Examkin

Tüm alıştırma soruları

2237 soru

Tüm türler2,237Çoktan seçmeli1,150Çoklu seçim488Sayısal30Eşleştirme350Sıralama201Kısa cevap18
Soru 2141Soru →

An enterprise router operating OSPF receives a Link-State Update (LSU) containing a revised Link-State Advertisement (LSA). Place the operational steps the router performs to process this update and adjust its routing table into the correct chronological order.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence begins with receiving the LSU packet, verifying the LSA sequence number, updating the LSDB while flooding the LSA, running the Dijkstra SPF algorithm, and installing the recalculated best routes into the RIB.
When an OSPF router receives an LSU, it must first inspect the LSA for validity and compare its sequence number against the existing database. Once validated, the router updates its LSDB and immediately floods the LSA out other active OSPF interfaces. After database synchronization, the router runs the Dijkstra SPF algorithm on the revised topology map and installs the recalculated shortest paths into the RIB.

Adım Adım Çözüm

1
Identify initial packet reception
The router receives the LSU packet on an interface.
Control plane processing is initiated by receiving the link-state update.
2
Perform LSA validation and age check
The router checks the LSA checksum and sequence number against current database records.
Invalid or older duplicate LSAs must be identified and discarded before modifying local topology data.
3
Synchronize database and flood update
The router updates its LSDB and forwards the LSA out all other OSPF interfaces.
Immediate flooding ensures fast convergence across the entire OSPF area.
4
Recalculate topology using SPF
The router executes the Dijkstra SPF algorithm.
The SPF algorithm processes the updated LSDB map to determine shortest paths from the router's perspective.
5
Update active routing table
Optimal routes are committed to the RIB.
Routes derived from the SPF tree replace outdated entries in the active routing table.

Anahtar Kavram

OSPF Link-State Processing and Convergence Sequence
Tahmini Süre:1m 30s
Soru 2142Soru →

A network administrator is updating perimeter firewall Access Control Lists (ACLs) to support secure, encrypted remote administration and file management across enterprise servers, replacing legacy unencrypted management traffic. Which of the following port and transport protocol combinations must be permitted through the firewall to support these secure services? (Select TWO.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: TCP port 22; TCP port 443

Cevap

TCP port 22 and TCP port 443 should be permitted on the firewall.
TCP port 22 (SSH/SFTP) and TCP port 443 (HTTPS) provide encrypted session channels for secure remote administration and file transfer capabilities required by modern security standards.

Adım Adım Çözüm

1
Identify the functional requirement
The firewall rules must permit secure, encrypted management and file transfer protocols while excluding unencrypted legacy alternatives.
Enterprise security baseline policies mandate transport-layer or session-layer encryption for administrative access.
2
Evaluate remote administration and secure file transfer options
SSH and SFTP utilize TCP port 22 to provide secure interactive shell access and encrypted file transfer. HTTPS uses TCP port 443 for secure web browser management.
Port 22 (SSH/SFTP) and Port 443 (HTTPS) provide cryptographic confidentiality and integrity.
3
Eliminate unencrypted protocol distractors
Telnet (TCP port 23) and TFTP (UDP port 69) transmit data without encryption.
Telnet sends credentials in plaintext and TFTP provides no authentication or encryption over UDP.

Anahtar Kavram

Common Secure Ports and Protocols for Remote Management
Soru 2143Soru →

A workstation user initiates a connection to a remote network resource. As the outgoing data travels down the local OSI stack, it transitions from the Application layer to the Transport layer (Layer 4). Which Protocol Data Unit (PDU) is constructed at Layer 4, and what primary header information is appended during this encapsulation step?

Cevabı ve açıklamayı göster

Cevap: A Segment (or Datagram), with source and destination port numbers added to the header.

Cevap

At the Transport layer (Layer 4), data is encapsulated into a Segment (or Datagram) by appending a header containing source and destination port numbers.
During outbound encapsulation, when data moves down to the Transport layer (Layer 4), the operating system protocol stack wraps the payload into a Segment (when using TCP) or a Datagram (when using UDP). This process attaches a Layer 4 header containing source and destination port numbers to direct traffic to the correct application process on the receiving endpoint.

Adım Adım Çözüm

1
Identify the OSI layer referenced in the scenario.
The scenario specifies data passing into Layer 4 (Transport layer).
Encapsulation naming conventions and header contents depend on the active layer.
2
Determine the PDU name used at Layer 4.
Layer 4 constructs Segments (TCP) or Datagrams (UDP).
Data units at upper layers are termed Application Data, while Layer 3 uses Packets and Layer 2 uses Frames.
3
Determine the specific addressing header added at Layer 4.
Transport layer headers encapsulate data with source and destination port numbers.
Port numbers enable process-to-process communication and multiplexing across network connections.

