Adding a second Internet connection

[blamb]

Looking to add a second Internet connection to an enterprise network.  We have

multiple campus-size sites connected via MPLS.  At the moment, we only have one Internet connection at the main site.  We're planning to add a second connection to another site on the MPLS cloud but what is the best way to route network traffic when you have multiple Internet connections on one large IP network.  We're running EIGRP at the local site and BGP on MPLS.  Both Internet connections should serve as a backup for the other.  Is it just a matter of adding a little weight to the default route for the second Internet connection?  Looking for suggestions and incites.  Thanks.

[Ajay Patel]

Hi Blamb,

Please could you let me know what kind of  Network setup; you would like to have in your Network? will you share  your proposal network topology & requirement so will help us to  suggest you better proposal.

There are lot of Way to perform the Secondry link migration,

Will  pramary link remain as it is for all traffic incoming or outgoing  traffic (Secondry link will be only for reduntancy) or you want to  utilize other link for load balancing; if yes then what kind of load  balancing?

for incoming traffic should use one link  and for outgoing traffic should use other link? or manupulating the  traffic based on filter list which allow the routes to come and go in  the same path?

Waiting for your input for better understanding.

Thank you

Ajay

[blamb]

Hi Ajay,

The topology-

We have our Main site where primary Internet connection is located.  Big campus, 10G connection between buildings, etc...

We have site B where will are thinking of putting a second Internet connection.

And, we have several other sites of various sizes.

All these sites are connected across a WAN via an MPLS network.  So, each site goes to the MPLS cloud.

The Main site and site B both have a DS3 size connection to the MPLS network.

We would want the primary Internet connection a the Main site to continue to operate the way it is for incoming and outgoing traffic.  But, we would like the traffic to fail-over to the second Internet connection if the primary connection fails.

Same for the second connection.  We want each connection to be in use and serve as fail-over for the other.  And, we want the connections to operate independently should the MPLS network fail.

[Reza Sharifi]

Hi,

You can achieve that by using out bound route maps to match certain prefixes.  This way you can use your local POP for outbound and inbound traffic and in case one site goes down, the traffic can be rerouted to the other site.

Have a look at this link for example and configuration:

http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00800945bf.shtml#conf3

HTH

Reza

[blamb]

Thanks Reza!  I'm going over the suggestions.  I've got to setup a test network and see how the network will respond when lines are cut.

[Ajay Patel]

Hi Blamb,

Thanks for your update,

As par your update I would suggest you go ahead with LAN redundancy as well for WAN redundancy that will safe you.

1). Use HSRP or VRRP for Lan redundancy

2). For WAN redundancy play with weight, local preference, MED or community As you were thinking that will provide better redundancy.

3). Not Idea suggetion but I would like to share with you; put default route pointing toward neighbor ISP (if multihomed)

for Example: router A connected to ISP1, Router B connected with ISP2

defualt Route on router A:

ip route 0.0.0.0 0.0.0.0 ISP2

defualt Route on router B:

ip route 0.0.0.0 0.0.0.0 ISP2

Note:  Need to reachable both the ISP from both the END by LAN network ( Need  to manupulate internal routing to reach the neighbor ISP)

4). if single homed then use Loopback interface for EBGP peering which will help during the any link failure.

Please let me know if you need configuration so I will prepare for you.

Thank you

Ajay

[blamb]

Thanks Ajay,

I am reviewing both Reza's and your suggestions.  I'm going to setup a test network and see which configuration will work best here.  One additional wrinkle I've thought about.  It might be possible that we would want to create a VPN between the two Internet connection if we lose the MPLS connection between the sites.  I'm considering what routing would be required if we had to do that as well.