wireless_dns_functions:
 subscriber_services:
 - device_registration: "Initial network attachment"
 - service_discovery: "Application and content servers"
 - load_balancing: "Traffic distribution across data centers"  network_infrastructure:
 - pgw_discovery: "Packet Gateway service location"
 - diameter_routing: "AAA server discovery"
 - policy_servers: "PCRF and PCEF integration"  operational_support:
 - monitoring_endpoints: "Network management systems"
 - logging_services: "Centralized log collection"
 - metrics_collection: "Performance monitoring"

# Private PGW network characteristics
private_pgw:
 isolation: "Air-gapped from public internet"
 latency: "< 5ms for subscriber services"
 availability: "99.999% (5.26 minutes downtime/year)"
 capacity: "Millions of concurrent subscribers"
 security: "Carrier-grade security requirements"

# CoreDNS configuration for wireless infrastructure
.:53 {
 # Consul integration for service discovery
 consul {
 endpoint http://consul.wireless.local:8500
 datacenter wireless-east
 ttl 30
 }  # Custom wireless plugin for PGW discovery
 wireless_pgw {
 pgw_pool_discovery true
 health_check_integration true
 load_balancing_aware true
 subscriber_affinity true
 }  # Prometheus metrics for wireless-specific monitoring
 prometheus :11915 {
 enable_wireless_metrics true
 pgw_health_metrics true
 subscriber_query_tracking true
 }  # Caching optimized for wireless query patterns
 cache 300 {
 success 9984 30 # 30s for successful queries
 denial 9984 5 # 5s for NXDOMAIN responses
 prefetch 1 60m 10% # Prefetch popular queries
 }  # Forward to telecommunications-grade resolvers
 forward . 10.20.30.40 10.20.30.41 {
 health_check 5s
 max_fails 3
 policy sequential
 }  log {
 class denial error
 format combined
 }
}

# Multi-region DNS deployment for wireless infrastructure
regions:
 primary:
 name: "wireless-east"
 pgw_pools: ["pgw-pool-1", "pgw-pool-2", "pgw-pool-3"]
 capacity: "10M subscribers"
 latency_target: "< 3ms"  secondary:
 name: "wireless-west" 
 pgw_pools: ["pgw-pool-4", "pgw-pool-5"]
 capacity: "5M subscribers"
 latency_target: "< 5ms"  disaster_recovery:
 name: "wireless-central"
 mode: "standby"
 activation_time: "< 30 seconds"

# Consul service registration for PGW instances
services:
 - name: "pgw-data-service"
 id: "pgw-east-01"
 address: "10.100.1.10"
 port: 2123
 tags: ["pgw", "data-plane", "active"]
 checks:
 - name: "PGW Health Check"
 http: "http://10.100.1.10:8080/health"
 interval: "10s"
 timeout: "3s"
 deregister_critical_service_after: "30s"  - name: "pgw-control-service" 
 id: "pgw-east-01-control"
 address: "10.100.1.10"
 port: 2124
 tags: ["pgw", "control-plane", "active"]
 meta:
 subscriber_capacity: "100000"
 current_load: "65000"
 health_score: "95"

# DNS zone structure for wireless infrastructure
zones:
 wireless.internal:
 type: "authoritative"
 records:
 - name: "pgw-pool.wireless.internal"
 type: "A"
 ttl: 30
 dynamic: true
 source: "consul_service_discovery"  - name: "subscriber-services.wireless.internal"
 type: "SRV"
 ttl: 60
 priority: 10
 weight: 50
 port: 80
 target: "service-gateway.wireless.internal"  - name: "metrics.wireless.internal"
 type: "CNAME"
 ttl: 300
 target: "prometheus.monitoring.wireless.internal"  subscriber.wireless:
 type: "dynamic"
 backend: "database"
 query_patterns:
 - "subscriber-*.subscriber.wireless"
 - "device-*.subscriber.wireless"
 ttl: 5 # Short TTL for mobile subscribers

# Wireless-specific DNS query patterns
wireless_query_patterns:  # PGW service discovery queries (high frequency)
 pgw_discovery:
 pattern: "pgw-*.wireless.internal"
 frequency: "10000 queries/second"
 latency_requirement: "< 2ms"
 caching_strategy: "aggressive_prefetch"  # Subscriber service queries (bursty)
 subscriber_services:
 pattern: "*.subscriber-services.wireless.internal"
 frequency: "5000 queries/second"
 peak_multiplier: "10x during handovers"
 latency_requirement: "< 5ms"  # Monitoring and metrics (steady)
 operational_queries:
 pattern: "*.monitoring.wireless.internal"
 frequency: "100 queries/second"
 latency_tolerance: "< 100ms"
 caching_strategy: "standard"

