Hello Sathish
As @davidilles mentioned, the IANA has defined these private ASNs in the 4-byte range as well. You can also see this at this NetworkLessons note on the topic.
I hope this has been helpful!
Laz
Hi Rene,
Quick question: In a BGP setup where a CE uses a private ASN and connects to a PE with a public ASN, can we use as-override instead of remove-private-as to prevent AS path loop issues?
Hello Daro
That’s an excellent and insightful question. The short answer is yes, you absolutely can use as-override instead of remove-private-as to solve the private ASN loop problem.
Both features are designed for the same scenario, but they achieve the goal in different ways, with different side effects.
The remove-private-as method will strip private ASNs before the update is sent across the provider’s core. It makes the path length shorter, but it’s simple, clean, and usually the default choice for most providers.
The as-override method will modify the AS_PATH just as the update is being sent out to the customer. It preserves the path length, but the AS_PATH content changes. It is used for more specific traffic engineering scenarios.
I hope this has been helpful!
Laz