Network Failures
Invisible Internally
Network failures often occur outside your infrastructure—ISP routing problems, BGP misconfigurations, and regional connectivity issues. External network monitoring detects these failures that internal tools cannot see, validating network reliability from the user's perspective.
Network Failures Invisible to Internal Monitoring
Many network failures occur outside your infrastructure and are completely invisible to internal monitoring tools
ISP Routing Failures
Internet Service Provider routing problems can make your services unreachable from specific ISPs or regions, even when your internal network is healthy.
Example Scenario
Your servers are running perfectly, but users on a specific ISP cannot reach them due to BGP routing issues or ISP network problems
Internal Monitoring View
Internal monitoring shows all servers healthy, network connectivity normal, no errors in logs
External Monitoring View
External monitoring detects complete unavailability from affected ISPs, validating routing failures
Impact: Service appears down to users on affected ISPs, but internal systems report no issues
BGP Misconfigurations
Border Gateway Protocol (BGP) misconfigurations can cause routing failures that make your services unreachable from certain network paths or regions.
Example Scenario
BGP routing table misconfiguration causes traffic to be routed incorrectly or dropped, preventing access from specific regions
Internal Monitoring View
Internal network appears healthy, servers accessible from within your infrastructure
External Monitoring View
External monitoring from affected regions detects routing failures and connection timeouts
Impact: Users in affected regions cannot access services, while internal monitoring shows everything healthy
Peering & Transit Issues
Network peering and transit provider failures can block traffic to your services, even when your infrastructure and direct connections are healthy.
Example Scenario
Network transit provider experiences outages or peering issues, blocking traffic to your services from certain network paths
Internal Monitoring View
Direct network connections healthy, internal routing normal, no infrastructure issues
External Monitoring View
External monitoring detects failures from network paths that depend on affected transit providers
Impact: Services unreachable from affected network paths, but internal monitoring cannot detect transit issues
Regional Network Outages
Regional network outages, submarine cable failures, or geographic connectivity issues can affect service availability in specific regions.
Example Scenario
Submarine cable failure or regional network outage prevents connectivity to your services from specific geographic areas
Internal Monitoring View
Servers healthy, internal network operational, no infrastructure problems
External Monitoring View
External monitoring from affected regions detects complete connectivity failures
Impact: Users in affected regions cannot access services, but internal monitoring shows no issues
DDoS & Network Attacks
Distributed Denial of Service (DDoS) attacks or network-level attacks can block legitimate traffic, even when your infrastructure is healthy.
Example Scenario
DDoS attack floods network paths or ISP connections, preventing legitimate users from reaching your services
Internal Monitoring View
Servers may remain healthy, but traffic cannot reach them due to network-level attacks
External Monitoring View
External monitoring detects connection failures and validates that services are unreachable from outside
Impact: Legitimate users cannot access services due to network-level attacks, while servers may appear healthy internally
CDN & Edge Network Failures
Content Delivery Network (CDN) edge failures or edge network problems can prevent content delivery, even when origin infrastructure is healthy.
Example Scenario
CDN edge locations fail or experience network issues, preventing content delivery to users in affected regions
Internal Monitoring View
Origin servers healthy, CDN dashboard may show normal operation
External Monitoring View
External monitoring from affected regions detects CDN edge failures and content delivery problems
Impact: Users in affected regions cannot access content, but origin infrastructure appears healthy
Why Internal Network Monitoring Misses These Failures
Internal network monitoring tools check connectivity from inside your infrastructure:
- •They test from within your network, missing external routing and ISP issues
- •They cannot detect BGP routing problems or ISP connectivity failures
- •They don't validate network paths from different ISPs or geographic regions
- •They may miss peering, transit, or CDN edge network failures
External network monitoring tests from outside your infrastructure, validating network paths that users actually take to reach your services.
ISP & Routing Issues
ISP routing problems, BGP misconfigurations, and network path failures can make your services unreachable, even when your infrastructure is healthy
ISP-Specific Routing Problems
Different ISPs use different network paths. Routing problems affecting one ISP may not affect others, creating inconsistent availability.
