Cisco CCNA (200-301)Network FundamentalsHard
An engineer configures the same IPv6 address on multiple servers located in different data centers so that client traffic is automatically delivered to the nearest server based on routing metrics. Which type of IPv6 address is being used?
- AAnycast address
- BUnicast address
- CLink-local address
- DMulticast address
Show answer & explanationAnswer & explanation
Correct answer: A. Anycast address
An anycast address is assigned to multiple interfaces, typically on different devices, and traffic sent to it is routed to the nearest instance according to the routing protocol's metric. Unicast identifies a single interface, multicast delivers to a group of interfaces simultaneously, and link-local addresses are restricted to the local network segment.
Why the other options are wrong
- B. Unicast addresses identify a single unique interface, not shared across multiple devices.
- C. Link-local addresses are confined to the local link and are not used for this kind of routing.
- D. Multicast delivers a packet to all members of a group simultaneously, not just the nearest one.
IPv6 Anycast Address
An anycast address is assigned to multiple interfaces on different devices; traffic sent to it is delivered to the nearest interface as determined by the routing protocol.
- Same address on multiple devices
- Delivered to nearest instance by routing metric
- Common use: DNS root servers, CDNs
- Syntactically identical to unicast addresses
Memory trick: Anycast = 'any nearest one will do' delivery.