Can any one please guide me how Active/Passive link be used from 2 different isp's!!

[Rohit Mangotra]

Hi,

My compnay wants to get a second interenet connection from isp 2. We already have internet connection running just fine from isp 1. We want to have a second link as backup link if the first one goes down due to any reason. We own the ips that we got from ISP 1. My questions are:

1. How does the connection from isp 2 will get to our website? so that people from outside do not see any change.

2. Can this process be automatic if primary link goes down then bacup link kicks in and vice-versa?

3. We are running OSPF in our Network environment do I need to change it to BGP for this?

4. The main area of our concern is everything should be working the same way as it was with isp 1?

5. Is it simple to configure if we get 2nd link from isp 1 as the backup link?

6. what configuration do we need to make if we get 2nd link from isp 1?

Thanks a lot in advance.

Kind Regards

Rohit Mangotra.

[O Bitar]

Hi Rohit,

     It really depends on who ISP2 is, whould be from the same provider or not. You should really break down the issue into two point:

1- How are you going to send the traffic (over which link)

2- How are you going to attract traffic (again over which link)

     Ideally you would need to run BGP process and advertise the block of addresses to both ISPs and receive a default routes from both. You can then manipulate the BGP process to answer the first point by changing the Local Preference or Wheight of BGP.

     The second point is trickier, you will ,most probably, need to manipulate BGP properties again so that the traffic gets attracted over the preferred ISP link. You will really need to contact the service providers to negotiate this as there are many ways of doing it ex inserting AS on the path value or adding Community String.

     As for your internal network, it should really stay the same as the changes would really need to be applied on the edge router only.

I hope that this provides some clue to your question.

Regards

Omar

[Rohit Mangotra]

Thanks Omar for your reply. In the first situation the isp 2 is different provider. In 2nd option its a second link from same provider isp 1.

[O Bitar]

Hi again,

     As I have mentioned ealirer, you will need to discuss with the two providers to see if you can force (in a way) the return traffic to be from a specific link. In the current ISP i am working with, we still receive the incoming traffic over the secondary link even after applying few measures.

Omar