Anahtar Kavram

OSI Layer 4 Transport Encapsulation and PDU Identification
Soru 2144Soru →

A network administrator is documenting core dynamic routing protocol classifications for an enterprise network audit. Match each dynamic routing protocol on the left with its corresponding path-selection algorithm and primary operational attribute on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

OSPF
BGP
EIGRP
RIPv2

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

OSPF matches with the link-state protocol using Dijkstra's algorithm; BGP matches with the path-vector exterior gateway protocol using AS path attributes; EIGRP matches with the protocol utilizing the DUAL algorithm and composite bandwidth/delay metrics; RIPv2 matches with the distance-vector protocol using hop count capped at 15.
Each routing protocol matches its exact architectural behavior: OSPF is a link-state protocol using Dijkstra's SPF algorithm; BGP is an exterior path-vector protocol using AS-Path attributes; EIGRP is an advanced distance-vector protocol using DUAL and bandwidth/delay metrics; RIPv2 is a distance-vector protocol capped at a 15-hop limit.

Adım Adım Çözüm

1
Identify the protocol classification and underlying algorithm for OSPF.
OSPF is a link-state interior routing protocol that relies on the Shortest Path First (SPF) Dijkstra algorithm.
Link-state updates allow OSPF routers to construct a complete map of network link states across an autonomous area.
2
Identify the scope and path-selection attribute system for BGP.
BGP is a path-vector exterior gateway protocol governed by Autonomous System hops and administrative policies.
BGP is specifically designed for inter-domain routing between autonomous systems on global networks.
3
Distinguish between EIGRP and RIPv2 distance-vector implementations.
EIGRP uses DUAL with composite metrics (bandwidth/delay), whereas RIPv2 uses hop count up to a maximum limit of 15.
EIGRP achieves fast loop-free convergence via DUAL feasible successors, while RIPv2 is constrained by classic distance-vector metric limitations.

Anahtar Kavram

Classification, algorithmic behavior, and path determination metrics of dynamic routing protocols.
Tahmini Süre:1m 30s
Soru 2145Soru →

A security operations engineer is setting up a centralized SIEM server to aggregate system logs and security events from enterprise core switches. To ensure standard unencrypted syslog traffic successfully reaches the collector, which port and transport protocol combination must be permitted on the network firewalls?

Cevabı ve açıklamayı göster

Cevap: UDP port 514

Cevap

Standard Syslog messages require UDP port 514 to be allowed through network firewalls.
Standard Syslog utilizes User Datagram Protocol (UDP) on port 514 to transmit event notification messages to a central log server without session establishment overhead.

Adım Adım Çözüm

1
Identify the protocol required for system logging
The scenario describes gathering system logs and security events via standard syslog messages.
Syslog is the standard protocol for message logging across network devices.
2
Determine the default port number and transport layer protocol for standard Syslog
Standard Syslog defaults to UDP port 514.
UDP 514 allows low-overhead, connectionless transmission of log data to the collector.

Anahtar Kavram

Syslog Protocol and Port Number
Tahmini Süre:1m 0s
Soru 2146Soru →

A network technician is verifying the IP configuration of a database server assigned the IP address 172.28.137.95/21172.28.137.95/21. Which of the following represents the broadcast address for the subnet to which this server belongs?

Cevabı ve açıklamayı göster

Cevap: 172.28.143.255172.28.143.255

Cevap

The broadcast address for the subnet is 172.28.143.255172.28.143.255.
For a /21/21 network prefix, the subnet mask is 255.255.248.0255.255.248.0. The block size in the third octet is 256−248=8256 - 248 = 8. Multiples of 8 in the third octet include 136 and 144, placing IP address 172.28.137.95172.28.137.95 within the 172.28.136.0/21172.28.136.0/21 subnet. The broadcast address is one address prior to the start of the next subnet (172.28.144.0172.28.144.0), which is 172.28.143.255172.28.143.255.

