Chapter 6: Networking Flashcards
Virtual Private Clouds
The fundamental network in the cloud is a virtual private cloud (VPC).
VPC’s are Global resources.
They are built inside projects and do NOT permit cross-project communication. (That requires a shared VPC)
Subnets
A subnet is a subnetwork, or a logical subdivision of your RFC 1918 IP space. (either IPv4 or IPv6 IP range)
Subnets are regional resources, whereas VPCs are global resources.
You can’t have a VPC network without at least one subnet in it.
Auto Mode vs Custom Mode Subnets
An auto mode VPC network is the default network that is created when you create a project. In this configuration, each region automatically gets a default /20 subnet created in it.
Custom mode VPC networks do not come with any subnets, giving the network administrator full control to define the subnets and IP ranges before the network is usable.
Only custom mode networks should be used for production environments.
Exam Tip
VPC networks are global resources.
Subnets are regional resources.
This design is one of the more significant advantages to using GCP over other clouds, because the global end-to-end physical network is fully owned by Google.
Exam Tip
You may see a scenario in which a web application has VMs running inside of a VPC, and you’re asked to restrict traffic between the instances to specific paths and ports that you authorize. The application autoscales, so you can’t route based on a static IP address.
In this case, you’d use firewall rules to authorize traffic based on network tags that are attached to your VMs.
Exam Tip
Know the difference between transitive and nontransitive peering. If, for example, VPC-A is connected to VPC-B using VPC peering, and VPC-B is connected to VPC-C via peering.
In a non-transitive model, VPC-A will still explicitly have to be connected to VPC-C to communicate.
In the transitive model, as long as routes and rules are properly configured, you can communicate across to any other connected networks, which is typically the pattern desired in a hub-and-spoke model.
Exam Tip
You likely won’t see anything too complex on the test about DNS, except maybe some questions about troubleshooting, where the answers could have to do with incorrect DNS records or setup.
Exam TIp
Don’t forget the bandwidth constraints of the various connectivity options.
Cloud VPN only supports up to 3 Gbps per tunnel
Partner Interconnect supports up to 10 Gbps
and Dedicated Interconnect supports up to 100 Gbps
If you get a question on the exam about speed, privacy, and connecting between on-premises to GCP—you know what to do.
