Examkin

Network Access

400 soru

Tüm türler400Çoktan seçmeli204Çoklu seçim91Eşleştirme23Sıralama82
Soru 161Soru →

A network administrator executes the following command on switch SW-1 to troubleshoot connectivity to an adjacent network device:

text
SW-1# show lldp neighbors detail
------------------------------------------------
Local Intf: Gi0/1
Chassis id: 0014.f25a.a100
Port id: GigabitEthernet1/0/24
Port Description: Trunk Link to SW-1
System Name: SW-2
System Description: Cisco IOS Software, C3750E Software (C3750E-UNIVERSALK9-M)
Time remaining: 98 seconds
System Capabilities: B, R
Enabled Capabilities: B
Management Addresses:
IP: 10.1.10.2
Auto Negotiation - supported, enabled
Physical media capabilities:
1000baseT(FD)
Media Attachment Unit type: 30
VLAN ID: 20

Based on the output provided, which conclusion accurately describes the neighbor relationship and port configuration?

Cevabı ve açıklamayı göster

Cevap: The adjacent switch SW-2 is connected via its interface GigabitEthernet1/0/24 to SW-1's local interface GigabitEthernet0/1, operating with a port VLAN ID of 20 and management address 10.1.10.2.

Cevap

The adjacent switch SW-2 is connected via its interface GigabitEthernet1/0/24 to SW-1's local interface GigabitEthernet0/1, operating with a port VLAN ID of 20 and management address 10.1.10.2.
The output of 'show lldp neighbors detail' shows that local interface Gi0/1 on SW-1 is connected to remote port GigabitEthernet1/0/24 on system SW-2. It also displays SW-2's management IP (10.1.10.2), system capabilities, and the advertised Port VLAN ID of 20.

Adım Adım Çözüm

1
Identify local vs. remote interface designations in the LLDP CLI output.
'Local Intf: Gi0/1' is the local interface on SW-1. 'Port id: GigabitEthernet1/0/24' represents the interface on the remote neighbor (SW-2).
Layer 2 discovery outputs distinguish between local ports where traffic is received and remote port IDs advertised by neighbors.
2
Analyze System Name, System Capabilities, and Management Addresses.
System Name is SW-2, Management IP is 10.1.10.2, and Enabled Capabilities is 'B' (Bridge/Switch).
Capability code 'B' stands for Bridge/Switch, proving the active role of the device is Layer 2 switching.
3
Evaluate the IEEE 802.1 TLV Port VLAN ID information.
'VLAN ID: 20' reflects the advertised Port VLAN ID (PVID) associated with the link.
LLDP advertises PVID through Organizationally Specific TLVs, allowing operators to verify VLAN settings on connected links.

Anahtar Kavram

Interpretation of IEEE 802.1AB LLDP detailed neighbor table outputs and TLV fields.
Tahmini Süre:2m 0s
Soru 162Soru →

A network administrator is attempting to establish an operational Layer 3 EtherChannel using LACP between two Cisco switches. After applying the initial configuration, the administrator issues the `show etherchannel summary` command on Switch1 and observes the following output:

Flags: D - down P - bundled in port-channel
I - stand-alone s - suspended
H - Hot-standby s - Layer2
R - Layer3 U - in use

Group Port-channel Protocol Ports
------+-------------+-----------+-----------------------------------------------
1 Po1(SD) LACP Gi0/1(D) Gi0/2(D)

Which configuration change on Switch1 is required to allow Port-Channel 1 to operate successfully as a Layer 3 EtherChannel?

Cevabı ve açıklamayı göster

Cevap: Configure the `no switchport` command on physical member interfaces GigabitEthernet0/1 and GigabitEthernet0/2 before adding them to the channel group.

Cevap

Configure the `no switchport` command on physical member interfaces GigabitEthernet0/1 and GigabitEthernet0/2 before adding them to the channel group.
For a Layer 3 EtherChannel to operate correctly, physical member interfaces must be explicitly configured as routed ports using the `no switchport` command. The flag `S` in `Po1(SD)` indicates the interface bundle is operating at Layer 2. Converting the physical member ports to Layer 3 allows the EtherChannel to transition to the `RU` (Layer 3, in use) operational state.

Adım Adım Çözüm

1
Analyze the output flags from `show etherchannel summary`.
The logical interface displays `Po1(SD)`, where `S` indicates Layer 2 operational mode and `D` indicates the channel is Down. Member interfaces display `(D)` for down.
The flag `S` indicates the physical interfaces are currently operating as Layer 2 switchports rather than Layer 3 routed ports.
2
Identify the requirement for creating a Layer 3 EtherChannel in Cisco IOS.
Both the physical member interfaces and the logical port-channel interface must be configured with `no switchport` to function as routed interfaces.
If physical interfaces remain in Layer 2 switchport mode, the port-channel cannot bundle them into a Layer 3 (`R`) operational state.
3
Determine the corrective CLI commands.
Navigate to `interface range GigabitEthernet0/1 - 2` and execute `no switchport`, then re-assign `channel-group 1 mode active`.
Disabling switchport mode allows the interfaces to negotiate as Layer 3 routed ports and transition the port-channel state flag from `SD` to `RU` (Layer 3, in use).

