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Tüm alıştırma soruları

1987 soru

Tüm türler1,987Çoktan seçmeli1,020Çoklu seçim452Sayısal18Eşleştirme229Sıralama203Boşluk doldurma22Kısa cevap43
Soru 381Soru →

A network administrator is configuring an 802.1Q trunk link between two Cisco Catalyst switches. By default, how does an 802.1Q trunk interface handle Ethernet frames associated with the native VLAN when forwarding them across the trunk?

Cevabı ve açıklamayı göster

Cevap: It transmits the frames across the trunk link without inserting an 802.1Q VLAN header tag.

Cevap

By default, an 802.1Q trunk interface transmits frames belonging to the configured native VLAN without adding a 4-byte 802.1Q tag.
Under IEEE 802.1Q trunking specifications, frames belonging to the configured native VLAN are transmitted across the trunk link without an added 802.1Q VLAN header tag. When the receiving switch accepts untagged frames on an 802.1Q trunk port, it implicitly assigns those frames to its local native VLAN.

Adım Adım Çözüm

1
Identify the frame tagging mechanism defined by IEEE 802.1Q for interswitch trunk links.
IEEE 802.1Q inserts a 4-byte VLAN tag field into Ethernet frames for all non-native VLAN traffic.
Trunk interfaces must distinguish traffic belonging to different VLANs over a shared physical medium.
2
Determine how 802.1Q treats traffic associated with the native VLAN.
Frames belonging to the native VLAN are forwarded untagged by default.
This behavior ensures backward compatibility with legacy devices and non-trunking switches that do not understand 802.1Q tags.

Anahtar Kavram

802.1Q Native VLAN Untagged Frame Forwarding
Soru 382Soru →

A network engineer is configuring internal host interfaces on a private enterprise network. According to RFC 1918, which of the following IP addresses falls within a reserved private IPv4 address block and can be assigned to internal network devices without public Internet routing?

Cevabı ve açıklamayı göster

Cevap: 172.20.45.10

Cevap

172.20.45.10 is a valid private IPv4 address as defined by RFC 1918.
The address 172.20.45.10 is part of the RFC 1918 Class B private address range (172.16.0.0/12), which covers all IP addresses from 172.16.0.0 through 172.31.255.255. Since the second octet is 20, it falls within this reserved range and can be used on internal private networks without public routing.

Adım Adım Çözüm

1
Recall the three designated RFC 1918 private IPv4 address ranges
The reserved ranges are: 10.0.0.0/8 (10.0.0.0 – 10.255.255.255), 172.16.0.0/12 (172.16.0.0 – 172.31.255.255), and 192.168.0.0/16 (192.168.0.0 – 192.168.255.255).
RFC 1918 specifies exact address ranges reserved strictly for internal private enterprise use.
2
Evaluate the second octet of the Class B candidate address 172.20.45.10
The second octet is 20, which lies inclusively between 16 and 31.
Addresses starting with 172 are only private if the second octet is within the 16 to 31 range inclusive.
3
Verify candidates against public address boundaries
The address 172.20.45.10 is private, while 172.32.10.1, 192.169.1.25, and 11.10.0.1 fall outside the RFC 1918 designated ranges and are public addresses.
Only addresses inside the designated RFC 1918 prefixes are valid private addresses.

Anahtar Kavram

RFC 1918 Private IPv4 Address Ranges
Soru 383Soru →

A network architect is designing an enterprise infrastructure integrating physical networking devices, wireless control elements, and virtualized compute resources. Match each network component on the left to its primary operational function on the right.

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Öğeler

Next-Generation Firewall (NGFW)
Centralized Wireless LAN Controller (WLC)
Multilayer Switch (Layer 3 Switch)
Type 1 Hypervisor

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Next-Generation Firewall matches application visibility and DPI inspection; Centralized WLC matches CAPWAP, RF management, and centralized authentication; Multilayer Switch matches ASIC-based Layer 2 switching and Layer 3 CEF routing; Type 1 Hypervisor matches running directly on host hardware to virtualize guest compute resources.
Each component is correctly paired with its defining architectural role: NGFW provides Layer 7 deep packet inspection and threat security; WLC centralizes CAPWAP and wireless control plane logic; Multilayer Switches process L2 switching and L3 IP routing at line rate using hardware ASICs; Type 1 hypervisors virtualize physical compute directly on bare metal.

Adım Adım Çözüm

1
Identify the primary role of the Next-Generation Firewall (NGFW).
Map NGFW to stateful security policy enforcement, deep packet inspection (DPI), and Layer 7 application control.
NGFWs extend traditional Layer 3/4 firewall capabilities into full application-layer inspection and threat prevention.
2
Identify the primary role of the Centralized Wireless LAN Controller (WLC).
Map Centralized WLC to control-plane operations like CAPWAP tunneling, RF management, and client authentication.
Centralized wireless deployment offloads control plane tasks from Lightweight APs to the centralized controller.
3
Identify the primary role of the Multilayer Switch.
Map Multilayer Switch to wire-speed Layer 2 switching and Layer 3 CEF routing via ASICs.
Multilayer switches handle both broadcast domain switching and inter-VLAN IP routing in hardware.
4
Identify the primary role of the Type 1 Hypervisor.
Map Type 1 Hypervisor to bare-metal hardware virtualization for guest virtual machines.
Type 1 hypervisors execute directly on host physical hardware rather than on top of an existing host OS.

Anahtar Kavram

Operational Roles and Control/Data Plane Functions of Enterprise Network Infrastructure Components
Soru 384Soru →

A network administrator is diagnosing physical layer and data link layer interface issues on Cisco Catalyst switches. Match each Cisco IOS interface state and CLI error counter signature on the left to its primary physical or configuration root cause on the right.

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Öğeler

Interface is up, line protocol is down, accompanied by rapidly incrementing runts, giants, and frame alignment errors on a copper Ethernet link.
Interface is up, line protocol is up, accumulating a high number of late collisions and FCS errors during high-volume data transmission.
Interface is down, line protocol is down (notconnect) on a 1000BASE-SX fiber link where transmit lasers are confirmed active at both ends.
Interface is up, line protocol is up, showing continuously incrementing deferred frame counters and normal collisions, with zero late collisions or FCS errors.

