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A network administrator is provisioning interface GigabitEthernet0/1 on a Cisco Catalyst switch to connect a newly deployed workstation. The workstation must belong to VLAN 15. Which two configuration steps are required under the interface configuration mode to correctly establish this interface as a static access port in VLAN 15? (Select two.)

Geçerli olan tümünü seçin

Execute the command switchport mode access to statically set the interface to access mode.

Execute the command switchport access vlan 15 to assign the interface to VLAN 15.

Execute the command switchport trunk native vlan 15 to map host traffic to VLAN 15.

Configure an IP address on interface GigabitEthernet0/1 because access ports require Layer 3 addresses to isolate broadcast domains.

Cevabı ve açıklamayı göster

Cevap: Execute the command switchport mode access to statically set the interface to access mode.; Execute the command switchport access vlan 15 to assign the interface to VLAN 15.

Cevap

Configuring a static access port in Cisco IOS requires explicitly defining the interface mode using switchport mode access and specifying the VLAN membership using switchport access vlan 15 under interface configuration mode.

Configuring an end-user host connection on a Cisco switch requires establishing static access mode using 'switchport mode access' and assigning the specific VLAN membership using 'switchport access vlan 15'. Together, these two commands ensure untagged traffic from the connected host is correctly mapped into VLAN 15.

Adım Adım Çözüm

Enter interface configuration mode for GigabitEthernet0/1.

Access the target interface CLI prompt: Switch(config-if)#

Configuration parameters for access port operation must be applied directly to the physical interface.

Set the administrative operational mode to access.

Run switchport mode access.

Ensures the switchport operates strictly as an access port and prevents DTP from negotiating a trunk link.

Assign the interface to the target VLAN.

Run switchport access vlan 15.

Places untagged host frames into broadcast domain VLAN 15.

Anahtar Kavram

Cisco IOS VLAN Access Port Configuration Syntax

Soru 1402Soru →

A network administrator is assigning static IP addresses to devices on a LAN segment allocated the network subnet block $10.88.160.0/20$ . Which of the following IPv4 addresses are valid, usable host addresses within this subnet? (Select TWO.)

Geçerli olan tümünü seçin

10.88.160.1

10.88.175.250

10.88.175.255

10.88.176.1

Cevabı ve açıklamayı göster

Cevap: $10.88.160.1$ ; $10.88.175.250$

Cevap

The IPv4 addresses

10.88.160.1

and

10.88.175.250

are valid usable host addresses within the

10.88.160.0/20

subnet.

For the subnet

10.88.160.0/20

, the usable host address range is

10.88.160.1

through

10.88.175.254

. The IPv4 addresses

10.88.160.1

and

10.88.175.250

fall directly within this valid host range.

Adım Adım Çözüm

Determine the subnet mask and block size for the /20 prefix.

A /20 prefix translates to the dotted-decimal subnet mask

255.255.240.0

. In the third octet, the block size is calculated as

256 - 240 = 16

Calculating the block size defines the boundary of consecutive subnets.

Calculate the network address, broadcast address, and host range for

10.88.160.0/20

The subnet starts at Network ID

10.88.160.0

. The third octet ranges from 160 up to

160 + 16 - 1 = 175

. The Broadcast address is

10.88.175.255

. The usable host range spans from

10.88.160.1

through

10.88.175.254

Usable host addresses consist of all IP addresses strictly between the Network ID and Broadcast address.

Evaluate the given choices against the calculated host range.

The addresses

10.88.160.1

and

10.88.175.250

lie within

10.88.160.1 - 10.88.175.254

. The address

10.88.175.255

is the broadcast address, while

10.88.176.1

belongs to the next network segment (

10.88.176.0/20

Only addresses within the usable range can be assigned to host devices.

Anahtar Kavram

Determining usable host address ranges in IPv4 subnetting with CIDR notation.

Tahmini Süre:1m 30s

Soru 1403Soru →

An enterprise deploys a Cisco Lightweight Access Point (LAP) in FlexConnect mode at a remote branch location connected via WAN to a centralized Wireless LAN Controller (WLC). The branch WLAN is configured for local switching and local authentication. If the WAN link fails and the CAPWAP connection to the controller is disconnected, which behavior will the access point exhibit for clients on this WLAN?

The access point operates in standalone mode, continuing to forward data traffic locally and processing new client authentication requests locally.

The access point stops broadcasting all SSIDs and disassociates all connected clients until the CAPWAP tunnel to the central WLC is re-established.

The access point automatically converts to Local mode and buffers all wireless client data frames in memory until controller reachability is restored.

The access point continues forwarding existing client data traffic locally but rejects all new client authentication attempts while disconnected from the WLC.

Cevabı ve açıklamayı göster

Cevap: The access point operates in standalone mode, continuing to forward data traffic locally and processing new client authentication requests locally.

Cevap

The access point operates in standalone mode, continuing to forward data traffic locally and processing new client authentication requests locally.

In Cisco wireless architectures, a FlexConnect AP configured for local switching and local authentication transitions into standalone mode when it loses its CAPWAP control connection to the WLC. In standalone mode, the AP continues to switch client traffic locally at the branch switch and can process new authentication requests locally without WLC intervention.

Adım Adım Çözüm

Identify the AP operating mode and failure scenario.

The AP is in FlexConnect mode and loses its CAPWAP control tunnel to the centralized WLC due to a WAN outage.

FlexConnect mode is designed for branch deployments to handle WAN loss gracefully.

Evaluate the traffic switching configuration.

The WLAN is configured for local switching, meaning user data packets are bridged directly onto the local trunk/VLAN rather than encapsulated in CAPWAP to the WLC.

Local switching allows data plane forwarding to function independently of the CAPWAP data tunnel.