Anahtar Kavram

Layer 3 EtherChannel Member Configuration
Tahmini Süre:1m 30s
Soru 163Soru →

An administrator is troubleshooting a connectivity issue on interface GigabitEthernet1/0/5, which connects to an IP phone with a co-located workstation. The IP phone successfully registers with the Voice over IP (VoIP) server, but the workstation connected to the phone cannot communicate on the network.

The output of `show interfaces status` displays:
text
Port Name Status Vlan Duplex Speed Type
Gi1/0/5 Workstation_PC connected inactive a-full a-1000 10/100/1000BaseTX

Additionally, `show running-config interface GigabitEthernet1/0/5` yields:
text
interface GigabitEthernet1/0/5
switchport mode access
switchport access vlan 30
switchport voice vlan 200

Which condition explains why the VLAN status displays as `inactive`, and what configuration step is required to restore workstation connectivity?

Cevabı ve açıklamayı göster

Cevap: Access VLAN 30 does not exist in the switch VLAN database; configuring `vlan 30` in global configuration mode will activate the access VLAN and restore traffic forwarding for the workstation.

Cevap

Access VLAN 30 does not exist in the switch VLAN database; configuring `vlan 30` in global configuration mode will activate the access VLAN and restore traffic forwarding for the workstation.
In Cisco IOS, when an interface is assigned to an access VLAN that is not currently present in the switch's VLAN database, the operational status of that VLAN on the port is set to `inactive`. As a result, untagged traffic from the attached workstation is dropped. The voice VLAN continues to operate independently because VLAN 200 exists in the database. Creating VLAN 30 using `vlan 30` in global configuration mode adds it to the VLAN database and immediately restores the port's access VLAN to active status.

Adım Adım Çözüm

1
Analyze the CLI output from `show interfaces status` and `show running-config interface GigabitEthernet1/0/5`.
The interface status is `connected`, but the assigned VLAN column shows `inactive`. The interface configuration shows `switchport access vlan 30` and `switchport voice vlan 200`.
An `inactive` VLAN status in `show interfaces status` occurs specifically when a port is assigned to a VLAN ID that does not exist in the switch's VLAN database (`vlan.dat`).
2
Determine why the IP phone functions while the workstation fails.
Voice VLAN 200 exists in the VLAN database and is active, allowing tagged voice frames from the phone to forward. VLAN 30 is missing from the VLAN database, causing untagged data frames from the workstation to be dropped.
Cisco IOS handles voice and access traffic separately on multi-VLAN access ports; missing access VLAN definitions render only the data VLAN inactive.
3
Identify the required remediation command sequence.
Enter global configuration mode and create VLAN 30 using the command `vlan 30`.
Creating the VLAN in the VLAN database immediately changes the port's operational access VLAN status from `inactive` to active without modifying interface commands.

Anahtar Kavram

VLAN Database Existence and Access Port Operational States
Tahmini Süre:2m 0s
Soru 164Soru →

A network engineer is configuring a routed (Layer 3) EtherChannel between Switch-A and Switch-B using LACP.

Switch-A is configured with the following commands:
text
interface Port-channel 1
no switchport
ip address 10.1.1.1 255.255.255.252
!
interface range GigabitEthernet1/0/1 - 2
no switchport
channel-group 1 mode passive

When verifying the EtherChannel status on Switch-B, the engineer observes the following output from `show etherchannel summary`:
text
Flags: D - down P - bundled in port-channel
I - stand-alone s - suspended
R - Layer3 S - Layer2
U - in use

Group Port-channel Protocol Ports
------+-------------+-----------+-----------------------------------------------
1 Po1(SD) LACP Gi1/0/1(D) Gi1/0/2(D)

Which configuration change on Switch-B will successfully resolve the issue and convert Port-channel 1 into an operational Layer 3 link?

Cevabı ve açıklamayı göster

Cevap: Configure 'no switchport' under interface Port-channel 1 and member interfaces GigabitEthernet1/0/1 - 2, and set 'channel-group 1 mode active' on the member interfaces.

Cevap

Configure 'no switchport' under interface Port-channel 1 and member interfaces GigabitEthernet1/0/1 - 2, and set 'channel-group 1 mode active' on the member interfaces.
To create a Layer 3 EtherChannel, the 'no switchport' command must be executed on the logical Port-channel interface as well as all physical member interfaces. Furthermore, because Switch-A is configured in LACP passive mode, Switch-B must be configured in LACP active mode ('channel-group 1 mode active') so that LACP control packets are actively sent to initiate port bundling.