# Advanced caching configuration for wireless workloads
cache 300 {
 # PGW service records - short TTL, high hit rate
 success 9984 30 {
 zones ["*.wireless.internal"]
 prefetch 5 30m 20%
 }  # Subscriber records - very short TTL due to mobility
 success 9984 5 {
 zones ["*.subscriber.wireless"]
 prefetch 2 5m 50%
 }  # Denial caching for invalid queries
 denial 9984 30 {
 aggressive_negative_caching true
 }  # Serve stale records during upstream failures
 serve_stale 30s
}

# DNS-based load balancing for PGW pools
load_balancing:
 algorithm: "weighted_round_robin"
 health_aware: true  pools:
 pgw_pool_east:
 members:
 - address: "10.100.1.10"
 weight: 100
 health_check: "gtp_echo"
 max_subscribers: 100000  - address: "10.100.1.11" 
 weight: 80
 health_check: "gtp_echo"
 max_subscribers: 80000  failover:
 enable: true
 threshold: "50% unhealthy"
 backup_pool: "pgw_pool_west"

# Security configuration for wireless DNS
security:
 access_control:
 # Restrict queries to known network segments
 allowed_networks:
 - "10.0.0.0/8" # Internal infrastructure
 - "172.16.0.0/12" # PGW subnets 
 - "192.168.100.0/24" # Management network  # Block potentially dangerous query types
 blocked_query_types: ["ANY", "AXFR", "IXFR"]  rate_limiting:
 # Prevent DNS-based DDoS attacks
 queries_per_second: 1000
 burst_allowance: 50
 client_subnet_tracking: true  logging:
 # Comprehensive logging for security analysis
 log_denied_queries: true
 log_client_ips: true
 include_query_details: true
 retention_period: "90 days"

# DNSSEC configuration for critical wireless zones
dnssec:
 enabled: true  zones:
 "wireless.internal":
 ksk_algorithm: "ECDSAP256SHA256"
 zsk_algorithm: "ECDSAP256SHA256"
 key_rotation: "quarterly"  "subscriber.wireless":
 algorithm: "RSASHA256" # Legacy compatibility
 key_rotation: "monthly"  validation:
 trust_anchors: ["/etc/dns/trust-anchors.conf"]
 negative_trust_anchors: ["test.wireless.internal"]

# Custom metrics for wireless DNS infrastructure # PGW health tracking
coredns_wireless_pgw_health{pool="east", status="healthy"} # Subscriber query patterns
rate(coredns_wireless_subscriber_queries_total[5m]) by (query_type, subscriber_segment) # Service discovery effectiveness
(
 rate(coredns_consul_service_queries_success[5m]) /
 rate(coredns_consul_service_queries_total[5m])
) * 100 # Latency distribution for critical queries
histogram_quantile(0.95, 
 rate(coredns_dns_request_duration_seconds_bucket{zone="wireless.internal"}[5m])
)

# Critical alerts for wireless DNS infrastructure
alerts:
 - name: "PGWPoolUnhealthy"
 condition: |
 (
 count(coredns_wireless_pgw_health{status="healthy"}) by (pool) /
 count(coredns_wireless_pgw_health) by (pool)
 ) < 0.6
 severity: "critical"
 notification: "immediate"  - name: "SubscriberQueryLatencyHigh"
 condition: |
 histogram_quantile(0.95,
 rate(coredns_dns_request_duration_seconds_bucket{zone="subscriber.wireless"}[5m])
 ) > 0.01
 severity: "warning"
 notification: "5 minutes"  - name: "ServiceDiscoveryFailure"
 condition: |
 rate(coredns_consul_service_errors_total[5m]) > 10
 severity: "critical" 
 notification: "immediate"

# SNMP bridge for traditional telecom NMS
snmp_integration:
 community: "wireless_readonly"  oid_mappings:
 "203.0.113.100.4.1.example.1.1": "coredns_dns_requests_total"
 "203.0.113.100.4.1.example.1.2": "coredns_wireless_pgw_health"
 "203.0.113.100.4.1.example.1.3": "coredns_cache_hits_total"  polling_interval: "30 seconds"
 trap_destinations: ["nms.wireless.local:162"]