Adım Adım Çözüm

1
Determine the subnet mask and block size for a /21/21 prefix.
A /21/21 CIDR prefix corresponds to subnet mask 255.255.248.0255.255.248.0. The third octet block size is 256−248=8256 - 248 = 8.
The prefix length determines how bits are split between network and host portions.
2
Calculate the network ID for IP address 172.28.137.95172.28.137.95.
The third octet value 137137 divided by 88 gives 17.12517.125. Multiplying 17×8=13617 \times 8 = 136. The network ID is 172.28.136.0/21172.28.136.0/21.
Network boundaries occur at multiples of the block size (0,8,16,…,136,1440, 8, 16, \dots, 136, 144).
3
Calculate the broadcast address of the network segment.
The next subnet begins at 172.28.144.0172.28.144.0. Subtracting 1 IP yields the broadcast address 172.28.143.255172.28.143.255.
The broadcast address is the highest IP address in the subnet range.

Anahtar Kavram

IPv4 CIDR Subnetting and Broadcast Address Calculation
Tahmini Süre:1m 30s
Soru 2147Soru →

An enterprise web server receives an incoming HTTP request over a wired Ethernet network. Place the de-encapsulation steps performed by the receiving host's network stack in the correct chronological order from first to last.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct chronological sequence for de-encapsulation is: 1) NIC converts signals to raw Ethernet frame bits, 2) Data Link layer verifies FCS and strips MAC headers/trailers, 3) Network layer verifies destination IP and removes IP header, 4) Transport layer checks TCP headers and delivers payload to the application.
De-encapsulation processes inbound network traffic from the bottom of the OSI model to the top. The physical NIC first receives raw signals and converts them to bits. Next, the Data Link layer verifies frame integrity via FCS and removes Layer 2 MAC headers. Then, the Network layer inspects destination IP addresses and strips Layer 3 headers. Finally, the Transport layer processes TCP ports/checksums and hands off the bare application payload to the upper-layer web process.

Adım Adım Çözüm

1
Identify physical bit reception at Layer 1
The physical NIC processes physical signals into a raw frame.
De-encapsulation always starts at the lowest layer (Physical/Layer 1) upon arrival.
2
Process Data Link (Layer 2) header and trailer
The MAC header and FCS trailer are validated and stripped, exposing the IP packet.
Layer 2 headers must be processed and removed before lower-level network protocol headers can be read.
3
Process Network (Layer 3) header
The destination IP address is checked, the IP header is stripped, and the Protocol field indicates TCP.
Layer 3 processing routes the packet to the local host and identifies the appropriate Layer 4 protocol.
4
Process Transport (Layer 4) header and deliver to Application (Layer 7)
The TCP header is checked and removed, delivering raw HTTP payload data to port 80/443.
Transport headers manage port multiplexing and payload handoff to the application layer process.

Anahtar Kavram

De-encapsulation sequence across OSI stack (Bottom-Up: Physical → Data Link → Network → Transport → Application)
Tahmini Süre:1m 30s
Soru 2148Soru →

A network administrator is reviewing dynamic routing protocol operational characteristics during an enterprise network redesign. Which of the following statements correctly compare link-state and distance-vector routing protocols? (Select TWO.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Link-state protocols maintain a full network topology map by exchanging link-state updates, whereas distance-vector protocols pass full or partial routing tables only to directly connected neighbors.; Link-state protocols typically achieve faster network convergence than distance-vector protocols because each router independently computes optimal paths using Dijkstra's Shortest Path First algorithm.

Cevap

Link-state protocols maintain a full network topology map by exchanging link-state updates while distance-vector protocols pass routing information only to directly connected neighbors, and link-state protocols converge faster because routers independently run Dijkstra's algorithm.
Link-state protocols (e.g., OSPF) exchange link status information to build a comprehensive map of the entire network topology and run Dijkstra's algorithm to converge rapidly when link states change. Distance-vector protocols (e.g., RIP) exchange routing tables directly with connected neighbors and process updates sequentially, resulting in slower convergence.

Adım Adım Çözüm

1
Analyze how topology awareness differs between protocol types.
Link-state protocols maintain a full topology map of the area (via LSAs), while distance-vector protocols rely on neighbor-provided routing tables (routing by rumor).
This is a fundamental architectural distinction between link-state and distance-vector protocol operation.
2
Analyze convergence mechanisms and calculation methods.
Link-state protocols react rapidly to state changes by recalculating paths using the Dijkstra Shortest Path First algorithm on local topology maps, achieving faster convergence.
Independent local calculation leads to significantly faster convergence than distance-vector hop-by-hop convergence mechanisms.
3
Evaluate OSI layer and NAT/PAT claims in the distractors.
Dynamic routing protocols evaluate Layer 3 logical network paths; they do not operate at Layer 2/Layer 4 frame/port headers or depend on Port Address Translation.
Routing protocols govern Layer 3 IP path selection.

