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1987 soru

Tüm türler1,987Çoktan seçmeli1,020Çoklu seçim452Sayısal18Eşleştirme229Sıralama203Boşluk doldurma22Kısa cevap43
Soru 241Soru →

Match each IPv6 address prefix on the left to its designated address scope or function on the right.

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Öğeler

2000::/3
fe80::/10
fc00::/7
ff00::/8

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

2000::/3 matches Global Unicast, fe80::/10 matches Link-Local, fc00::/7 matches Unique Local, and ff00::/8 matches Multicast.
Each prefix correctly maps to its standard RFC-defined IPv6 address scope: 2000::/3 is Global Unicast, fe80::/10 is Link-Local, fc00::/7 is Unique Local, and ff00::/8 is Multicast.

Adım Adım Çözüm

1
Identify the Global Unicast range
2000::/3 covers 2000:: through 3fff:ffff:ffff:ffff:ffff:ffff:ffff:ffff, which represents Global Unicast.
Standard IANA IPv6 allocation reserves 2000::/3 for public Internet routing.
2
Identify the Link-Local prefix
fe80::/10 covers fe80:: through febf::, which is reserved for Link-Local addresses.
Link-Local addresses are automatically configured on enabled IPv6 interfaces for local link communication.
3
Identify the Unique Local prefix
fc00::/7 covers fc00:: through fdff::, designated as Unique Local.
Unique Local addresses provide private addressing space within internal networks and are not routed on the global Internet.
4
Identify the Multicast prefix
ff00::/8 covers all multicast traffic.
IPv6 uses multicast exclusively instead of broadcast; all multicast addresses begin with ff00::/8.

Anahtar Kavram

IPv6 Address Scopes and Prefixes
Soru 242Soru →

An enterprise network engineer is auditing the IPv4 addressing scheme across several newly acquired branch office routers. Corporate security policy strictly mandates that all internal host interfaces must be configured within RFC 1918 private IPv4 address space to prevent internal routing leakage over the public Internet. During the audit, the engineer inspects four interface IP configurations. Which of the following IPv4 address and subnet mask assignments represents a public IPv4 host address that violates RFC 1918 guidelines?

Cevabı ve açıklamayı göster

Cevap: 172.32.14.50/20

Cevap

The address 172.32.14.50/20 is a public IPv4 address because it falls outside the RFC 1918 private Class B prefix range of 172.16.0.0/12.
The RFC 1918 Class B private address space spans from 172.16.0.0 to 172.31.255.255 (CIDR prefix 172.16.0.0/12). The address 172.32.14.50 has a second octet of 32, placing it outside the private address block and into public IPv4 space.

Adım Adım Çözüm

1
Recall the defined RFC 1918 private IPv4 address blocks
Class A: 10.0.0.0/8 (10.0.0.0 – 10.255.255.255), Class B: 172.16.0.0/12 (172.16.0.0 – 172.31.255.255), Class C: 192.168.0.0/16 (192.168.0.0 – 192.168.255.255).
Identifying private space requires strict matching against the starting and ending boundaries of RFC 1918 blocks.
2
Evaluate the second octet of the Class B candidate addresses
The address 172.31.240.100 has a second octet of 31, which is inside the range 16–31. The address 172.32.14.50 has a second octet of 32, which is outside the range 16–31.
The /12 prefix for Class B private space covers second octet values from 16 to 31 inclusive (172.16.0.0−172.31.255.255172.16.0.0 - 172.31.255.255).
3
Determine which address violates RFC 1918 private designation
172.32.14.50 is public and cannot be routed across private networks without public IP ownership.
Addresses starting with 172.32.x.x are allocated globally by IANA as public IP addresses.

Anahtar Kavram

RFC 1918 Private IPv4 Address Ranges
Tahmini Süre:1m 30s
Soru 243Soru →

A Cisco switch receives an untagged Ethernet frame on an IEEE 802.1Q trunk link and forwards it out another 802.1Q trunk link. Arrange the operational steps in the correct order from initial frame arrival to final frame transmission.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct operational sequence begins with the arrival of an untagged Ethernet frame on an 802.1Q trunk port, followed by internal mapping to the ingress port's native VLAN, executing a MAC address table lookup within that native VLAN, and finally transmitting the frame untagged out an egress trunk configured with a matching native VLAN.
IEEE 802.1Q trunks handle untagged traffic by implicitly classifying ingress frames into the configured native VLAN. The switch uses that native VLAN's MAC address table for forwarding decisions and sends the frame out an egress trunk untagged if the egress interface shares the same native VLAN configuration.

