Free and Premium Cisco 300-540 Dumps Questions Answers

Comprehensive and Detailed Explanation

BGP Flowspec allows routers to distributetraffic-filtering rulesusing BGP NLRI.

To enable Flowspec, after neighbors are configured, the essential next step is:

✔Activate the Flowspec address-family under BGP

Example:

router bgp 65000

address-family ipv4 flowspec

neighbor X.X.X.X activate

exit-address-family

This enables:

FlowSpec NLRI exchange

Distribution of drop rules (rate-limit, redirect, null route, etc.)

Automatic ACL/class-map/policy-map generation on edge routers

Why the other options are incorrect:

B. Set BGP routing process→ already done when neighbors were configured

C. Activate neighbors→ only makes senseinsidean address-family; flowspec AF must be enabled first

D. Configure route reflector→ optional and not required for Flowspec to operate

Thus, the correct next step isA. Configure Flowspec for the BGP address-family.

Phase 1 of an IPsec tunnel (ISAKMP/IKE) must havematching proposalson both peers for:

Encryption algorithm

Hash (integrity) algorithm

Authentication method

DH group

The requirement states thatAESandSHA-256must be used. The current configuration uses:

encryption 3des → incorrect (must be AES)

hash md5 → incorrect (must be SHA-256)

To meet the requirement, we must modify the ISAKMP policy:

crypto isakmp policy 10

encryption aes ← change 3DES to AES

hash sha256 ← change MD5 to SHA-256

authentication pre-share

group 12

Therefore, the necessary commands on PE1 are:

encryption aes→ optionB

hash sha256→ optionE

Options C and D are invalid syntax (encryption sha256 and hash aes are not supported). Changing the DH group (A) is not required by the problem statement and would not by itself fix the mismatch related to encryption and hash algorithms.

InCisco Enterprise NFVIS, time synchronization is configured using thesystem time ntpcommand structure. NFVIS requires a primary and optionally a backup NTP server to maintain accurate system time for the hypervisor and guest VMs.

Correct NFVIS command syntax for NTP configuration:

system time ntp preferred_server This command configures thepreferred (primary)NTP server used for system clock synchronization.

system time ntp backup_server This command configures thebackupNTP server, which the system uses if the primary becomes unreachable.

These two commands match Cisco NFVIS time-configuration behavior described in NFV infrastructure design and implementation guidelines.

Why the Correct Answers Are A and E

Option A: system time ntp preferred_server 192.168.1.1

This properly configures the primary NTP server in NFVIS. The preferred server is always the first choice for time synchronization.

Option E: system time ntp backup_server 192.168.2.1

This correctly configures the backup NTP server. If the preferred server fails, NFVIS automatically falls back to the backup server.

Both commands directly match NFVIS’s NTP command hierarchy and are the only ones that correctly apply to NFVIS.

Why the Other Options Are Not Correct

Option Buses utils ntp, which is not an NFVIS command.

Option Csets manual time and does not configure NTP servers.

Option Dalso uses the utils ntp syntax, which applies to other Cisco platforms but not NFVIS.

In an NFV environment following Cisco NFV Infrastructure and ETSI MANO architecture, the onboarding workflow for VNF deployment follows this high-level order:

Define VNF descriptors (VNFD and NSD)– Includes implementation details and service definitions.

Prepare virtual machine resources– Flavor, image, CPU/memory/storage, and placement.

Define the NFV network– This step builds the underlay/overlay connectivity needed for the VNF.– It includes virtual network creation, interfaces, VLs (Virtual Links), connection points, and mapping into OpenStack (Neutron networks, subnets, ports).– No VNF can be deployed until the NFV service networks (management, control, data, HA) are defined.

Apply Day-0 configuration– Bootstrapping/initial config.

Apply Day-1 operational characteristics– Routing, services, policies.

Configure operational monitoring (KPIs)– Performance and fault measurements.

Since the question states“after the VM resources are prepared”, the next mandatory stage is defining the virtual network connectivity on which the VNFs will operate.

