300-415 Question 23
Single answerA network engineer is configuring a Cisco SD-WAN environment and notices that a branch router has multiple TLOCs defined. Each TLOC is associated with a different transport type: MPLS, Internet, and LTE. The engineer wants to ensure traffic is routed over the most reliable transport, MPLS, and only uses Internet or LTE in case of MPLS failure. Which configuration will achieve this?
- A
Set the MPLS TLOC as the primary color and configure Internet and LTE TLOCs as backup colors.
- B
Configure MPLS as the active TLOC and set Internet and LTE TLOCs with a higher preference value.
- C
Assign MPLS the highest preference in TLOC configuration and assign lower preferences for Internet and LTE.
- D
Configure MPLS TLOC with a lower cost and set Internet and LTE TLOCs with a higher cost.
Show answer and explanation
Correct answer: C
Explanation
In Cisco SD-WAN, TLOC preference values determine which transport is used first. A lower numerical preference value indicates higher priority. By assigning MPLS the highest preference (lowest value), it will be selected for traffic routing unless it becomes unavailable, at which point the next TLOC with a higher preference value (lower priority) will be used. This allows the engineer to ensure MPLS is the primary transport and Internet or LTE act as backups.
- A. Incorrect.
This option is incorrect because TLOCs do not use the concept of primary and backup colors. Traffic selection is based on preference, not a primary/backup model.
- B. Incorrect.
This option is incorrect because TLOC preference values function inversely; a lower preference value takes precedence, not higher.
- C. Correct.
This option is correct because TLOC preference determines the priority of routing traffic. Assigning MPLS the highest preference (lowest numerical value) ensures it is used first, and Internet or LTE will only be used if MPLS becomes unavailable.
- D. Incorrect.
This option is incorrect because TLOC cost is not a factor in determining transport selection. Cost is used for OMP route selection, not TLOC prioritization.