Adım Adım Çözüm

1
Identify ingress frame format
The switch identifies that the incoming frame lacks a 4-byte IEEE 802.1Q tag header.
Trunk ports process both tagged and untagged frames depending on whether traffic belongs to tagged VLANs or the native VLAN.
2
Classify frame to native VLAN
The frame is internally tagged/associated with the ingress port's native VLAN ID.
IEEE 802.1Q specification requires untagged frames traversing a trunk to be implicitly assigned to the native VLAN.
3
Execute Layer 2 forwarding lookup
The switch consults the MAC address table for the destination address within the native VLAN domain.
VLANs maintain isolated broadcast domains and separate MAC lookup tables to prevent cross-VLAN frame leakage.
4
Evaluate egress tagging behavior
The frame is forwarded across the egress trunk port without inserting an 802.1Q header tag.
To maintain compatibility, 802.1Q does not tag frames belonging to the native VLAN when sending them over trunk links.

Anahtar Kavram

IEEE 802.1Q Native VLAN Ingress and Egress Processing Mechanics
Soru 244Soru →

A network technician is reviewing transport layer protocol characteristics to evaluate protocol overhead. Which statement correctly describes the header size of UDP compared to TCP?

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Cevap: UDP operates with a fixed header size of 8 bytes, whereas TCP has a minimum header size of 20 bytes.

Cevap

UDP operates with a fixed header size of 8 bytes, whereas TCP has a minimum header size of 20 bytes.
UDP headers consist of four 2-byte fields (Source Port, Destination Port, Length, Checksum), resulting in a fixed size of 8 bytes. In contrast, TCP headers require a minimum of 20 bytes (up to 60 bytes with options) to accommodate fields such as Sequence Number, Acknowledgment Number, Data Offset, Flags, Window Size, and Urgent Pointer required for reliable, connection-oriented data transfer.

Adım Adım Çözüm

1
Analyze UDP header structure
UDP contains 4 fields (Source Port, Destination Port, Length, Checksum) at 2 bytes each, totaling 8 bytes.
UDP provides connectionless delivery with minimal protocol overhead.
2
Analyze TCP header structure
TCP header includes sequence numbers, acknowledgment numbers, flags, window size, and checksum, requiring a minimum of 20 bytes without options.
TCP requires additional fields to guarantee stateful, reliable connection delivery.
3
Compare header overhead
UDP uses an 8-byte header and TCP uses a minimum 20-byte header.
Direct comparison identifies UDP as having lower protocol overhead than TCP.

Anahtar Kavram

TCP vs UDP Header Size Comparison
Soru 245Soru →

A network technician installs a standard Layer 2 Ethernet switch to connect multiple client computers in an office network. What is the primary operational function of this device?

Cevabı ve açıklamayı göster

Cevap: Forwarding Ethernet frames based on destination MAC addresses while separating collision domains per port

Cevap

The primary operational function of a Layer 2 switch is forwarding Ethernet frames using MAC addresses and placing each switch port into its own independent collision domain.
A standard Layer 2 switch learns source MAC addresses and builds a MAC address table to forward incoming frames to their intended destination ports. Each physical port on the switch acts as an isolated collision domain, preventing frame collisions.

Adım Adım Çözüm

1
Identify the OSI operational layer of a standard Ethernet switch.
Standard Layer 2 switches operate at the Data Link Layer (Layer 2).
Layer 2 switches process Ethernet frame headers rather than inspecting Layer 3 IP packet headers for forwarding decisions.
2
Determine the forwarding logic and domain boundaries established by the switch.
The switch inspects destination MAC addresses to forward frames and isolates collision domains on each individual port, while leaving all ports in a single broadcast domain by default.
Port micro-segmentation eliminates collisions on full-duplex Ethernet connections while preserving broadcast reachability.

Anahtar Kavram

Layer 2 Switch Roles and Collision Domain Isolation
Soru 246Soru →

Match each Cisco IOS interface line status or counter symptom on the left to its most likely physical or data link layer cause on the right.

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Öğeler

Interface status is 'GigabitEthernet0/1 is down, line protocol is down'
Interface status is 'FastEthernet0/1 is up, line protocol is down'
Interface status is 'GigabitEthernet0/2 is up, line protocol is up' with rapidly incrementing late collisions
Interface status is 'FastEthernet0/2 is administratively down, line protocol is down'

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

The interface conditions match as follows: 'down/down' indicates a Layer 1 physical carrier loss; 'up/down' indicates a Layer 2 framing or encapsulation failure; 'late collisions' on an operational interface indicate a duplex mismatch; and 'administratively down' indicates the port is disabled by configuration.
In Cisco IOS interface diagnostics: physical layer carrier loss generates 'down/down'; data-link framing or keepalive failures generate 'up/down'; duplex mismatches generate late collisions; and administrative shutdown settings generate 'administratively down'.

