Cisco 300-540 Actual Questions

Comprehensive and Detailed Explanation Based on Designing and Implementing Cisco Service Provider Cloud Network Infrastructure Knowledge

When connectingcarrier-neutral facilities (CNFs)ordata centerswithin the same metropolitan area, service providers typically usehigh-bandwidth, low-latency optical transport methods. The most appropriate and commonly deployed interconnection technology is:

DWDM (Dense Wavelength Division Multiplexing) ring, which provides:

High capacity (10G, 40G, 100G, 400G)

Low latency

Redundancy through ring or mesh topologies

Multi-wavelength multiplexing for cost efficiency

Carrier-grade reliability for metro interconnect services

This aligns with cloud interconnect and metro transport design used in service provider environments.

Evaluation of the Options

A. OSPF backbone area adjacency

This is a routing protocol adjacency, not a physical connection method. It requires a transport link underneath but does not represent the physical interconnect itself.

B. Private wireless connection

Not suitable for CNF or metro DC interconnect because it lacks the bandwidth, reliability, and deterministic performance required for large-scale carrier-grade interconnects.

C. DWDM ring

This is the correct method. DWDM-based metro fiber rings are the standard for connecting carrier-neutral facilities in the same metro region.

D. CAT6e connection

This is limited to short-distance copper Ethernet (tens of meters). It is not used for metro-scale interconnects or between CNFs.

Comprehensive and Detailed Explanation

For distancesgreater than 20 miles, valid inter-facility transport options must support:

Metro-scale connectivity

High bandwidth

Low latency

Carrier-grade reliability

Acarrier access Ethernet ring (MEN / Metro Ethernet)is designed for:

Interconnecting data centers or meet-me rooms

Distances far exceeding 20 miles

High-availability layer-2 or layer-3 transport

Why the others are invalid:

CAT6e→ maximum ~100 meters

Multimode fiber→ typically <2 km (~1.25 miles)

Private wireless→ not used for high-capacity DC interconnects, unreliable for core transport

Thus, the only correct carrier-grade method isCarrier access Ethernet ring.

Comprehensive and Detailed Explanation

For virtualization functions and operational reliability, the architecture must leverageCisco NSO (Network Services Orchestrator)capabilities. NSO provides:

Transactional service modeling

Automatic rollbackwhen any step of a transactional deployment fails

Real-time network-state visibilityvia NSO CLI and live device synchronization

End-to-end service lifecycle automation

Among the options:

Why B is correct

"Virtualization service modeling" fits NSO’s core design principle: model the service, not individual devices.

NSO’s CLI providesstate visibility, operational introspection, transaction logs, and commit details.

NSO’s transactional engine providesautomatic rollbackupon any device or service failure.

This option capturesfull lifecycle automation,real-time state visibility, andreliability, exactly as required.

Why others are incorrect

A: CLI NED alone does not provide real-time state visibility or automated rollback; manual rollback contradicts requirements.

C: Only focuses on service modeling + CLI, but doesnotinclude rollback or lifecycle automation.

D: Templates alone do not ensure rollback or real-time operational state.

Comprehensive and Detailed Explanation

In Cisco high-availability LAN gateway designs, the requirement is:

Multiple L3 gateways sharing avirtual MAC and virtual IP

Ability toload balanceacross multiple active gateways

Capability toseamlessly take overgateway forwarding during a failure

Among Cisco First Hop Redundancy Protocols (FHRPs):

HSRP→ Active/standby only

VRRP→ Active/standby only

GLBP (Gateway Load Balancing Protocol)→The only FHRP providing active/active load balancing

GLBP allows multiple routers to share:

Acommon virtual IP

Multiplevirtual MAC addresses

Multipleactive forwardersthat load-balance end hosts

Automatic failover if any gateway fails

Thus, GLBP is the only correct protocol matching the requirement forredundant default gateways with load balancing and shared MAC addressing.