Comprehensive and Detailed Explanation From Cisco SP Security Knowledge

Cisco Always-On Cloud DDoS Protection is a cloud-based, carrier-grade security service used by service providers to protect customers from volumetric and application-layer DDoS attacks.

Its core protection mechanism is the use ofglobal scrubbing centers, which:

Receive diverted attack traffic

Scrub (clean) malicious packets

Forward clean traffic back to the customer

Use behavioral analysis and real-time detection

Protect against volumetric, TCP state-exhaustion, and application-layer attacks

Why other answers are incorrect:

Load balancing (A)doesnotmitigate DDoS attacks; it distributes traffic across servers.

Botnet zombies (B)aresourcesof DDoS attacks, not protection.

Traffic mirroring (C)is used for analysis and monitoring, not active DDoS protection.

Comprehensive and Detailed Explanation (Cisco NFVI / Virtualization Knowledge)

SR-IOV (Single Root I/O Virtualization)allows a VM to access the network interface hardwaredirectly, without going through the hypervisor’s virtual switch.

This is achieved by:

Assigning Virtual Functions (VFs) directly to VMs

Allowing high-performance, low-latency packet I/O

Bypassing the hypervisor datapath

Therefore, SR-IOV doesnotbypass the guest OS; it bypasses thehypervisor I/O virtualization layer, delivering near-native performance.

Thus the correct answer isC.

In Cisco data center and cloud-scale designs, adouble-sided vPC(also called vPC-to-vPC) is used when both ends of a Layer 2 port channel are formed by a pair of switches that operate as vPC peers. In this model:

On the aggregation or leaf side, two switches (in this case,LEAF1 and LEAF2) form a vPC domain with a vPC peer-link and keepalive.

On the access or ToR side, two switches (in this case,TOR1 and TOR2) must also form their ownvPC domainwith a peer-link and vPC keepalive.

The port-channel that interconnects the two vPC domains is then configured as a vPC on both sides, creating a vPC-to-vPC topology.

The problem statement specifies thatLEAF1 and LEAF2 are already configured as vPC peers. For a double-sided vPC to work, the other side (TOR1 and TOR2) must also behave as a single logical entity for the downstream Cisco UCS server and for the upstream vPC connection towards LEAF1 and LEAF2. This is only achieved when TOR1 and TOR2 are configured as vPC peers with:

A vPC domain ID

A vPC peer-link between TOR1 and TOR2

vPC member port-channels towards LEAF1 and LEAF2 and towards the Cisco UCS server

Therefore, the next required step is to configure avPC between TOR1 and TOR2.

Evaluation of the options:

Option A, “Add all the switches to the fabric,” is generic and not specific to vPC configuration. It does not address the technical requirement to form a vPC domain on the ToR side.

Option B, “Configure peering between LEAF1 and LEAF2 and TOR1 and TOR2,” is incorrect because vPC peering is only configured between the two switches that form each vPC domain (LEAF1–LEAF2 and TOR1–TOR2), not across all four switches together.

Option C, “Configure MSTP between TOR1 and TOR2,” is not required for establishing a double-sided vPC. vPC designs rely on the vPC control plane and the peer-link, not on spanning-tree between the vPC peers for normal operation.

Option D, “Configure a vPC between TOR1 and TOR2,” correctly describes configuring TOR1 and TOR2 as a vPC pair (vPC domain with peer-link), which is the mandatory step to create a double-sided vPC topology with LEAF1 and LEAF2.

Comprehensive and Detailed Explanation

AWSSecurity Groupsact as the primary stateful firewalls for EC2 instances.

To restrict SSH (TCP/22) to a single host (20.20.20.20/32), aSecurity Groupmust be configured with:

Inbound rule: TCP 22

Source: 20.20.20.20/32

ACLs operate at the subnet level but are not used for instance-specific SSH restrictions.

WAF controls HTTP/HTTPS traffic, not SSH.

Resource groups only organize cloud assets.

Thus,Bis the correct solution.

In a cloud-scale or data center–scale environment,Virtual Extensible LAN (VXLAN)is used as anoverlay technologyto transportLayer 2 segments over a Layer 3 underlay network. VXLAN encapsulates Layer 2 Ethernet frames inside UDP/IP packets, allowing broadcast, unknown unicast, and multicast (BUM) traffic and tenant Layer 2 domains to be extended across a routed IP fabric.