Adım Adım Çözüm

1
Analyze the 'down/down' state symptom.
Identified Layer 1 Physical connection failure.
When both hardware and line protocol report down, physical signal detection has failed completely.
2
Analyze the 'up/down' state symptom.
Identified Layer 2 Data Link framing or protocol failure.
The physical medium is receiving carrier signals, but data link frames or keepalives are not being successfully negotiated.
3
Analyze late collisions on an up/up link.
Identified duplex mismatch condition.
Late collisions happen when a full-duplex port sends frames without checking for carrier sense while the connected half-duplex port transmits simultaneously.
4
Analyze the 'administratively down' state symptom.
Identified local software configuration state ('shutdown').
Cisco IOS explicitly marks interfaces that have not been enabled with 'no shutdown' as administratively down.

Anahtar Kavram

Cisco IOS interface line status, protocol states, and error counter interpretation
Soru 247Soru →

A network engineer is troubleshooting severe wireless performance degradation in an enterprise cafeteria. Spectrum analysis reveals significant non-802.11 radio frequency (RF) interference originating from operating microwave ovens and legacy Bluetooth IoT sensors. Which modification to the wireless infrastructure will best mitigate this specific source of RF interference?

Cevabı ve açıklamayı göster

Cevap: Migrate client data traffic to the 5 GHz radio band

Cevap

Migrate client data traffic to the 5 GHz radio band
Migrating wireless traffic to the 5 GHz band provides an effective solution because 5 GHz operates in a separate radio frequency spectrum unaffected by 2.4 GHz consumer emissions such as microwave ovens, Bluetooth devices, and cordless phones.

Adım Adım Çözüm

1
Identify the RF frequency spectrum shared by the interference sources.
Microwave ovens and Bluetooth devices radiate RF energy within the 2.4 GHz2.4\text{ GHz} ISM frequency band (2.400 GHz2.400\text{ GHz} to 2.4835 GHz2.4835\text{ GHz}).
Understanding the physical band limitations isolates the cause of non-802.11 interference.
2
Evaluate alternative frequency bands available in enterprise wireless deployments.
The 5 GHz5\text{ GHz} frequency band operates completely outside the 2.4 GHz2.4\text{ GHz} range and offers significantly more non-overlapping channels unaffected by microwave radiation or Bluetooth signals.
Shifting wireless traffic to 5 GHz5\text{ GHz} bypasses the polluted spectrum entirely.

Anahtar Kavram

RF Interference and Frequency Band Characteristics (2.4 GHz vs 5 GHz)
Soru 248Soru →

A network administrator is configuring IPv6 auto-configuration using SLAAC and EUI-64 process on Cisco router interfaces. Match each 48-bit MAC address on the left to its corresponding EUI-64 derived IPv6 Link-Local address on the right.

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Öğeler

0012.3456.789A
0212.3456.789A
1012.3456.789A
1212.3456.789A

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

MAC 0012.3456.789A matches fe80::212:34ff:fe56:789a; MAC 0212.3456.789A matches fe80::12:34ff:fe56:789a; MAC 1012.3456.789A matches fe80::1212:34ff:fe56:789a; MAC 1212.3456.789A matches fe80::1012:34ff:fe56:789a.
Each MAC address is correctly converted to EUI-64 format by inserting FFFE into the middle of the 48-bit address and inverting the 7th bit (the Universal/Local bit) of the first byte. The resulting 64-bit interface ID is appended to the Link-Local prefix fe80::/64, with leading zeros in any 16-bit block omitted per standard IPv6 address formatting rules.

Adım Adım Çözüm

1
Split each MAC address into its OUI (first 24 bits) and NIC-specific extension (last 24 bits), and insert FFFE in hex between them.
For MAC 0012.3456.789A, the split sequence becomes 00-12-34-FF-FE-56-78-9A.
EUI-64 expansion requires inserting the 16-bit reserved value FFFE into the center of a 48-bit MAC address.
2
Invert the 7th bit (Universal/Local bit) of the first byte in binary representation.
Byte 0x00 (00000000200000000_2) becomes 0x02 (00000010200000010_2); 0x02 becomes 0x00; 0x10 (00010000200010000_2) becomes 0x12 (00010010200010010_2); 0x12 becomes 0x10.
IEEE EUI-64 specification requires flipping the 7th bit of the first octet to represent global/local scope.
3
Combine the inverted 64-bit interface ID with the fe80::/10 link-local prefix (defaulting to /64 subnet prefix fe80::/64) and apply standard RFC 4291 zero compression rules.
The 64-bit interface ID 0012:34ff:fe56:789a compresses leading zeros to 12:34ff:fe56:789a, resulting in fe80::12:34ff:fe56:789a.
Standard IPv6 address formatting suppresses leading zeros in each 16-bit hex field.

Anahtar Kavram

EUI-64 Interface Identifier Generation and SLAAC Link-Local Addressing
Soru 249Soru →

A network technician is configuring an isolated staging environment and must assign a dedicated IPv4 subnet using unroutable addresses specified in RFC 1918. Which of the following network prefixes represents a valid private IPv4 address block according to RFC 1918?