Evaluate the authentication configuration during standalone mode.

Because local authentication is configured, the FlexConnect AP acts as a local authenticator when disconnected from the controller.

Local authentication ensures both existing client sessions and new client join requests continue operating normally during a WAN link disruption.

Anahtar Kavram

Cisco FlexConnect AP Standalone Mode Operations

Soru 1404Soru →

A Cisco router receives an IP packet with a destination address of 10.45.12.85. Examine the following excerpt from the router's routing table:

text
Gateway of last resort is 192.168.1.1 to network 0.0.0.0

O 10.45.12.0/25 [110/20] via 192.168.12.2, GigabitEthernet0/0/1
D 10.45.12.64/26 [90/307200] via 192.168.14.2, GigabitEthernet0/0/2
S 10.45.12.80/28 [1/0] via 192.168.16.2, GigabitEthernet0/0/3
O 10.45.12.80/29 [110/50] via 192.168.18.2, GigabitEthernet0/0/4

Which next-hop IP address and exit interface will the router select to forward this packet?

192.168.18.2 via GigabitEthernet0/0/4 because 10.45.12.80/29 is the longest matching prefix for the destination IP address.

192.168.16.2 via GigabitEthernet0/0/3 because the static route has the lowest administrative distance among matching routes.

192.168.14.2 via GigabitEthernet0/0/2 because EIGRP has a lower administrative distance than the OSPF route matching 10.45.12.80/29.

192.168.12.2 via GigabitEthernet0/0/1 because 10.45.12.85 is an invalid host address in a /29 subnet, forcing a fallback to the /25 route.

Cevabı ve açıklamayı göster

Cevap: 192.168.18.2 via GigabitEthernet0/0/4 because 10.45.12.80/29 is the longest matching prefix for the destination IP address.

Cevap

The router forwards the packet to next-hop IP 192.168.18.2 via exit interface GigabitEthernet0/0/4 based on the Longest Prefix Match rule.

When a router receives a packet, it compares the destination IP address (10.45.12.85) against all entries in the routing table. It selects the route with the most specific match (the longest subnet mask prefix length). In this scenario, 10.45.12.80/29 matches 10.45.12.85 (range 10.45.12.80–10.45.12.87) with a 29-bit prefix length, which is longer than /28, /26, /25, or /0. Consequently, the router routes traffic out GigabitEthernet0/0/4 to 192.168.18.2. Administrative distance is ignored because the matching routes do not have identical prefix lengths.

Adım Adım Çözüm

Identify all candidate routes matching destination IP 10.45.12.85

Candidate routes: 10.45.12.0/25 (range .0-.127), 10.45.12.64/26 (range .64-.127), 10.45.12.80/28 (range .80-.95), 10.45.12.80/29 (range .80-.87), and default route 0.0.0.0/0.

The router compares the destination IP address against all routing table prefix entries.

Apply the Longest Prefix Match rule to determine the winning route

The route 10.45.12.80/29 has the longest prefix mask (/29 = 29 matching bits).

Prefix length (/29 > /28 > /26 > /25 > /0) takes precedence over administrative distance and metric during forwarding lookup.

Extract the next-hop IP and exit interface associated with the longest matching route

Next-hop: 192.168.18.2, Exit Interface: GigabitEthernet0/0/4.

The router uses the interface and gateway specified by the selected longest matching routing table entry.

Anahtar Kavram

Longest Prefix Match (LPM) Rule in Cisco Forwarding Decision Logic

Tahmini Süre:1m 30s

Soru 1405Soru →

Fill in the blank with the exact Cisco IOS command needed to configure the specified static route.

Aşağıdaki boşlukları doldurun

To configure a fully specified IPv6 static route for the destination subnet 2001:db8:acad:1::/64 using the outbound interface GigabitEthernet0/1 and the next-hop link-local address fe80::1, enter the command:

Cevabı ve açıklamayı göster

Cevap

ipv6 route 2001:db8:acad:1::/64 GigabitEthernet0/1 fe80::1

When specifying an IPv6 link-local address as the next-hop, Cisco IOS requires a fully specified static route where both the local outbound interface and the neighbor's link-local IPv6 address are declared.

Adım Adım Çözüm

Identify the target network prefix and length.

Destination network prefix is 2001:db8:acad:1::/64.

Static routing in IPv6 requires specifying the target prefix alongside its prefix length.

Determine the interface and next-hop address requirement for link-local routing.

Exit interface is GigabitEthernet0/1 and link-local next-hop address is fe80::1.

Because link-local addresses (fe80::/10) are only unique to a local link, Cisco IOS requires specifying the exit interface along with the link-local next-hop address to form a fully specified static route.

Assemble the complete global configuration mode command syntax.

ipv6 route 2001:db8:acad:1::/64 GigabitEthernet0/1 fe80::1

The correct command syntax in Cisco IOS is 'ipv6 route <prefix/length> <exit-interface> <next-hop-link-local-address>'.

Anahtar Kavram

IPv6 Fully Specified Static Route Syntax

Soru 1406Soru →

An interface on a Cisco IOS router is dynamically generating its IPv6 address using the EUI-64 standard. Output from the command `show ipv6 interface GigabitEthernet0/0` reveals that the link-local address assigned to the interface is `fe80::1a2b:3cff:fe4d:5e6f`. Based on this address, what is the burned-in MAC address of the Ethernet interface?

1a2b.3c4d.5e6f

182b.3c4d.5e6f

102b.3c4d.5e6f

182b.3cff.fe4d

Cevabı ve açıklamayı göster

Cevap: 182b.3c4d.5e6f

Cevap

The MAC address of the interface is 182b.3c4d.5e6f.