Adım Adım Çözüm

1
Analyze the 'show etherchannel summary' output on Switch-B.
The flags show Po1(SD) and member interfaces Gi1/0/1(D) Gi1/0/2(D). 'S' indicates Layer 2 operational state, and 'D' indicates Down state.
Layer 3 EtherChannels require explicit conversion using the 'no switchport' command on both the Port-channel logical interface and the physical member interfaces.
2
Evaluate the LACP negotiation mode requirements.
Switch-A is configured with 'channel-group 1 mode passive'.
LACP requires at least one participating switch to be in 'active' mode. Passive-to-passive mode matching will never initiate LACP control traffic, keeping the bundle down.
3
Determine the necessary configuration on Switch-B.
Apply 'no switchport' to interface Port-channel 1 and member interfaces, then assign 'channel-group 1 mode active' to member interfaces.
This establishes a Layer 3 interface ('R' flag) and enables LACP active negotiation to complement Switch-A's passive mode.

Anahtar Kavram

Layer 3 EtherChannel LACP Negotiation and CLI State Verification
Tahmini Süre:2m 0s
Soru 165Soru →

A network technician connects interface GigabitEthernet0/1 on Switch-A to interface GigabitEthernet0/1 on Switch-B using an Ethernet link. Switch-A retains its factory default interface configuration of `switchport mode dynamic auto`, while Switch-B is explicitly configured with `switchport mode dynamic desirable`. Which two operational conditions describe the resulting state of this interswitch link?

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The link successfully negotiates and operates as an 802.1Q trunk link.; Frames belonging to the native VLAN traverse the trunk link without an 802.1Q header tag by default.

Cevap

The link negotiates to operate as an 802.1Q trunk, and native VLAN frames cross the trunk link untagged by default.
When configuring interswitch trunking via DTP, combining `dynamic desirable` on one end with `dynamic auto` on the other results in successful 802.1Q trunk negotiation because `desirable` actively initiates the negotiation state while `auto` accepts it. Additionally, under IEEE 802.1Q standard operation, frames destined for the native VLAN (default VLAN 1) are transmitted across the trunk link without an added 802.1Q header tag.

Adım Adım Çözüm

1
Evaluate the Dynamic Trunking Protocol (DTP) negotiation between dynamic auto and dynamic desirable modes.
Dynamic desirable actively initiates DTP negotiation, and dynamic auto listens and agrees to form a trunk. Thus, the operational mode becomes an 802.1Q trunk.
DTP operational logic forms a trunk whenever at least one side actively negotiates (desirable or trunk) and the opposite side is willing to negotiate (auto or desirable).
2
Analyze standard 802.1Q frame encapsulation mechanics for native VLAN traffic.
By default, VLAN 1 is the native VLAN, and standard 802.1Q trunking does not insert a 4-byte 802.1Q tag into frames matching the native VLAN.
IEEE 802.1Q specifies native VLAN traffic as untagged to maintain backwards compatibility with legacy non-trunking Ethernet devices.

Anahtar Kavram

DTP Mode Negotiation and 802.1Q Native VLAN Tagging Mechanics
Soru 166Soru →

A network engineer is configuring network topology discovery across a multi-vendor environment containing both Cisco and non-Cisco switches. Which IEEE standard defines the open, vendor-neutral Layer 2 discovery protocol used to identify neighboring devices?

Cevabı ve açıklamayı göster

Cevap: IEEE 802.1AB

Cevap

IEEE 802.1AB is the IEEE standard that defines Link Layer Discovery Protocol (LLDP).
The IEEE 802.1AB standard formally defines Link Layer Discovery Protocol (LLDP). LLDP allows network devices to advertise identity, capabilities, and neighbor information across heterogeneous multi-vendor networks.

Adım Adım Çözüm

1
Identify the protocol requirements from the scenario
The scenario calls for an open, vendor-neutral Layer 2 discovery protocol usable across multi-vendor equipment.
Cisco Discovery Protocol (CDP) is Cisco-proprietary, whereas Link Layer Discovery Protocol (LLDP) is open-standard.
2
Map LLDP to its governing IEEE standard specification
LLDP is standardized under IEEE 802.1AB.
IEEE 802.1AB specifies the Type-Length-Value (TLV) frame format and operational procedures for LLDP.

Anahtar Kavram

Link Layer Discovery Protocol (LLDP) IEEE standard identification
Soru 167Soru →

A network engineer is configuring a Link Aggregation Control Protocol (LACP) EtherChannel between two switches. Which TWO channel-group mode combinations between the interconnected switch ports will successfully establish an operational EtherChannel bundle? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Active mode on the local switch port and active mode on the remote switch port; Active mode on the local switch port and passive mode on the remote switch port

Cevap

The configurations that successfully form an LACP EtherChannel bundle are active-to-active and active-to-passive mode combinations.
For an IEEE 802.3ad Link Aggregation Control Protocol (LACP) EtherChannel to form, at least one interface must be set to active mode so that LACP frames are transmitted across the link. Consequently, combining an active interface with another active interface, or an active interface with a passive interface, results in a operational EtherChannel bundle.

