The Global Route Table (GRT) to VPRN route leaking feature allows actual routes from the global route table to be exported into specific VPRN instances allowing those routes to be used for forwarding as well as being re-advertised within the VPRN context.
There are two stages for route leaking. The first stage requires the configuration of a set of leak-export route policies that identifies which GRT routes are subject to being exported into VPRN services. The leak-export command in the configure>router context is used to configure between one and four route policies. The GRT routes must match the policy entries configured with action accept. In addition, the leak-export-limit command is used to specify the maximum number of GRT routes that can be included in the GRT leak pool.
The second stage requires the configuration of an import-grt policy that specifies which routes within the GRT leak pool that are leaked into the associated VPRN instances route table. The import-grt command in the config>service>vprn>grt-lookup context is used and accepts one route policy. In order for the GRT route to be leaked into the local VPRN, the route must match a policy entry with action accept.
If a GRT route passes both stages, it is added into the VPRN route table which it to be used for IP forwarding as well as re-advertisement within other routing protocols within the VPRN context.
Both IPv4 and IPv6 routes can be leaked using this process from the GRT into one or more VPRN instances. The GRT route types that can be leaked using this process are:
RIP, OSPF, and IS-IS routes
Direct routes
Static routes