To reverse the EUI-64 generation process and recover the original 48-bit MAC address from the interface ID `1a2b:3cff:fe4d:5e6f`: first, remove the inserted `FFFE` bytes from the midpoint to get `1a2b:3c4d:5e6f`. Next, convert the first byte (`1A` hex) to binary (`0001 1010`) and flip the 7th bit (the Universal/Local bit), resulting in `0001 1000` (`18` hex). Assembling the modified octets gives the hardware MAC address `182b.3c4d.5e6f`.

Adım Adım Çözüm

Extract the 64-bit Interface Identifier from the IPv6 address.

The Interface ID portion of `fe80::1a2b:3cff:fe4d:5e6f` is `1a2b:3cff:fe4d:5e6f`.

In IPv6 link-local addresses, the last 64 bits represent the Interface Identifier.

Remove the inserted 16-bit hex sequence `ff:fe` (`FFFE`) from the middle of the Interface ID.

Removing `ff:fe` from `1a:2b:3c:ff:fe:4d:5e:6f` yields 6 bytes: `1a:2b:3c:4d:5e:6f`.

The IEEE EUI-64 process inserts `FFFE` into the middle of a 48-bit MAC address to expand it to 64 bits.

Invert the 7th bit (Universal/Local bit) of the first byte.

The first byte `1A` in binary is `0001 1010`. Inverting the 7th bit (2nd bit from the left) changes it to `0001 1000`, which is `18` in hexadecimal.

EUI-64 inverts the Universal/Local bit (7th bit of the first byte) when creating an interface identifier from a MAC address.

Format the resulting 48 bits into standard Cisco MAC address notation.

Combining `18`, `2b`, `3c`, `4d`, `5e`, and `6f` produces `182b.3c4d.5e6f`.

Cisco CLI format uses three sets of four hexadecimal digits separated by dots.

Anahtar Kavram

Reversing the EUI-64 interface identifier process to determine the burned-in MAC address

Soru 1407Soru →

A network administrator is evaluating physical cabling and optical transceiver specifications for a new campus network deployment. Which two statements accurately describe Ethernet physical interface and cabling requirements? (Select TWO.)

Geçerli olan tümünü seçin

10GBASE-SR transceivers utilize multimode fiber (MMF) with LC connectors for short-distance transmission up to several hundred meters.

1000BASE-T operation requires all four wire pairs of Category 5e or higher unshielded twisted-pair (UTP) cabling.

1000BASE-SX optical transceivers use single-mode fiber (SMF) to achieve link distances of up to 10 kilometers.

Connecting two like devices, such as switch-to-switch FastEthernet interfaces with Auto-MDIX disabled, requires a standard straight-through cable.

Category 6a UTP cabling restricts 10GBASE-T copper Ethernet links to a maximum distance of 37 meters.

Cevabı ve açıklamayı göster

Cevap: 10GBASE-SR transceivers utilize multimode fiber (MMF) with LC connectors for short-distance transmission up to several hundred meters.; 1000BASE-T operation requires all four wire pairs of Category 5e or higher unshielded twisted-pair (UTP) cabling.

Cevap

The correct statements are that 10GBASE-SR transceivers utilize multimode fiber (MMF) with LC connectors for short distances, and 1000BASE-T requires all four pairs of UTP cabling.

10GBASE-SR is designed for short-reach multimode fiber up to 300 meters using LC connectors. Additionally, 1000BASE-T standard mandates the use of all four pairs (8 wires) in Cat5e or higher twisted-pair cabling to transmit 1 Gbps data rates.

Adım Adım Çözüm

Analyze optical transceiver standards and media compatibility

10GBASE-SR specifies Short Range operation over 850 nm multimode fiber using LC connectors, making the 10GBASE-SR MMF statement correct. 1000BASE-SX also uses MMF (not SMF), making the 1000BASE-SX SMF statement incorrect.

Optical optics are differentiated by wavelength, distance capability (SR vs LR/LX), and fiber modal type (MMF vs SMF).

Analyze copper twisted-pair cabling specifications and pinouts

1000BASE-T requires all four pairs of Category 5e/6 UTP for full Gigabit transmission. Category 6a supports 10GBASE-T up to 100 meters (not restricted to 37 meters).

Gigabit Ethernet utilizes five-level pulse amplitude modulation (PAM-5) across all four pairs simultaneously.

Verify MDI/MDI-X cable requirements

Connecting identical layer devices (switch to switch) when Auto-MDIX is turned off requires crossover wiring so transmit pins connect to receive pins.

Straight-through cables connect MDI to MDI-X devices (e.g., switch to host); like-to-like connections require crossover pinouts.

Anahtar Kavram

Physical Ethernet standards specify distinct transceiver optics, fiber types, cable categories, and pinout pairings based on bandwidth and distance requirements.

Soru 1408Soru →

A network engineer inspects a router configuration designed to provide a redundant secondary path to a branch subnet $10.240.12.0/24$ . The primary path to this destination is dynamically learned via OSPF (default Administrative Distance of $110$ ). The engineer finds the following static route entry in the running configuration:

`ip route 10.240.12.0 255.255.255.0 192.168.1.2 95`

During normal operation with the OSPF link operational, traffic continues to traverse the backup link. Which TWO statements accurately explain this behavior and the required configuration fix?

Geçerli olan tümünü seçin

The configured static route takes precedence over the OSPF route because its configured administrative distance of

95

is lower than the OSPF default administrative distance of

110

Reconfiguring the static route with an administrative distance greater than

110

allows OSPF to act as the primary route while maintaining the static route as a floating backup.

The router load-balances traffic between OSPF and the static route because static routes automatically inherit the metric of active dynamic protocols.

Changing the static route's administrative distance to

90

will deactivate the static route and restore the OSPF path into the routing table.

