on the router's subinterfaces.

You could buy either a PPPoA/PPPoE modem and an ethernet HWIC, or an ADSL HWIC, but be aware they're bloody expensive.

The cisco etherswitch modules are similarly pricy. I'd probably be tempted to get a second hand Cisco Catalyst 2950 off ebay, and use that for the Vlan solution.

share|improve this answer
Thank you for your reply Tom. My existing LAN switch doesn't support VLAN. So if I understand your solution, I just need to get Catalyst 2950 switch. Can you please tell me how the physical cabling will look like means where the router ports(FE 0/0 & 0/1), LAN switch will be connected.. Thank you in advance for reply.. – Hemal Nov 3 '10 at 17:37

An alternative if you're not dead set on Cisco you could get a small branch series Juniper SRX220 or 240 with two ADSL2 adapters in it. Set equal cost routing to each interface and it would load balance or set a secondary default route preference to the other interface. I like things integrated. This would also give you a ton more ethernet interfaces and they're not too pricy.

If you stick with the Cisco, you're short on Ethernet interfaces to be able to connect to the device upstream to two DSL modem. I'd get the ADSL WIC myself.

share|improve this answer
Thank you Tom.. – Hemal Nov 3 '10 at 20:25

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.