Example Scenario
Users on ISP A cannot reach your services due to routing issues, while users on ISP B experience no problems
How External Monitoring Detects It
External monitoring from multiple ISPs detects ISP-specific routing failures
Business Impact
Partial user base affected, but single-ISP monitoring may not detect issues
BGP Route Hijacking
BGP route hijacking or misconfigurations can redirect traffic away from your services, making them unreachable from certain network paths.
Example Scenario
BGP route hijacking redirects traffic intended for your IP addresses to incorrect destinations
How External Monitoring Detects It
External monitoring detects routing anomalies and validates correct network paths
Business Impact
Traffic is misrouted, preventing users from reaching your services
Geographic Routing Failures
Regional routing problems can affect connectivity from specific geographic areas, even when your infrastructure is globally distributed.
Example Scenario
Routing failures in Asia-Pacific region prevent users in that area from reaching your services
How External Monitoring Detects It
External monitoring from multiple global locations detects regional routing failures
Business Impact
Users in affected regions cannot access services, while other regions work normally
Transit Provider Failures
Network transit provider outages or failures can block traffic to your services, even when your direct connections are healthy.
Example Scenario
Transit provider experiences outages, blocking traffic to your services from certain network paths
How External Monitoring Detects It
External monitoring detects failures from network paths that depend on affected transit providers
Business Impact
Services unreachable from affected network paths, but direct connections appear healthy
Peering Point Failures
Network peering point failures can disrupt connectivity between networks, preventing traffic from reaching your services.
Example Scenario
Peering point between networks fails, blocking traffic from certain ISPs or network providers
How External Monitoring Detects It
External monitoring validates connectivity through peering points and detects failures
Business Impact
Traffic from affected networks cannot reach your services
The Complexity of Internet Routing
Internet routing is complex and involves multiple layers:
- •ISPs: Different Internet Service Providers use different network paths and routing policies
- •BGP: Border Gateway Protocol determines how traffic is routed between networks
- •Transit Providers: Networks that provide connectivity between ISPs and organizations
- •Peering Points: Network interconnection points where traffic is exchanged
- •Geographic Routing: Regional network infrastructure and submarine cables affect connectivity
External network monitoring validates connectivity through all these layers, detecting routing and ISP issues that internal monitoring cannot see.
Why External Network Monitoring Matters
External network monitoring validates network reliability from outside your infrastructure, detecting failures that internal tools cannot see
Validates User Network Paths
External monitoring tests the actual network paths that users take to reach your services, including ISP routing, BGP paths, and transit provider connections.
Key Benefits:
- Tests real user network paths
- Validates ISP routing
- Detects BGP issues
- Checks transit provider connectivity
Detects Invisible Failures
Many network failures occur outside your infrastructure and are completely invisible to internal monitoring. External monitoring detects these failures.
Key Benefits:
- Detects ISP routing problems
- Identifies BGP misconfigurations
- Finds transit provider failures
- Discovers peering point issues
Multi-ISP & Multi-Region Testing
External monitoring tests from multiple ISPs and geographic regions, detecting ISP-specific and regional network failures that single-point monitoring misses.
Key Benefits:
- Tests from multiple ISPs
- Validates regional connectivity
- Detects geographic failures
- Identifies ISP-specific issues
Independent Network Validation
External monitoring provides independent validation of network reliability from outside your infrastructure, testing the same paths users experience.
Key Benefits:
- Independent verification
- User perspective validation
- Objective network testing
- Third-party confirmation
Early Detection of Network Issues
External monitoring detects network problems before they become full outages, enabling proactive resolution and minimizing user impact.
Key Benefits:
- Early problem detection
- Proactive issue resolution
- Minimizes user impact
- Faster incident response
Complete Network Visibility
External monitoring provides complete visibility into network reliability from the user perspective, complementing internal network monitoring.
Key Benefits:
- Complete network visibility
- User perspective validation
- Complements internal monitoring
- Comprehensive network coverage
The Network Monitoring Gap
Internal network monitoring validates connectivity within your infrastructure and direct connections. External network monitoring validates the complete network path from users to your services, including:
- •ISP routing and network paths that users actually experience
- •BGP routing and network path selection from outside your network
- •Transit provider and peering point connectivity
- •Regional and geographic network failures
- •ISP-specific routing problems and network path issues
Leading organizations use both internal network monitoring for infrastructure health and external network monitoring for user-facing network reliability. Learn more about external monitoring and how it validates network reliability from the user perspective.