mpls/bgp and mlppp

[jonesl1]

I have a question regarding mlppp and bonding mpls T1 circuits.   For the longest time we have been able to get by on one T1 circuit coming into

our 3845 router.   Well this T1 has now become congested and they are wanting to add bandwidth to this T1.   We connect to the phone company

via an MPLS T1 currently.   So now it appears as though we are going to purchase another MPLS T1 circuit and bond the two T1's together. The way our network is currently set up, we utilize the same AS number on all of our remote routers regardless of location.  Keep in

mind I don't have any sort of mlppp set up at this moment, so unfortunately I can't post any configs.  I'm just questioning the design portion and how

to go about doing this.

Here is where my dilemma begins........

For every MPLS circuit we order on the remote end, we specifiy an IP for the remote router itself and one for the provider to assign to their equipment

(the bgp neighbor statements).   Now granted i'm no BGP extraordinaire, not even a novice really, but I don't understand how I am going to bring two

T1 circuits into the same router (basically with 2 pairs of IP's).   In order to bond the two T1's together, i'll need to create a multilink interface and

assign an IP to that, but yet I still have 2 SETS of ip addresses.   And if that isn't enough of a dilemma, I also need to spedify a neighbor statement in

order for my AS to bind to the adjacent provider AS, but yet I have two IP addresses for that as well.   

Can someone give me a hand and explain this to me or how I need to go about doing it?  I would greatly appreciate it as i'm a bgp idiot!  However, I

assure you i'm a 'bgp idiot' that values all information and assistance provided. 

Thanks, 

[Vaibhava Varma · Accepted solution]

Hi jonesl1

Regarding your question for creating a ML-PPP link on your existing T1 circuit the solution way out is to let your ISP understand that your going to create ML-PPP for the existing T1 circuit we have and this way he would only assign you a new Physical T1 Circuit but not L3-T1 circuit means no IPs on new T1. Instead with a planned outage along with the ISP during the maintenance window you and ISP Tech has to work together to erase the existing T1 config and create the ML-PPP config and move both the T1s new and old one under that and same time moving the IP address from Old T1 to ML-PPP

This way the BGP config stays same, The IPs remain same, we don't need new IPs, no new BGP config and just the ML-PPP takes the IP of the existing T1.

The only thing to be cautious about this kind of existing T1 to ML-PPP upgrade is that you do need to have a way out to access yoour router if somehow there's issue with the ML-PPP config and the access to router across WAN is lost.

Hope this helps you in your query.

Regards

Varma

[jonesl1]

Ok....that makes total sense!  Thank you for explaining that in terms I could understand.   I just couldn't figure out how to

go about doing this, but now that I know that the provider can assign it as a non L3 circuit, then that makes a huge difference!!!  

Thank you very much for your information!   Much appreciated!!!