Ch 15 Review Q6 anycast

[aetelman]

The chapter, under "Address Types" indicates a "one-to-nearest", as well as the anycast packet being delivered to only one device.

• The question suggests the answer as "one-to-one-of-many;" never mentioned in the chapter.

• The book answer does suggest anycast being delivered to one device (gee, thanks

I picked the answer as A: delivered to a single interface.
Who's right?
Thanks, good people

[lammle]

Anycast is defined as one-to-many.
However, with that said, the bottom line is that a single packet will be delivered to only one to device.
With anycast, many servers, as an example, will have the same IPv6 unicast address. Routers will load balance on a link to these servers and deliver the packet to the nearest anycast address, but they won't deliver the packet to more than one device. The next packet might go to a different device, or the same, depending on the routers.
This is basically a very cool load-balancing technique built inside IPv6.
Hope this helps.
Todd