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How to configure a VRF for a secondary ISP?
For the secondary ISP, a VRF named ISP2 is configured. The tunnel vrf ISP1 and tunnel vrf ISP2 are configured on interfaces Tunnel0 and Tunnel1, respectively, in order to indicate that the forwarding lookup for the post-GRE encapsulated packet is performed in either VRF ISP1 or ISP2.
How to configure VRF on a Cisco router?
Configuration Example on Cisco Router The router used is CISCO891-K9 with image c890-universalk9-mz.151-4.M4.bin installed. Each VRF Instance will have two Layer3 routed interfaces associated with it as shown below. Consider each VRF Instance as a virtual router with two interfaces.
Can you use VRF and MPLS on the same router?
Now, although VRFs and MPLS are usually configured on high-end ISP routers, you can still use this feature on some smaller Cisco ISR routers in a simplified manner called VRF Lite and have the same advantages. With VRF Lite, you can have separate routing tables on the same physical router device.
What’s the difference between a VPN and a VRF?
VRFs employ essentially the same concept as VLANs and Trunking, but at Layer 3. VRF (Virtual Routing and Forwarding) is traditionally associated with IP MPLS technology whereby an ISP creates Layer3 (or Layer2) VPNs for customers using VRF.
What happens if both ISPs terminate in the global VRF?
If both of the ISPs terminate in the global VRF, they share the same routing table and both of the mGRE interfaces rely on the global routing information. In this case, if the primary ISP fails, the primary ISP interface might not go down if the failure point is in the backbone network of ISPs and not directly connected.
How does the VRF-Lite feature work in DMVPN?
The VRF-Lite feature forces the traffic from multiple Multipoint Generic Routing Encapsulation (mGRE) tunnel interfaces to use their respective VRF routing tables.
How to use dual ISPs for DMVPN redundancy?
The use of dual ISPs for redundancy has become a common practice. Administrators use two ISP links; one acts as a primary connection and the other acts as a backup connection. The same concept can be implemented for DMVPN redundancy on a spoke with the use of dual ISPs.