Use route aggregation and egress filtering to control the set of routes advertised to SDDC network uplinks like Direct Connect, VMware Transit Connect and the Connected VPC. You'll need this in cases where you have to reduce the number of entries in a VPC route table or limit the set of routes that are advertised to uplinks.
In SDDCs at version 1.18 and later, you can use NSX Manager to aggregate routes to the INTRANET and SERVICES uplinks. And beginning at SDDC version 1.20, you can also use NSX Manager to filter the set of routes advertised to those uplinks. Route aggregation and filtering are not exposed in the legacy VMware Cloud Console Networking & Security tab.
In the default configuration, all segments in the SDDC Compute Network are advertised to the Connected Amazon VPC and external connections such as AWS Direct Connect and VMware Transit Connect. You can manage the list of CIDRs that get advertised this way by aggregating and optionally filtering these routes. Filtered routes are not advertised to the selected uplinks. Management subnets are always advertised. When both aggregation and filtering are applied, aggregated subnets are advertised even if they include CIDRS that would normally be filtered out. To view or download the current set of routes advertised to the Connected VPC open the NSX Manager Networking tab and click . To view or download the current set of routes advertised to Transit Connect, see View Routes Learned and Advertised over VMware Transit Connect.
See Enabling and Using IPv6 in SDDC Networks for additional information about route aggregation requirements when using IPv6 to communicate between members of an SDDC group.