Adım Adım Çözüm

1
Analyze LACP mode behaviors
Active mode actively originates LACP negotiation frames. Passive mode only listens and responds to incoming LACP frames.
For negotiation to take place, at least one endpoint must generate negotiation frames.
2
Evaluate the mode combinations for compatibility
Active-to-active and active-to-passive form valid LACP EtherChannels. Passive-to-passive fails because neither interface transmits LACP negotiation frames. Active-to-desirable fails because LACP and PAgP are incompatible protocols.
EtherChannel negotiation protocols must match on both ends, and at least one port must actively send negotiation frames.

Anahtar Kavram

LACP EtherChannel Mode Negotiation Rules
Soru 168Soru →

A network administrator executes the global configuration command `vlan dot1q tag native` on a Cisco Catalyst switch. Interface GigabitEthernet1/0/1 on the switch is explicitly configured with `switchport mode trunk` and `switchport trunk native vlan 50`. Which TWO operational behaviors occur on this trunk interface as a result of this configuration? (Select TWO.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Egress frames originating from VLAN 50 exiting interface GigabitEthernet1/0/1 are encapsulated with an 802.1Q header specifying VLAN ID 50.; Ingress untagged Ethernet frames received on interface GigabitEthernet1/0/1 are dropped by the switch interface.

Cevap

Enabling the global command `vlan dot1q tag native` forces the switch to place an 802.1Q tag on all native VLAN traffic (VLAN 50) egressing trunk ports and causes the switch to drop incoming untagged frames received on those trunk ports.
Under default 802.1Q operation, native VLAN traffic is sent untagged. Executing `vlan dot1q tag native` globally forces the switch to insert an 802.1Q tag into egress frames for the native VLAN (VLAN 50) and drop any untagged frames received on trunk interfaces.

Adım Adım Çözüm

1
Analyze standard IEEE 802.1Q native VLAN default operation.
By default, IEEE 802.1Q trunks transmit traffic belonging to the configured native VLAN without adding a 4-byte 802.1Q header (untagged).
Backward compatibility with non-802.1Q legacy devices requires native VLAN traffic to remain untagged unless configured otherwise.
2
Determine the impact of the global command `vlan dot1q tag native` on egress traffic.
The command alters global switch behavior such that native VLAN frames (VLAN 50 in this scenario) are encapsulated with an 802.1Q header containing the native VLAN ID prior to egress transmission.
Tagging native VLAN traffic prevents VLAN hopping security attacks and ensures consistent identification across switch fabrics.
3
Determine the impact of the global command `vlan dot1q tag native` on ingress traffic.
Because the switch now expects tagged frames for all assigned VLANs on 802.1Q trunk links, any incoming untagged Ethernet frames arriving on the trunk interface are discarded.
Accepting untagged frames when native VLAN tagging is enabled would create ambiguity regarding frame classification.

Anahtar Kavram

Global 802.1Q Native VLAN Tagging Behavior
Tahmini Süre:2m 0s
Soru 169Soru →

A network administrator is converting an existing Layer 2 switch port channel into a routed Layer 3 EtherChannel interface on a Cisco switch. Which interface configuration command must be executed on both the physical member interfaces and the logical Port-channel interface to enable Layer 3 IP address assignment?

Cevabı ve açıklamayı göster

Cevap: no switchport

Cevap

The 'no switchport' command must be configured on both the physical interfaces and the Port-channel interface.
To create a routed (Layer 3) EtherChannel on a Cisco Catalyst switch, the interface must be changed from Layer 2 mode to Layer 3 mode using the 'no switchport' command. This command must be executed on both the physical member interfaces and the logical Port-channel interface before an IP address can be configured.

Adım Adım Çözüm

1
Identify the requirement for establishing a Layer 3 EtherChannel
Recognize that physical switch ports default to Layer 2 switchport operation.
By default, Cisco switch ports operate in Layer 2 mode and do not accept IP addressing commands.
2
Select the proper command to convert Layer 2 ports to Layer 3 ports
Apply 'no switchport' under the physical member interfaces and the Port-channel interface.
The 'no switchport' command turns off Layer 2 processing and makes the interface operate as a routed Layer 3 interface.

Anahtar Kavram

Layer 3 EtherChannel Configuration
Soru 170Soru →

A network engineer needs to implement an open standard, vendor-neutral Layer 2 neighbor discovery protocol across a mixed enterprise network containing both Cisco and non-Cisco devices. Which protocol defined under IEEE 802.1AB meets this requirement?

Cevabı ve açıklamayı göster

Cevap: Link Layer Discovery Protocol (LLDP)

Cevap

Link Layer Discovery Protocol (LLDP) is the IEEE 802.1AB standard protocol used for Layer 2 discovery in multi-vendor network environments.
Link Layer Discovery Protocol (LLDP) is defined by IEEE 802.1AB. It provides vendor-neutral Layer 2 neighbor discovery functionality, making it ideal for heterogeneous network environments with devices from multiple vendors.