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

The correct matches pair: (1) Runts, giants, and alignment errors with physical cable corruption or NEXT; (2) Late collisions and FCS errors with a local half-duplex mismatch; (3) Fiber link down despite active lasers with Tx/Rx polarity reversal; (4) Deferred frames without late collisions or FCS errors with standard half-duplex CSMA/CD backoff.
Each physical symptom maps to its exact root cause: distorted frame dimensions (runts/giants) result from signal corruption or bad cabling; late collisions stem from full/half duplex mismatch timing conflicts; down fiber links with active lasers indicate swapped Tx/Rx strands; and deferred frames without errors represent normal half-duplex CSMA/CD deferral behavior.

Adım Adım Çözüm

1
Analyze symptom 1 (runts, giants, and frame alignment errors).
Corrupted frame sizes and framing errors reflect Layer 1 electrical noise, bad terminations, or cable length violations.
Damaged copper media distorts bits in flight, causing the receiving MAC layer to receive malformed frame lengths.
2
Analyze symptom 2 (late collisions and FCS errors).
Late collisions indicate a collision occurring after transmitting the first 64 bytes of a frame.
This symptom is indicative of a duplex mismatch where the opposite end is configured for full-duplex and transmits asynchronously.
3
Analyze symptom 3 (fiber link down/notconnect with active Tx lasers).
Optical transceivers require Tx-to-Rx cross-wiring.
If light is emitting from both ends but link is not established, the optical strands are connected Tx-to-Tx and Rx-to-Rx.
4
Analyze symptom 4 (high deferred transmission counter without late collisions).
Deferred frames count the number of times an interface delays sending a frame due to carrier detect on a half-duplex link.
This is normal CSMA/CD behavior on a busy segment and does not indicate physical cable or hardware failure.

Anahtar Kavram

Cisco IOS Interface Counters and Physical Layer Diagnostics
Soru 385Soru →

A network engineer is configuring a Cisco router interface with a MAC address of `0050.568A.B1C2`. The interface is enabled for IPv6 using SLAAC with EUI-64 interface identifier generation under the prefix `2001:db8:1:1::/64`. Additionally, the engineer plans to configure a Unique Local Address (ULA) on the same interface. Which TWO statements regarding the IPv6 addressing for this interface are correct? (Select TWO.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The dynamically generated link-local IPv6 address on the interface is `fe80::250:56ff:fe8a:b1c2`.; Any valid Unique Local Address configured on this interface must fall within the prefix range `fc00::/7`.

Cevap

The correct statements are that the dynamically generated link-local IPv6 address is `fe80::250:56ff:fe8a:b1c2` and that any Unique Local Address must fall within the `fc00::/7` prefix block.
Generating an EUI-64 address from MAC `0050.568A.B1C2` involves inserting `FFFE` into the middle (`0050:56FF:FE8A:B1C2`) and toggling the 7th bit from 0 to 1 (`00` hex becomes `02` hex), producing interface ID `0250:56ff:fe8a:b1c2`. Prepended with `fe80::`, this forms the valid link-local address `fe80::250:56ff:fe8a:b1c2`. Furthermore, RFC 4193 specifies `fc00::/7` as the designated address range for IPv6 Unique Local Addresses.

Adım Adım Çözüm

1
Calculate the EUI-64 interface identifier from MAC address `0050.568A.B1C2`.
Insert `FFFE` in the middle of the 48-bit MAC address: `0050:56FF:FE8A:B1C2`. Invert the 7th bit (Universal/Local bit) of the first byte: `00` (`0000 0000`) becomes `02` (`0000 0010`). The resulting EUI-64 interface ID is `0250:56ff:fe8a:b1c2`.
IEEE EUI-64 conversion rules mandate inserting `FFFE` between the OUI and NIC specific identifier and setting the 7th bit to 1 for globally unique MAC addresses.
2
Form the link-local address using the EUI-64 interface ID.
Combine `fe80::/10` with interface ID `0250:56ff:fe8a:b1c2` to get `fe80::250:56ff:fe8a:b1c2`.
Link-local addresses start with the `fe80::/10` prefix followed by 54 zero bits and the 64-bit interface identifier.
3
Identify the reserved prefix scope for IPv6 Unique Local Addresses (ULA).
ULAs are defined under `fc00::/7`.
RFC 4193 designates `fc00::/7` for Unique Local Unicast addresses, serving a role similar to RFC 1918 private IPv4 addresses.

Anahtar Kavram

EUI-64 Interface Identifier Generation & IPv6 Address Scopes
Soru 386Soru →

A network administrator configures an interswitch link between Switch-A and Switch-B using interface GigabitEthernet1/0/24 on both switches.

Switch-A interface configuration:
text
interface GigabitEthernet1/0/24
switchport trunk encapsulation dot1q
switchport mode dynamic auto
switchport trunk native vlan 20
switchport trunk allowed vlan 10,20,30

Switch-B interface configuration:
text
interface GigabitEthernet1/0/24
switchport trunk encapsulation dot1q
switchport mode dynamic desirable
switchport trunk native vlan 1
switchport trunk allowed vlan 10,30,40

Assuming both switches support DTP and IEEE 802.1Q encapsulation, what is the operational behavior of this interswitch link?

Cevabı ve açıklamayı göster

Cevap: The trunk link forms successfully; tagged traffic for VLANs 10 and 30 is forwarded normally, but untagged VLAN 20 frames sent by Switch-A are dropped upon ingress at Switch-B because Switch-B's native VLAN (VLAN 1) is not in its allowed VLAN list.

Cevap

The trunk link forms successfully; tagged traffic for VLANs 10 and 30 is forwarded normally, but untagged VLAN 20 frames sent by Switch-A are dropped upon ingress at Switch-B because Switch-B's native VLAN (VLAN 1) is not in its allowed VLAN list.
Dynamic Trunking Protocol (DTP) successfully negotiates an operational 802.1Q trunk because Switch-A is set to dynamic auto and Switch-B is set to dynamic desirable. Tagged VLANs present in both allowed lists (VLAN 10 and VLAN 30) traverse the link normally. However, Switch-A transmits VLAN 20 frames untagged because VLAN 20 is Switch-A's native VLAN. Upon receiving these untagged frames, Switch-B assigns them to its local native VLAN (VLAN 1). Since VLAN 1 is omitted from Switch-B's explicit allowed list (10, 30, 40), Switch-B drops the frames upon ingress.

