On the enterprise network shown in the figure, R3 is connected to the NMS, and...

Comprehensive and Detailed In-Depth Explanation:

1. Understanding VPN Route Targets (RTs) in MPLS VPNs

Route Targets (RTs) define which VPN routes should be imported and exported among PE routers.

Import-extcommunity: Specifies which VPN routes should be accepted into a VRF.

Export-extcommunity: Specifies which VPN routes should be advertised from a VRF.

Correctly configuring RTs ensures proper route exchange between VPN sites.

2. Analyzing the RTs in the Diagram

R3 ' s Current Configuration:

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vpn-target 3:1 export-extcommunity

vpn-target 3:2 export-extcommunity

vpn-target 1:3 export-extcommunity

vpn-target 1:3 import-extcommunity

vpn-target 3:1 import-extcommunity

vpn-target 3:2 import-extcommunity

R1 ' s Configuration:

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vpn-target 1:3 export-extcommunity

vpn-target 3:1 import-extcommunity

R2 ' s Configuration:

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vpn-target 2:3 export-extcommunity

vpn-target 3:2 import-extcommunity

R3 has redundant RTs because it both exports and imports unnecessary RTs.

We need to remove only redundant RTs without affecting NMS connectivity.

3. Evaluating Each Answer Choice

A. " undo vpn-target 3:1 import-extcommunity " (❌ Incorrect)

R1 exports RT 1:3, and R3 imports it as 3:1.

Removing 3:1 import-extcommunity would block R3 from receiving routes from R1, disrupting connectivity to NMS.

Thus, this option is incorrect.

B. " undo vpn-target 1:3 export-extcommunity " (✅ Correct)

R3 exports RT 1:3, but there is no need for R3 to advertise routes with 1:3.

R1 already exports 1:3, and R3 only needs to import it.

Removing vpn-target 1:3 export-extcommunity does not affect connectivity but eliminates redundancy.

✅ This is a correct choice.

C. " undo vpn-target 1:3 import-extcommunity " (❌ Incorrect)

R3 needs to import 1:3 to receive routes from R1 (which is required for NMS communication).

If removed, R3 will not receive necessary routes, breaking connectivity.

Thus, this option is incorrect.

D. " undo vpn-target 2:3 export-extcommunity " (✅ Correct)

R2 exports RT 2:3, but R3 does not need to receive it.

This RT is redundant and can be removed without affecting connectivity.

✅ This is a correct choice.

4. Evaluating the Answer Choices

Option

Correct?

Reasoning

A

❌ Incorrect

R3 must import 3:1 from R1 to maintain connectivity.

B

✅ Correct

Removing export-extcommunity 1:3 eliminates redundancy without affecting connectivity.

C

❌ Incorrect

Removing import-extcommunity 1:3 would block R3 from receiving necessary routes.

D

✅ Correct

Removing export-extcommunity 2:3 eliminates redundancy without affecting connectivity.

✅ Correct Answer: B and D.

Final Conclusion:

Route Targets (RTs) are used in MPLS VPNs to control route import/export policies.

R3 has redundant RTs, and removing unnecessary exports (1:3 and 2:3) optimizes configuration.

Correct commands to remove redundancy without affecting connectivity are:

✅ undo vpn-target 1:3 export-extcommunity

✅ undo vpn-target 2:3 export-extcommunity

Thus, the correct answer is: B and D.