Anahtar Kavram

Link-State vs. Distance-Vector Dynamic Routing Characteristics
Soru 2149Soru →

A network engineer is configuring perimeter firewall security rules and monitoring agents across an enterprise environment. Match each protocol on the left with its default port number and operational description on the right. Which pairs correctly associate each protocol with its respective port and function?

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

TACACS+
SIP
BGP
SNMP Trap

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

TACACS+ corresponds to TCP Port 49 for AAA services; SIP corresponds to UDP Port 5060 for VoIP session control; BGP corresponds to TCP Port 179 for inter-domain routing peer sessions; SNMP Trap corresponds to UDP Port 162 for receiving unsolicited agent notifications.
Each protocol is accurately matched to its default port and transport mechanism: TACACS+ (TCP 49), SIP (UDP 5060), BGP (TCP 179), and SNMP Trap (UDP 162).

Adım Adım Çözüm

1
Identify the primary function and transport requirement for administrative AAA services using TACACS+.
TACACS+ uses TCP port 49 to securely communicate full-payload encrypted access requests.
Centralized AAA protocols require reliable transport over TCP port 49.
2
Identify the signaling protocol used for VoIP session management.
SIP uses port 5060 (typically over UDP for low latency) to set up and tear down multimedia calls.
Voice and video signaling standards use port 5060.
3
Determine the transport mechanism for inter-autonomous system routing updates via BGP.
BGP establishes connection-oriented TCP peering sessions on port 179.
Routing protocol data exchange between BGP peers requires reliable delivery over TCP port 179.
4
Distinguish between standard SNMP queries and SNMP Trap notifications.
While SNMP queries originate from the manager on UDP port 161, unsolicited SNMP Traps are sent by managed devices to the NMS listener on UDP port 162.
Trap notifications specifically target port 162 on the management server.

Anahtar Kavram

Port mapping and transport protocol selection for core network administration, routing, VoIP signaling, and event monitoring.
Soru 2150Soru →

A network administrator is assigning static IP addresses to newly deployed hypervisor hosts within the assigned IPv4 subnet block 172.16.48.0/22172.16.48.0/22. Which of the following IPv4 addresses represent valid, assignable host addresses on this network? (Select TWO.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: 172.16.48.1172.16.48.1; 172.16.51.200172.16.51.200

Cevap

The addresses 172.16.48.1 and 172.16.51.200 are valid, usable host IPv4 addresses on the 172.16.48.0/22 subnet.
The CIDR block 172.16.48.0/22 provides a usable host range of 172.16.48.1 through 172.16.51.254. The addresses 172.16.48.1 and 172.16.51.200 both fall within this valid range and can be assigned to host interfaces.

Adım Adım Çözüm

1
Determine the subnet mask and block size for a CIDR prefix of /22.
A /22 prefix corresponds to a subnet mask of 255.255.252.0. The third octet block size is 256 - 252 = 4.
Calculating the block size in the third octet establishes the boundary increments for subnet networks.
2
Calculate the network address and broadcast address boundaries for the subnet.
The network address is 172.16.48.0. The next subnet boundary begins at 172.16.52.0, making the broadcast address 172.16.51.255.
Network boundaries define the first address (network ID) and last address (broadcast ID) of the subnet block.
3
Identify the range of usable host IP addresses.
The range of usable host addresses spans from 172.16.48.1 (first usable) to 172.16.51.254 (last usable).
Usable host addresses exclude the network ID and broadcast ID.
4
Evaluate each candidate address against the usable host range.
172.16.48.1 and 172.16.51.200 fall strictly within the usable range (172.16.48.1 to 172.16.51.254), while 172.16.48.0 (network ID) and 172.16.51.255 (broadcast ID) are reserved and invalid for host assignment.
Host assignment requires selecting IP addresses strictly inside the usable range.

Anahtar Kavram

Determining Usable Host Ranges in IPv4 Subnetting
Soru 2151Soru →

An enterprise router receives two dynamic route updates for the destination network 172.16.40.0/24. The first update is received from OSPF with a metric cost of 45. The second update is received from RIPv2 with a hop count metric of 2. Default administrative distance values are configured across all protocols on the router. Which path will be installed into the active IP routing table?

Cevabı ve açıklamayı göster

Cevap: The OSPF route, because OSPF has a lower default administrative distance than RIPv2.