Cevabı ve açıklamayı göster

Cevap: 172.25.0.0/16

Cevap

172.25.0.0/16 is the valid RFC 1918 private IPv4 network prefix.
The prefix 172.25.0.0/16 lies within the 172.16.0.0/12 block reserved by RFC 1918 for private IPv4 networks (spanning from 172.16.0.0 to 172.31.255.255).

Adım Adım Çözüm

1
Recall the defined RFC 1918 private IPv4 address ranges
Class A: 10.0.0.0/8 (10.0.0.0 – 10.255.255.255), Class B: 172.16.0.0/12 (172.16.0.0 – 172.31.255.255), Class C: 192.168.0.0/16 (192.168.0.0 – 192.168.255.255).
RFC 1918 explicitly reserves these three specific IP address blocks for private internal networks.
2
Evaluate the candidate prefixes against the RFC 1918 boundaries
The prefix 172.25.0.0/16 is inside the Class B range of 172.16.0.0 to 172.31.255.255. All other options fall outside the private boundaries (172.33.0.0/16, 192.169.1.0/24, and 11.0.0.0/8 are all public IPv4 ranges).
Addresses outside the three defined blocks are globally routable public addresses.

Anahtar Kavram

RFC 1918 Private IPv4 Address Ranges
Soru 250Soru →

In network infrastructure virtualization, hypervisors are categorized based on their relationship with the underlying physical hardware. Which statement accurately describes the operation of a Type 1 hypervisor?

Cevabı ve açıklamayı göster

Cevap: It installs directly on server bare-metal hardware and manages virtual machine resource access without requiring a host operating system.

Cevap

A Type 1 hypervisor installs directly on server bare-metal hardware and manages virtual machine resource access without requiring a host operating system.
Type 1 (bare-metal) hypervisors run directly on server physical hardware without an intervening host operating system. This provides direct resource scheduling, low latency, and enhanced reliability for enterprise virtual machine workloads.

Adım Adım Çözüm

1
Identify the primary distinction in hypervisor architecture.
Hypervisors are classified as Type 1 (bare-metal) or Type 2 (hosted) depending on whether an underlying host operating system is present.
Type 1 hypervisors sit directly between the physical hardware and the virtual machine operating systems.
2
Evaluate the choices to find the description matching Type 1 virtualization.
Direct installation on physical bare-metal hardware without an intermediate host operating system defines a Type 1 hypervisor.
Direct hardware control minimizes overhead and improves resource management in enterprise deployments.

Anahtar Kavram

Type 1 (Bare-Metal) vs. Type 2 (Hosted) Hypervisor Architecture
Soru 251Soru →

A network engineer is reviewing a branch deployment where a bare-metal Type 1 hypervisor host running multiple virtual machines (VMs) across VLAN 10 and VLAN 20 is connected via a single interface to a physical Layer 2 switch. Users report that VMs on VLAN 10 cannot communicate with VMs on VLAN 20, and broadcast storms generated by a misconfigured endpoint on VLAN 10 are flooding all physical ports on the switch. Which statement correctly identifies the operational roles of the network components involved and the required architectural change?

Cevabı ve açıklamayı göster

Cevap: The Layer 2 switch limits collision domains per port but forwards broadcast frames across the entire VLAN; inter-VLAN traffic requires a Layer 3 device or router-on-a-stick, while the Type 1 hypervisor runs directly on hardware to manage virtual switch port groups.

Cevap

The Layer 2 switch limits collision domains per port but forwards broadcast frames across the entire VLAN; inter-VLAN traffic requires a Layer 3 device or router-on-a-stick, while the Type 1 hypervisor runs directly on hardware to manage virtual switch port groups.
Layer 2 switches isolate collision domains on a per-port basis, but broadcast traffic is flooded across all ports belonging to the same VLAN. Furthermore, traffic traversing different VLANs (VLAN 10 to VLAN 20) requires a Layer 3 routing function (such as a Layer 3 switch or router-on-a-stick). A Type 1 hypervisor operates bare-metal directly on physical hardware to manage virtual switches and guest VMs.

Adım Adım Çözüm

1
Analyze the role of a Layer 2 switch regarding domain boundaries.
A Layer 2 switch creates a separate collision domain for each connected port, but all ports assigned to a single VLAN belong to the same broadcast domain. Broadcast traffic will flood all ports in that VLAN.
Layer 2 switches forward frames based on MAC addresses and broadcast frames (FF:FF:FF:FF:FF:FF) out all unassigned/active ports in the VLAN.
2
Analyze the requirement for inter-VLAN communication between VLAN 10 and VLAN 20.
Communication across distinct VLANs (IP subnets) requires Layer 3 packet forwarding (routing). A standard Layer 2 switch cannot perform IP routing without a Layer 3 device or Layer 3 switch capabilities.
VLANs define logical Layer 2 boundaries; traversing between different VLANs requires rewriting Layer 2 headers via a default gateway router or Layer 3 switch.
3
Verify the role and definition of a Type 1 hypervisor.
A Type 1 hypervisor (bare-metal) installs directly on the physical host hardware and manages virtual switches (vSwitches) and VM access directly without relying on an intermediate desktop OS.
Understanding Type 1 hypervisor deployment clarifies that virtual networking components (port groups/VLAN tags) interface directly with the physical NICs.

