Load sharing between P2P link abd MPLS USING ibgp

[Dipesh Patel]

Dear Experts,

We need to have a load sharing between 2 MPLS links and 2 P2P links;

Topology is :

The Requirement is :

• Load Sharing between TATA MPLS, Airtel MPLS, TATA P2P link and Airtel P2P link. In this case Only Local segments from Mahalaxmi and Kurla should pass from P2P links.
  
• When P2P link will fail than these local segments should pass from MPLS link.
  
• MPLS link will be use for the remote location which are reaching to Kurla via Mahalaxmi (We can say other traffic other than Local segments).
  
• There should be auto failover among all the links.
  
• All the Routing need to be done using BGP only. There will be iBGP between TATA MPLS CE router, Airtel MPLS CE router and CORE switch.
  
• P2P link will be terminating on TATA and Airtel MPLS router as shown in diagram.
  
• One more thing need to consider that when Any one of the P2P link will fail than only specific traffic need to pass on one available P2P link in order to prevent BW congestion on single P2P link.
  

Load Sharing between TATA and Airtel MPLS is working.

How to configure P2P link in this case as per the shown topology.

Regards

[Edison Ortiz]

If you use BGP as the routing protocol, the P2P links will be used as primary for inter-site connectivity due to the BGP Best Path Algorithm. The shortest AS_PATH information will be chosen in this case.

In case both P2P links are down, the routes will be learned via the MPLS Cloud. If you want to prevent these locations from becoming transit segments, make sure to have a ^$ egress filter - for instance:

ip as-path access-list 1 permit ^$

router bgp x

neighbor x.x.x.x filter-list 1

[Dipesh Patel]

Dear Edition,

How can I do the load sharing means my all four links will be use at a time.

e.g I have 4 segment im LAN say A,B,C and D than

When all links are up:

- A should go via TATA MPLS link

- B should go via Airtel MPLS link

- C should go via P2P link between TCE1-TCE2

- D should go via P2P link between ACE1-ACE2

Now when P2P link between TCE1-TCE2  down :

- C shuld go via P2P link between ACE1-ACE2.

When both P2P link will be down than only,

- C and D should go via TATA and AIRTEL MPLS link respectively.

When TATA MPLS link will be down than

- A should go via AIRTEL link not via P2P links.

and vice a versa for Airtel MPLS link also.

Please help in this regards,

[Edison Ortiz]

Based on your requirements, you want to perform source-based routing.

Source-Based routing can only be accomplish with Policy-Based Routing (PBR).

You can use BGP for destination based routing by manipulating the BGP metrics.

With PBR, you create a route-map that matches the respective subnet and set the ip next-hop to the desired link.

With BGP, you can use AS_PATH prepend inbound or outbound to make a subnet less desirable.

I suggest putting up a lab together and play around with all scenarios and failures.

Regards,

Edison