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Huawei HCIE-Datacom practice questions

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Question 1Datacom

In VXLAN, which field of the outer UDP header is used together with the VNI to identify the VPN instance on the receiving VTEP?

  1. The UDP source port, which identifies the ingress VTEP and is often derived from a hash of the inner frame Correct answer.
  2. The UDP length field, which is set to 8 plus the VNI
  3. The UDP destination port, which encodes the VNI
  4. The UDP checksum, which carries the VNI in its lower 24 bits

Explanation

The VXLAN header itself carries the 24-bit VNI, while the outer UDP source port is normally a hash of the inner packet fields so that ECMP can spread traffic across the underlay. It also identifies the originating VTEP for return-path and loop-detection purposes. The destination port is fixed (4789 by default) and does not encode the VNI.

Question 2Datacom

A network engineer wants to reduce broadcast flooding in a VXLAN EVPN fabric while still supporting ARP. Which mechanism should be enabled on the leaf switches?

  1. Unicast reverse path forwarding on the NVE interface
  2. STP root guard on the VTEP interfaces
  3. IGMP snooping on the underlay core
  4. ARP suppression with distributed anycast gateway Correct answer.

Explanation

EVPN ARP suppression lets the ingress VTEP answer ARP requests locally from a cache built from EVPN MAC/IP advertisements, so ARP requests are not flooded across the fabric. It is normally combined with a distributed anycast gateway so every leaf can answer for the subnet's gateway MAC and IP. Flooding is reduced without breaking ARP resolution.

Question 3Datacom

Which OSPF LSA type is generated by an ABR to describe a summary route for an inter-area prefix?

  1. Type 1 Router LSA
  2. Type 5 AS External LSA
  3. Type 3 Summary LSA Correct answer.
  4. Type 2 Network LSA

Explanation

An ABR originates Type 3 Summary LSAs to advertise inter-area prefixes into another area, replacing the detailed topology of the source area with a summary. Type 1 and Type 2 LSAs stay within a single area, and Type 5 LSAs describe external routes redistributed into OSPF.

Question 4Datacom

An engineer configures 'bgp 65001' and 'peer 10.0.0.2 as-number 65002' on a Huawei router but the session stays in Active state. Which action most directly addresses the most common cause?

  1. Verify that the peer address is reachable and that a route to 10.0.0.2 exists in the routing table Correct answer.
  2. Enable BGP synchronization
  3. Configure a route reflector on the local router
  4. Increase the BGP hold timer to 180 seconds

Explanation

A BGP session stuck in Active usually means the local router cannot reach the peer's address, so TCP cannot complete the three-way handshake. Checking reachability and the routing table for the peer address (or fixing an ACL/firewall filter) is the first diagnostic step. Timers and reflector configuration do not affect the TCP connection setup.

Question 5Datacom

Which MPLS label distribution mode has a router advertise a label for a prefix to all its LDP peers regardless of whether it is the next hop for that prefix?

  1. Downstream on demand
  2. Independent control
  3. Unsolicited downstream Correct answer.
  4. Ordered control

Explanation

In unsolicited downstream mode, a router distributes labels to all LDP peers without waiting for a request from an upstream neighbor. Downstream on demand only distributes a label when an upstream peer asks for it. Control modes (ordered versus independent) govern how a router binds a label relative to its next hop, not whether distribution is solicited.

Question 6Datacom

A customer requires that traffic from VLAN 10 always leave the PE toward CE-A, and traffic from VLAN 20 always leave toward CE-B, on a single physical interface toward the customer. Which feature accomplishes this on a Huawei device?

  1. BGP route reflector placement
  2. OSPF virtual link
  3. Local preference on the PE
  4. VLAN-based forwarding on the sub-interfaces Correct answer.

Explanation

VLAN-based forwarding (VLAN-based Layer 3 forwarding on sub-interfaces) allows a single physical link to carry multiple VLANs, each mapped to a different VRF or next hop. This is the standard way to separate customer traffic on a shared physical interface. Local preference and route reflectors affect BGP path selection, not per-VLAN egress selection.

Question 7Datacom

Which IPv6 address type is used by a host to send a packet to all routers on its local link?

  1. ff02::1:2
  2. ff02::2 Correct answer.
  3. ff02::5
  4. ff02::1

Explanation

ff02::2 is the all-routers link-local multicast address; every router on the link joins it and hosts use it to reach routers. ff02::1 is all-nodes, ff02::5 is all OSPF routers, and ff02::1:2 is all DHCP servers.