Anahtar Kavram

Operational Roles of Layer 2 Switches, Routers, and Bare-Metal Type 1 Hypervisors
Soru 252Soru →

An organization is deploying a database cluster on a bare-metal Type 1 hypervisor architecture. A network engineer needs to determine how frame forwarding occurs between two virtual machines (VM-A and VM-B) located on the same physical host and assigned to the same VLAN. Which mechanism correctly describes how traffic is handled between these two virtual machines?

Cevabı ve açıklamayı göster

Cevap: The internal virtual switch (vSwitch) inside the hypervisor performs Layer 2 forwarding between vNICs without sending frames onto the physical network interface card (pNIC).

Cevap

The internal virtual switch (vSwitch) inside the hypervisor performs Layer 2 forwarding between vNICs without sending frames onto the physical network interface card (pNIC).
In a Type 1 (bare-metal) hypervisor, a virtual switch (vSwitch) runs directly inside the hypervisor software layer. It maintains virtual ports connected to each virtual machine's vNIC. When two VMs residing on the same host and VLAN communicate, the vSwitch performs Layer 2 MAC address lookup and switches frames entirely in RAM, bypassing the physical NIC and external physical switches.

Adım Adım Çözüm

1
Analyze the hypervisor architecture and VM placement
Identify that the environment uses a Type 1 bare-metal hypervisor hosting both virtual machines on the same physical host and VLAN.
Understanding hypervisor architecture determines how traffic flows between virtualized network components.
2
Evaluate the operational role of the virtual switch (vSwitch)
Recognize that the internal vSwitch maintains a MAC address table connecting the vNICs of VM-A and VM-B.
Because both VMs are attached to the same vSwitch on the same VLAN, the hypervisor can switch traffic internally in system memory.
3
Determine physical network interface involvement
Confirm that traffic remains within the hypervisor software and does not traverse the physical NIC (pNIC).
Physical network interfaces and physical switches are only engaged when sending frames to external hosts or across different physical hypervisors.

Anahtar Kavram

Virtual Switch (vSwitch) operation and intra-host Layer 2 frame forwarding in Type 1 hypervisor architectures
Tahmini Süre:1m 30s
Soru 253Soru →

A network technician is verifying the operational characteristics of an IEEE 802.1Q trunk link established between two Cisco Catalyst switches. Which two statements describe correct behavior or features of IEEE 802.1Q trunking? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Frames belonging to the configured native VLAN are transmitted across the trunk link untagged by default.; IEEE 802.1Q inserts a 4-byte header into the standard Ethernet frame to carry VLAN identification information.

Cevap

The correct statements are that native VLAN frames are transmitted untagged across an 802.1Q trunk by default, and that IEEE 802.1Q inserts a 4-byte header into the Ethernet frame.
IEEE 802.1Q trunking inserts a 4-byte tag between the MAC Source Address and EtherType fields of an Ethernet frame for tagged VLAN traffic. By default, frames originating from or destined for the native VLAN are sent across the trunk link without any 802.1Q tag attached.

Adım Adım Çözüm

1
Analyze frame tagging mechanics for IEEE 802.1Q trunk links.
IEEE 802.1Q inserts a 4-byte tag into the frame header for tagged VLANs, while natively configured VLAN traffic remains untagged by default.
This maintains backward compatibility with legacy non-trunking devices.
2
Evaluate operational misconfiguration consequences on trunks.
Native VLAN mismatches generate warnings (via CDP/STP) without err-disabling ports, and PortFast is explicitly restricted from switch-to-switch links.
PortFast bypasses listening/learning states which can cause bridging loops on interswitch trunk paths.

Anahtar Kavram

IEEE 802.1Q Trunking Fundamentals and Native VLAN Mechanics
Soru 254Soru →

A network administrator is troubleshooting poor file transfer performance on a switch interface connected to an enterprise application server. The administrator executes the `show interfaces gigabitethernet 0/1` command on the switch and receives the following CLI output:

GigabitEthernet0/1 is up, line protocol is up
Hardware is GigabitEthernet, address is 0007.ec29.2101
Full-duplex, 100Mb/s, media type is 100BaseTX
12458 input errors, 12458 CRC, 0 frame, 0 overrun, 0 ignored
0 output errors, 45211 collisions, 1204 late collision, 0 deferred

Based on this output, what is the most likely cause of the interface errors?

