Anycast, explained
Anycast advertises the same network address from more than one location, allowing routing to direct traffic to one of them.
- The field
- Technical
- Reading time
- 1 minute
- In this entry
- Meaning · relevance · limits
The meaning
Anycast advertises the same network address from more than one location, allowing routing to direct traffic to one of them.
Why it matters
It can support distributed delivery or attack mitigation. Actual behaviour depends on route announcements, connectivity and the service architecture.
The boundary
A geographically near site is not always the route selected, and stateful applications need appropriate design.
Routing is part of the availability design
Several sites advertise the same IP prefix, and network routing selects a path to one of them. That can distribute traffic and support resilience when the service is designed for it. It does not automatically synchronise application state or send every user to the geographically closest site, so failover behaviour still needs testing.
- Plan state replication, health withdrawal and connection handling across sites.
- Do not infer that a single VPS address is anycast from a DDoS marketing description.