One LAN with two ISP

[JudAster2010]

Hello,

I need advice on how to make use of the two Internet accesses we have/need.

Now we have two separated networks that we need to join. We'll use different VLANs and we'll route them with the Cisco 3560. Now the doubt, is how do we have to configure the two Internet connections because a small group of computers need to use a different ISP.

Do we have to route the internet access on the  3560?. Our firewall (Zyxel ZyWALL USG200) has two WAN connections, and I don't know what would be easier.

Is this the best configuration?:

ISP1    ISP2

    |       |

   ZyWALL

        |

     3560

        |

Other switches

Thanks a lot,

Jud

[Giuseppe Larosa]

Hello Jud,

>> Now the doubt, is how do we have to configure the two Internet connections because a small group of computers need to use a different ISP.

C3560 cannot perform NAT, so it is the other box that has to handle NAT and it can use a different pool of addresses for different source private ip addresses.

or if NAT is not involved you need to implement a sort of policy based routing.

if the zyxel does not support PBR you can implement it on the C2560 but you will need the zyxel to offer two different IP next-hops in order for PBR to work.

in this case the zyxel should implement a sort of VRF lite to segregate traffic.

I don't know about ZyWALL features but your proposed setup should be correct because NAT cannot be performed on the C3560.

Hope to help

Giuseppe