Istio vs Calico differences

Calico at Network/Transport layer, Istio at Application layer

Layer of Operation:

Calico: Works at L3/L4 (Network/Transport layer)

• Handles basic network connectivity
• Manages IP addressing and routing
• Implements network policies at IP/port level
• Uses BGP for route distribution

Istio: Works at L7 (Application layer)

• Handles service-to-service communication
• Manages API calls and HTTP/gRPC traffic
• Implements fine-grained traffic management
• Uses Envoy proxies for traffic interception

Image. Istio vs Calico difference in functionality

Primary functions

Calico

1. Pod IP address management
2. Network policy enforcement
3. BGP routing between routes
4. Security policies at network level
5. Direct pod-to-pod communication
6. Network isolation and segmentation

Istio

1. Service discovery
2. Load balancing
3. Traffic routing and splitting
4. mTLS encryption
5. Observability (metrics, traces, logs)
6. API management