What is IBM Cloud Transit Gateway?
IBM Cloud® Transit Gateway is a network service used to interconnect IBM Cloud classic IaaS and IBM Cloud Virtual Private Cloud (VPC) resources across an IBM public cloud.
With IBM Cloud Transit Gateway, you can connect and manage your IBM Cloud VPC networks. IBM Cloud Transit Gateway gives clients dynamic scalability for easier business growth, high availability for better customer satisfaction and peace of mind that their data isn’t traversing the public internet. IBM Cloud Transit Gateway can support hybrid workloads, frequent data transfers, and private workloads, and can ease the administration of your IBM Cloud environment.

Features
Routing options
IBM Cloud Transit Gateway supports local and global routing between VPCs and IBM Cloud classic infrastructure. Traffic doesn’t traverse the public internet.
Privacy controls
Define your own IP addresses and reduce threat vectors by remaining on the IBM private network. Administer access policies through integration with IBM Cloud Identity and Access Management.
Centralized management
IBM Cloud Transit Gateway centralizes your private network across IBM Cloud VPC and IBM classic infrastructure connections in a single console.
High availability
Available in all multizone regions (MZRs) worldwide to provide global solutions, IBM Cloud Transit Gateway has a high availability 99.99% SLA and no single point of failure.
Private interconnectivity
Privately interconnect IBM Cloud VPC to VPCs (gen 1 and gen 2 VPCs). Privately interconnect VPCs between accounts, between different companies. Opt-in model per specific VPC connection.
Use cases
Connect cloud-native applications
IBM Cloud VPC makes it easier to host cloud-native applications on the public cloud. IBM Cloud Transit Gateway connects those applications for high availability, disaster recovery and edge access.
Extend applications globally
Securely connect to existing data centers, optimizing elasticity and global reach of the public cloud for applications to help support disaster recovery.
Increase network capacity and manage centrally
Move internal corporate applications to the cloud, provide additional capacity or plan for peak capacity.
Routing options
Local routing
Local routing provides interconnectivity to all accessible resources within the same IBM Cloud MZR within an account. Local routing is latency-tolerant to improve network performance and the user experience.

Global routing
Global routing expands connection capabilities to all accessible MZRs and resources in your account. For example, it can connect resources within the US South region with resources in the US East region, or with any MZR in your account.

Multi-account routing
Multi-account routing allows enterprises with multiple accounts under their control to interconnect VPC resources through an opt-in model between VPC account owners. The transit gateway account owner can send a connection request to a VPC owner in a different account (same or different company).

Optimized routing
Traffic within the same MZR routes locally so that latency is minimized. Intra-region traffic and classic access doesn’t incur data transfer charges. By providing support for multiple Transit Gateways per VPC, you can achieve traffic isolation.