Cevap

The OSPF route will be selected and installed into the routing table because OSPF has a lower default administrative distance (110) than RIPv2 (120).
When a router receives candidate routes to the exact same prefix length from two different dynamic routing protocols, it evaluates Administrative Distance (AD) first. By default, OSPF has an AD of 110 and RIPv2 has an AD of 120. The lower AD value indicates a more reliable route source, so the OSPF path is chosen for installation in the routing table.

Adım Adım Çözüm

1
Identify the routing protocols providing updates for the target network
Two distinct protocols (OSPF and RIPv2) are offering paths to 172.16.40.0/24.
When multiple sources offer paths to the same destination network prefix, the router must decide which source is more trustworthy.
2
Compare the default Administrative Distance (AD) for both protocols
OSPF has a default AD of 110, while RIPv2 has a default AD of 120.
Administrative Distance ranks the reliability of routing protocols; lower numerical AD values indicate higher trustworthiness.
3
Determine which route is selected for routing table insertion
The OSPF route is selected due to its lower AD (110 vs 120).
Because AD resolves route selection between different protocols, protocol metric values (cost of 45 vs hop count of 2) are not compared against each other.

Anahtar Kavram

Administrative Distance in Multi-Protocol Routing Selection
Soru 2152Soru →

A network administrator is provisioning a dedicated IPv4 subnet for a smart building automation system that requires static IP addresses for 5858 environmental sensors. To conserve address space, which of the following CIDR prefix lengths represents the smallest subnet that accommodates this requirement?

Cevabı ve açıklamayı göster

Cevap: /26/26

Cevap

The prefix length /26/26 provides 6262 usable host IP addresses, which is the smallest subnet that can accommodate 5858 sensors.
The prefix length /26/26 allocates 6 host bits (26=642^6 = 64 total IP addresses). Subtracting 2 reserved addresses (one for network ID and one for broadcast) yields 6262 usable host IP addresses. This is the smallest subnet size that accommodates all 5858 required hosts without unnecessary address wastage.

Adım Adım Çözüm

1
Determine required host capacity including overhead
58 hosts needed + 2 overhead addresses (network ID and broadcast address) = 60 total IP addresses minimum.
Every IPv4 subnet requires one address for the network ID and one address for the subnet broadcast.
2
Calculate the required host bits (h)
2^h >= 60 total addresses. For h = 5, 2^5 = 32 (too small). For h = 6, 2^6 = 64 (sufficient).
We need the smallest power of 2 that is greater than or equal to 60.
3
Calculate prefix length
32 total IPv4 bits - 6 host bits = /26.
Subtracting host bits from 32 gives the network prefix length.

Anahtar Kavram

Determining Minimum IPv4 Subnet Mask / CIDR Prefix for Host Requirements
Tahmini Süre:1m 0s
Soru 2153Soru →

A network engineer is evaluating dynamic routing protocols for an enterprise network expansion. The requirement is to implement a protocol that maintains a detailed topology map of the network and converges quickly upon topology changes. Which of the following statements accurately describe operational characteristics of Link-State dynamic routing protocols? (Select TWO)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Routers build an independent, complete view of the network topology stored in a Link-State Database (LSDB).; Routers transmit triggered Link-State Advertisements (LSAs) immediately upon detecting link updates rather than periodically sending full routing tables.

Cevap

Link-State routing protocols are characterized by each router maintaining a complete topology map in its Link-State Database (LSDB) and using event-driven Link-State Advertisements (LSAs) to notify neighbors of topology changes.
Link-state protocols function by having every router build an identical topology database (LSDB) for its area using the Shortest Path First (SPF) algorithm. In addition, link-state protocols do not send their full routing tables on a periodic timer; instead, they flood incremental Link-State Advertisements (LSAs) immediately when a link status change occurs.

Adım Adım Çözüm

1
Identify the fundamental mechanics of Link-State routing protocols.
Link-state protocols (such as OSPF and IS-IS) rely on neighbor discovery, LSA flooding, and the Dijkstra Shortest Path First (SPF) algorithm to calculate optimal paths.
Unlike distance-vector protocols that route by rumor, link-state routers possess full topology visibility.
2
Evaluate statements regarding LSDB structure and update mechanisms.
The statement regarding routers building an independent topology map in an LSDB and the statement regarding event-driven, triggered LSA updates are both true characteristics of link-state protocols.
Event-driven updates ensure fast convergence, while the LSDB provides full topology awareness.
3
Eliminate statements describing distance-vector features or Layer 2 misattributions.
The statement describing periodic routing table broadcasts based on hop count refers to distance-vector protocols (e.g., RIP), and the statement claiming routing logic operates strictly at Layer 2 confuses OSI layer roles.
Link-state protocols use cost metrics based on bandwidth (not hop count) and function within Layer 3 routing control plane processes.