Question 8Datacom

Which statement best describes the purpose of the P bit and B bit in an MPLS label stack entry?

  1. The P bit indicates the label is a prefix label and the B bit indicates a backup path
  2. The P bit marks the bottom of the stack and the B bit indicates a PHP operation Correct answer.
  3. The P bit identifies a protected label and the B bit identifies a backup label
  4. The P bit is the bottom-of-stack bit and the B bit is the explicit-null indicator

Explanation

The S (bottom-of-stack) bit in an MPLS shim header marks the final label in the stack, after which the payload follows. It is often called the P bit in some vendor terminology, and the B bit in Huawei's implementation is used to indicate penultimate-hop popping behavior. Correct interpretation of these bits matters for label stack processing.

Question 9Datacom

A Huawei device is configured with 'interface GigabitEthernet0/0/1' and 'ip address 10.1.1.1 255.255.255.0'. Which command is required to enable OSPF on this interface when using a network statement?

  1. 'silent-interface GigabitEthernet0/0/1' under the OSPF process
  2. 'ospf enable 1 area 0' under the interface
  3. 'network 10.1.1.0 0.0.0.255' under the OSPF process Correct answer.
  4. 'import-route direct' under the OSPF process

Explanation

With Huawei VRP, OSPF can be enabled on an interface either by a network statement inside the OSPF process matching the interface address, or by the interface-level 'ospf enable' command. The network statement with a wildcard mask is the classic method. Import-route direct redistributes routes but does not enable OSPF on the interface.

Question 10Datacom

Which BGP attribute is used by a Huawei router to prefer routes learned from a specific peer without affecting other peers' traffic, and is not propagated to other autonomous systems?

  1. LOCAL_PREF Correct answer.
  2. ORIGIN
  3. AS_PATH
  4. MED

Explanation

LOCAL_PREF is an iBGP-only attribute that influences outbound path selection within an AS and is not advertised to eBGP peers. It is widely used to prefer one exit point over another inside the local autonomous system. AS_PATH and MED are propagated and affect inter-AS selection.

Question 11Datacom

A network engineer must ensure that a CE router's default route is preferred over any routes learned from the PE in a BGP/MPLS L3VPN. Which configuration achieves this?

  1. Configure the CE with 'peer default-originate'
  2. Set the MED to 0 on the default route
  3. Apply a route policy on the CE that sets local preference to 200 for the default route Correct answer.
  4. Set local preference to 200 on the PE for the CE's routes

Explanation

Local preference is a per-AS attribute and higher values are preferred, so setting local preference to 200 on the default route at the CE ensures it wins over routes learned from the PE. Setting it on the PE would affect the PE's outbound selection, not the CE's. MED affects inbound selection across ASes and does not override local preference.

Question 12Datacom

Which QoS mechanism is applied on an interface to shape outbound traffic to a committed rate while buffering excess packets?

  1. Congestion avoidance (WRED)
  2. Class-based marking
  3. Policing
  4. Shaping Correct answer.

Explanation

Shaping buffers excess packets and delays them to smooth the output rate to the committed rate, which avoids drops at the expense of delay. Policing drops or remarks excess traffic instead of buffering it. WRED drops packets proactively based on queue thresholds, and marking sets DSCP/CoS bits.

Question 13Datacom

A network uses VLAN 100 as the native VLAN on a trunk between two Huawei switches. What is the recommended security practice?

  1. Disable the native VLAN on one side only
  2. Assign the native VLAN to the management subnet
  3. Enable DTP on the trunk
  4. Change the native VLAN to an unused VLAN ID on both ends Correct answer.

Explanation

VLAN hopping attacks exploit a native VLAN that matches an access port, so best practice is to set the native VLAN to an unused, dedicated VLAN ID on both ends of the trunk. Using the management subnet as the native VLAN exposes management traffic to untagged injection. DTP should be disabled, not enabled.

Question 14Datacom

Which protocol is used by Huawei's iMaster NCE-Campus to deliver configuration to switches in a cloud-managed fabric, typically over a secure channel?

  1. TFTP
  2. NETCONF over SSH Correct answer.
  3. Telnet
  4. SNMPv1

Explanation

NETCONF over SSH (or RESTCONF) is the standard model-driven interface used by controllers such as iMaster NCE-Campus to push configuration to devices securely. SNMPv1 and Telnet are unencrypted legacy protocols, and TFTP is only for file transfer.

Question 15Datacom

Which VXLAN gateway type performs Layer 2 bridging between a VXLAN segment and a traditional VLAN?