Cevabı ve açıklamayı göster

Cevap: The configured static route takes precedence over the OSPF route because its configured administrative distance of $95$ is lower than the OSPF default administrative distance of $110$ .; Reconfiguring the static route with an administrative distance greater than $110$ allows OSPF to act as the primary route while maintaining the static route as a floating backup.

Cevap

The static route currently pre-empts OSPF because its administrative distance (

95

) is lower than OSPF's default (

110

). To function correctly as a floating backup, the static route's administrative distance must be set to a value greater than

110

Cisco IOS routing table selection relies strictly on Administrative Distance (AD) when comparing routes learned from different sources for the exact same network prefix. OSPF has a default AD of

110

. The configured static route has an AD explicitly set to

95

. Because

95

is lower than

110

, the router prefers the static route, placing it into the routing table and routing all traffic across the backup link. To convert this into a functional floating static route, the AD of the static route must be increased to a value higher than

110

(for example,

120

), allowing OSPF to be preferred while the primary link is healthy.

Adım Adım Çözüm

Analyze the Administrative Distance (AD) of the primary path protocol.

OSPF has a standard Cisco IOS default AD of

110

Routing decisions prioritize paths with the lowest administrative distance when identical prefix lengths are compared.

Evaluate the configured static route's AD.

The command `ip route 10.240.12.0 255.255.255.0 192.168.1.2 95` assigns an explicit AD of

95

Since

95 < 110

, the router installs the static route into the routing table as the active route, suppressing the OSPF route.

Determine the required administrative distance for a floating static route.

The static route's AD must be set higher than the primary path (

> 110

), such as

120

130

A floating static route remains out of the routing table until the primary lower-AD route is removed due to network topology changes or link failure.

Anahtar Kavram

Floating static routes rely on configuring an Administrative Distance higher than the primary dynamic routing protocol.

Tahmini Süre:2m 0s

Soru 1409Soru →

An enterprise router displays the following output in its routing table:

text
Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
O 10.45.0.0/16 [110/20] via 192.168.1.1, 00:04:12, GigabitEthernet0/0

A network administrator needs to configure a backup floating static route to destination prefix $10.45.0.0/16$ via next-hop IP $192.168.2.1$ . The backup route must remain inactive in the routing table until the primary OSPF route becomes unavailable. Which command must be configured on the router to fulfill this requirement?

ip route 10.45.0.0 255.255.0.0 192.168.2.1 120

ip route 10.45.0.0 255.255.0.0 192.168.2.1 100

ip route 10.45.0.0 255.255.0.0 192.168.2.1

ip route 10.45.0.0 255.255.0.0 192.168.2.1 110

Cevabı ve açıklamayı göster

Cevap: ip route 10.45.0.0 255.255.0.0 192.168.2.1 120

Cevap

The command 'ip route 10.45.0.0 255.255.0.0 192.168.2.1 120' correctly configures the floating static route.

The active route to network

10.45.0.0/16

is learned via OSPF, which has an Administrative Distance of 110. To create a floating static route that serves strictly as a backup, the static route must be configured with an Administrative Distance strictly greater than 110. Specifying a distance of 120 keeps the route out of the routing table while OSPF is functional, and allows Cisco IOS to automatically insert the static route if OSPF fails.

Adım Adım Çözüm

Identify the Administrative Distance (AD) of the active primary route.

The routing table shows OSPF route [110/20], indicating a default Administrative Distance of

110

for OSPF.

Floating static routes rely on Administrative Distance comparison to determine installation eligibility in the routing table.

Determine the required Administrative Distance for a floating static backup route.

The backup static route must have an AD strictly greater than

110

(such as

120

Cisco IOS installs the route with the lowest Administrative Distance. Setting a higher AD keeps the static route floating in configuration without entering the active routing table until the primary route fails.

Formulate the correct Cisco IOS static route command syntax.

ip route 10.45.0.0 255.255.0.0 192.168.2.1 120

The trailing argument in the 'ip route' command defines the custom Administrative Distance.

Anahtar Kavram

Floating Static Route Administrative Distance Selection

Tahmini Süre:1m 30s

Soru 1410Soru →

A network engineer is configuring a new WLAN on a Cisco Wireless LAN Controller (WLC) using the GUI to support wireless clients using WPA2-Personal authentication. Under which tab and sub-tab in the WLANs edit menu must the pre-shared key (PSK) format and secret key be configured?

Security tab > Layer 2 sub-tab

Security tab > Layer 3 sub-tab

General tab > Radio Policy dropdown

Advanced tab > Client Exclusion settings

Cevabı ve açıklamayı göster

Cevap: Security tab > Layer 2 sub-tab

Cevap

Security tab > Layer 2 sub-tab

WPA2-Personal (PSK) is a Layer 2 security mechanism. On the Cisco WLC GUI, navigating to WLANs > Edit > Security > Layer 2 allows the administrator to select WPA+WPA2 security, check the PSK box under Auth Key Management, and specify the pre-shared key format and value.

Adım Adım Çözüm

Navigate to the WLANs menu in the Cisco WLC GUI and click on the target WLAN ID.

The WLANs > Edit page opens with multiple configuration tabs.

Access to specific WLAN parameters requires opening the specific WLAN edit panel.

Select the Security tab and verify the Layer 2 sub-tab is active.

Layer 2 security protocols (such as WPA+WPA2) are accessible.

WPA2 encryption and key management operate at Layer 2 of the OSI model.

Enable WPA2 Policy, select PSK under Auth Key Management, and enter the pre-shared key.

The pre-shared key policy is assigned to the WLAN.

PSK key management requires entering the ASCII or Hex pre-shared key under Layer 2 security settings.