Anahtar Kavram

Operational characteristics of Link-State dynamic routing protocols (LSDB, event-driven LSAs, SPF algorithm)
Soru 2154Soru →

A router's IP routing table contains four active paths capable of reaching the IP address 10.1.4.1010.1.4.10:

Prefix / SubnetRouting ProtocolAdministrative Distance
10.1.0.0/1610.1.0.0/16OSPF110110
10.1.4.0/2410.1.4.0/24EIGRP9090
10.1.4.0/2810.1.4.0/28RIPv2120120
0.0.0.0/00.0.0.0/0Static Route11

When a frame containing a packet destined for 10.1.4.1010.1.4.10 arrives at the router, which route will be selected to forward the packet?

Cevabı ve açıklamayı göster

Cevap: The RIPv2 route (10.1.4.0/2810.1.4.0/28), because the longest prefix match is evaluated before administrative distance.

Cevap

The router selects the RIPv2 route (10.1.4.0/2810.1.4.0/28) because the longest prefix match (LPM) rule dictates that the route with the most specific subnet mask matching the destination IP address is always selected first.
When a router receives a packet, it performs a lookup in its forwarding table and prioritizes routes based on Longest Prefix Match (LPM). The route with the narrowest host range (longest network prefix mask length) matching the destination IP address is selected regardless of administrative distance or protocol metric. In this scenario, 10.1.4.0/2810.1.4.0/28 has 28 matching network bits, which is longer than /24/24, /16/16, or /0/0.

Adım Adım Çözüm

1
Determine which routes in the table match the destination address 10.1.4.1010.1.4.10.
All four routes (10.1.0.0/1610.1.0.0/16, 10.1.4.0/2410.1.4.0/24, 10.1.4.0/2810.1.4.0/28, and 0.0.0.0/00.0.0.0/0) enclose the IP address 10.1.4.1010.1.4.10.
Any route encompassing the IP subnet ranges can technically handle the traffic.
2
Compare prefix lengths (subnet mask bits) among matching candidate routes.
The prefix lengths are /28/28 (28 bits), /24/24 (24 bits), /16/16 (16 bits), and /0/0 (0 bits).
The longest prefix match (LPM) decision rule mandates that the most specific matching prefix (highest prefix mask length) is chosen prior to evaluating Administrative Distance or Metric.
3
Select the route with the longest prefix match.
The /28/28 prefix (10.1.4.0/2810.1.4.0/28 learned via RIPv2) is chosen as the forwarding entry.
Because /28/28 is the longest matching subnet mask, Administrative Distance is not evaluated across the differing prefix lengths.

Anahtar Kavram

Longest Prefix Match (LPM) Rule
Tahmini Süre:1m 0s
Soru 2155Soru →

A core router receives a packet destined for a remote subnet and must select the best path from multiple overlapping entries in its routing database. Place the decision criteria in the exact sequence the routing logic applies them to determine the single active forwarding path.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The router first evaluates the longest prefix match to narrow candidate routes. If multiple routes match the same prefix length, it evaluates Administrative Distance to select the most trustworthy protocol. If routes originate from the same protocol with equal AD, it uses the metric to break the tie, and finally installs the path or enables ECMP load balancing.
The proper decision path evaluation sequence starts with Longest Prefix Match (prefix specificity), followed by Administrative Distance (protocol believability), then internal protocol metric (path cost), culminating in forwarding path installation or load balancing.

Adım Adım Çözüm

1
Evaluate subnet mask prefix length
Candidate routes are narrowed to those with the most specific prefix matching the destination IP.
Prefix length takes absolute precedence over protocol trustworthiness or metric values.
2
Evaluate Administrative Distance
The route with the lowest AD is selected among matching routes with identical prefix lengths.
Administrative distance rates the believability of different routing sources (e.g., OSPF vs. RIP).
3
Evaluate protocol metric cost
The route with the lowest metric cost is chosen if multiple routes come from the same routing protocol.
Metrics are internal values (like hop count or bandwidth cost) used to rank paths within a single protocol instance.
4
Perform FIB installation or ECMP
The single best route is active in the FIB, or traffic is load-balanced across equal-cost paths.
This is the final operational phase of path selection before packet transmission.

