About Transit Gateway Advanced Settings

The following advanced configuration applies to Aviatrix Transit gateways.

To edit the advanced configuration for a Transit gateway, see Modifying a Transit Gateway.

Connected Transit

By default, Aviatrix Spoke VPCs/VNets do not have routing established to communicate with each other via Transit. They are completely segmented.

If you would like to build a full mesh network where Spoke VPCs/VNets communicate with each other via Transit GW, you can achieve that by enabling Connected Transit mode. All connections are encrypted.

For a Spoke VPC/VNet in a multicloud transit to communicate with a Spoke VPC in TGW Orchestrator, connected Transit must be enabled on the Aviatrix Transit Gateway that connects both sides.

All Spoke gateways must be either in high-availability (HA) mode or non-HA mode. A mixed deployment (where some Spoke gateways have HA enabled and some Spoke gateways have non-HA mode) does not work when a failover happens on a HA-enabled Spoke gateway.

The Advertise Transit VPC/VNet Network CIDR setting is only applicable to Transit GW established by Transit Network workflow.

By default, Aviatrix Transit gateway does not advertise Transit VPC/VNet CIDR.

When this setting is enabled, Aviatrix Transit GW advertises the Transit VPC/VNet CIDR to VGW. The Controller programs the 3 RFC1918 routes in the AWS route table to point to the Transit gateway. It also programs the learned routes from VGW into the AWS route table.

If you deploy instances in the Transit VPC/VNet, enabling "Advertise Transit VPC CIDR(s) mode allows the instance to communicate both to Spoke VPCs and the on-prem network, assuming the Spoke VPCs are in the RFC1918 range.

To enable this setting, see Enable Advertise Transit VPC/VNet Network CIDR(s).

Multi-Tier Transit

Use the Multi-Tier Transit setting to implement a hierarchical transit gateway architecture that permits packets to traverse more than 2 Aviatrix transit gateways. Previously, full-mesh transit peering was required. You can now connect two CSPs or regions through one peered connection. You must use ActiveMesh 2.0 to use multi-tier transit gateways, but full-mesh transit peering is not required.

Guidelines:

  • You can use Multi-Tier Transit option with or without HPE.

  • Inter and intra-region peering are both supported.

  • Inter-CSP HPE over Internet is supported between AWS and Azure.

  • AWS TGW peering is not supported.

Refresh BGP Advertised Routes

This setting resets BGP connection to the remote BGP peers.

Use this option to enable new features such as Segmentation based BGP CIDR Advertisements where on-prem receives BGP advertisement for networks on-prem has connection policy or in the same Security Domain.

AWS TGW Edge Segmentation

Refer to TGW Edge Segmentation for details.

TGW Edge Segmentation can be enabled at given time. Select a connection to enable or disable.

Summarize CIDR(s) to AWS TGW

  • Enable this setting to limit routes propagated to TGW to only 3 RFC1918 CIDRs and specific non-RFC1918 CIDRs. Limiting routes saves route propagation time.

  • Leave this setting disabled (the default setting) to maintain better segmentation behavior without improving performance.