Adım Adım Çözüm

1
Evaluate DTP negotiation outcome between Switch-A and Switch-B.
Switch-A is in 'dynamic auto' mode (listens for trunking requests) and Switch-B is in 'dynamic desirable' mode (actively solicits trunking). Combining 'auto' and 'desirable' successfully negotiates an operational 802.1Q trunk.
DTP operational state matrix specifies that auto + desirable results in a trunking interface.
2
Determine tagged VLAN forwarding behavior for matched allowed VLANs.
VLAN 10 and VLAN 30 are explicitly included in Switch-A's allowed list (10, 20, 30) and Switch-B's allowed list (10, 30, 40). Frames for VLAN 10 and 30 carry standard 802.1Q tags and pass bidirectionally.
Traffic for non-native allowed VLANs is tagged with 802.1Q headers and permitted across the link.
3
Analyze 802.1Q native VLAN egress tagging and ingress classification.
Switch-A has native VLAN 20, so frames originating from VLAN 20 are transmitted across the trunk link without an 802.1Q tag. When Switch-B receives an untagged frame on its trunk port, it implicitly maps the frame to its own configured native VLAN (VLAN 1).
802.1Q trunks send native VLAN frames untagged, and receiving switches associate untagged ingress frames with their local native VLAN configuration.
4
Evaluate allowed VLAN filtering logic on Switch-B for the ingress untagged traffic.
Switch-B's trunk allowed list is restricted to '10, 30, 40'. Because native VLAN 1 is not included in Switch-B's allowed VLAN list, Switch-B drops the untagged frames received from Switch-A.
Before accepting traffic into a VLAN on a trunk, the switch verifies that the destination VLAN ID is explicitly permitted in the switchport trunk allowed vlan list.

Anahtar Kavram

802.1Q Trunking Mechanics, DTP Negotiation, Native VLAN Ingress Processing, and Allowed VLAN List Enforcement
Soru 387Soru →

Network engineers must evaluate transport layer characteristics to optimize application performance and troubleshoot communication issues across enterprise networks. Match each transport layer protocol feature or header characteristic on the left with its corresponding operational behavior on the right. Which pairs correctly match each feature to its correct transport protocol mechanism?

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Öğeler

Uses a fixed 20-byte base header with flow control provided by dynamic window sizes and optional Selective Acknowledgments (SACK).
Uses a minimal 8-byte header containing four 16-bit fields: Source Port, Destination Port, Length, and Checksum.
Establishes stateful session context via a control flag handshake while synchronizing Initial Sequence Numbers (ISNs).
Delivers connectionless datagrams with minimal overhead, where checksum verification is optional in IPv4 but strictly mandatory in IPv6.

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

The correct pairings match TCP dynamic windowing and SACK to TCP Reliability and Flow Control Mechanics; the 4-field 8-byte header to UDP Header Structure and Overhead; SYN handshake and ISN synchronization to TCP Connection Establishment and State Tracking; and the connectionless IPv6 checksum requirement to UDP Stateless Operation and IPv6 Checksum Rule.
TCP uses a minimum 20-byte header to carry sequence numbers, acknowledgment numbers, and dynamic window sizes for flow control. UDP uses an 8-byte header containing only source port, destination port, length, and checksum. TCP establishes state using the 3-way handshake with SYN/ACK flags, whereas UDP operates statelessly and requires a checksum in IPv6.

Adım Adım Çözüm

1
Analyze transport layer header size and flow control features.
Identified that a 20-byte base header with dynamic windowing and SACK corresponds to TCP flow control and reliability.
TCP requires a minimum of 20 bytes of header space to store sequence numbers, acknowledgment numbers, flags, and window size.
2
Analyze UDP header composition.
Identified that the 8-byte header with Source Port, Destination Port, Length, and Checksum defines UDP header structure.
UDP avoids connection states and sequence tracking, allowing its header to remain fixed at 8 bytes (64 bits).
3
Evaluate connection setup mechanisms.
Matched SYN/SYN-ACK control flags and Initial Sequence Number (ISN) synchronization to TCP session establishment.
TCP must establish bidirectionally synchronized sequence numbers before data transfer can begin.
4
Examine protocol behavior differences across IP versions.
Matched connectionless delivery with mandatory IPv6 checksum calculation to UDP operation.
Because IPv6 removes the Layer 3 header checksum field, it forces Layer 4 protocols like UDP to perform mandatory checksum calculations for integrity.

Anahtar Kavram

TCP vs UDP Header Fields, Connection Management, and IPv4/IPv6 Operational Rules
Soru 388Soru →

A network engineer is troubleshooting performance issues across several switch interfaces using Cisco IOS CLI outputs. Match each interface status or error counter symptom on the left to its corresponding Layer 1 or Layer 2 root cause on the right.

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Öğeler

Interface shows incrementing 'late collisions' and FCS errors on a local interface set to half-duplex while experiencing poor throughput.
Interface shows status 'GigabitEthernet0/1 is down, line protocol is down' when connecting two switch interfaces with Auto-MDIX disabled using a straight-through cable.
Interface shows status 'GigabitEthernet0/2 is up, line protocol is down (disabled)' accompanied by encapsulation error messages.
Interface shows incrementing 'giants' and CRC errors on an Ethernet port receiving traffic from a server.

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Each interface symptom matches its specific root cause based on Cisco IOS interface operation: Late collisions match a duplex mismatch; physical down/down with straight-through and disabled Auto-MDIX matches pinout misconfiguration requiring a crossover cable; up/down (disabled) matches Layer 2 framing or keepalive failure; incrementing giants with CRC errors matches oversized frame transmission exceeding MTU.
Each symptom accurately maps to its fundamental physical or data-link root cause: late collisions indicate duplex mismatch; down/down with straight-through cabling on switch-to-switch links without Auto-MDIX indicates incorrect pinout; up/down indicates Layer 2 framing/keepalive failure; and giants indicate frames received that exceed the allowable maximum frame size.