  1. Anycast gateway
  2. Layer 3 VXLAN gateway
  3. Route reflector
  4. Layer 2 VXLAN gateway Correct answer.

Explanation

A Layer 2 VXLAN gateway bridges a VXLAN segment to a VLAN, forwarding frames between the overlay and legacy Layer 2 domains. A Layer 3 gateway routes between VXLAN segments or between VXLAN and VLAN subnets. Anycast gateways and route reflectors serve different roles in the fabric.

Question 16Datacom

In Segment Routing over MPLS, which segment type represents an adjacency to a specific neighbor and is locally significant?

  1. Anycast segment
  2. Adjacency segment Correct answer.
  3. Node segment
  4. Prefix segment

Explanation

An adjacency segment (Adj-SID) is locally significant to the advertising node and steers traffic over a specific link to a specific neighbor. Node and prefix segments identify a router or prefix globally within the SR domain. Anycast segments are shared by multiple nodes to provide redundancy.

Question 17Datacom

Which mechanism allows a Huawei router to detect a failed BGP peer faster than the default hold timer?

  1. BFD for BGP Correct answer.
  2. Graceful restart
  3. BGP confederation
  4. Route reflection

Explanation

BFD provides sub-second failure detection independent of the BGP hold timer, and when bound to BGP it tears down the session quickly on link or path failure. Graceful restart preserves forwarding during a restart, and route reflection and confederation are scalability mechanisms.

Question 18Datacom

Which field in an IPv4 header prevents packets from looping indefinitely in the network?

  1. Identification
  2. Time to Live Correct answer.
  3. Header Checksum
  4. Type of Service

Explanation

The Time to Live field is decremented by each router, and the packet is discarded when it reaches zero, which prevents endless looping. Identification supports fragmentation reassembly, and the header checksum protects the header only.

Question 19Datacom

A network engineer observes that a Huawei switch is dropping frames from a newly attached server on an access port. Which feature is most likely causing the drop if port security is enabled with a maximum MAC count of one?

  1. Port security MAC limit Correct answer.
  2. STP BPDU guard
  3. DHCP snooping
  4. ARP inspection

Explanation

Port security with a maximum MAC address count of one drops frames from additional source MAC addresses once the limit is reached. BPDU guard disables a port on receiving a BPDU, DHCP snooping filters DHCP messages, and ARP inspection validates ARP bindings.

Question 20Datacom

Which OSPF network type is default on a Huawei GigabitEthernet interface, and what is the default hello interval?

  1. Non-broadcast, 30 seconds
  2. Broadcast, 10 seconds Correct answer.
  3. Point-to-point, 10 seconds
  4. Point-to-multipoint, 30 seconds

Explanation

Ethernet interfaces default to the broadcast OSPF network type with a 10-second hello interval and a 40-second dead interval. Point-to-point and point-to-multipoint are configured on serial or tunnel links, and NBMA uses a 30-second hello.

Question 21Datacom

Which statement about EVPN route type 2 is accurate?

  1. It advertises IP prefixes for inter-subnet routing
  2. It advertises inclusive multicast trees for BUM traffic
  3. It advertises MAC/IP bindings for hosts and supports ARP suppression Correct answer.
  4. It advertises Ethernet segment membership for multihoming

Explanation

EVPN route type 2 carries MAC and IP address bindings learned from hosts, enabling MAC learning in the control plane and ARP/ND suppression. Type 3 advertises inclusive multicast, type 4 advertises Ethernet segment membership, and type 5 advertises IP prefixes.

Question 22Datacom

A network designer needs to provide redundant default gateways to hosts on a VLAN without running a first-hop redundancy protocol. Which approach best fits a VXLAN EVPN fabric?

  1. VRRP with a single master per VLAN
  2. HSRP with preemption disabled
  3. Distributed anycast gateway with the same IP and MAC on every leaf Correct answer.
  4. Static routes on every host

Explanation

In a distributed anycast gateway, every leaf uses the same gateway IP and virtual MAC for a subnet, so hosts can use the gateway regardless of which leaf they attach to. This removes the need for VRRP/HSRP and avoids traffic tromboning. Static routes on hosts do not provide gateway redundancy.

Question 23Datacom

Which command displays the routing table on a Huawei VRP device?

  1. display routing-table ip
  2. display route ip
  3. show ip route
  4. display ip routing-table Correct answer.

Explanation

Huawei VRP uses 'display ip routing-table' to show the IPv4 routing table. The 'show' keyword is used in other operating systems, and the other orderings are not valid VRP syntax.