Cevabı ve açıklamayı göster

Cevap: A duplex mismatch between the switch port and the connected server interface

Cevap

A duplex mismatch between the switch port and the connected server interface
A duplex mismatch occurs when one end of an Ethernet segment is configured for full-duplex while the opposite end operates in half-duplex mode. Because full-duplex mode disables CSMA/CD collision detection, the full-duplex side transmits data whenever ready. The half-duplex side, which is actively listening for carrier sense, experiences collisions and late collisions during its transmissions. The full-duplex side receives colliding signals mid-transmission, registering them as input CRC errors.

Adım Adım Çözüm

1
Analyze the interface status and line protocol state.
The link status is 'up/up', proving Layer 1 signaling and Layer 2 framing are established.
Eliminates total physical disconnection or wrong pinout issues that prevent link activation.
2
Examine the duplex settings and error counters in the CLI output.
The interface reports 'Full-duplex' along with non-zero 'collisions', 'late collision', and 'CRC' errors.
In true full-duplex operation, collisions should never occur because transmit and receive pathways are independent.
3
Correlate late collisions and CRC errors to physical layer operations.
Late collisions occur when the remote half-duplex side detects a collision after the slot time because the local full-duplex side transmits without checking CSMA/CD carrier sense.
This symptom pattern unequivocally points to a duplex mismatch between the two connected devices.

Anahtar Kavram

Duplex Mismatch Symptoms and Error Counters
Tahmini Süre:1m 30s
Soru 255Soru →

In a centralized Cisco wireless network deployment using Split-MAC architecture, operational tasks are divided between Lightweight Access Points (LAPs) and the Wireless LAN Controller (WLC). Which two functions are performed by the Wireless LAN Controller rather than the Lightweight Access Points? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Executing Radio Resource Management (RRM) to dynamically adjust RF channels and power levels across access points; Aggregating wireless client authentication traffic and managing integration with central RADIUS servers

Cevap

The Wireless LAN Controller handles Radio Resource Management (RRM) for dynamic channel/power optimization and processes centralized client authentication requests.
In a centralized Split-MAC architecture, the Wireless LAN Controller performs high-level management and control-plane tasks. This includes Radio Resource Management (RRM) to continuously calculate optimal channel assignments and transmit power for all connected access points, as well as handling centralized client authentication and external RADIUS server communications.

Adım Adım Çözüm

1
Identify control-plane and management functions in a centralized Split-MAC wireless architecture.
Radio Resource Management (RRM) and centralized AAA/RADIUS security integration belong to the WLC.
Lightweight Access Points handle real-time frame transmission, beacons, and signal measurements, while system-wide management is offloaded to the central WLC.
2
Evaluate the incorrect choices to identify misconceptions regarding component roles.
A WLC does not replace Layer 3 routers for broadcast domain isolation, nor does it function as a Type 2 hypervisor.
Layer 3 devices break broadcast domains, and physical wireless frame transmission is handled by AP radio hardware.

Anahtar Kavram

Wireless LAN Controller (WLC) vs Lightweight Access Point (LAP) Functional Roles
Soru 256Soru →

A network engineer observes that hosts in VLAN 10 on Switch-1 are unexpectedly communicating with hosts in VLAN 20 on Switch-2 across a direct 802.1Q trunk link. Upon reviewing the interface configurations, the engineer finds that Switch-1 has its trunk native VLAN set to VLAN 10, while Switch-2 has its trunk native VLAN set to VLAN 20. When a host in VLAN 10 on Switch-1 sends an uncompressed Ethernet broadcast frame, what is the exact behavior of Switch-2 when it receives this frame?

Cevabı ve açıklamayı göster

Cevap: Switch-2 accepts the untagged frame and forwards it out all active ports belonging to VLAN 20.

Cevap

Switch-2 accepts the untagged frame and forwards it out all active ports belonging to VLAN 20.
When a switch transmits a frame for its configured native VLAN over an IEEE 802.1Q trunk link, it strips the VLAN tag and sends the frame untagged. When the receiving switch accepts an untagged frame on an 802.1Q trunk port, it associates that frame with its own locally configured native VLAN. Because Switch-1 has native VLAN 10 and Switch-2 has native VLAN 20, frames originating in VLAN 10 leave Switch-1 untagged and are ingested into VLAN 20 by Switch-2, causing cross-VLAN traffic leakage.

