300-410 · Question #44
Which two statements about VRF-Lite configurations are true? (Choose two)
The correct answer is B. Different customers can have overlapping IP addresses on different VPNs E. Each customer has its own private routing table. VRF-Lite enables multiple virtual routing and forwarding (VRF) instances on a single router, providing logically separate routing tables and allowing overlapping IP addresses for different customers.
Question
Options
- AThey support the exchange of MPLS labels
- BDifferent customers can have overlapping IP addresses on different VPNs
- CThey support a maximum of 512,000 routes
- DEach customer has its own dedicated TCAM resources
- EEach customer has its own private routing table.
- FThey support IS-IS
How the community answered
(40 responses)- A3% (1)
- B88% (35)
- C3% (1)
- D8% (3)
Why each option
VRF-Lite enables multiple virtual routing and forwarding (VRF) instances on a single router, providing logically separate routing tables and allowing overlapping IP addresses for different customers.
VRF-Lite operates at Layer 3 on a router and does not support the exchange of MPLS labels; MPLS VPNs are required for label distribution between PE routers.
VRF-Lite creates separate routing and forwarding tables for each VRF instance, which allows different customers to use overlapping IP address spaces without conflict, as traffic for each customer is isolated within its own VRF.
A maximum of 512,000 routes is a general capacity limit for some high-end routers, not a specific characteristic or limitation of VRF-Lite itself, which is more about logical separation.
While VRF-Lite uses TCAM (Ternary Content Addressable Memory) for fast lookups, it utilizes shared TCAM resources by partitioning them logically, rather than dedicating separate physical TCAM resources to each customer.
Each VRF instance maintains its own independent routing table (known as a Routing Information Base or RIB) and Forwarding Information Base (FIB), ensuring complete separation of routing information and forwarding decisions for each customer or service.
Concept tested: VRF-Lite capabilities and characteristics
Source: https://www.cisco.com/c/en/us/td/docs/ios/iproute/configuration/guide/irr_vrf.html
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