Part-2 of this blog series discussed some of the key design consideration of enterprise multi-homing. Also in part-2 the following scenario was presented and this blog will analyze it and address it.
- ISP-A owns AS 105 and ISP-B owns AS 106
- Customer-X with AS 65001 is multi-homed to both ISPs, AS 105 and AS 106
- ISP-B allocated the public IP range (PA) 220.127.116.11/16 to Customer-X
- Customer-X advertised this range over both links toward both ISPs
Customer-X goal is use upstream AS 106 as the primary path for both inbound and outbound traffic for 18.104.22.168/24, and AS 105 as the back path.
based on the provided information, do you see any issue(s) to achieve Customer-X traffic routing goal? If yes, what and why?
Note: with the PI IP range you may be able to advertise longer subnet than /22 but this has to be confirmed with your direct peering ISP(s)