Adım Adım Çözüm

1
Identify the protocol requirements from the scenario.
The scenario specifies an open-standard, vendor-neutral Layer 2 discovery protocol governed by IEEE 802.1AB.
Multivendor environments cannot rely on proprietary protocols like CDP across non-Cisco switches.
2
Evaluate candidate protocols against IEEE standards.
LLDP is explicitly defined under the IEEE 802.1AB standard for network device discovery.
LLDP allows heterogeneous network devices to advertise capabilities, management IP, and interface details across vendor boundaries.

Anahtar Kavram

Layer 2 Discovery Protocols: CDP vs. LLDP Standards
Soru 171Soru →

A network administrator executes the command `show etherchannel summary` on a Cisco switch to troubleshoot a newly configured EtherChannel link. The output displays the following information:

text Flags: D - down P - bundled in port-channel I - stand-alone s - suspended H - Hot-standby (LACP only) S - Layer2 U - in use Group Port-channel Protocol Ports ------+--------------+---------+----------------------------------------------- 1 Po1(SU) LACP Gi0/1(I) Gi0/2(I)

Based on the output, which configuration state is the primary cause of both physical member interfaces remaining in the `(I)` stand-alone state?

Cevabı ve açıklamayı göster

Cevap: Both interconnecting switches have their physical member interfaces configured in LACP passive mode.

Cevap

Both interconnecting switches have their physical member interfaces configured in LACP passive mode.
In LACP negotiation, an interface configured in passive mode will listen for LACP packets but will never initiate transmission of LACP PDUs. If both switches across a link are set to passive mode, neither switch sends LACP packets. Consequently, LACP negotiation never completes, and member interfaces remain in the stand-alone state indicated by the flag (I) in the show etherchannel summary output.

Adım Adım Çözüm

1
Analyze the output of the show etherchannel summary command
Port-channel status is SU (Layer 2, in use), protocol is LACP, but member ports GigabitEthernet0/1 and GigabitEthernet0/2 are marked with flag (I).
According to the output flags, (I) indicates stand-alone mode, meaning the physical interfaces are operating independently and have not successfully negotiated into the bundled channel group.
2
Evaluate LACP mode negotiation mechanics
LACP supports two modes: active (initiates negotiation by sending LACP PDUs) and passive (responds to LACP PDUs but does not initiate them).
At least one side of the link must be set to active mode to initiate the exchange of LACP packets.
3
Identify the cause of stand-alone state
When both sides are configured as passive, neither switch initiates LACP PDU exchange. As a result, LACP negotiation fails to start, leaving member ports in the stand-alone (I) state.
Matching passive-passive modes fail to negotiate an operational EtherChannel.

Anahtar Kavram

LACP Mode Negotiation and Verification Flags
Soru 172Soru →

A network administrator is migrating a pair of trunk links connecting two distribution switches to a routed Layer 3 EtherChannel using IEEE 802.3ad LACP. Interfaces GigabitEthernet1/0/1 and GigabitEthernet1/0/2 need to be bundled into Port-channel 5 with IPv4 address 10.0.5.1/3010.0.5.1/30 assigned to the logical interface. In what operational sequence must these CLI configuration steps be executed on the switch to successfully create this Layer 3 EtherChannel?

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct operational sequence begins by selecting physical member interfaces via interface range mode, converting them to Layer 3 routed ports using `no switchport`, binding them to LACP bundle 5 with `channel-group 5 mode active`, entering `interface Port-channel 5` configuration mode, and finally assigning IPv4 address 10.0.5.1/3010.0.5.1/30 directly to the logical port-channel.
To build an operational Layer 3 LACP EtherChannel, physical member links must first be selected and converted into routed interfaces (`no switchport`). Adding these converted interfaces to a channel group with `mode active` automatically creates a Layer 3 logical port-channel and starts LACP negotiation. Finally, configuration transitions to `interface Port-channel 5`, where the IP address is applied to the logical bundle.

Adım Adım Çözüm

1
Execute `interface range GigabitEthernet1/0/1 - 2`.
Enters range interface configuration mode for both physical member interfaces.
Configuration commands must be applied simultaneously to member interfaces to maintain identical operational states.
2
Execute `no switchport` on the physical interface range.
Converts physical member interfaces from Layer 2 switchports into Layer 3 routed ports.
Member interfaces must be routed ports prior to group assignment so that Cisco IOS instantiates a Layer 3 Port-channel interface.
3
Execute `channel-group 5 mode active`.
Instantiates Port-channel 5 and enables active IEEE 802.3ad LACP negotiation on the physical interfaces.
Active mode ensures the switch actively sends LACP Link Aggregation Control Protocol Data Units (LACPDUs) to negotiate EtherChannel formation.
4
Execute `interface Port-channel 5`.
Enters interface configuration sub-mode for logical interface Port-channel 5.
Layer 3 protocol configuration and IP routing parameters belong to the logical bundle interface.
5
Execute `ip address 10.0.5.1 255.255.255.252` on the port-channel interface.
Configures the IP address and subnet mask on the logical EtherChannel bundle.
In Layer 3 EtherChannels, packets are routed to the port-channel interface, which then distributes traffic across physical member links using the load-balancing hash.