Adım Adım Çözüm

1
Analyze frame egress behavior on Switch-1
Frames originating in VLAN 10 match Switch-1's native VLAN setting (VLAN 10) on the 802.1Q trunk, so Switch-1 transmits the frame across the link untagged (without an 802.1Q VLAN header tag).
By 802.1Q standards, traffic for the configured native VLAN on a trunk link is egressed without adding a 4-byte 802.1Q tag.
2
Analyze frame ingress behavior on Switch-2
Switch-2 receives the untagged frame on its trunk interface. It maps any incoming untagged frame to its local native VLAN configuration, which is VLAN 20.
Switch ports process untagged incoming frames as belonging to whatever native VLAN is locally configured on that receiving trunk port.
3
Determine forwarding decision
Because the frame is now assigned to VLAN 20 inside Switch-2, the broadcast frame is flooded to all active access ports in VLAN 20 on Switch-2.
This behavior results in VLAN hopping / traffic leakage across distinct VLANs due to mismatched native VLAN configurations.

Anahtar Kavram

IEEE 802.1Q Native VLAN Tagging and Mismatch Behavior
Tahmini Süre:1m 30s
Soru 257Soru →

A Cisco Catalyst switch operating with default MAC address table aging timer settings (300 seconds) has an existing dynamic entry for Host A (MAC: 0010.a412.1111) on interface GigabitEthernet0/1 with a current age of 295 seconds. At time t=0t = 0 seconds, Host B (MAC: 0010.a412.2222) connected to GigabitEthernet0/2 sends a unicast frame destined to Host A. Host A sends no traffic during this period. At time t=10t = 10 seconds, Host B sends a second unicast frame destined to Host A. How does the switch process the frame sent at t=10t = 10 seconds?

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Cevap: The switch floods the frame out all operational ports within the VLAN except GigabitEthernet0/2 because Host A's entry aged out 5 seconds prior.

Cevap

The switch floods the frame out all operational ports within the VLAN except GigabitEthernet0/2 because Host A's entry aged out 5 seconds prior.
Switches update and refresh MAC address table entries strictly based on the Source MAC address of ingress frames. When Host B sends a frame destined for Host A at t = 0 seconds, Host A's entry timer is NOT reset because Host A did not transmit any frame. Consequently, Host A's dynamic entry reaches the 300-second threshold at t = 5 seconds and is removed from the MAC table. When Host B sends another frame at t = 10 seconds, the switch finds no matching destination entry and floods the unknown unicast frame out all active ports in the VLAN except the receiving port (GigabitEthernet0/2).

Adım Adım Çözüm

1
Analyze MAC address table aging mechanics for the frame transmitted at t = 0 seconds.
Host B (0010.a412.2222) is learned on GigabitEthernet0/2. The frame is forwarded out GigabitEthernet0/1 using Host A's existing MAC table entry.
MAC address aging timers are refreshed ONLY when a frame is received containing that MAC address as the Source MAC. Destined (destination MAC) lookups do not reset the aging timer.
2
Calculate the expiration time of Host A's MAC address entry.
Host A's entry had an age of 295 seconds at t = 0. With a 300-second default timer and no incoming frames originating from Host A, the entry expires at t = 5 seconds (295 + 5 = 300 seconds).
Host A remained silent, so no frames with Source MAC 0010.a412.1111 entered the switch to reset the timer.
3
Evaluate the switch forwarding logic for the frame sent at t = 10 seconds.
At t = 10 seconds, the destination MAC 0010.a412.1111 is no longer in the MAC address table. The switch performs unknown unicast flooding.
When a destination unicast MAC address is not present in the L2 MAC table, Layer 2 switches flood the frame out all active interfaces in the same VLAN except the ingress port.

Anahtar Kavram

L2 MAC Table Aging and Unknown Unicast Flooding Logic
Soru 258Soru →

An enterprise network architect is designing a two-tier Spine-Leaf (Clos) topology for a data center hosting high-performance containerized workloads. The design deploys 4 Spine switches and multiple Leaf switches. Each Leaf switch is configured with 48 x 25GbE downlink ports for server connections and 4 x 100GbE uplink ports, with exactly one uplink connecting to each of the 4 Spine switches. Layer 3 routing with Equal-Cost Multi-Pathing (ECMP) is configured across all spine-leaf interconnections. Which statement correctly evaluates the architectural traits and bandwidth performance of this Spine-Leaf deployment?

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Cevap: The Leaf switch layer exhibits a 3:1 oversubscription ratio for East-West traffic while delivering deterministic, equal-latency forwarding across the spine fabric between any two Leaf switches.

Cevap

The Leaf switch layer exhibits a 3:1 oversubscription ratio for East-West traffic while delivering deterministic, equal-latency forwarding across the spine fabric between any two Leaf switches.
The total host downlink bandwidth per Leaf switch is 48×25 Gbps=1200 Gbps48 \times 25\text{ Gbps} = 1200\text{ Gbps}, while the total fabric uplink bandwidth is 4×100 Gbps=400 Gbps4 \times 100\text{ Gbps} = 400\text{ Gbps}. Dividing downlink by uplink capacity yields an oversubscription ratio of 1200:4001200:400, which simplifies to 3:13:1. Additionally, because every Leaf switch connects directly to all 4 Spine switches in a two-tier Clos architecture, any inter-leaf traffic takes exactly 2 switch hops (Leaf →\rightarrow Spine →\rightarrow Leaf), guaranteeing consistent, deterministic latency across equal-cost paths.