Key points aligned with Cisco Service Provider Cloud Infrastructure design principles:

VXLAN creates aLayer 2 overlay on top of a Layer 3 underlay.

TheVXLAN Network Identifier (VNI)provides a much larger segmentation space than traditional VLANs, enabling multi-tenancy at cloud scale.

Because the underlay is pure Layer 3 (IP routed fabric), VXLAN allows you tointerconnect Layer 2 segments between leaf switches or data centers over an IP/MPLS backbonewithout relying on large Layer 2 domains in the physical network.

Why the options evaluate as follows:

Option A: extends Layer 2 segments across the underlying Layer 3 infrastructure✅This is the core benefit of VXLAN in cloud-scale designs. VXLAN encapsulates Layer 2 frames intoIP/UDP headers, allowing isolated Layer 2 segments (per VNI) to be stretched across a routed IP network. This enables:

Multi-tenant Layer 2 connectivity across a distributed cloud fabric

Mobility of virtual machines or containers while keeping same IP/MAC addressing

Use of an IP-based leaf–spine or service provider underlay for scalability and resiliency

Option B: extends Layer 3 segments across the underlying Layer 2 infrastructure❌This is the opposite of what VXLAN does. VXLAN is explicitlyL2-over-L3, not L3-over-L2. Extending pure Layer 3 segments over Layer 2 is not the VXLAN use case.

Option C: reduces spanning-tree complexity across the Layer 2 infrastructure⚠️(Partially related but not the primary or direct benefit)In modern designs, the underlay isLayer 3 routed, and VXLAN overlays provide logical Layer 2 segments. This designavoids dependence on spanning tree in the fabric, whichindirectlyreduces STP complexity. However, the fundamental, exam-relevant benefit isL2 extension over L3, so C is not the best or most accurate answer compared to A.

Option D: eliminates the need for a Layer 3 underlay in the service provider infrastructure❌VXLAN absolutelyrequiresan IP (Layer 3) underlay for transport. VXLAN tunnels are built over a routed infrastructure (leaf–spine, MPLS/IP core, etc.). It does not remove the need for Layer 3; it depends on it.

Comprehensive and Detailed Explanation (Cisco NFVI / Virtualization Knowledge)

SR-IOV (Single Root I/O Virtualization)allows a VM to access the network interface hardwaredirectly, without going through the hypervisor’s virtual switch.

This is achieved by:

Assigning Virtual Functions (VFs) directly to VMs

Allowing high-performance, low-latency packet I/O

Bypassing the hypervisor datapath

Therefore, SR-IOV doesnotbypass the guest OS; it bypasses thehypervisor I/O virtualization layer, delivering near-native performance.

Thus the correct answer isC.

From Cisco’s EVPN VXLAN multihoming design requirements,port-active multihominguses asingle LAG (EtherChannel / Bundle-Ether)between the host/router and the pair of leaf switches. All physical interfaces participating in that bundle must be configured with:

bundle id mode active

This command:

Associates the physical interfaces (g1/0 and g1/1) withBundle-Ether1.

UsesLACP activemode, which is required for EVPN port-active multihoming.

Enables the host-facing port-channel required to support EVPN multihomed connectivity.

In the exhibit, R1 already has:

interface Bundle-Ether1

description "Bundle to Leaf-1"

interface Bundle-Ether1.10

ip address 192.168.10.1 255.255.255.0

This confirms that the engineer intends to bundleg1/0andg1/1together intoBundle-Ether1, and the missing step is adding the interfaces into that bundle.

The correct configuration is:

interface g1/0

bundle id 1 mode active

interface g1/1

bundle id 1 mode active

Why the other options are incorrect

A. evpn ethernet-segment 1This command is used on EVPN leaf switches (not R1) to define an ESI for multihoming. R1 is not an EVPN VTEP.

B. switchport mode trunkR1 is a router, not a switch. L3 interfaces do not use switchport.

C. encapsulation dot1q 1This applies only to subinterfaces, not physical interfaces, and is unrelated to building a LAG for port-active multihoming.

