hybrid-cloud-networking

SKILL.md

Hybrid Cloud Networking

Configure secure, high-performance connectivity between on-premises and cloud environments using VPN, Direct Connect, ExpressRoute, Interconnect, and FastConnect.

Purpose

Establish secure, reliable network connectivity between on-premises data centers and cloud providers (AWS, Azure, GCP, OCI).

When to Use

Connect on-premises to cloud

Extend datacenter to cloud

Implement hybrid active-active setups

Meet compliance requirements

Migrate to cloud gradually

Connection Options

AWS Connectivity
1. Site-to-Site VPN

IPSec VPN over internet

Up to 1.25 Gbps per tunnel

Cost-effective for moderate bandwidth

Higher latency, internet-dependent

resource "aws_vpn_gateway" "main" {
  vpc_id = aws_vpc.main.id
  tags = {
    Name = "main-vpn-gateway"
  }
}

resource "aws_customer_gateway" "main" {
  bgp_asn    = 65000
  ip_address = "203.0.113.1"
  type       = "ipsec.1"
}

resource "aws_vpn_connection" "main" {
  vpn_gateway_id      = aws_vpn_gateway.main.id
  customer_gateway_id = aws_customer_gateway.main.id
  type                = "ipsec.1"
  static_routes_only  = false
}

2. AWS Direct Connect

Dedicated network connection

1 Gbps to 100 Gbps

Lower latency, consistent bandwidth

More expensive, setup time required

Reference: See references/direct-connect.md

Azure Connectivity

1. Site-to-Site VPN

resource "azurerm_virtual_network_gateway" "vpn" {
  name                = "vpn-gateway"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name

  type     = "Vpn"
  vpn_type = "RouteBased"
  sku      = "VpnGw1"

  ip_configuration {
    name                          = "vnetGatewayConfig"
    public_ip_address_id          = azurerm_public_ip.vpn.id
    private_ip_address_allocation = "Dynamic"
    subnet_id                     = azurerm_subnet.gateway.id
  }
}

2. Azure ExpressRoute

Private connection via connectivity provider

Up to 100 Gbps

Low latency, high reliability

Premium for global connectivity

GCP Connectivity

1. Cloud VPN

IPSec VPN (Classic or HA VPN)

HA VPN: 99.99% SLA

Up to 3 Gbps per tunnel

2. Cloud Interconnect

Dedicated (10 Gbps, 100 Gbps)

Partner (50 Mbps to 50 Gbps)

Lower latency than VPN

OCI Connectivity

1. IPSec VPN Connect

IPSec VPN with redundant tunnels

Dynamic routing through DRG

Good fit for branch offices and migration phases

2. OCI FastConnect

Private dedicated connectivity through Oracle or partner edge

Suitable for predictable throughput and lower-latency hybrid traffic

Commonly paired with DRG for hub-and-spoke designs

Hybrid Network Patterns

Pattern 1: Hub-and-Spoke

On-Premises Datacenter
         ↓
    VPN/Direct Connect
         ↓
    Transit Gateway (AWS) / vWAN (Azure)
         ↓
    ├─ Production VPC/VNet
    ├─ Staging VPC/VNet
    └─ Development VPC/VNet

Pattern 2: Multi-Region Hybrid

On-Premises
    ├─ Direct Connect → us-east-1
    └─ Direct Connect → us-west-2
            ↓
        Cross-Region Peering

Pattern 3: Multi-Cloud Hybrid

On-Premises Datacenter
    ├─ Direct Connect → AWS
    ├─ ExpressRoute → Azure
    ├─ Interconnect → GCP
    └─ FastConnect → OCI

Routing Configuration

BGP Configuration

On-Premises Router:
- AS Number: 65000
- Advertise: 10.0.0.0/8

Cloud Router:
- AS Number: 64512 (AWS), 65515 (Azure), provider-assigned for GCP/OCI
- Advertise: Cloud VPC/VNet CIDRs

Route Propagation

Enable route propagation on route tables

Use BGP for dynamic routing

Implement route filtering

Monitor route advertisements

Security Best Practices

Use private connectivity (Direct Connect/ExpressRoute/Interconnect/FastConnect)

Implement encryption for VPN tunnels

Use VPC endpoints to avoid internet routing

Configure network ACLs and security groups

Enable VPC Flow Logs for monitoring

Implement DDoS protection

Use PrivateLink/Private Endpoints

Monitor connections with CloudWatch/Azure Monitor/Cloud Monitoring/OCI Monitoring

Implement redundancy (dual tunnels)

Regular security audits

High Availability

Dual VPN Tunnels

resource "aws_vpn_connection" "primary" {
  vpn_gateway_id      = aws_vpn_gateway.main.id
  customer_gateway_id = aws_customer_gateway.primary.id
  type                = "ipsec.1"
}

resource "aws_vpn_connection" "secondary" {
  vpn_gateway_id      = aws_vpn_gateway.main.id
  customer_gateway_id = aws_customer_gateway.secondary.id
  type                = "ipsec.1"
}

Active-Active Configuration

Multiple connections from different locations

BGP for automatic failover

Equal-cost multi-path (ECMP) routing

Monitor health of all connections

Monitoring and Troubleshooting

Key Metrics

Tunnel status (up/down)

Bytes in/out

Packet loss

Latency

BGP session status

Troubleshooting

# AWS VPN
aws ec2 describe-vpn-connections
aws ec2 get-vpn-connection-telemetry

# Azure VPN
az network vpn-connection show
az network vpn-connection show-device-config-script

# OCI IPSec VPN
oci network ip-sec-connection list
oci network cpe list

Cost Optimization

Right-size connections based on traffic

Use VPN for low-bandwidth workloads

Consolidate traffic through fewer connections

Minimize data transfer costs

Use dedicated private links for high bandwidth

Implement caching to reduce traffic

Related Skills

multi-cloud-architecture - For architecture decisions

terraform-module-library - For IaC implementation