Anahtar Kavram

WLC GUI WLAN Layer 2 Security Configuration

Tahmini Süre:1m 0s

Soru 1411Soru →

A network administrator observes the following syslog message on a Cisco Catalyst switch:

`%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet1/0/1 (10), with SW-Floor2 GigabitEthernet0/1 (20).`

Which mechanism enables the switch to detect this misconfiguration?

CDP carries a Native VLAN Type-Length-Value (TLV) field in its Layer 2 advertisements, allowing the switch to compare its locally configured native VLAN against the neighbor's advertised native VLAN.

CDP misinterprets the remote interface ID received in an LLDP-MED TLV and automatically modifies the native VLAN on GigabitEthernet1/0/1 to match the remote switch.

LLDP exchanges IEEE 802.1Q tagged frames across the trunk link and disables the local interface when mismatched VLAN IDs are detected in the frame header.

The switch analyzes Spanning Tree Protocol (STP) BPDUs to extract the remote interface native VLAN and generates a CDP error log.

Cevabı ve açıklamayı göster

Cevap: CDP carries a Native VLAN Type-Length-Value (TLV) field in its Layer 2 advertisements, allowing the switch to compare its locally configured native VLAN against the neighbor's advertised native VLAN.

Cevap

CDP carries a Native VLAN Type-Length-Value (TLV) field in its advertisements, allowing switches to compare their configured native VLAN with that of directly connected Cisco neighbors.

Cisco Discovery Protocol (CDP) periodically sends Layer 2 multicast messages containing Type-Length-Value (TLV) metadata structures. One of these structures is the Native VLAN TLV. When a switch receives a CDP frame on an 802.1Q trunk interface, it compares the native VLAN ID advertised in the Native VLAN TLV with the local native VLAN configured on that port. If the two values differ (e.g., VLAN 10 vs. VLAN 20), the switch logs a %CDP-4-NATIVE_VLAN_MISMATCH message.

Adım Adım Çözüm

Identify the protocol generating the syslog message.

The prefix %CDP indicates the message was generated by Cisco Discovery Protocol.

Syslog events starting with %CDP originate from the active CDP process.

Analyze how CDP exchanges configuration details across Layer 2 links.

CDP packs information elements into Type-Length-Value (TLV) fields within Layer 2 frames.

TLVs allow CDP to transmit specific device attributes, such as platform, capabilities, management addresses, and native VLAN IDs.

Determine how the native VLAN mismatch condition is detected.

The local switch compares its configured native VLAN (10) against the Native VLAN TLV value (20) in the neighbor's CDP frame.

When a discrepancy is detected between local interface configuration and incoming TLV payload, a Native VLAN Mismatch syslog event is triggered.

Anahtar Kavram

CDP Native VLAN TLV and Mismatch Detection

Tahmini Süre:1m 15s

Soru 1412Soru →

A network administrator is inspecting a Cisco Catalyst switch interface that connects to a user PC. Running the command `show interfaces FastEthernet 0/4 switchport` displays the following output:

text
Name: Fa0/4
Administrative Mode: dynamic auto
Operational Mode: static access
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: native
Negotiation of Trunking: On
Access Mode VLAN: 1 (default)

The administrator needs to permanently configure this interface as a static access port assigned to VLAN 30 and disable DTP negotiation. Which set of commands must be executed under interface configuration mode to achieve this objective?

switchport mode access
switchport access vlan 30
switchport nonegotiate

switchport trunk native vlan 30
switchport mode trunk

vlan 30
switchport mode dynamic desirable

ip address 192.168.30.1 255.255.255.0
no shutdown

Cevabı ve açıklamayı göster

Cevap: switchport mode access
switchport access vlan 30
switchport nonegotiate

Cevap

The command sequence consisting of `switchport mode access`, `switchport access vlan 30`, and `switchport nonegotiate` correctly assigns the port statically to VLAN 30 and disables DTP negotiation.

The correct command sequence explicitly configures the interface as a static access port (`switchport mode access`), assigns it to the designated access VLAN (`switchport access vlan 30`), and prevents the port from sending Dynamic Trunking Protocol frames (`switchport nonegotiate`).

Adım Adım Çözüm

Analyze current interface state

The administrative mode is `dynamic auto`, meaning it will dynamically negotiate a trunk if the opposing side initiates negotiation.

To secure and statically assign an access port, dynamic trunking must be overridden.

Statically set access mode and assign target VLAN

`switchport mode access` forces static access behavior, and `switchport access vlan 30` binds untagged traffic to VLAN 30.

Access ports belong to a single broadcast domain (VLAN) for end-host traffic.

Disable DTP frame generation

`switchport nonegotiate` stops DTP frames from being sent out the port.

Disabling DTP prevents unauthorized trunk establishment attempts on access ports.

Anahtar Kavram

Configuring Layer 2 Static Access Ports and Disabling DTP Negotiation

Tahmini Süre:1m 30s

Soru 1413Soru →

An administrator must create a static route on a Cisco router for destination prefix $2001:\text{db8}:\text{fed}::/64$ . The next-hop router's link-local address is $\text{fe80}::2$ , reached via local interface GigabitEthernet0/1, and the route must be configured with an administrative distance of 110. Which Cisco IOS command correctly completes this configuration?

ipv6 route 2001:db8:fed::/64 GigabitEthernet0/1 fe80::2 110

ipv6 route 2001:db8:fed::/64 fe80::2 110

ip route 2001:db8:fed::/64 GigabitEthernet0/1 fe80::2 110

ipv6 route 2001:db8:fed::/64 GigabitEthernet0/1 fe80::2

Cevabı ve açıklamayı göster

Cevap: ipv6 route 2001:db8:fed::/64 GigabitEthernet0/1 fe80::2 110

Cevap

ipv6 route 2001:db8:fed::/64 GigabitEthernet0/1 fe80::2 110

The correct command follows the exact Cisco IOS syntax for a fully specified IPv6 static route: 'ipv6 route <destination-prefix/mask> <exit-interface> <next-hop-link-local-address> [administrative-distance]'.

