To deploy anycast IP addressing effectively, you'll need to meet these fundamental requirements:

• ASN (Autonomous System Number): Public anycast requires your own AS number from RIRs like ARIN/RIPE/APNIC. For private networks, you can use private ASNs (64512-65534).
• BGP Routing Protocol: Essential for announcing the same IP prefix from multiple locations. Example BGP configuration snippet:

router bgp 64512
 network 192.0.2.0/24
 neighbor 203.0.113.1 remote-as 64513

For internal networks, you can implement anycast without BGP using these approaches:

• OSPF/IS-IS with equal-cost paths:

interface Loopback0
 ip address 10.0.0.1 255.255.255.255
!
router ospf 1
 network 10.0.0.1 0.0.0.0 area 0

For public anycast:

Here's a complete anycast DNS server setup using BIRD on Linux:

# /etc/bird.conf
protocol kernel {
    scan time 20;
    export all;
}

protocol device {
    scan time 10;
}

protocol bgp {
    local as 64512;
    neighbor 198.51.100.1 as 64513;
    export all;
    import all;
}

• Routing loops - Implement BGP communities or AS path prepending
• Traffic asymmetry - Use anycast-aware monitoring systems
• Convergence delays - Tune BGP timers appropriately

Monitoring example using Prometheus:

# anycast_monitor.yml
- targets: ['anycast-dns:9123']
  labels:
    service: 'dns-anycast'
    location: 'europe-west'

To properly implement anycast at the global internet level, you must have your own Autonomous System Number (ASN). Here's why:

# BGP configuration example for anycast announcement
router bgp 64512
 network 192.0.2.0/24
 neighbor 203.0.113.1 remote-as 64500

Key requirements for global anycast:

• Registered ASN from RIR (ARIN, RIPE, APNIC etc.)
• Public IP address space (either PI or PA)
• BGP peering with at least one upstream provider

For internal networks, you don't need an ASN. Common implementations include:

# Linux VRAD (Virtual Router Anycast Daemon) example
vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    virtual_ipaddress {
        10.0.0.100/24
    }
}

Internal anycast options:

• VRRP (Virtual Router Redundancy Protocol)
• ECMP (Equal-Cost Multi-Path routing)
• DNS-based load balancing

For public anycast, you'll need:

# WHOIS record requirements for anycast IPs
inetnum:        192.0.2.0 - 192.0.2.255
netname:        ANYCAST-NET
descr:          Anycast service network
country:        US
admin-c:        AH123-RIPE
tech-c:         TH456-RIPE
status:         ASSIGNED ANYCAST

Key considerations:

• IP addresses must be registered as anycast with RIR
• Proper reverse DNS (PTR) records for each location
• Clear documentation of anycast service purpose

Minimum requirements for anycast deployment:

Here's a complete example using Linux and BIRD for anycast:

# /etc/bird.conf
protocol kernel {
    scan time 20;
    export all;
}

protocol device {
    scan time 10;
}

protocol bgp {
    local as 64512;
    neighbor 203.0.113.1 as 64500;
    import all;
    export all;
    next hop self;
}

protocol static {
    route 192.0.2.0/24 via 172.16.0.1;
}