350-401 Practice Question: Examine the following VRF configuration: vrf…

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  The VRF exports routes tagged with RT 1:1 and imports routes tagged with RT 2:2, enabling selective route exchange.

  Why this is correct

  This is correct because in a VRF, the route-target export (RT 1:1) is attached as a BGP extended community to all routes the VRF advertises, while the route-target import (RT 2:2) filters incoming routes based on whether they carry RT 2:2. Since the export and import RTs are independent, this asymmetric configuration allows the VRF to selectively exchange routes with other VRFs or VRF instances in a hub-and-spoke or inter-VRF routing design, without needing the RTs to match.

• ✗

  The configuration is invalid because export and import RTs must be identical.

  Why it's wrong here

  This is incorrect because export and import route targets are configured as separate commands under the VRF — 'route-target export' and 'route-target import' — and they are intentionally allowed to differ. Cisco IOS and IOS-XE do not require them to be identical; in fact, asymmetric RTs are a common technique to create directional route exchange, such as allowing a hub to import spokes' routes while spokes only import the hub's routes, or to control route distribution in MPLS L3VPN inter-AS scenarios.

• ✗

  The VRF will only import routes from other VRFs that also have RT 1:1.

  Why it's wrong here

  This is incorrect because it reverses the role of the route targets. The VRF's import RT is 2:2, meaning it accepts and installs routes that carry the RT 2:2 extended community, regardless of which VRF or PE router exported them. A route carrying RT 1:1 would be ignored by this VRF's import process, since the import filter matches only RT 2:2, so the claim that it imports routes with RT 1:1 is the opposite of what actually happens.

• ✗

  This configuration disables route advertisement for VRF BLUE.

  Why it's wrong here

  This is incorrect because configuring an export route-target does not disable route advertisement; it enables it by tagging the VRF's routes with the specified RT. In this scenario, VRF BLUE's routes are exported with RT 1:1, allowing them to be advertised to other VRFs or VRF instances that import RT 1:1. Disabling advertisement would require a different configuration, such as removing the export RT, applying a route-map that denies redistribution, or using 'no export' in BGP—none of which are implied by the given configuration.

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