Adım Adım Çözüm

Identify the proper global configuration command prefix for IPv6 static routing.

Use 'ipv6 route' rather than IPv4's 'ip route'.

Cisco IOS separates IPv4 and IPv6 routing table management commands.

Evaluate link-local next-hop address rules in Cisco IOS IPv6 static routes.

When a link-local address (fe80::/10) is used as the next hop, the local exit interface (GigabitEthernet0/1) MUST also be specified (fully specified static route).

Link-local addresses are valid only on the local link and are shared across multiple interfaces, creating ambiguity if an exit interface is not designated.

Append the optional Administrative Distance (AD) value to the end of the command.

Place '110' at the end of the command string.

Setting an explicit AD overrides the default static route administrative distance of 1.

Anahtar Kavram

Fully specified IPv6 static route command syntax requiring an exit interface when using a link-local next-hop address.

Tahmini Süre:1m 15s

Soru 1414Soru →

During network troubleshooting, an administrator discovers that Router A is receiving OSPFv2 Hello packets from directly connected Router B. However, Router B is dropping all incoming Hello packets from Router A because of an inbound interface access list. In which OSPF neighbor state will Router A remain with respect to Router B?

Init

2-Way

ExStart

Attempt

Cevabı ve açıklamayı göster

Cevap: Init

Cevap

Router A will remain in the Init neighbor state.

When a router receives an OSPF Hello packet from a neighbor, it places that neighbor into the Init state. To transition to the 2-Way state, bidirectional communication must be verified—meaning the receiving router must see its own Router ID listed inside the neighbor's Hello packet. Because the access list blocks Router A's Hellos from reaching Router B, Router B never learns of Router A and never includes Router A's Router ID in its Hellos. Consequently, Router A remains stuck in the Init state.

Adım Adım Çözüm

Analyze the flow of OSPF Hello packets between Router A and Router B.

Router A receives Hello packets sent by Router B, but Router B does not receive Hello packets from Router A due to the inbound access list.

Unidirectional communication is occurring.

Evaluate the requirement for transitioning out of the Init state.

To move from Init to 2-Way state, Router A must see its own Router ID listed in the Neighbor field of Router B's Hello packet.

This verifies bidirectional communication between the two neighbors.

Determine Router A's resulting neighbor state.

Because Router B never receives Router A's Hellos, Router B never includes Router A's Router ID in its Hello packets. Router A remains stuck in the Init state.

Receiving a Hello packet without seeing one's own Router ID keeps the neighbor in the Init state.

Anahtar Kavram

OSPF Neighbor State Machine (Init State & Bidirectional Communication)

Soru 1415Soru →

A Cisco router receives an IPv4 packet on an ingress interface. Place the sequential steps of the router's forwarding decision and packet processing logic in the correct order from initial receipt to egress transmission.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence for router forwarding decision logic is: 1) Inspect the destination IPv4 address and search the routing table for matching prefixes, 2) Select the route with the longest prefix match, 3) Extract the next-hop IPv4 address and exit interface, 4) Query the ARP cache for the next-hop Layer 2 MAC address, and 5) Decrement packet TTL, encapsulate into a new Layer 2 frame, and transmit out the exit interface.

When a router receives an IPv4 packet, the forwarding process follows a strict sequence: First, the destination IPv4 address is compared against candidate routes in the routing table. Next, the router selects the route entry with the longest prefix match (most specific subnet mask). Once the best route is selected, the router identifies the next-hop IPv4 address and exit interface. It then queries the local ARP cache to find the corresponding destination MAC address for the next hop. Finally, it modifies the packet by decrementing the Time to Live (TTL) by 1, recalculating the IPv4 checksum, encapsulating the packet into a new Layer 2 frame with updated source/destination MAC addresses, and forwarding it out the exit interface.

Adım Adım Çözüm

Receive packet and parse IPv4 header.

Destination IPv4 address extracted for routing table comparison.

The router must compare the destination address against candidate prefix entries in the routing table.

Apply Longest Prefix Match (LPM) evaluation.

The route entry with the highest mask length (e.g., /28 over /24) is selected.

LPM is the primary rule for forwarding lookup in Cisco routers.

Identify forwarding path details.

Next-hop IPv4 address and egress interface determined.

The matching route entry specifies the destination gateway and physical/logical outbound interface.

Perform Layer 2 resolution.

Target MAC address obtained from the ARP table.

Layer 2 framing requires the destination MAC address of the next-hop router or end-host.

Process packet header modifications and frame encapsulation.

Frame transmitted out the egress interface.

The router updates TTL/checksum fields and constructs new source/destination MAC addresses for outbound transmission.

Anahtar Kavram

Router Forwarding Decision Logic and Layer 2 Frame Rewrite

Tahmini Süre:1m 30s

Soru 1416Soru →

Arrange the evaluation steps in the correct order of precedence used by OSPFv2 routers to determine Designated Router (DR) selection on a multiaccess network segment, from the initial eligibility filter to the final tie-breaker.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct order of precedence for OSPFv2 DR selection is: 1) Disqualify priority 0 interfaces, 2) Select the candidate with the highest OSPF interface priority, 3) Break priority ties using the highest explicit Router ID or loopback IPv4 address, and 4) Break remaining ties using the highest active physical interface IPv4 address.

During an OSPFv2 DR election on a multiaccess network segment, candidate routers first exclude any interfaces configured with an OSPF priority of 0. Next, routers compare interface priorities to select the highest value. If interface priorities tie, OSPF compares Router IDs by selecting the candidate with the highest explicitly configured Router ID or highest loopback IPv4 address. Finally, if no loopback interface is present, the highest active physical interface IPv4 address is used as the tie-breaker.