Anahtar Kavram

Layer 3 EtherChannel LACP Configuration Sequence
Soru 173Soru →

A network technician is configuring Layer 2 neighbor discovery protocols on a Cisco Catalyst switch connected to non-Cisco IP phones and third-party switches. Which two statements regarding the default operations and characteristics of CDP and LLDP are accurate?

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: LLDP is an open-standard protocol defined under IEEE 802.1AB, whereas CDP is a Cisco-proprietary protocol.; CDP is enabled globally by default on Cisco IOS switches, while LLDP typically requires global enablement using the 'lldp run' command.

Cevap

The two correct statements are that LLDP is an IEEE 802.1AB open standard while CDP is Cisco-proprietary, and that CDP is enabled by default on Cisco IOS switches while LLDP must be globally enabled using the 'lldp run' command.
LLDP is defined by IEEE 802.1AB as an open standard protocol, making it suitable for environments with equipment from multiple vendors, whereas CDP is a Cisco-proprietary protocol. Furthermore, Cisco switches default to having CDP enabled out-of-the-box, while LLDP must be globally enabled using the global configuration command 'lldp run'.

Adım Adım Çözüm

1
Analyze standard compliance for Layer 2 discovery protocols.
LLDP is standardized under IEEE 802.1AB for multi-vendor interoperability, whereas CDP is proprietary to Cisco.
Understanding standard vs. proprietary protocol behavior is fundamental for multi-vendor network integration.
2
Evaluate default operating states on Cisco switches.
CDP is active globally out of the box on Cisco IOS, while LLDP requires explicit global activation via 'lldp run'.
Knowing default service states prevents assumptions about neighbor discovery availability.

Anahtar Kavram

Layer 2 Discovery Protocol Differences (CDP vs LLDP)
Soru 174Soru →

Two switches are connected using two physical Ethernet interfaces. A network technician configures the interfaces on Switch A with the command `channel-group 1 mode passive` to form a Link Aggregation Control Protocol (LACP) EtherChannel. Which mode must be configured on Switch B's interfaces to successfully negotiate and establish the EtherChannel bundle?

Cevabı ve açıklamayı göster

Cevap: active

Cevap

active mode must be configured on Switch B.
Link Aggregation Control Protocol (LACP) requires at least one switch to actively initiate packet negotiation. Since Switch A is set to passive mode, Switch B must be configured in active mode to send LACP negotiation frames and bring up the EtherChannel.

Adım Adım Çözüm

1
Identify the protocol in use.
The scenario uses LACP (IEEE 802.3ad) based on the passive mode keyword.
LACP uses active and passive modes, whereas PAgP uses desirable and auto modes.
2
Analyze LACP negotiation requirements.
Passive mode responds to LACP packets but does not send initial negotiation requests. At least one side must actively send LACP frames.
If both sides are set to passive, neither initiates negotiation and no EtherChannel is formed.
3
Determine the required remote configuration.
Switch B must be set to active mode.
An active-passive pairing successfully establishes an LACP EtherChannel bundle.

Anahtar Kavram

LACP Mode Negotiation Compatibility
Tahmini Süre:45s
Soru 175Soru →

A network administrator executes the `show etherchannel summary` command on Switch-1 to inspect an EtherChannel connection to Switch-2:

text
Flags: D - down P - bundled in port-channel
I - stand-alone s - suspended
H - Hot-standby
SD - Layer2&Down SU - Layer2&In-use

Group Port-channel Protocol Ports
------+-------------+-----------+-----------------------------------------------
1 Po1(SD) LACP Gi0/1(I) Gi0/2(I)

Which condition on Switch-2 is the most likely cause of the `(I)` flag on the Switch-1 member interfaces?

Cevabı ve açıklamayı göster

Cevap: Switch-2 member interfaces are configured with the `channel-group 1 mode desirable` command.

Cevap

Switch-2 member interfaces are configured with the `channel-group 1 mode desirable` command.
The `(I)` flag in `show etherchannel summary` output stands for stand-alone, meaning the physical interfaces are operating as separate single links rather than a bundled channel. Switch-1 is configured for LACP (Link Aggregation Control Protocol). If Switch-2 is configured with `channel-group 1 mode desirable`, it attempts to use PAgP (Port Aggregation Protocol). Because LACP and PAgP are incompatible aggregation protocols, negotiation fails completely, placing Switch-1's ports into stand-alone state.

