How to interconnect two vrfs in the same switch Catalyst 6500

In a virtualized Data Centre environment, service is provided to customers with isolation in mind using vlans, vrfs and context based services in physical appliances such as firewalls, loadbalancers and Intrusion detection amd also as virtual appliances inside hypervisors.

When this level of virtualization is achieved, it is common that your requirement also increases and some impossible things are demanded. One of these situations are the interconnection of two vrfs in the same switch.

As you know, there can only be one layer3 vlan interface inside a 6500 chassis provided by the supervisor.

The following are solutions to interconnect two vrfs:

• Use an external firewall or router to route the traffic (bad option)
• Cross over cable in two ports (Most common)
• GRE connection between VRFs.
• Use RD for this requirement

The one that I find more stable is the crossover cable or fiber but it depends on a physical component which can fail.

The most clean solution is the GRE connection, but I have never tested in prodution.