Adım Adım Çözüm

1
Analyze the late collisions symptom
Identified duplex mismatch as the root cause
Late collisions happen when one side sends frames mid-transmission because it is configured as full-duplex while the local side is half-duplex.
2
Analyze the line status down / line protocol down scenario with Auto-MDIX disabled
Identified pinout misconfiguration requiring a crossover cable
Switch-to-switch links connect MDI-X to MDI-X. Without Auto-MDIX, a straight-through cable causes Tx-to-Tx mapping, resulting in Layer 1 link failure.
3
Analyze the up / line protocol down (disabled) state
Identified Layer 2 framing or encapsulation mismatch
Layer 1 is active (up), but Layer 2 fails to establish framing or keepalive communication, causing line protocol to be down.
4
Analyze incrementing 'giants' and CRC counters
Identified oversized frame transmission exceeding MTU limits
'Giants' explicitly refer to frames received over 1518 bytes (or configured MTU), typically caused by jabbering NICs or MTU mismatch.

Anahtar Kavram

Cisco IOS Interface Counter Analysis and Physical/Data-Link Troubleshooting
Soru 389Soru →

A network engineer executes the following configuration commands on a Cisco router interface with a MAC address of 54e1.ad12.345654\text{e}1.\text{ad}12.3456:

text
interface GigabitEthernet0/0/0
ipv6 address 2001:db8:abc:10::/64 eui-64
ipv6 address fe80::1 link-local

Which two statements accurately describe the resulting IPv6 addressing and prefix properties for this interface? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The dynamically generated Global Unicast Address on the interface is 2001:db8:abc:10:56e1:adff:fe12:3456/642001:\text{db8}:\text{abc}:10:56\text{e}1:\text{adff}:\text{fe}12:3456/64.; The explicitly configured link-local address fe80::1\text{fe80}::1 replaces the auto-generated EUI-64 link-local address while staying within the reserved fe80::/10\text{fe80}::/10 scope.

Cevap

The correct statements are that the dynamically generated Global Unicast Address is 2001:db8:abc:10:56e1:adff:fe12:3456/64, and the explicitly configured link-local address fe80::1 replaces the auto-generated EUI-64 link-local address within the fe80::/10 scope.
The EUI-64 process takes the 48-bit MAC address 54e1.ad12.3456, inserts FFFE in the middle to make it 64 bits, and flips the 7th bit of the first byte from 54 hex to 56 hex, yielding the interface ID 56e1:adff:fe12:3456. Combining this with the configured prefix 2001:db8:abc:10::/64 produces 2001:db8:abc:10:56e1:adff:fe12:3456/64. Additionally, manual link-local configuration overrides the default EUI-64 link-local address and uses the fe80::/10 scope.

Adım Adım Çözüm

1
Calculate the EUI-64 Interface Identifier from the MAC address
Interface ID is 56e1:adff:fe12:3456
Split MAC address 54e1.ad12.3456 into two 24-bit halves (54-E1-AD and 12-34-56). Insert FFFE in the center (54E1:ADFF:FE12:3456). Invert the 7th bit of the first byte: 54 in hex is 01010100 in binary; flipping bit 7 yields 01010110 binary, which is 56 in hex.
2
Combine prefix with EUI-64 Interface Identifier
Global Unicast Address is 2001:db8:abc:10:56e1:adff:fe12:3456/64
The prefix specified is 2001:db8:abc:10::/64. Appending the 64-bit interface identifier derived in Step 1 forms the full address.
3
Evaluate link-local address configuration and reserved scope
fe80::1 is assigned as link-local within fe80::/10
Explicit link-local configuration replaces the automatically derived EUI-64 link-local address. The prefix fe80::/10 covers fe80:: through febf::, so fe80::1 is valid.

Anahtar Kavram

EUI-64 Interface ID Generation and IPv6 Address Scopes
Tahmini Süre:2m 0s
Soru 390Soru →

A Cisco Catalyst switch maintains the following dynamic MAC address table entries across multiple VLANs:

VLANMAC AddressTypePort
100050.56a1.1a01DYNAMICGigabitEthernet0/1
100050.56a2.2b02DYNAMICGigabitEthernet0/2
200050.56a1.1a01DYNAMICGigabitEthernet0/3

A host connected to port GigabitEthernet0/1 sends an ingress Ethernet frame tagged for VLAN 20 with a Source MAC address of 0050.56a1.1a010050.56a1.1a01 and a Destination MAC address of 0050.56a3.3c030050.56a3.3c03.

How does the switch update its MAC address table and handle the forwarding of this ingress frame?

Cevabı ve açıklamayı göster

Cevap: The switch updates the VLAN 20 MAC address table entry for 0050.56a1.1a01 to port GigabitEthernet0/1 while preserving the VLAN 10 entry, and floods the frame out all active VLAN 20 ports except GigabitEthernet0/1.

Cevap

The switch updates the VLAN 20 MAC table entry for source MAC 0050.56a1.1a01 to GigabitEthernet0/1 while preserving the VLAN 10 entry, and floods the unknown unicast frame out all active interfaces belonging to VLAN 20 except the ingress port GigabitEthernet0/1.
The correct response reflects two core switching mechanics: (1) Per-VLAN MAC learning updates the MAC address table for VLAN 20 on port GigabitEthernet0/1 without impacting entries in other VLANs (such as VLAN 10). (2) Destination MAC address lookup for an unlisted MAC address causes the switch to treat the frame as unknown unicast, flooding it out all active ports in VLAN 20 except the port on which the frame was received.