Adım Adım Çözüm

1
Analyze the CLI output flags from `show etherchannel summary`.
The port-channel Po1 is in Layer 2 Down state `(SD)`, and the physical member interfaces GigabitEthernet 0/1 and 0/2 display the `(I)` flag, indicating stand-alone mode.
The `(I)` flag signifies that the physical interfaces are operating independently as individual links because EtherChannel negotiation failed.
2
Evaluate the configured protocol and negotiation modes.
Switch-1 is attempting to form an EtherChannel using IEEE 802.3ad LACP.
LACP and Cisco proprietary PAgP protocols are mutually incompatible and cannot negotiate an aggregation bundle together.
3
Determine the configuration on Switch-2 that caused the negotiation failure.
Setting Switch-2 to `desirable` mode forces it to use PAgP. PAgP packets are ignored by Switch-1 running LACP, preventing bundle aggregation.
To form an LACP EtherChannel bundle, Switch-2 must use LACP modes (`active` or `passive`), with at least one side set to `active`.

Anahtar Kavram

LACP vs PAgP Protocol Mismatch and EtherChannel Verification
Soru 176Soru →

When a non-PortFast interface on a Cisco switch using classic IEEE 802.1D Spanning Tree Protocol (STP) comes up, it undergoes a specific sequence of port states to prevent Layer 2 loops before it begins processing user traffic. Place the following STP port states in the correct chronological order from link initialization to full data forwarding.

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Cevap

The correct operational sequence of classic 802.1D STP port states is Blocking State, followed by Listening State, then Learning State, and finally Forwarding State.
Under standard IEEE 802.1D Spanning Tree Protocol operational rules, an interface transitions sequentially from Blocking (preventing loops) to Listening (participating in BPDU role election), then to Learning (building MAC table entries), and finally reaches Forwarding (processing and forwarding user traffic).

Adım Adım Çözüm

1
Identify the initial port state upon link initialization.
The switch interface starts in the Blocking state where it drops user frames and does not learn MAC addresses to prevent loops.
STP defaults to a loop-preventative state whenever a link transitions to up.
2
Determine the state focused on root bridge election and port role determination.
The interface moves to the Listening state, where BPDUs are processed and sent, but user data is still dropped and MAC learning is disabled.
The switch must determine topology roles (Root Port, Designated Port, or Alternate Port) before modifying table structures.
3
Determine the intermediate state focused on MAC table population.
After the first 15-second Forward Delay timer, the interface enters the Learning state, where it populates the MAC table from incoming frame headers but still drops user payload data.
Populating MAC addresses in advance prevents massive unicast flooding when the port starts forwarding.
4
Identify the final operational state allowing full traffic transmission.
After the second 15-second Forward Delay timer, the interface transitions to the Forwarding state.
The port is now confirmed loop-free and fully prepared to forward data frames.

Anahtar Kavram

IEEE 802.1D STP Port State Convergence Sequence
Tahmini Süre:45s
Soru 177Soru →

An engineer wants to establish an LACP-based EtherChannel between Switch-A and Switch-B. Switch-A is configured with the `channel-group 5 mode passive` interface command. Which mode must be configured on Switch-B for the link aggregation bundle to form successfully?

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Cevap: active

Cevap

The interface mode on Switch-B must be set to 'active'.
Link Aggregation Control Protocol (LACP) requires at least one side of the connection to actively initiate negotiations. Because Switch-A is set to passive mode, it will only respond to LACP frames. Configuring Switch-B in active mode ensures LACP negotiation packets are transmitted, bringing up the EtherChannel.

Adım Adım Çözüm

1
Identify protocol and mode characteristics
Switch-A is using LACP in passive mode.
Passive mode responds to LACP packets but does not transmit initial negotiation frames.
2
Evaluate negotiation requirements
At least one endpoint must actively initiate LACP frames.
Without an active initiator, no LACP control frames are sent.
3
Select matching mode for Switch-B
Switch-B must use 'active' mode.
Setting Switch-B to active mode initiates LACP negotiations.

Anahtar Kavram

LACP Mode Compatibility
Soru 178Soru →

A network engineer is configuring a routed (Layer 3) EtherChannel between two Cisco Catalyst switches, Switch-1 and Switch-2, across physical interfaces GigabitEthernet 0/1 and GigabitEthernet 0/2. Switch-1 is configured with LACP in active mode (`channel-group 10 mode active`). Which TWO requirements must be met to correctly establish and operate this Layer 3 LACP EtherChannel bundle? (Select two choices.)

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Cevap: The `no switchport` command must be applied to both the logical interface Port-channel 10 and the physical member interfaces prior to configuring the IP address.; Switch-2 physical member interfaces can be configured with `channel-group 10 mode passive` to negotiate the LACP bundle successfully.

Cevap

The correct requirements are converting both the physical member interfaces and the logical port-channel interface to Layer 3 using the 'no switchport' command before assigning the IP address, and configuring Switch-2 in LACP passive mode (or active mode) to pair with Switch-1 active mode.
For Layer 3 EtherChannels, physical member ports and the port-channel interface must be configured as routed interfaces via `no switchport`, and the IP address is assigned to the logical port-channel interface. Furthermore, LACP allows dynamic bundle establishment when one side is in active mode and the peer side is in passive mode.

