View Full Cisco 350-401 Exam Dumps and Practice Test Dumps

 

Question 161

Which protocol is used to dynamically exchange routing information between autonomous systems?

1. OSPF
2. EIGRP
3. BGP
4. RIP

Correct Answer: 3

Explanation

Border Gateway Protocol (BGP) is the primary routing protocol used to exchange routing information between autonomous systems. It is classified as an exterior gateway protocol and is widely used on the Internet and in large enterprise environments. BGP uses path attributes to make routing decisions and supports extensive policy control. OSPF, EIGRP, and RIP are interior gateway protocols designed primarily for routing within an autonomous system. BGP establishes neighbor relationships and exchanges network reachability information using reliable TCP connections.

Question 162

Which spanning-tree feature allows an access port to transition immediately to the forwarding state?

1. PortFast
2. Root Guard
3. BPDU Filter
4. Loop Guard

Correct Answer: 1

Explanation

PortFast allows an access interface connected to an end device to transition directly to the forwarding state instead of going through the normal spanning-tree transitional states. This reduces the time required for devices such as computers and printers to obtain network connectivity. PortFast should normally be enabled only on ports connected to end devices because connecting a switch to such a port could create Layer 2 topology problems. BPDU Guard is often paired with PortFast to protect against unexpected spanning-tree BPDUs.

Question 163

Which OSPF area type allows external routes while reducing the amount of routing information inside the area?

1. Backbone area
2. Stub area
3. NSSA
4. Normal area

Correct Answer: 3

Explanation

A Not-So-Stubby Area (NSSA) provides a way for an OSPF area to remain largely stub-like while still allowing an internal router to introduce external routing information. External routes can be represented using Type 7 LSAs inside the NSSA and can be translated by an appropriate Area Border Router into Type 5 LSAs for other OSPF areas. This makes NSSA useful when an area needs limited external route redistribution without requiring the full external routing information of a normal area.

Question 164

Which protocol can dynamically assign IPv6 addresses and additional configuration information to hosts?

1. DHCPv6
2. ARP
3. NTP
4. SNMP

Correct Answer: 1

Explanation

DHCPv6 provides dynamic IPv6 configuration services to hosts. Depending on the deployment, it can provide IPv6 addresses as well as additional parameters such as DNS server information. IPv6 hosts can also use Stateless Address Autoconfiguration (SLAAC), so DHCPv6 is not always required for address assignment. ARP is not used by IPv6; Neighbor Discovery provides related functionality. NTP synchronizes device clocks, while SNMP is used for network management. DHCPv6 is therefore the appropriate protocol when centralized IPv6 host configuration is required.

Question 165

Which BGP attribute is Cisco-specific and has the highest priority in the BGP path-selection process?

1. MED
2. Weight
3. Local Preference
4. Origin

Correct Answer: 2

Explanation

BGP Weight is a Cisco-specific attribute that has a very high priority in the Cisco BGP best-path selection process. A higher weight is preferred, and the value is locally significant to the router where it is configured. Weight is useful when an administrator wants to control which path a particular Cisco router selects without advertising that preference to other routers. Local Preference can influence outbound path selection throughout an autonomous system, but Weight takes precedence on the Cisco router when both are applicable.

Question 166

Which technology separates routing information for different customers or departments on the same physical infrastructure?

1. VRF
2. STP
3. SPAN
4. EtherChannel

Correct Answer: 1

Explanation

Virtual Routing and Forwarding (VRF) provides separate routing tables on the same physical device, allowing traffic from different customers, departments, or logical environments to remain isolated. Each VRF can have its own interfaces, routes, and forwarding decisions. This capability is widely used in service-provider networks and enterprise environments requiring overlapping IP address spaces or strong Layer 3 separation. STP controls Layer 2 loops, SPAN provides traffic mirroring, and EtherChannel combines physical links. VRF is specifically designed for logical routing-table isolation.

Question 167

Which protocol is commonly used to advertise routes between a customer edge router and a service-provider network in an MPLS Layer 3 VPN?

1. BGP
2. STP
3. CDP
4. LACP

Correct Answer: 1

Explanation

BGP is commonly used in MPLS Layer 3 VPN environments to exchange VPN routing information, particularly between provider and customer routers depending on the design. Multiprotocol BGP can carry VPNv4 or VPNv6 routes and associated route-target information across the provider network. VRFs keep customer routing tables separate on provider edge devices. MPLS provides the underlying label-switched transport. STP, CDP, and LACP perform unrelated Layer 2 functions. BGP’s policy capabilities and scalability make it suitable for exchanging large amounts of VPN routing information.