Adım Adım Çözüm

1
Examine the ingress frame's VLAN tag, Source MAC address, and ingress interface.
The ingress frame is tagged for VLAN 20, has Source MAC 0050.56a1.1a01, and arrives on port GigabitEthernet0/1.
Source MAC learning occurs on every incoming frame within the context of the frame's assigned VLAN.
2
Perform MAC address learning/station move update for VLAN 20.
The MAC table entry for VLAN 20 and MAC 0050.56a1.1a01 is updated from GigabitEthernet0/3 to GigabitEthernet0/1. The VLAN 10 table entry remains intact.
Cisco Catalyst switches maintain independent per-VLAN MAC address tables (PVST / per-VLAN learning context). Updating an entry in VLAN 20 does not purge entries in VLAN 10.
3
Perform Destination MAC lookup for 0050.56a3.3c03 in VLAN 20.
Destination MAC 0050.56a3.3c03 is not found in the VLAN 20 MAC address table (Unknown Unicast).
Layer 2 switches check the destination MAC address against the forwarding table for the matching VLAN.
4
Determine the Layer 2 forwarding decision for an unknown unicast frame.
The switch floods the frame out all operational access/trunk interfaces forwarding for VLAN 20, excluding the ingress port GigabitEthernet0/1.
Unknown unicast traffic must be flooded within the broadast domain (VLAN boundary) to reach the intended destination, but ingress interface split-horizon rules prevent returning the frame out its receiving port.

Anahtar Kavram

Per-VLAN MAC Address Table Operation and Unknown Unicast Flooding
Soru 391Soru →

A network administrator executes the following command sequence on a freshly unboxed Cisco Catalyst switch interface to connect an unmanaged host:

Switch(config)# interface FastEthernet0/12
Switch(config-if)# switchport mode access
Switch(config-if)# switchport access vlan 40

Prior to this configuration, VLAN 40 was not created in the switch VLAN database. Assuming all other interfaces remain in their default factory state, how does Cisco IOS process ingress frames from this host and manage the broadcast domain?

Cevabı ve açıklamayı göster

Cevap: Cisco IOS automatically creates VLAN 40 in the VLAN database, assigns FastEthernet0/12 to VLAN 40, and confines ingress broadcast frames from the host strictly within VLAN 40.

Cevap

Cisco IOS automatically creates VLAN 40 in the VLAN database, assigns FastEthernet0/12 to VLAN 40, and confines ingress broadcast frames from the host strictly within VLAN 40.
When configuring an access port with 'switchport access vlan <id>', Cisco IOS checks if the specified VLAN exists in the VLAN database. If it does not exist, Cisco IOS automatically creates the VLAN in the database and assigns the interface to it. The interface then functions as an active access port within that dedicated VLAN broadcast domain.

Adım Adım Çözüm

1
Analyze the interface commands provided.
The command 'switchport mode access' sets the port to access mode, and 'switchport access vlan 40' targets VLAN 40 for access traffic.
This establishes static L2 access port membership.
2
Evaluate Cisco IOS dynamic VLAN creation behavior.
When a non-existent VLAN ID is referenced in an access port configuration, Cisco IOS automatically generates that VLAN in the local VLAN database.
Cisco Catalyst switch software automatically creates missing access VLANs to ensure seamless port assignment.
3
Determine Layer 2 broadcast domain boundaries.
Traffic received on FastEthernet0/12 is tagged internally as belonging to VLAN 40, isolating broadcast traffic to ports within VLAN 40.
Each VLAN represents a distinct Layer 2 broadcast domain.

Anahtar Kavram

Automatic VLAN Creation on Access Port Assignment
Soru 392Soru →

Match each network topology architecture to its corresponding structural design trait and traffic flow optimization behavior.

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Öğeler

Routed Access 3-Tier Campus Architecture
Spine-Leaf (Clos) Data Center Architecture
Collapsed Core 2-Tier Architecture
Traditional Layer 2 Access 3-Tier Architecture

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Routed Access 3-Tier Campus Architecture pairs with terminating VLANs at the access switch using IGP routing. Spine-Leaf Data Center Architecture pairs with predictable single-hop latency via a bipartite non-interconnected tier design. Collapsed Core 2-Tier Architecture pairs with consolidating core routing and aggregation into a unified switch pair. Traditional Layer 2 Access 3-Tier Architecture pairs with extending VLANs across access switches requiring STP loop blocking.
Each topology pattern is accurately matched based on its architectural boundaries and operational characteristics: Routed Access eliminates STP on uplinks via Layer 3 edge routing; Spine-Leaf uses a bipartite design for consistent East-West latency; Collapsed Core combines core and aggregation layers to save cost; and Traditional Layer 2 Access relies on STP to block redundant Layer 2 uplinks.

Adım Adım Çözüm

1
Analyze the Layer 2/Layer 3 boundary for Routed Access.
In a Routed Access model, routing occurs at the access switch, so uplinks are routed point-to-point links. This eliminates Layer 2 loops and Spanning Tree Protocol blocking on uplinks.
Moving the routing boundary to the access switch limits broadcast domains to a single switch.
2
Evaluate the connectivity rules of Spine-Leaf (Clos) topologies.
Spine-Leaf uses a bipartite graph (leaf switches connect to all spines; spine switches connect to all leaves; no intra-tier links).
This guarantees equal distance (two hops) and equal-cost multi-pathing (ECMP) for East-West server traffic.
3
Examine the physical consolidation in a Collapsed Core design.
A Collapsed Core merges Distribution (policy/aggregation) and Core (high-speed transport) into a single layer.
This reduces equipment count, cabling complexity, and cost for smaller deployment environments.
4
Identify the primary operational requirement of Traditional Layer 2 Access designs.
Extending Layer 2 VLANs across multiple access switches to distribution switches creates Layer 2 loops across redundant uplinks.
Spanning Tree Protocol must block redundant paths to maintain a loop-free topology.

Anahtar Kavram

Comparison of Enterprise Campus and Data Center Network Topology Architectures
Soru 393Soru →

A network engineer is configuring Link Aggregation (LAG) on a Cisco Wireless LAN Controller (WLC) connected to an access layer switch stack. The deployment includes central site Local mode APs and remote branch FlexConnect APs using local traffic switching. Which TWO configuration statements correctly describe the requirements and behavior of this WLAN infrastructure connection setup? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: All distribution system physical ports on the Cisco WLC are bundled into a single logical link, requiring the connected switch ports to be configured as a single static EtherChannel (mode ON) without dynamic LACP or PAgP negotiation.; Switch ports connecting directly to FlexConnect APs operating in local switching mode must be configured as 802.1Q trunks (or VLAN-tagged access ports) to locally bridge client WLAN traffic to the infrastructure switch.