Adım Adım Çözüm

1
Evaluate Layer 3 EtherChannel interface configuration requirements.
Layer 3 EtherChannels require member interfaces and the port-channel interface to have switchport functionality disabled using `no switchport`. The IP address is configured on the Port-channel interface, not on individual member interfaces.
Physical member ports inherit Layer 3 configurations from the logical port-channel.
2
Analyze protocol compatibility for LACP mode negotiation.
LACP uses modes `active` and `passive`. Active-Active and Active-Passive pairings form LACP bundles. Modes `auto` and `desirable` belong to PAgP and cannot interoperate with LACP.
Mixing LACP and PAgP protocols prevents EtherChannel formation.

Anahtar Kavram

Layer 3 EtherChannel LACP Mode Negotiation and Routed Interface Setup
Soru 179Soru →

A network engineer is configuring a routed (Layer 3) EtherChannel bundle (Port-channel 12) on a Cisco Catalyst switch using Link Aggregation Control Protocol (LACP). The bundle must aggregate physical interfaces GigabitEthernet1/0/1 and GigabitEthernet1/0/2, actively negotiate LACP trunking, and host the IPv4 default gateway subnet interface with IP address 192.168.100.1/30. Place the Cisco IOS configuration command steps in the correct sequential order from first to last to complete this configuration cleanly.

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Cevap

The correct sequence of commands is: 1) interface range GigabitEthernet1/0/1 - 2, 2) no switchport, 3) channel-group 12 mode active, 4) interface Port-channel 12, 5) ip address 192.168.100.1 255.255.255.252.
To create a routed (Layer 3) EtherChannel using LACP, the physical interfaces must first be selected ('interface range GigabitEthernet1/0/1 - 2') and converted to Layer 3 routed ports ('no switchport'). Next, the LACP dynamic bundle is formed using 'channel-group 12 mode active'. Afterwards, the administrator switches to the logical bundle interface context ('interface Port-channel 12') to assign the IPv4 address ('ip address 192.168.100.1 255.255.255.252').

Adım Adım Çözüm

1
Select the target physical member interfaces
Enters interface range configuration mode for GigabitEthernet1/0/1 and 1/0/2.
Configuration changes must apply to both member links simultaneously.
2
Remove Layer 2 switching capabilities
Converts physical member interfaces to Layer 3 routed ports.
Issuing 'no switchport' on member interfaces prior to bundling ensures the created port-channel automatically inherits routed Layer 3 operational mode.
3
Create and bind member interfaces to the channel-group
Adds physical member interfaces to Port-channel 12 using LACP active mode.
The 'mode active' keyword specifies active LACP packet transmission to initiate bundle formation.
4
Navigate to the logical bundle interface
Enters configuration mode for interface Port-channel 12.
Logical layer configurations (such as IP addressing) must be applied directly to the port-channel interface.
5
Configure IP address on the port-channel
Assigns IP address 192.168.100.1/30 to Port-channel 12.
Layer 3 EtherChannels hold IP configuration on the logical interface, allowing traffic routing over the aggregated links.

Anahtar Kavram

Layer 3 EtherChannel LACP Configuration Sequence
Soru 180Soru →

A network engineer is configuring a newly installed Cisco Catalyst switch interface connected to a workstation. VLAN 40 does not currently exist in the switch VLAN database. The engineer enters the following CLI commands:

text
Switch(config)# interface GigabitEthernet1/0/4
Switch(config-if)# switchport mode access
Switch(config-if)# switchport access vlan 40

Which two outcomes occur immediately upon applying this configuration sequence? (Select two.)

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Cevap: VLAN 40 is automatically created and added to the switch VLAN database.; Interface GigabitEthernet1/0/4 is statically assigned to VLAN 40 and transmits untagged frames toward the connected workstation.

Cevap

The switch automatically creates VLAN 40 in the VLAN database, and interface GigabitEthernet1/0/4 is configured as an access port that transmits untagged Ethernet frames to the workstation.
Executing 'switchport access vlan 40' when VLAN 40 does not exist causes Cisco IOS to automatically create VLAN 40 in the VLAN database. Furthermore, configuring the interface with 'switchport mode access' assigns GigabitEthernet1/0/4 to VLAN 40 as a standard access port, which forwards untagged Ethernet frames to connected end-user hosts.

Adım Adım Çözüm

1
Analyze the automatic VLAN creation behavior in Cisco IOS CLI.
Executing 'switchport access vlan 40' when VLAN 40 is missing triggers dynamic creation of VLAN 40 in the VLAN database.
Cisco IOS prevents port isolation by automatically creating non-existent VLANs assigned to access ports.
2
Determine the framing behavior of an interface in access mode.
The interface operates as an access port in VLAN 40 and strips 802.1Q encapsulation from outgoing frames.
End-user hosts expect standard untagged Ethernet frames rather than 802.1Q tagged frames.

Anahtar Kavram

Cisco IOS dynamic VLAN creation and access port framing mechanics
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