Adım Adım Çözüm

Filter out non-eligible candidate interfaces.

Interfaces configured with `ip ospf priority 0` are excluded from DR/BDR candidacy.

A priority of 0 explicitly revokes a router's ability to serve as DR or BDR.

Compare candidate interface priority values.

The router with the highest numeric priority value (1 to 255) is preferred.

Interface priority is the primary metric for OSPF DR election.

Evaluate Router ID using explicit setting or loopback addresses.

If interface priorities tie, the router with the highest explicit Router ID or highest active loopback IP address is selected.

Router ID serves as the secondary selection criteria when priorities are tied.

Evaluate physical interface IP addresses.

If no explicit Router ID or loopback interfaces exist, the highest active physical interface IPv4 address breaks the tie.

Physical interface IPv4 addresses are the final tie-breaker for Router ID assignment and election decisions.

Anahtar Kavram

OSPFv2 DR/BDR Election Precedence

Soru 1417Soru →

In a network running Rapid PVST+ for VLAN 30, Switch-4 has two direct Gigabit Ethernet connections to Switch-2, which is the Root Bridge. Link 1 connects Switch-4 port GigabitEthernet0/1 to Switch-2 port GigabitEthernet0/1. Link 2 connects Switch-4 port GigabitEthernet0/2 to Switch-2 port GigabitEthernet0/2. All interface costs use default values. Which port role and state will port GigabitEthernet0/2 on Switch-4 assume after STP convergence completes?

Alternate port in the Discarding state

Backup port in the Discarding state

Root port in the Forwarding state

Designated port in the Forwarding state

Cevabı ve açıklamayı göster

Cevap: Alternate port in the Discarding state

Cevap

Port GigabitEthernet0/2 on Switch-4 will become an Alternate port in the Discarding state.

When a non-root switch has multiple parallel links connected to the same upstream Root Bridge, the tie-breakers for selecting a Root Port are: lowest cumulative Root Path Cost, lowest Designated Bridge ID, lowest upstream Designated (Sender) Port ID, and lowest local Port ID. Here, cumulative cost and Bridge ID are equal for both links. The tie is broken by Switch-2's sender Port ID: Gi0/1 has a lower numerical Port ID than Gi0/2. Thus, Switch-4's GigabitEthernet0/1 becomes the Root Port in the Forwarding state, while GigabitEthernet0/2 assumes the Alternate port role in the Discarding state to block switching loops.

Adım Adım Çözüm

Determine Root Port selection on Switch-4 across redundant paths to the Root Bridge.

Both local ports (Gi0/1 and Gi0/2) connect directly to Root Bridge Switch-2, resulting in identical Root Path Cost (

4

) and identical Root/Designated Bridge ID.

When Root Path Cost and Designated Bridge ID are tied, Rapid PVST+ evaluates the upstream Designated (Sender) Port ID to break the tie.

Compare upstream sender Port IDs from Switch-2.

Switch-2 sends BPDUs out its Gi0/1 port (Port ID

128.1

) to Switch-4's Gi0/1, and out its Gi0/2 port (Port ID

128.2

) to Switch-4's Gi0/2. Lower port priority/number wins.

Since

128.1 < 128.2

, Switch-4 selects port GigabitEthernet0/1 as its single Root Port.

Determine the role and state for the remaining unselected port GigabitEthernet0/2 on Switch-4.

GigabitEthernet0/2 receives superior BPDUs from Switch-2 compared to any BPDUs Switch-4 could send, so Switch-4 places GigabitEthernet0/2 into the Alternate port role, which operates in the Discarding state.

Alternate ports offer an alternate path to the Root Bridge and remain blocked (Discarding) to prevent Layer 2 loops.

Anahtar Kavram

Rapid PVST+ Root Port selection tie-breaking via upstream Sender Port ID and Alternate port role assignment.

Soru 1418Soru →

A Cisco router initializes OSPFv2 Process 1 with the following operational interfaces:
- Loopback0: 10.1.1.1/32 (status up, line protocol up)
- GigabitEthernet0/0: 172.16.10.1/24 (status up, line protocol up)

After OSPF Process 1 is fully active, a network engineer performs the following configuration actions in exact chronological sequence:
1. Configures Loopback1 with IP address 10.254.254.254/32 (status up, line protocol up).
2. Enters OSPF router configuration mode and executes the command `router-id 192.168.99.1`.
3. Configures GigabitEthernet0/1 with IP address 192.168.200.1/24 (status up, line protocol up).

Assuming no router reboot or `clear ip ospf process` command has been executed, what IP address is currently used as the operational OSPFv2 Router ID for Process 1?

Cevabı ve açıklamayı göster

Cevap: 10.1.1.1

Cevap

10.1.1.1

When OSPF Process 1 initially started, 10.1.1.1 was elected as the Router ID because Loopback0 was the sole operational loopback interface. OSPF Router ID selection is non-preemptive once an active process has selected its ID. Adding a loopback with a higher IP address (10.254.254.254), configuring an explicit `router-id 192.168.99.1` command, or activating new physical interfaces will not modify the operational Router ID until `clear ip ospf process` is executed or the router reboots. Thus, the active Router ID remains 10.1.1.1.

Adım Adım Çözüm

Determine the initial OSPFv2 Router ID selected when Process 1 started.

Loopback0 (10.1.1.1) was selected because operational loopback interface IP addresses take priority over physical interface IP addresses during initial Router ID election.

In Cisco IOS OSPFv2, if no manual router ID is configured at startup, the router chooses the highest IP address among operational loopback interfaces.