Anahtar Kavram

IP Route Selection Decision Process
Soru 2156Soru →

An enterprise network engineer is provisioning an isolated management subnet using the IPv4 block 10.150.80.0/2310.150.80.0/23. Out of the total usable host IP addresses in this subnet, 55 IP addresses are statically reserved for gateway redundancy protocols and infrastructure monitoring agents. How many usable host IP addresses remain available for assignment to endpoint workstations in this subnet?

Cevabı ve açıklamayı göster

Cevap: 505

Cevap

The total number of usable host IP addresses remaining available for endpoint workstations is 505.
A /23 CIDR prefix allocates 9 bits for host addressing, yielding 29=5122^9 = 512 total IP addresses. Subtracting 2 addresses for the network ID and broadcast address leaves 510 usable host IP addresses. Deducting the 5 statically reserved infrastructure addresses results in 505 remaining usable host addresses for endpoint workstations.

Adım Adım Çözüm

1
Calculate the total IP address capacity of a /23 prefix block.
A /23 subnet contains 232−23=29=5122^{32 - 23} = 2^9 = 512 total IP addresses.
The prefix length of /23 leaves 9 bits available for host addressing.
2
Subtract the non-assignable network ID and broadcast address.
512−2=510512 - 2 = 510 standard usable host IP addresses.
The first address in the block is the network identifier and the last address is the subnet broadcast address.
3
Deduct the statically reserved IP addresses from the usable host pool.
510−5=505510 - 5 = 505 host IP addresses remaining.
Five addresses are designated for gateway redundancy and monitoring infrastructure, leaving 505 addresses for workstations.

Anahtar Kavram

IPv4 Subnet Usable Host Calculation with Infrastructure Reservations
Tahmini Süre:1m 30s
Soru 2157Soru →

A network administrator is configuring a interface on a syslog server with the IPv4 address 192.168.45.138/26192.168.45.138/26. What is the network ID (subnet address) of the subnetwork to which this server belongs?

Cevabı ve açıklamayı göster

Cevap: 192.168.45.128; 192.168.45.128/26

Cevap

192.168.45.128
With a /26/26 prefix, the subnet mask is 255.255.255.192255.255.255.192. The block size in the fourth octet is 256−192=64256 - 192 = 64. Subnets in this range start at .0.0, .64.64, .128.128, and .192.192. Since the host address fourth octet is 138138, it resides within the 192.168.45.128/26192.168.45.128/26 subnet (covering addresses 192.168.45.128192.168.45.128 through 192.168.45.191192.168.45.191). The network ID is 192.168.45.128192.168.45.128.

Adım Adım Çözüm

1
Determine the subnet mask block size from the CIDR prefix length.
A /26/26 prefix leaves 32−26=632 - 26 = 6 host bits in the fourth octet. The block size (increment value) is 26=642^6 = 64.
Knowing the block size allows identification of the subnet boundaries in the relevant octet.
2
Calculate the subnet boundaries in the fourth octet.
The fourth octet subnet ranges start at increments of 6464: .0.0, .64.64, .128.128, and .192.192.
Subnet IDs always begin on multiples of the block size starting from 0.
3
Locate the range containing the host IP fourth octet (138138).
The fourth octet value 138138 falls between 128128 and 191191. Therefore, the network ID is 192.168.45.128192.168.45.128.
The network ID is the lowest address (boundary start) of the subnet containing the host.

Anahtar Kavram

Determining Network Address from IPv4 Host Address and CIDR Prefix
Soru 2158Soru →

A network engineer is configuring an interface on a gateway router for an isolated security camera subnet with the network IP address block 192.168.88.192/27192.168.88.192/27. What is the last usable host IP address that can be assigned to a device on this subnet?

Cevabı ve açıklamayı göster

Cevap: 192.168.88.222

Cevap

192.168.88.222
For the IPv4 subnet block 192.168.88.192/27192.168.88.192/27, a block size of 32 addresses spans from 192.168.88.192 to 192.168.88.223. The network ID is 192.168.88.192 and the broadcast address is 192.168.88.223. Consequently, the assignable host range is 192.168.88.193 through 192.168.88.222, making 192.168.88.222 the last usable host IP address.

Adım Adım Çözüm

1
Determine the block size for a /27 subnet mask.
A /27 prefix leaves 5 host bits (32−27=532 - 27 = 5). The total address count per block is 25=322^5 = 32.
Calculating the block size establishes the address boundary for the subnet.
2
Identify the broadcast address for the subnet block starting at 192.168.88.192.
Adding the block size of 32 to the network ID gives 192+32=224192 + 32 = 224 (the start of the next subnet). Thus, the broadcast address for this block is 192.168.88.223.
The last IP address in any subnet block is reserved for broadcast traffic.
3
Calculate the last usable host IP address.
Subtracting 1 from the broadcast address (192.168.88.223−1192.168.88.223 - 1) yields 192.168.88.222.
Usable host addresses exist strictly between the network ID and the broadcast address.

