GCP Networking

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Resource in GCP


  • Can be accessed by any other resource, across regions and zones 

  • Creating VPC is a global operation because a network is a global resource 

  • Different from AWS and Azure because the VPC and routing is global, not within a region 


  • Can be accessed only by resources in the same region 

  • Reserving an IP address is a regional operation 


  • Can be accessed only by resources in the same zone 

  • Disks can be attached to computers in the same zone   

GCP Projects

  • Projects are the fundamental organizational structure 

  • GCP resources must belong to a project 

  • Made up of settings, permissions, and other metadata that describe applications 

  • Contains the computing, storage, and networking resources 

  • A project can’t access other projects resources unless you use 

    • Shared VPC 

    • VPC Network Peering 


Basic GCP Network Components  

  • GCP Regions and Zones 

  • VPC/Subnets 

  • VPC Peering 

  • Implicit Routing 

  • VPN Gateway 

VPC Network 

  • Global Routing: 

    • VPC is a global resource 

    • All the subnets irrespective of region are inherently routable within a VPC 

  • Subnets/CIDR are a regional resource  

  • Projects can contain multiple VPC networks 

Routes in GCP 

  • Routes created by GCP for users are system generated routes 

    • Default route 

    • Subnet gateway 

  • User Defined Route 

    • Static Routing 

    • Dynamic Routing 

Transit (Inter-VPC) Networking 

  • Lacks native transit solution to interconnect VPC’s 

    • VPC peering preferred 

    • Preaching single VPC 

  • VPC Peering 

    • Same qualities as other CSP’s 

    • All preprogrammed routes from the two VPC’s are announced to each other 

    • Used to connect multiple VPC’s  

    • Non-transitive 

Cloud Interconnect 

  • Connect your On-Prem network to your VPC network through a private connection 

  • Limitation: Not encrypted 

  • Dedicated Interconnect 

    • Enables users to connect existing network to the VPC network through a highly available, low latency, enterprise grade connection 

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  • When VPC is global service in GCP why would there be a Shared VPC or VPC peering?

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    • Anil K The global routing stays inside the VPC. The reality is that enterprises would need number of VPCs for segregation, isolation and security reasons. So you need a proper transit solution that is Aviatrix transit to connect those VPCs for proper routing, control and traffic engineering.

      Shared VPC is is mainly for network admins to check-out resources such a subnets and firewall rules to tenants or service projects.

      Like 1
  • What is the difference between Cloud Interconnect and Dedicated Interconnect.

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