CODEWITHSUNDEEP
ipbgpanycast
Liu Yao
Liu Yao

Reputation: 21

Can one IP address correspond to multiple ASNs

Can one IP address correspond to multiple ASNs? If so, what were the circumstances? Is it related to anycast ip address? thanks!

Upvotes: 2

Views: 1167

Answers (2)

crafter
crafter

Reputation: 84

Yes, it's called a Multi Origin AS (MOAS). Here is a brief explanation to a stack readers:

To exchange reachability information about IP addresses, different Autonomous Systems (ASes) in the Internet use BGP. In BGP, each IP address prefix (i.e., collection of IP addresses) is usually originated by a single AS. There are, however, also cases where multiple ASes originate the same prefix, this prefix is in turn called a Multi Origin AS (MOAS) prefix. Network operators use MOAS prefixes to e.g., provide resilience, load balancing, and multi-homing.

Further details: https://arxiv.org/pdf/2307.08490.pdf
Proof of concept:
https://bgp.he.net/report/multi-origin-routes#_ipv4multioriginroutes
https://stat.ripe.net/ui2013/193.104.254.82#tabId=routing

Must mention though that it's not recommended to do, but it terms of the question, it's possible and present all over the internet.

Upvotes: 2

user11844224
user11844224

Reputation:

No, each IP address is associated with a unique origin ASN. You could however have a more specific prefix from a different ASN. For example, 189.50.192.0/20 => ASN1 and 189.50.192.0/22 => ASN2.

All anycast locations would need to be originated from the same ASN.

Upvotes: 1

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