In Cisco Catalyst SD-WAN cloud integration, when the requirement is:

Automatically discovering AWSVPCs

Automatically identifying AWSservices

Allowing the user to choose whichprivate SD-WAN networkconnects to the cloud

UsingAWS credentials(Access Key / Secret Key) for automatic provisioning

…the Cisco-supported mechanism is theCisco SD-WAN Transit VPC solution.

Why Transit VPC is the correct answer:

It is specifically designed to integrateCisco SD-WANwith AWS environments.

Uses AWS APIs and user credentials to automatically discover:

VPC IDs

Subnets

Regions

Routing tables

Automatically deploys and configures CSR1000v or Catalyst 8000V routers into the VPC.

Provides a centralized “hub” in AWS to interconnect multiple SD-WAN sites.

Enables the user to choose which SD-WAN segments connect to which VPCs.

This matches the requirement ofautomatic cloud resource identification based on user credentials.

Why the other options are incorrect

A. AWS Direct Connect

This is a physical/private Layer 2 cloud connection.

It doesnotauto-discover VPCs or integrate through credentials.

It does not provide automated SD-WAN service provisioning.

C. IPsec VPN

Works for connectivity but ismanual, not automated.

Does not identify AWS cloud resources via credentials.

D. Segment routing

A transport technology used inside SP networks, irrelevant to AWS API-based VPC discovery.

Thus, onlyTransit VPCprovides automatic AWS cloud discovery and integration with SD-WAN.

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.

Comprehensive and Detailed Explanation From Cisco SP Cloud Network Infrastructure Security Knowledge

Cloud security compliance frameworks (such as ISO 27001, PCI-DSS, GDPR, SOC 2, HIPAA) require:

Evidence of security events

Retention of logs for audit periods

Ability to generate compliance reports

Traceability and accountability

Incident investigation support

Effective log management enables:

Centralized collection of application, network, and system logs

Storage of logs for mandated retention periods

Generation ofaudit-ready reports

Documentation required for compliance assessments

Demonstration that monitoring and security controls are active and functioning

Therefore, the role of log management in regulatory compliance is primarily aboutdocumentation, traceability, auditing, and reporting, which aligns only with Option A.

The other options do not directly serve regulatory compliance requirements:

Brelates to resource optimization, not compliance.

Crefers to interoperability, which is unrelated to regulatory auditing.

Dimproves security but does not directly address compliance documentation.

In a VXLAN BGP EVPNMulti-Siteenvironment:

DCI trackingmonitors the health of the DCI links. If all DCI-tracking interfaces go down, the leaf can incorrectly keep advertising or learning remote MAC/IP reachability, leading to packet loss and sub-optimal forwarding for servers in that VLAN/L2VNI.

For proper operation, eachDCI-facing interfacemust be enabled with evpn multisite dci-tracking so that the Multi-Site border leaf tracks reachability over that link.

When using EVPN Multi-Site, BUM (broadcast, unknown unicast, multicast) traffic toward remote sites is typically handled viaingress replication, not multicast groups, for each L2VNI participating in Multi-Site. The configuration snippet shows an L2VNI (vn-segment 16535) still mapped to mcast-group 239.1.1.0, which is inconsistent with Multi-Site recommendations and contributes to packet loss.

Therefore, to fix the problem:

Enable DCI tracking on the uplink:

interface Ethernet1/1

evpn multisite dci-tracking

This restores proper DCI-link state monitoring for Multi-Site. →Option C

Change the L2VNI behavior from multicast to Multi-Site ingress replication:

Under the VNI for VLAN 11, configure:

evpn

vni 16535 l2

multisite ingress-replication

or the equivalent command for the specific NX-OS release, thereby aligning the L2VNI with EVPN Multi-Site design and eliminating packet loss. →Option D

Options A and B are ELAM (embedded logic analyzer) filters used only for packet capture and do not resolve the forwarding issue.

Option E is an ACL line unrelated to EVPN VXLAN or DCI tracking and does not address the underlying problem.