Question 168

Which Cisco feature can track the availability of an IP SLA operation and influence a static route?

1. HSRP
2. Object tracking
3. Port security
4. CDP

Correct Answer: 2

Explanation

Object tracking can monitor the state of an IP SLA operation and use that result to influence other configuration elements, such as static routes. For example, a router can use an IP SLA probe to test whether a remote destination is reachable. If the probe fails, tracking can cause a tracked static route to be removed or another path to become preferred. This creates a form of dynamic failover using otherwise static routing mechanisms. It is useful for improving path availability without requiring a dynamic routing protocol.

Question 169

Which protocol is commonly used to discover the default gateway and other router information in IPv6?

1. ICMPv6
2. TCP
3. UDP
4. FTP

Correct Answer: 1

Explanation

IPv6 uses ICMPv6 Neighbor Discovery messages for functions such as router discovery. Router Advertisement messages allow hosts to learn information about available routers, prefixes, address configuration methods, and other network parameters. Hosts can use Router Solicitation messages to request router information when needed. IPv6 relies heavily on ICMPv6 for control and discovery operations, making it an essential component of IPv6 functionality. TCP and UDP provide transport services, while FTP is an application-layer file-transfer protocol and does not provide IPv6 router discovery.

Question 170

Which network architecture separates the control plane from the forwarding plane and enables centralized programmability?

1. Traditional LAN switching
2. SDN
3. STP
4. NAT

Correct Answer: 2

Explanation

Software-Defined Networking (SDN) separates network control functions from packet-forwarding functions and enables centralized, programmable management. An SDN controller can maintain a broader view of the network and apply policies through software interfaces. This approach can simplify automation, improve consistency, and enable applications to interact programmatically with network infrastructure. Traditional switching protocols such as STP solve specific Layer 2 problems, while NAT performs address translation. SDN is an architectural approach rather than a single routing or switching protocol.

Question 171

Which routing protocol uses hop count as its primary metric and considers 16 hops unreachable?

1. OSPF
2. EIGRP
3. RIP
4. BGP

Correct Answer: 3

Explanation

Routing Information Protocol (RIP) uses hop count as its routing metric. A route with a hop count of 15 is considered reachable, while a metric of 16 represents an unreachable destination. RIP is simple to configure but has scalability limitations because of its relatively small metric range and periodic update behavior. OSPF uses a cost metric, EIGRP uses a composite metric, and BGP relies on path attributes rather than hop count. RIP is therefore more appropriate for small or legacy environments than large modern enterprise networks.

Question 172

Which BGP attribute identifies the autonomous systems through which a route has passed?

1. MED
2. AS Path
3. Weight
4. Local Preference

Correct Answer: 2

Explanation

The BGP AS Path attribute records the sequence of autonomous system numbers through which a route advertisement has traveled. BGP uses this information both for path selection and loop prevention. A shorter AS Path is generally preferred when other relevant path-selection factors are equal. If a router sees its own AS number in the AS Path of an incoming route, it normally rejects the route to prevent a routing loop. Administrators can also manipulate AS Path length using techniques such as AS-path prepending.

Question 173

Which protocol is used to negotiate VLAN trunking dynamically between Cisco switches?

1. DTP
2. VTP
3. STP
4. LLDP

Correct Answer: 1

Explanation

Dynamic Trunking Protocol (DTP) is a Cisco proprietary protocol used to negotiate trunking behavior between compatible Cisco switch interfaces. Depending on the configured switchport modes, DTP can determine whether a link should operate as a trunk. Administrators can also manually configure trunking rather than relying on dynamic negotiation. VTP distributes VLAN information, STP prevents Layer 2 loops, and LLDP discovers neighboring devices. DTP should be used carefully because automatically negotiated trunking can create security concerns if unauthorized devices are connected to network ports.

Question 174

Which BGP feature allows a router to advertise a route to an external neighbor without requiring the route to be installed in the local routing table?

