Release notes for IBM Cloud Transit Gateway

Find out about new and updated features in IBM Cloud® Transit Gateway.

06 November 2025

Support for VPN gateway connections: You can now create VPN gateway connections to a transit gateway in IBM Cloud using route-based VPNs over redundant GRE tunnels. Attaching a VPN gateway to a transit gateway requires a dynamic VPN connection. This connection type enables more efficient and scalable hybrid cloud networking, allowing services like Power Virtual Server to seamlessly connect through VPN gateway connections. For more information, see VPN gateway connection considerations.

27 August 2025

GRE enhanced route propagation: Allows routes to propagate between all GRE tunnels connected to the same transit gateway. This enables data traffic to flow between GRE tunnels that were previously isolated. GRE tunnels connected to networks that couldn’t communicate before can now exchange traffic.; This option reduces the need to create multiple GRE tunnels for communication between route tables in the same multi-zone region. By default, the GRE enhanced route propagation toggle is disabled to maintain existing behavior. For more information, see GRE enhanced route propagation considerations.

27 March 2025

4-way ECMP support now available: Newly created transit gateways now support 4-way ECMP. Existing gateways can be enabled upon request. For more information, see ECMP planning considerations.

13 March 2025

Montreal region now available: Montreal is now a supported region for the Transit Gateway service, available in zone ca-mon-1 for Generic Routing Encapsulation (GRE) tunnels. For more information, see IBM Cloud region and data center locations for resource deployment.

30 January 2025

Metrics routing support: You can now monitor and track metrics for Transit Gateway physical connections and virtual interfaces, allowing you to analyze traffic flow and set up alerts. This way, you can be notified and take appropriate action if any anomalies or unusual traffic patterns are detected. For more information, see Monitoring Transit Gateway.

12 June 2024

Support for redundant GRE tunnel connections: To build in redundancy and eliminate the need to schedule an outage when a Transit Gateway router must go down for maintenance, there is a new Redundant GRE connection type, which is essentially a grouping of at least two GRE tunnels that can connect to classic or VPC networks. This connection type allows GRE tunnels to be placed on different devices in the same zone and not flag overlapping routes that are in the redundant GRE's tunnels. For more information, see Creating a redundant GRE tunnel.

1 May 2024

Behavior change: Disable advertisement of service network routes from transit gateway connections: If any connection on a transit gateway advertises a service route, the service route is not advertised to any classic connections on that transit gateway. Before this change, Transit Gateway advertised all routes (from any connection) to all of its other connections. For more information, see Preparing for Transit Gateway changes to advertised service network routes.

24 June 2023

Power Virtual Server connections for transit gateways: Transit gateways now support Power Virtual Server connections. A Power Virtual Server connection allows a network to connect to other networks (for instance, VPC and classic infrastructure) that are connected to the same transit gateway. This adds a new Power Systems Virtual Server option when creating a new connection. For details, see Adding a connection.

22 June 2023

Madrid multi-zone region (MZR) support: Madrid MZR is now supported.

24 April 2023

Multi-account support for IBM Cloud Direct Link: Transit Gateway now includes cross-account support for Direct Link connections. For more information, see Ordering a transit gateway and Adding a cross-account connection.

30 November 2022

Unbound GRE tunnels

You can now use an unbound Generic Routing Encapsulation (GRE) tunnel transit gateway connection to connect endpoints, which allows a transit gateway to connect to overlay networks hosted on classic infrastructure resource. Unbound GRE tunnels have the following advantages over legacy GRE tunnels:

The ability to receive classic network subnets from a classic connection.
The ability to communicate through other unbound GRE tunnels on the same transit gateway.
Do not require a classic connection on the transit gateway. The classic network's subnets will not be advertised to all the connections on the transit gateway and vice versa.

For more information, see Creating an unbound GRE tunnel.