Anycast IP addresses on internet

[carl_townshend]

Hi All

I am curious how providers such as AWS etc use Anycast IP addresses in their global load balancers etc.

Does the IP address get advertised from multiple locations?

Do they advertise it via BGP?

Would you see the route to the IP multiple times over different routes from an ISP router?

[MHM Cisco World]

can you more elaborate.

[carl_townshend]

Hi,

sure, I just want to know how providers like aws use anycast up addresses, do they just advertise to there local isps the same address from multiple data centres via bgp?

cheers

[Giuseppe Larosa]

Hello @carl_townshend 

>> do they just advertise to there local isps the same address from multiple data centres via bgp?

basically the idea is this one. So your understanding is correct. The problem is that legitimate public IP addresses can be used in private clouds as they were private.

So NAT is also part of the picture.

Hope to help

Giuseppe

[Giuseppe Larosa]

Hello @carl_townshend ,

the basic concept is provided by the Anycast DNS server 8.8.8.8 and 8.8.4.4 provided by Google but these are exposed on the public IPv4 Internet.

Cloud networking is more complex.

Anycast IP in AWS services are provided with redundancy in different "regions" or fault domains.

But as noted you should provide more information about the scenario you are interested in.

Hope to help

Giuseppe