# Integration with Operations Support Systems
oss_integration:
 provisioning:
 api_endpoint: "https://oss.wireless.local/dns-api/v1"
 authentication: "oauth2"  operations:
 - service: "subscriber_provisioning"
 trigger: "new_subscriber_activation"
 action: "create_dns_records"  - service: "device_management"
 trigger: "device_replacement"
 action: "update_device_dns_mapping"

# Multi-site disaster recovery strategy
disaster_recovery:
 primary_site: "datacenter_east"
 secondary_site: "datacenter_west"  replication:
 method: "real_time_sync"
 tools: ["consul_replication", "dns_zone_transfer"]
 rpo: "< 1 second" # Recovery Point Objective
 rto: "< 30 seconds" # Recovery Time Objective  failover:
 trigger_conditions:
 - "primary_site_unreachable"
 - "response_time_degradation > 50ms"
 - "error_rate > 1%"  automation: "fully_automated"
 rollback: "manual_approval_required"

# Data protection and privacy for wireless DNS
data_protection:
 encryption:
 at_rest: "AES-256"
 in_transit: "TLS 1.3"
 key_management: "hsm_integration"  subscriber_privacy:
 query_anonymization: true
 log_retention: "30 days"
 pii_masking: true  compliance:
 standards: ["GDPR", "CCPA", "telecom_regulations"]
 audit_logging: "comprehensive"
 data_classification: "subscriber_sensitive"

# Low-level network optimizations for wireless DNS
network_optimization:
 socket_configuration:
 receive_buffer: "16MB"
 send_buffer: "16MB"
 tcp_nodelay: true  kernel_tuning:
 net.core.rmem_max: "134217728"
 net.core.wmem_max: "134217728"
 net.ipv4.udp_mem: "102400 873800 16777216"  dns_specific:
 udp_payload_size: "1232" # Avoid fragmentation
 tcp_timeout: "5s"
 edns_client_subnet: true

# Infrastructure sizing for wireless DNS
hardware_requirements:
 compute:
 cpu_cores: "16 cores minimum"
 cpu_type: "High frequency (3.0GHz+)"
 memory: "32GB RAM"  network:
 interfaces: "10Gbps bonded"
 latency: "< 0.1ms to PGW network"
 bandwidth: "Sustained 1Gbps"  storage:
 type: "NVMe SSD"
 iops: "> 10000 IOPS"
 capacity: "500GB"

# DNS integration with 5G Service-Based Architecture
5g_integration:
 nf_discovery:
 # Network Function discovery using DNS
 amf_discovery: "_amf._tcp.5g.wireless.local"
 smf_discovery: "_smf._tcp.5g.wireless.local"
 upf_discovery: "_upf._tcp.5g.wireless.local"  service_mesh:
 integration: "istio"
 dns_integration: true
 load_balancing: "5g_aware"  network_slicing:
 slice_aware_dns: true
 slice_isolation: "dns_namespace_separation"
 qos_integration: true

# DNS for Multi-Access Edge Computing (MEC)
edge_integration:
 deployment_model: "distributed_dns"  edge_locations:
 - location: "cell_tower_cluster_1"
 capacity: "1000 subscribers"
 latency_target: "< 1ms"  - location: "regional_datacenter"
 capacity: "100000 subscribers" 
 latency_target: "< 5ms"  content_delivery:
 cdn_integration: true
 edge_caching: "intelligent"
 subscriber_affinity: true

# Key performance insights from production
performance_insights:
 cache_tuning:
 discovery: "Wireless query patterns differ significantly from web DNS"
 optimization: "Shorter TTLs with aggressive prefetching"
 result: "40% latency reduction"  connection_pooling:
 discovery: "UDP connection reuse critical at scale"
 optimization: "Connection pool per upstream resolver"
 result: "25% throughput improvement"  memory_management:
 discovery: "Garbage collection pauses impact real-time performance"
 optimization: "Tuned GC settings for low-latency workloads"
 result: "Eliminated P99 latency spikes"

# Scaling insights for wireless DNS
scaling_solutions:
 horizontal_scaling:
 challenge: "State synchronization across DNS instances"
 solution: "Stateless design with external state store"  query_volume:
 challenge: "Peak query rates during network events"
 solution: "Predictive scaling based on network patterns"  geographic_distribution:
 challenge: "Consistent view across regions"
 solution: "Eventually consistent replication with conflict resolution"