Evaluate the impact of configuring Loopback1 (10.254.254.254/32).

The active Router ID remains 10.1.1.1.

OSPF Router ID election is non-preemptive. Dynamically elected Router IDs do not change automatically when new interfaces with higher IP addresses come online.

Evaluate the impact of executing `router-id 192.168.99.1`.

The active Router ID remains 10.1.1.1.

Configuring a manual OSPF router ID on an already running OSPF process does not take effect until the process is reset or the router is rebooted.

Evaluate the impact of adding GigabitEthernet0/1 and determine the final operational Router ID.

The active Router ID stays 10.1.1.1.

Without a process reset via `clear ip ospf process` or a device reload, none of the subsequent configuration changes displace the active Router ID.

Anahtar Kavram

OSPFv2 Router ID Non-Preemption and Reset Requirement

Soru 1419Soru →

A network administrator is deploying Cisco Lightweight Access Points (LAPs) at a remote branch office connected to a main campus Wireless LAN Controller (WLC) over a WAN link. The branch APs are configured in FlexConnect mode with local switching configured for the primary employee WLAN. Which two statements accurately describe the operational behavior of these access points under normal operations and during a WAN outage? (Select two.)

Geçerli olan tümünü seçin

During normal operations with an active WAN connection, control traffic is encapsulated in a CAPWAP tunnel to the central WLC while user data traffic on locally switched WLANs is bridged directly onto the local branch switch.

If the WAN link fails and the AP enters Standalone mode, existing client sessions on locally switched WLANs using local authentication methods continue to transmit traffic without disruption.

If the WAN link fails, the FlexConnect access point automatically reboots into Local mode and attempts to establish a central CAPWAP data tunnel to the local branch default gateway.

All wireless client data traffic must be encapsulated in a CAPWAP data tunnel and routed through the centralized controller regardless of whether local switching is configured.

Cevabı ve açıklamayı göster

Cevap: During normal operations with an active WAN connection, control traffic is encapsulated in a CAPWAP tunnel to the central WLC while user data traffic on locally switched WLANs is bridged directly onto the local branch switch.; If the WAN link fails and the AP enters Standalone mode, existing client sessions on locally switched WLANs using local authentication methods continue to transmit traffic without disruption.

Cevap

In FlexConnect mode with local switching, CAPWAP control traffic goes to the central WLC while client data traffic is bridged directly to the local branch network. If the WAN connection to the WLC fails, the AP transitions to Standalone mode and continues forwarding data for locally switched WLANs.

FlexConnect mode is designed for branch office deployments connected over WAN links. Under normal conditions, CAPWAP control traffic is tunneled to the central Wireless LAN Controller, while client data traffic on locally switched WLANs is bridged directly to the local Ethernet switch. When WAN connectivity to the controller is lost, the AP transitions into Standalone mode and maintains data forwarding and local authentication for locally switched WLANs without dropping client traffic.

Adım Adım Çözüm

Analyze FlexConnect mode functionality during normal operations (Connected state).

Control traffic (CAPWAP control) is sent over the WAN to the central WLC, whereas data traffic for locally switched WLANs stays local and is switched onto the branch network.

FlexConnect implements split-MAC architecture flexible enough to separate control plane encapsulation from local data plane forwarding.

Evaluate FlexConnect mode behavior during a WAN connectivity loss (Standalone state).

The AP continues operating locally switched WLANs in Standalone mode, allowing active clients and locally authenticated clients to remain connected.

Standalone mode provides high availability at remote sites by avoiding complete wireless downtime when WLC reachability drops.

Anahtar Kavram

FlexConnect AP Mode Local Switching vs Central Switching Mechanics

Soru 1420Soru →

A network router currently receives its primary path to network 10.0.0.0/24 via RIP, which has a default administrative distance of 120. A network engineer needs to configure a static route to network 10.0.0.0/24 via the next-hop address 192.168.1.2 to act as a floating backup, activating only if the primary RIP route fails. Which command correctly configures this floating static route?

ip route 10.0.0.0 255.255.255.0 192.168.1.2 130

ip route 10.0.0.0 255.255.255.0 192.168.1.2

ip route 10.0.0.0 255.255.255.0 192.168.1.2 110

ip route 10.0.0.0 255.255.255.0 192.168.1.2 120

Cevabı ve açıklamayı göster

Cevap: ip route 10.0.0.0 255.255.255.0 192.168.1.2 130

Cevap

ip route 10.0.0.0 255.255.255.0 192.168.1.2 130

The command 'ip route 10.0.0.0 255.255.255.0 192.168.1.2 130' assigns an administrative distance of 130 to the static route. Because 130 is greater than RIP's administrative distance of 120, Cisco IOS keeps the static route out of the routing table as long as the RIP route remains active. If the RIP route fails, the floating static route is inserted into the routing table as the backup path.

Adım Adım Çözüm

Identify the primary routing protocol and its administrative distance.

The primary route is learned via RIP, which has a default administrative distance of 120.

Floating static routes rely on administrative distance values to determine route priority.

Determine the required administrative distance for a floating static route.

The administrative distance of the floating static route must be configured strictly greater than 120 (e.g., 130).

Cisco IOS prefers routes with lower administrative distances. To remain inactive in the routing table as a backup until the primary path disappears, the backup static route's administrative distance must be higher than that of the primary route.

Select the Cisco IOS command line syntax matching the required administrative distance.

The command 'ip route 10.0.0.0 255.255.255.0 192.168.1.2 130' correctly specifies a distance of 130.

Specifying 130 trailing the next-hop address correctly sets the administrative distance higher than RIP (120).

Anahtar Kavram

A floating static route requires an administrative distance configured higher than that of the active primary dynamic routing protocol.

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