Adım Adım Çözüm

1
Calculate total host-facing downlink capacity per Leaf switch.
48 ports × 25 Gbps = 1200 Gbps total downlink bandwidth.
Host access capacity is determined by multiplying the number of downlink access ports by their individual link speed.
2
Calculate total fabric-facing uplink capacity per Leaf switch.
4 ports × 100 Gbps = 400 Gbps total uplink bandwidth.
Fabric uplink capacity is determined by multiplying the number of uplink connections to the spine by their link speed.
3
Determine the oversubscription ratio of the Leaf layer.
1200 Gbps : 400 Gbps = 3:1 oversubscription ratio.
Oversubscription ratio is calculated as Total Ingress (Downlink) Bandwidth divided by Total Egress (Uplink) Bandwidth.
4
Analyze path latency and forwarding behavior of the Spine-Leaf (Clos) fabric.
Every leaf-to-leaf path is exactly 2 fabric hops (Leaf A → Spine → Leaf B) using Layer 3 ECMP across all available Spine switches.
Spine-Leaf architectures guarantee consistent East-West latency because all endpoints connected to different leaf switches are separated by the exact same number of switch hops.

Anahtar Kavram

Spine-Leaf Architecture Oversubscription and ECMP Operation
Soru 259Soru →

A network administrator is evaluating transport layer options for application traffic. Which two characteristics accurately describe User Datagram Protocol (UDP)? (Select two.)

Geçerli olan tümünü seçin

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Cevap: It operates as a connectionless protocol without establishing a session prior to data transmission; It maintains a fixed 8-byte header to keep processing overhead low

Cevap

User Datagram Protocol (UDP) is connectionless and features an 8-byte header overhead.
The correct responses highlight UDP's core design as a lightweight, connectionless protocol. UDP sends datagrams without a three-way handshake and uses an 8-byte header containing source port, destination port, length, and checksum fields.

Adım Adım Çözüm

1
Analyze transport layer requirements and connection states.
Identify that UDP is a stateless, connectionless protocol that transmits data without initiating a preliminary handshake.
UDP avoids the setup latency required by connection-oriented protocols like TCP.
2
Compare protocol header sizes and operational mechanisms.
Confirm that the UDP header requires only 8 bytes of overhead, compared to TCP's 20-byte baseline header.
A small header minimizes network overhead and speeds up datagram parsing for real-time applications.

Anahtar Kavram

Characteristics of User Datagram Protocol (UDP)
Soru 260Soru →

A network administrator connects two Cisco Catalyst switches via their GigabitEthernet0/1 interfaces. Switch-A is configured with `switchport mode dynamic desirable`, while Switch-B remains in its default `dynamic auto` mode. What is the correct chronological sequence of operational events during Dynamic Trunking Protocol (DTP) negotiation to establish an IEEE 802.1Q trunk link?

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Cevap

The correct sequence is: Switch-A transmits a DTP frame requesting a trunk, Switch-B receives and parses the DTP frame, Switch-B transmits a DTP acknowledgment frame, both switches agree upon IEEE 802.1Q encapsulation, and finally both switch interfaces transition to the operational trunk state.
The correct order follows the DTP state machine negotiation flow. A port in `dynamic desirable` mode actively sends DTP request frames to its link partner. The neighboring port in `dynamic auto` mode receives and processes this request, responding with a DTP acknowledgment frame to consent to trunking. Following parameter exchange, both switches negotiate the trunk encapsulation (IEEE 802.1Q) and finally transition both interface operational states to trunking.

Adım Adım Çözüm

1
Identify the initiating interface state and behavior
Switch-A (`dynamic desirable`) actively sends DTP negotiation frames to initiate trunking.
Interfaces in `dynamic desirable` mode actively attempt to convert the link to a trunk.
2
Determine the receiving interface processing
Switch-B (`dynamic auto`) receives the request and evaluates parameters.
Interfaces in `dynamic auto` mode do not initiate DTP requests but respond to incoming requests.
3
Trace the protocol response and handshake
Switch-B sends a DTP response agreeing to form a trunk link.
A `dynamic auto` port agrees to become a trunk when requested by a `dynamic desirable` port.
4
Resolve encapsulation negotiation
Both switches negotiate and agree on 802.1Q encapsulation.
Trunking encapsulation must be determined prior to bringing up the operational trunking state.
5
Confirm operational state transition
Both ports transition to operational trunking mode.
Once negotiation handshakes and parameters match, the link operational mode becomes trunk.

Anahtar Kavram

Dynamic Trunking Protocol (DTP) negotiation flow between dynamic desirable and dynamic auto interface modes in IEEE 802.1Q trunking.
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