Cevap

The correct requirements are: 1) Switch ports connected to the WLC must be bundled into a static EtherChannel using mode ON because Cisco WLCs do not support dynamic EtherChannel protocols like LACP or PAgP. 2) Switch ports connected to FlexConnect APs using local switching must be configured with appropriate 802.1Q VLAN trunking so local client traffic can be bridged directly to the local network infrastructure.
Enabling LAG on a Cisco WLC consolidates all distribution ports into a single logical link requiring the adjacent switch ports to be placed into a single static EtherChannel (mode ON). Additionally, FlexConnect APs configured for local switching require their direct access switch connections to be configured as 802.1Q trunks (or appropriately tagged ports) so that client VLAN traffic can be locally switched into the wired LAN infrastructure.

Adım Adım Çözüm

1
Analyze WLC LAG behavior and switch link aggregation requirements.
Cisco AireOS WLCs merge all physical distribution ports into a single logical interface that requires static EtherChannel grouping (mode ON) on the connected switch.
The WLC does not support dynamic negotiation protocols such as LACP or PAgP.
2
Analyze FlexConnect AP infrastructure port requirements for local switching mode.
Traffic from SSIDs configured for local switching is mapped directly to VLAN tags on the AP's physical switch interface.
The switch port connecting to the FlexConnect AP must be an 802.1Q trunk (or access port supporting the required VLAN setup) to correctly forward local data frames without sending them through the central WLC CAPWAP tunnel.

Anahtar Kavram

WLAN Infrastructure Link Aggregation (LAG) and FlexConnect AP Switch Port Requirements
Tahmini Süre:2m 0s
Soru 394Soru →

A Cisco router interface GigabitEthernet0/1 has a burned-in MAC address of `0050.56a1.b2c3`. The interface is enabled and configured with the Cisco IOS command `ipv6 address fe80::/64 eui-64`. What is the complete compressed IPv6 link-local address assigned to this interface?

Cevabı ve açıklamayı göster

Cevap: fe80::250:56ff:fea1:b2c3; fe80::0250:56ff:fea1:b2c3; FE80::250:56FF:FEA1:B2C3; FE80::0250:56FF:FEA1:B2C3

Cevap

fe80::250:56ff:fea1:b2c3
The standard EUI-64 process converts the 48-bit MAC address `0050.56a1.b2c3` by inserting `FFFE` into the midpoint (`0050.56FF.FEa1.b2c3`) and inverting the 7th bit of the first byte (`00` hex = `00000000` binary -> `00000010` binary = `02` hex). Appending this 64-bit interface identifier `0250:56ff:fea1:b2c3` to the link-local prefix `fe80::/64` yields `fe80::250:56ff:fea1:b2c3` after omitting leading zeros.

Adım Adım Çözüm

1
Split the 48-bit MAC address into two 24-bit halves and insert the 16-bit hex value `FFFE` in the middle.
The MAC `0050.56a1.b2c3` becomes `0050:56FF:FEA1:B2C3`.
EUI-64 standard requires expanding a 48-bit MAC address into a 64-bit interface identifier by inserting `FFFE` between the OUI and the vendor-assigned NIC bytes.
2
Invert the 7th bit (Universal/Local bit) of the first byte.
First byte `00` (0000 000020000\ 0000_2) with the 7th bit inverted becomes `02` (0000 001020000\ 0010_2). The 64-bit Interface Identifier is `0250:56ff:fea1:b2c3`.
The 7th bit of the first byte indicates universal (00) vs local (11) scope; inverting 00 yields 11 (0202 hex).
3
Combine the link-local prefix `fe80::/64` with the generated EUI-64 interface identifier and apply standard IPv6 leading-zero compression.
`fe80::250:56ff:fea1:b2c3`
Link-local addresses always begin with `fe80::/64`, followed by the 64-bit interface identifier, suppressing leading zeros in hex quartets.

Anahtar Kavram

EUI-64 Link-Local IPv6 Address Calculation
Tahmini Süre:1m 30s
Soru 395Soru →

When establishing an OSPFv2 neighbor relationship between two Cisco routers on a broadcast multiaccess network, which parameter in the Hello packet must match on both routers?

Cevabı ve açıklamayı göster

Cevap: OSPF Area ID

Cevap

OSPF Area ID
For two routers to form an OSPFv2 neighbor adjacency, several parameters in the Hello packet must match exactly, including the OSPF Area ID, Hello/Dead timers, IP subnet mask, authentication details, and stub area flag. If the Area ID differs, the routers discard the Hello packets and fail to form an adjacency.

Adım Adım Çözüm

1
Identify mandatory parameters exchanged in OSPF Hello packets that must match for neighbor formation.
Hello packet fields that must match include Area ID, Subnet Mask, Hello and Dead intervals, Authentication parameters, and Stub area flag.
OSPF requires routers to reside in the same area to exchange Link State Advertisements (LSAs) for that area.
2
Evaluate non-matching or locally significant parameters.
Process ID is locally significant, Router IDs must be unique, and Router Priority determines DR/BDR election roles.
These parameters do not need to match across neighbors for the adjacency to form.

Anahtar Kavram

OSPFv2 Hello Packet Parameter Requirements for Adjacency
Tahmini Süre:45s
Soru 396Soru →

A network engineer is integrating non-Cisco VoIP endpoints and access points into an existing Cisco Catalyst switch infrastructure. The engineer needs to ensure automated VLAN assignment and power negotiation function properly across the multi-vendor environment while maintaining Layer 2 discovery. Which two statements regarding the operation and configuration of CDP and LLDP in this scenario are correct?

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: LLDP-MED (Media Endpoint Discovery) is an IEEE 802.1AB extension that enables detailed power management, location identification, and automated voice VLAN policy discovery between network switches and IP endpoints.; CDP and LLDP operate as completely independent processes, allowing both protocols to run concurrently on the same interface without interfering with each other's neighbor tables.

Cevap

The two correct statements state that LLDP-MED is an IEEE 802.1AB extension enabling automated endpoint discovery features like voice VLAN policy assignment and power management, and that CDP and LLDP operate independently as separate protocols on the same interface.
LLDP-MED enhances standard IEEE 802.1AB by defining specific Type-Length-Value (TLV) fields for voice VLAN policy, location, and PoE management when connecting third-party endpoints. Additionally, CDP and LLDP are completely decoupled protocol stacks within Cisco IOS, running concurrently without mutual interference.