1. Route reflector
2. Next-hop-self
3. BGP synchronization
4. Add-Path

Correct Answer: 3

Explanation

BGP synchronization was historically used to ensure that an iBGP-learned route would not be advertised to an external neighbor unless the route was also present in the IGP routing table. This requirement was relevant in older network designs where not all routers participated in BGP. In modern networks, BGP synchronization is generally disabled because network architectures typically provide full internal reachability through appropriate IGP or other mechanisms. Route reflectors, next-hop-self, and Add-Path address different BGP design and path-advertisement requirements.

Question 175

Which mechanism allows a router to distribute traffic across multiple paths that have identical routing metrics?

1. ECMP
2. PAT
3. VRF
4. NAT

Correct Answer: 1

Explanation

Equal-Cost Multipath (ECMP) allows a router to install and use multiple routes to the same destination when those routes have equal cost. Traffic can then be distributed across the available paths according to the device’s forwarding algorithm. ECMP improves link utilization and can provide additional redundancy because traffic does not depend entirely on a single path. The exact load-balancing behavior varies by platform and configuration. PAT and NAT perform address translation, while VRF provides separate routing tables.

Question 176

Which security feature limits the number of MAC addresses that can be learned on a switch port?

1. DHCP snooping
2. Port security
3. DAI
4. IP Source Guard

Correct Answer: 2

Explanation

Port security can limit the number of source MAC addresses allowed on a switch interface. This helps control which devices can connect to an access port and can reduce certain unauthorized-access scenarios. Administrators can configure a maximum number of secure MAC addresses and specify actions for violations, such as dropping unauthorized traffic, generating notifications, or shutting down the interface. DHCP snooping, Dynamic ARP Inspection, and IP Source Guard protect different aspects of network operation. Port security is specifically focused on controlling MAC addresses on switch ports.

Question 177

Which protocol provides encrypted web-based communication commonly used by RESTCONF?

1. HTTP
2. HTTPS
3. TFTP
4. Telnet

Correct Answer: 2

Explanation

HTTPS provides encrypted web communication by combining HTTP with TLS. RESTCONF commonly operates over HTTPS so that network-management requests and responses are protected while traveling between an automation client and a network device. Encryption helps protect configuration data, authentication information, and operational information from unauthorized interception. HTTP does not provide encryption, while TFTP and Telnet also lack the security mechanisms expected for protected management communication. Using HTTPS is therefore an important security consideration when deploying RESTCONF-based network automation.

Question 178

Which OSPF process allows a router to determine the shortest path through the topology database?

1. DUAL
2. Bellman-Ford
3. SPF
4. Path Vector

Correct Answer: 3

Explanation

OSPF uses the Shortest Path First (SPF) algorithm, based on Dijkstra’s algorithm, to calculate the best paths through its link-state database. Each router builds a topology representation from received LSAs and then runs SPF to determine the shortest paths from itself to other destinations. The resulting routes are considered for installation in the routing table. EIGRP uses DUAL, RIP is based on a distance-vector approach, and BGP uses a path-vector model. SPF is therefore fundamental to OSPF route calculation.

Question 179

Which technology allows a network administrator to collect packets from a switch without interrupting the original traffic flow?

1. SPAN
2. HSRP
3. VRRP
4. DHCP

Correct Answer: 1

Explanation

SPAN mirrors selected traffic from source interfaces or VLANs to a destination interface where a monitoring device can capture and analyze the traffic. Because the original traffic continues through its normal forwarding path, SPAN provides a convenient method for troubleshooting and visibility without requiring an inline monitoring device. Administrators can use packet analyzers to inspect mirrored traffic for protocol behavior, connectivity issues, or suspicious activity. HSRP and VRRP provide gateway redundancy, while DHCP provides host configuration. SPAN is specifically designed for traffic monitoring.

Question 180

Which routing protocol is classified as a link-state protocol?

1. RIP
2. BGP
3. OSPF
4. EIGRP

Correct Answer: 3

Explanation

OSPF is classified as a link-state routing protocol. OSPF routers exchange Link-State Advertisements to build a synchronized topology database for their respective areas. Each router then runs the SPF algorithm to calculate the shortest paths to destinations. This approach allows OSPF to converge efficiently and support hierarchical designs through areas. RIP is a distance-vector protocol, BGP is a path-vector protocol, and EIGRP uses an advanced distance-vector approach with DUAL. Understanding routing-protocol classifications helps engineers select and troubleshoot appropriate routing technologies.