Anahtar Kavram

Subnet Host Boundaries and Usable IP Allocation
Soru 2159Soru →

A network administrator is inspecting a packet capture file on a host receiving an automated file transfer. As the destination host de-encapsulates the incoming data unit from the physical network interface up to the application process, the protocol stack must inspect specific header fields to identify which higher-layer protocol or service should receive the payload next. Which of the following correctly identifies the sequential order of header fields evaluated at Layer 2, Layer 3, and Layer 4 to route the payload to the correct application process?

Cevabı ve açıklamayı göster

Cevap: EtherType in the Ethernet frame header, Protocol field in the IPv4 packet header, and Destination Port in the Transport segment header

Cevap

EtherType in the Ethernet frame header, Protocol field in the IPv4 packet header, and Destination Port in the Transport segment header
De-encapsulation is a bottom-up process where each OSI layer evaluates specific header fields to demultiplex and route the payload to the next higher layer protocol. At Layer 2 (Data Link), the EtherType field specifies the Layer 3 protocol (such as IPv4 or IPv6). At Layer 3 (Network), the Protocol field specifies the Layer 4 transport protocol (such as TCP or UDP). At Layer 4 (Transport), the Destination Port number identifies the target service or process at the Application layer.

Adım Adım Çözüm

1
Analyze Layer 2 de-encapsulation requirements
The network interface card processes the Ethernet frame header and evaluates the EtherType field (e.g., 0x0800 for IPv4) to determine which Network layer protocol driver should process the frame payload.
Layer 2 headers use EtherType to demultiplex traffic to the proper Layer 3 protocol.
2
Analyze Layer 3 de-encapsulation requirements
The Internet Protocol driver processes the IPv4 packet header and evaluates the Protocol field (e.g., 6 for TCP, 17 for UDP) to determine which Transport layer protocol module receives the packet payload.
Layer 3 headers use the Protocol field to demultiplex traffic to the proper Layer 4 protocol.
3
Analyze Layer 4 de-encapsulation requirements
The Transport layer protocol processes the segment header and evaluates the Destination Port number to direct the data payload to the specific socket/application bound to that port.
Layer 4 headers use port numbers to direct data to the correct application layer process.

Anahtar Kavram

De-encapsulation Demultiplexing Fields
Soru 2160Soru →

Match each IEEE 802.1Q trunking component or configuration behavior to its correct technical description.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

Native VLAN frame egress behavior
802.1Q frame tagging mechanism
Allowed VLAN list filtering
Native VLAN mismatch condition

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Native VLAN frame egress behavior matches with un-tagged frame transmission. 802.1Q frame tagging mechanism matches with inserting a 4-byte field containing a 12-bit VLAN ID. Allowed VLAN list filtering matches with restricting allowed VLAN IDs across the trunk interface. Native VLAN mismatch condition matches with traffic leakage across differing native VLAN IDs and protocol warnings.
Each trunking feature maps to its core operational behavior under 802.1Q: native VLAN frames travel untagged; standard tagged frames carry a 4-byte 802.1Q header; allowed lists define authorized VLAN IDs; and native VLAN mismatches lead to cross-VLAN traffic leaking and administrative errors.

Adım Adım Çözüm

1
Analyze IEEE 802.1Q standard frame format requirements.
Identified that standard 802.1Q trunking inserts a 4-byte tag into frames for tagged VLANs, whereas native VLAN frames are transmitted untagged.
Understanding frame header modifications is essential for troubleshooting trunk link behavior.
2
Evaluate trunk interface filtering mechanisms.
Determined that allowed VLAN lists act as interface-level filters to prune unnecessary VLAN traffic from traversing trunk connections.
Restricting allowed VLANs conserves bandwidth and enhances network security across switch trunks.
3
Examine the operational impact of configuration discrepancies.
Confirmed that mismatched native VLAN configurations cause traffic sent untagged from one VLAN to be processed by the remote switch on a different VLAN.
Native VLAN consistency is critical to prevent unwanted broadcast domain merging and STP topology instability.

Anahtar Kavram

802.1Q Trunking Fundamentals and Native VLAN Processing
ÖncekiSayfa 108 / 112Sonraki
Tüm alıştırma soruları — CompTIA Network+ | Examkin