I'm assuming that your question is asking- "Why do we need dedicated private line WAN links when we can communicate over the Internet via Internet Service Providers?"The main issue is reliability and performance. With an Internet connection, you ha...
You need to worry about two things for a primary/backup ISP config-outbound traffic- set weight or local preference to favor ISP A.inbound traffic- If some traffic over ISP-B is okay, use AS-prepend. If you must avoid traffic to ISP-B unless ISP-A i...
A minor correction- AS-path prepend is used to influence inbound traffic. Perhaps it would be better to say that in this case one might want to use both if you want traffic to prefer both to come in and go out of ISPA. Otherwise you might send the ...
You can use BGP to announce your new APNIC assigned addressing while still using the ISP-assigned addressing. This will allow you to test the BGP-based connectivity, gain confidence that it is working properly, then readdress your hosts into the new...