Our school just received a bunch of hardware from a corporation leaving a location, so now we are upgrading our networking in four classrooms. The rooms have fiber connections to each other. The hardware we have are a Cisco 7606-s router and a Cisco 6506 router and a bunch of switches. The connections between the routers and switches will be 10 Gbit/s fiber links.

The problem is that we have two 100 Mbit/s and a single DSL uplink in one room (with the 6505), one 100 Mbit/s and a DSL in another room (with the 7606-s) and a single DSL connection in the third. So how would we bring the 100 Mbit/s connections together so we could do link aggregation? Also the DSL connections should work as a failover (they are independant from each other, but from the same ISP).

I thought that routing the uplinks through the routers and switches to a single router would be bit of a hack, so would there be any way to balance the traffic between the two routers? That is a bit problematic too, since they are not identical and would have a different number of uplinks.

Edit: I think we could get the faster connections to come to a single location. That would leave only the DSL connections to figure out

  • How fast are the DSL connections? Do you have firewalls for all your internet connections?
    – Ron Trunk
    Commented Feb 17, 2017 at 17:52
  • The DSL connections are ~20 Mbit/s. All the connections are currently going through their own consumer grade routers which have their own firewalls. We do have a Cisco ASA unit too (can't remember the exact model) that we are planning on using if it fits. If not, we'll set up a firewall on our server that's next to the 7606-s (bandwidth won't be a problem since it has a dual-slot 10 GBit/s fiber NIC). Commented Feb 17, 2017 at 19:36
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Commented Aug 16, 2017 at 22:05

1 Answer 1


First, you can't do link aggregation unless the carrier is also doing it on their end. But you can load balance between all three 100 m connections. It's best if you can run a routing protocol with your carrier, so you know that each link is available. Your routers can certainly do that.

IMO the dsl lines are not needed if you have 300 Mb spread over three connections. You could save yourself some money.

  • Well, the faster links are not directly connected to an ISP, but the guest network of our school (not under our administration but we can work with them), and when that network is down or the ISP providing that has problems, all three of them are down. The DSL connections are there so we can bypass the restricted guest network when we do some exercises. Also there have been problems regularly with the faster links, so we would prefer to have a failover. Commented Feb 18, 2017 at 5:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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