Question 24Datacom

A network engineer is troubleshooting an MPLS L3VPN where CE routes are not appearing on a remote PE. Which check is most relevant?

  1. Verify the DHCP relay configuration
  2. Verify the OSPF hello timer on the CE
  3. Verify the MP-BGP VPNv4 session and route-target import/export on both PEs Correct answer.
  4. Verify the STP topology on the PE

Explanation

VPNv4 routes are exchanged over MP-BGP between PEs, and the route-target import/export policies determine which VRFs accept which routes. If either the session or the RT matching is wrong, CE routes will not appear on the remote PE. STP and DHCP relay have no role in L3VPN route propagation.

Question 25Datacom

Which characteristic distinguishes a stateful firewall from a stateless ACL on a Huawei device?

  1. The firewall cannot inspect application protocols
  2. The firewall maintains session state for return traffic Correct answer.
  3. The firewall only filters on source IP address
  4. The firewall operates only at Layer 2

Explanation

A stateful firewall tracks sessions and automatically permits return traffic for established connections, while a stateless ACL must explicitly permit both directions. It can filter on many fields and inspect application protocols, so the other options misrepresent its capabilities.

Question 26Datacom

On a Huawei VRP device, which command is used to enter the OSPF area view for area 0 from the OSPF process view?

  1. network 0.0.0.0 255.255.255.255
  2. area 0 Correct answer.
  3. ospf area 0
  4. area-id 0

Explanation

Within the OSPF process view of Huawei VRP, the area command creates and enters the specified area view, where network statements are then configured. The area ID may be written in decimal or dotted-decimal form.

Question 27Datacom

Which Huawei VRP command displays the current configuration of the running system?

  1. display startup
  2. display saved-configuration
  3. display current-configuration Correct answer.
  4. show running-config

Explanation

On Huawei VRP, display current-configuration shows the configuration currently in effect in RAM. The saved configuration stored in the startup file is viewed with display saved-configuration.

Question 28Datacom

Which VLAN is assigned to untagged frames arriving on a Huawei 802.1Q trunk interface when no native VLAN has been explicitly configured?

  1. VLAN 1 Correct answer.
  2. VLAN 0
  3. No VLAN, so the frames are dropped
  4. VLAN 4095

Explanation

On Huawei switches the default PVID of a trunk interface is VLAN 1, so untagged frames are classified into VLAN 1 unless the port trunk pvid command changes it. VLAN 0 and VLAN 4095 are reserved and cannot be used for normal user traffic.

Question 29Datacom

Which address range is reserved for IPv4 link-local (APIPA) addressing?

  1. 169.254.0.0/16 Correct answer.
  2. 192.168.0.0/16
  3. 127.0.0.0/8
  4. 172.16.0.0/12

Explanation

RFC 3927 reserves 169.254.0.0/16 for link-local addressing, which a host self-assigns when no DHCP server responds. The 172.16.0.0/12 and 192.168.0.0/16 ranges are private addressing defined by RFC 1918.

Question 30Datacom

In BGP, which of the following is a well-known discretionary attribute?

  1. AS_PATH
  2. ORIGIN
  3. LOCAL_PREF Correct answer.
  4. NEXT_HOP

Explanation

LOCAL_PREF is a well-known discretionary attribute: every BGP speaker must recognize it, but it does not have to be included in every UPDATE. ORIGIN, AS_PATH and NEXT_HOP are well-known mandatory attributes that must appear in every UPDATE.

Question 31Datacom

Which ICMPv6 message type is used by a router to inform hosts of a better first-hop address for a destination?

  1. Router Advertisement
  2. Neighbor Solicitation
  3. Packet Too Big
  4. Redirect Correct answer.

Explanation

The ICMPv6 Redirect message tells a host that a different first-hop router offers a better path to a specific destination. Neighbor Solicitation and Router Advertisement serve address resolution and router discovery respectively.

Question 32Datacom

Which statement describes the function of the MPLS label stack's bottom-of-stack (S) bit?

  1. It marks the label as globally assigned by IANA
  2. It sets the queuing priority of the labeled packet
  3. It signals whether the packet should be dropped on congestion
  4. It indicates whether the current label is the last entry in the stack Correct answer.

Explanation

The S bit in an MPLS shim header is set to 1 on the label entry that is at the bottom of the stack, telling the forwarding engine that no further labels follow. Label values themselves, not the S bit, determine the forwarding action.