Adım Adım Çözüm

1
Evaluate the capabilities of LLDP-MED in multi-vendor endpoint deployments.
Identified that LLDP-MED (Media Endpoint Discovery) is designed to supply Voice VLAN network policies, location info, and PoE details to multi-vendor devices.
Standard LLDP provides basic device discovery, whereas LLDP-MED extends IEEE 802.1AB for media endpoints such as IP phones.
2
Analyze protocol independence between CDP and LLDP.
Confirmed that Cisco IOS handles CDP (Cisco proprietary) and LLDP (IEEE standard) as separate internal processes.
Both protocols can simultaneously build their respective neighbor tables ('show cdp neighbors' and 'show lldp neighbors') on a shared interface.
3
Inspect interface command behavior for LLDP transmission and reception.
Disproved the claim that disabling transmit disables receive.
In Cisco IOS, 'lldp transmit' and 'lldp receive' are distinct granular interface commands.
4
Evaluate CDP framing standards.
Disproved the claim that CDP changes to IEEE 802.1AB.
CDP remains Cisco-proprietary regardless of connected neighbor devices.

Anahtar Kavram

CDP and LLDP Protocol Differences and Multi-Vendor Operations
Soru 397Soru →

An enterprise router R1 learns a primary path to the remote network 172.16.50.0/24172.16.50.0/24 dynamically through OSPF with an Administrative Distance of 110. A network administrator needs to configure a floating static backup route to 172.16.50.0/24172.16.50.0/24 via the next-hop IPv4 address 10.0.12.210.0.12.2. Which TWO statements accurately describe the requirements and operational behavior of this IPv4 static route configuration? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The floating static route command must specify an administrative distance value greater than 110 (such as 120) so that it is installed in the routing table only if the primary OSPF route fails.; When configured using only the next-hop IPv4 address 10.0.12.210.0.12.2, the router must perform a recursive lookup in the routing table to resolve the outbound interface.

Cevap

The floating static route must be configured with an administrative distance greater than 110 (such as 120) to remain inactive while OSPF is up, and specifying only a next-hop IP address requires the router to perform a recursive routing lookup to resolve the exit interface.
For a static route to function as a floating backup, its Administrative Distance must be configured higher than the primary route's protocol AD (110 for OSPF). Additionally, static routes configured with only an IP next-hop rely on recursive lookup logic to identify the outgoing interface.

Adım Adım Çözüm

1
Analyze the Administrative Distance (AD) requirement for floating static routes.
OSPF has an AD of 110. Standard static routes have an AD of 1. To make a static route act as a floating backup, its AD must be manually set higher than the active protocol (e.g., AD > 110).
The Cisco IOS routing table installs the route with the lowest Administrative Distance when multiple sources offer routes to the exact same prefix.
2
Evaluate router forwarding lookup behavior for next-hop static routes.
Specifying only the next-hop IPv4 address (10.0.12.210.0.12.2) obligates the router to recursively search the routing table to match 10.0.12.210.0.12.2 against directly connected egress interfaces.
Without an explicitly named local exit interface, the control plane must resolve how to reach the next-hop address.
3
Evaluate Longest Prefix Match rules against Administrative Distance.
A default route (0.0.0.0/00.0.0.0/0) is less specific than a /24 route. Longest prefix matching occurs prior to AD comparison, so a /24 route always beats a /0 default route.
Prefix length is the primary criterion in IPv4 forwarding decisions.

Anahtar Kavram

Floating Static Route Administrative Distance and Recursive Next-Hop Lookup
Soru 398Soru →

Refer to the following partial IPv4 routing table output from a Cisco router:

text
Gateway of last resort is 192.168.1.1 to network 0.0.0.0

S* 0.0.0.0/0 [1/0] via 192.168.1.1
O 172.16.0.0/16 [110/50] via 10.1.1.1, 01:14:22, GigabitEthernet0/0/1
D 172.16.35.0/24 [90/2172416] via 10.2.2.2, 00:42:10, GigabitEthernet0/0/2
S 172.16.35.32/27 [1/0] via 10.3.3.3
O 172.16.35.40/29 [110/30] via 10.4.4.4, 00:08:15, GigabitEthernet0/0/3

A packet with a destination IP address of 172.16.35.42172.16.35.42 arrives at the router. Which two statements correctly describe how the router makes its forwarding decision for this packet? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The router forwards the packet to next-hop 10.4.4.4 because 172.16.35.40/29 provides the longest matching prefix for the destination address.; Administrative distance is evaluated only after the router identifies all candidate routes that share the longest matching prefix length.

Cevap

The router forwards the packet to next-hop 10.4.4.4 because 172.16.35.40/29 is the longest matching prefix, and administrative distance is evaluated only after determining candidate routes with the longest matching prefix length.
When a router receives a packet, it compares the destination IP against all entries in its routing table and selects the entry with the longest prefix match (most specific mask). Here, 172.16.35.40/29 matches 29 bits of the destination address 172.16.35.42, making it more specific than the /27 static route or /24 EIGRP route. Administrative distance is only evaluated when choosing among routes with identical prefix lengths.

Adım Adım Çözüm

1
Evaluate all routes matching the destination IP address 172.16.35.42.
Matching routes: 0.0.0.0/0 (/0), 172.16.0.0/16 (/16), 172.16.35.0/24 (/24), 172.16.35.32/27 (/27), and 172.16.35.40/29 (/29).
The destination address 172.16.35.42 resides within the IP range 172.16.35.40 to 172.16.35.47 defined by the /29 subnet mask.
2
Apply the Longest Prefix Match (LPM) rule.
The route 172.16.35.40/29 has a 29-bit mask, which is longer than /27, /24, /16, or /0.
Routers always prefer the route with the most specific (longest) subnet mask first, before considering administrative distance or metric.
3
Verify if 172.16.35.42 is a valid unicast host IP in 172.16.35.40/29.
Subnet ID: 172.16.35.40, Usable hosts: 172.16.35.41 - 172.16.35.46, Broadcast: 172.16.35.47.
172.16.35.42 is a valid host address, so the packet is forwarded to next-hop 10.4.4.4 via GigabitEthernet0/0/3.