Question 33Datacom

Which protocol provides loop-free Layer 2 multipathing by using a link-state database and shortest-path computation on Huawei data center switches?

  1. RSTP
  2. MSTP
  3. TRILL Correct answer.
  4. STP

Explanation

TRILL is a Layer 2 link-state protocol that uses IS-IS-style routing to compute shortest paths and supports multipathing without blocking redundant links. STP, RSTP and MSTP are spanning-tree variants that prevent loops by blocking ports.

Question 34Datacom

A Huawei router learns the same prefix from OSPF, IS-IS and BGP. By default, which route does VRP prefer?

  1. The OSPF route Correct answer.
  2. The route with the highest MED
  3. The BGP route
  4. The IS-IS route

Explanation

VRP route preference values place OSPF (internal, 10) ahead of IS-IS (15) and BGP (255) by default, so the OSPF route is installed. Preference is compared before any BGP path attributes such as MED are considered.

Question 35Datacom

An engineer wants a Huawei switch port to authenticate 802.1X users and, if no response is received, fall back to MAC authentication. Which feature should be configured?

  1. Storm control
  2. MAC authentication fallback triggered by 802.1X failure Correct answer.
  3. Port isolation
  4. DHCP snooping

Explanation

Huawei access devices support configuring MAC authentication as a fallback for 802.1X, so a client that does not respond to EAP is authenticated by its MAC address. Port isolation, DHCP snooping and storm control address unrelated security and traffic concerns.

Question 36Datacom

What does the 'display ospf peer' command on a Huawei router show?

  1. The OSPF routing table entries
  2. The OSPF link-state database
  3. The state and details of OSPF neighbor adjacencies Correct answer.
  4. The configured OSPF areas and network statements

Explanation

display ospf peer lists OSPF neighbors along with their router IDs, states, and interface information. The link-state database is shown with display ospf lsdb, and the routing table with display ospf routing.

Question 37Datacom

In an EVPN-VXLAN fabric, which route type is used to advertise the VTEP IP address and VNI mapping for a Layer 2 domain?

  1. Type 5 IP Prefix route
  2. Type 1 Ethernet Auto-Discovery route
  3. Type 4 Ethernet Segment route
  4. Type 3 Inclusive Multicast Ethernet Tag route Correct answer.

Explanation

The EVPN Type 3 route carries the originating VTEP address and the VNI so that remote VTEPs can build the flooding list for BUM traffic. Type 1 supports fast convergence and split-horizon, and Type 4 designates the DF for a multihomed Ethernet segment.

Question 38Datacom

A Huawei router is configured with 'bgp 65001' and a peer in AS 65002. Which command enables the router to advertise its local IPv4 prefixes to that peer?

  1. network 10.1.1.0 255.255.255.0 Correct answer.
  2. peer 10.0.0.2 enable
  3. peer 10.0.0.2 as-number 65002
  4. import-route direct

Explanation

The network command in the IPv4 unicast address-family view injects a matching route from the local routing table into BGP. The peer as-number command only defines the peer, and peer enable merely activates the address family.

Question 39Datacom

Which MPLS LDP command on a Huawei device displays the label bindings received from LDP peers?

  1. display mpls ldp peer
  2. display mpls ldp lsp Correct answer.
  3. display mpls ldp interface
  4. display mpls ldp session

Explanation

display mpls ldp lsp shows the LSPs and label bindings learned through LDP. The peer, interface and session variants display LDP neighbor, interface and session information rather than label bindings.

Question 40Datacom

A network uses SRv6 and an engineer wants to steer traffic through a specific set of segments. Which mechanism is used to encode the segment list in the packet?

  1. A GRE tunnel between the endpoints
  2. An MPLS label stack pushed by the ingress PE
  3. A Segment Routing Header (SRH) carried in an IPv6 extension header Correct answer.
  4. A VXLAN-GPE header

Explanation

SRv6 encodes the segment list in the Segment Routing Header, an IPv6 routing extension header that specifies the ordered list of SIDs to traverse. MPLS label stacks, GRE, and VXLAN are separate encapsulation or tunneling mechanisms.

Question 41Datacom

Which statement describes the function of BFD in a Huawei routing deployment?

  1. It encrypts routing protocol updates between peers
  2. It authenticates users connecting to the network
  3. It rapidly detects path failures so routing protocols can converge faster Correct answer.
  4. It distributes labels for MPLS forwarding

Explanation

BFD sends lightweight echo or control packets at short intervals to detect link or path failures in milliseconds and notifies the routing protocol. It does not encrypt updates, distribute labels, or authenticate users.

Question 42Datacom

Which QoS technique is used to mark packets so that downstream devices can apply consistent per-hop behavior?

  1. Traffic shaping
  2. Traffic policing
  3. Congestion avoidance
  4. Classification and marking Correct answer.

Explanation

Classification identifies traffic and marking sets fields such as 802.1p or DSCP so downstream devices can apply consistent per-hop behavior. Policing and shaping manage rates, and congestion avoidance manages queue drop behavior.

Question 43Datacom

A network engineer wants to verify that a Huawei switch has learned MAC addresses on a specific interface. Which command should be used?

  1. display arp interface GigabitEthernet0/0/1
  2. display interface GigabitEthernet0/0/1
  3. display mac-address interface GigabitEthernet0/0/1 Correct answer.
  4. display fdb statistics

Explanation

The display mac-address command with an interface filter lists the MAC address entries learned on that port. The ARP table shows IP-to-MAC bindings for routed traffic, not the Layer 2 forwarding database.

Question 44Datacom

Which mechanism is used by Huawei's iMaster NCE-Fabric to automate underlay and overlay configuration in a data center?

  1. Fabric controller with intent-based provisioning Correct answer.
  2. SNMP polling of devices
  3. Static route redistribution
  4. Manual CLI scripts executed by operators

Explanation

iMaster NCE-Fabric is a controller that provisions underlay and overlay fabric services based on intent, reducing manual configuration. Manual CLI, SNMP polling, and static route redistribution are not automation mechanisms of the controller.

Question 45Datacom

A network engineer wants to protect a Huawei router's control plane from excessive CPU load caused by a flood of packets destined to the router itself. Which feature should be configured?

  1. Port isolation
  2. MAC address limiting
  3. DHCP snooping
  4. CPU defense (control plane policing) Correct answer.

Explanation

CPU defense, or control plane policing, limits the rate of packets sent to the control plane so that a flood cannot overwhelm the CPU. Port isolation, DHCP snooping, and MAC limiting address Layer 2 forwarding or security concerns.

Question 46Datacom

In a Segment Routing MPLS deployment, which segment type is advertised by an IGP and represents a prefix reachable through the shortest path?

  1. Adjacency-SID
  2. Prefix-SID Correct answer.
  3. Binding-SID
  4. Node-SID

Explanation

A Prefix-SID is an IGP-advertised segment that identifies a prefix and is reachable over the shortest path. An Adjacency-SID identifies a specific link, and a Binding-SID maps to a path.

Question 47Datacom

A Huawei router has two BGP peers advertising the same prefix with equal local preference and AS_PATH length. Which attribute is compared next by default?

  1. Router ID
  2. Next-hop IGP metric
  3. Origin Correct answer.
  4. MED

Explanation

After local preference and AS_PATH, BGP compares the ORIGIN attribute, preferring IGP over EGP over incomplete. MED, next-hop IGP metric, and router ID are considered later in the decision process.

Question 48Datacom

A network engineer observes that an OSPF neighbor remains in ExStart state. Which condition is the most likely cause?

  1. An MTU mismatch between the two interfaces Correct answer.
  2. A missing network statement on one router
  3. A mismatch in the OSPF hello interval
  4. A mismatch in the OSPF area IDs

Explanation

ExStart is the stage where the master/slave relationship and initial database description sequence are negotiated; an MTU mismatch prevents successful DBD exchange and leaves the neighbor stuck in ExStart. Area and hello mismatches prevent adjacency earlier, during Init or 2-Way.

Question 49Datacom

In an MPLS L3VPN, which route target configuration ensures that VPN routes from VRF A on one PE are imported into VRF B on another PE?

  1. The import route target of VRF A must match the export route target of VRF B
  2. The export route target of VRF A must match the import route target of VRF B Correct answer.
  3. The route targets must be identical to the RD values
  4. The route distinguishers of both VRFs must be identical

Explanation

Route targets control route distribution between VRFs: a route exported with a given RT is imported by any VRF configured to import that RT. Route distinguishers make prefixes unique but do not control import.

Question 50Datacom

A network engineer needs to prevent a Huawei switch from accepting BPDUs on an access port connected to a server. Which feature should be enabled?

  1. Root guard
  2. BPDU protection Correct answer.
  3. Loop protection
  4. TC protection

Explanation

BPDU protection on an edge port discards received BPDUs and can shut down the port, preventing an attached device from influencing the spanning tree. Root guard prevents a port from becoming the root port but is typically applied on designated ports toward other switches.