Anahtar Kavram

Longest Prefix Match (LPM) Rule in Cisco IPv4 Forwarding Logic
Tahmini Süre:1m 30s
Soru 399Soru →

A network administrator is troubleshooting an OSPFv2 neighbor relationship between two Cisco routers, Edge-R1 and Core-R1. Running the command 'show ip ospf neighbor' on Edge-R1 indicates that Core-R1 is persistently stuck in the INIT state. Verification confirms that both router interfaces are assigned to Area 0, have matching IP subnet masks, and share identical Hello and Dead timer intervals. Which underlying condition is the most likely cause of the neighbor relationship remaining stuck in the INIT state?

Cevabı ve açıklamayı göster

Cevap: An Access Control List (ACL) on Core-R1 is filtering incoming OSPF Hello packets sent by Edge-R1.

Cevap

An Access Control List (ACL) on Core-R1 is filtering incoming OSPF Hello packets sent by Edge-R1.
The correct answer identifies that an inbound ACL on the remote router is filtering Hello packets in one direction. In OSPF, a router transitions a peer to the INIT state upon receiving a Hello packet. To progress to 2-WAY state, the router must see its own Router ID in the active neighbor list of the peer's incoming Hello packet. If an ACL blocks Hellos in one direction, the peer never receives the Hellos, never lists the local router's ID, and leaves the local router stuck in the INIT state.

Adım Adım Çözüm

1
Analyze OSPF neighbor state progression mechanics.
Transition to the 2-WAY state requires bidirectional communication, meaning a router must see its own Router ID listed in the Received Hello packet's neighbor list from its peer.
When Edge-R1 sees Core-R1's Hello packet, it places Core-R1 into its neighbor table in the INIT state.
2
Evaluate the impact of unidirectionally dropped Hello packets.
Edge-R1 is receiving Hellos from Core-R1, but Core-R1 is NOT receiving Hellos from Edge-R1 due to an inbound ACL filter on Core-R1.
Because Core-R1 never receives Edge-R1's Hellos, Core-R1 cannot add Edge-R1's Router ID to its outgoing Hello packet neighbor list. Thus, Edge-R1 stays stuck in INIT.
3
Differentiate INIT state causes from EXSTART state and configuration parameters.
MTU mismatches cause EXSTART/EXCHANGE stuck states, whereas mismatched process IDs or priority 0 do not prevent FULL neighbor adjacency.
Only unidirectional traffic flow (or filtering of Hellos in one direction) accounts for a persistent INIT state when basic parameters like Area ID and timers match.

Anahtar Kavram

OSPFv2 Neighbor States and Bidirectional Hello Communication Requirements
Tahmini Süre:2m 0s
Soru 400Soru →

An engineer is troubleshooting OSPFv2 neighbor establishment between Router-Edge1 and Router-Edge2 over their directly connected GigabitEthernet0/0/1 link. The running configurations for both routers are provided below:

text
[Router-Edge1]
interface Loopback0
ip address 10.255.255.1 255.255.255.255
shutdown
!
interface Loopback1
ip address 172.16.10.1 255.255.255.255
!
interface GigabitEthernet0/0/1
ip address 192.168.12.1 255.255.255.252
ip mtu 1500
ip ospf hello-interval 10
ip ospf dead-interval 40
ip ospf 1 area 0
!
router ospf 1
router-id 1.1.1.1

[Router-Edge2]
interface Loopback0
ip address 10.255.255.2 255.255.255.255
!
interface GigabitEthernet0/0/1
ip address 192.168.12.2 255.255.255.252
ip mtu 1400
ip ospf hello-interval 10
ip ospf dead-interval 30
ip ospf 1 area 0
!
router ospf 1

Based on these configurations, which TWO statements accurately describe the OSPFv2 neighbor behavior and Router ID operation between these routers? (Select TWO.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The routers will fail to establish an initial 2-WAY neighbor relationship because the configured OSPF Dead intervals on GigabitEthernet0/0/1 do not match.; If the Dead interval mismatch is corrected, the routers will become stuck in the EXSTART/EXCHANGE state due to the IP MTU mismatch on the GigabitEthernet0/0/1 interfaces.

Cevap

The correct statements are that the routers will fail to establish a 2-WAY neighbor state due to mismatched Dead intervals, and if resolved, will remain stuck in EXSTART/EXCHANGE due to the IP MTU mismatch.
The option stating that mismatched Dead intervals prevent the 2-WAY neighbor relationship is correct because Hello and Dead intervals are mandatory parameters in OSPF Hello packets that must match between neighbors. The option noting that an IP MTU mismatch causes routers to become stuck in EXSTART/EXCHANGE is also correct because MTU validation occurs during DBD packet exchanges.

Adım Adım Çözüm

1
Evaluate OSPF Hello packet parameter requirements for 2-WAY adjacency formation.
Router-Edge1 is configured with a Dead interval of 40 seconds, whereas Router-Edge2 is configured with 30 seconds. Hello/Dead intervals MUST match exactly between neighbors on a common link. Therefore, Hello packets are rejected, preventing 2-WAY state.
Matching Hello/Dead timers are a mandatory prerequisite for OSPF neighbor discovery and adjacency.
2
Analyze the impact of MTU settings during Database Description (DBD) packet negotiation.
Router-Edge1 has an IP MTU of 1500 bytes, while Router-Edge2 has an IP MTU of 1400 bytes. When MTUs mismatch, routers fail to process DBD packets during Master/Slave negotiation, remaining stuck in EXSTART/EXCHANGE state.
OSPF includes interface MTU in DBD packets to ensure MTU parity across adjacent neighbors.
3
Verify Router ID election logic for Router-Edge1 and Router-Edge2.
Router-Edge1 uses explicit 'router-id 1.1.1.1', which overrides all loopbacks and physical interfaces. Router-Edge2 has no explicit router-id command, so it selects its active Loopback0 IP (10.255.255.2), because loopbacks always take priority over physical interfaces.
Election order is strictly: 1. Manual 'router-id' command -> 2. Highest active loopback IP -> 3. Highest active non-loopback interface IP.

Anahtar Kavram

OSPFv2 Adjacency Requirements and Router ID Selection Order
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