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Soru 1281Soru →

A network engineer is establishing an EtherChannel bundle between two Cisco Catalyst switches using the Link Aggregation Control Protocol (LACP). Which two mode combinations across the opposing switches will result in a successfully negotiated EtherChannel? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Configuring 'channel-group 5 mode active' on the first switch and 'channel-group 5 mode passive' on the second switch; Configuring 'channel-group 5 mode active' on both switches

Cevap

The correct answers are configuring active mode on one switch and passive mode on the other switch, and configuring active mode on both switches.
LACP requires at least one switch interface to actively initiate LACP protocol negotiations. The combination of active mode on both switches and the combination of active mode on one switch with passive mode on the opposing switch both satisfy this requirement, allowing the LACP negotiation handshake to complete successfully.

Adım Adım Çözüm

1
Identify the aggregation protocol requested in the scenario.
The scenario explicitly specifies Link Aggregation Control Protocol (LACP), an IEEE 802.3ad open standard.
LACP supports only 'active' and 'passive' negotiation modes (or 'on' for unconditional bundling without LACP packets).
2
Analyze how LACP active and passive modes interact.
Active mode transmits LACP control frames proactively. Passive mode listent silently and responds only upon receiving LACP control frames.
At least one side of the connection must be set to active mode to initiate the protocol handshake.
3
Evaluate the provided configuration options against negotiation rules.
Active-to-passive and active-to-active combinations succeed. Passive-to-passive fails due to lack of initiation. Active-to-desirable fails due to mixing LACP with Cisco proprietary PAgP.
Matching compatible protocol negotiation settings is mandatory for EtherChannel establishment.

Anahtar Kavram

LACP EtherChannel Mode Negotiation Rules
Soru 1282Soru →

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

Codes: C - connected, S - static, R - RIP, D - EIGRP, O - OSPF

Gateway of last resort is not set

S 172.20.0.0/16 [1/0] via 10.0.0.1, GigabitEthernet0/0
D 172.20.100.0/24 [90/2578560] via 10.0.0.2, GigabitEthernet0/1
O 172.20.100.32/27 [110/20] via 10.0.0.3, GigabitEthernet0/2
S 172.20.100.40/30 [1/0] via 10.0.0.4, GigabitEthernet0/3

Which next-hop IP address and exit interface will the router select to forward an ingress IPv4 packet destined for 172.20.100.45?

Cevabı ve açıklamayı göster

Cevap: 10.0.0.3 via GigabitEthernet0/2 because 172.20.100.32/27 is the longest matching prefix for the destination address.

Cevap

The router forwards the packet to next-hop 10.0.0.3 out interface GigabitEthernet0/2 because 172.20.100.32/27 is the longest matching prefix that encompasses destination 172.20.100.45.
When a router receives a packet, it compares the destination IPv4 address against all routes in the Routing Information Base (RIB). Destination 172.20.100.45 matches three routes: 172.20.0.0/16, 172.20.100.0/24, and 172.20.100.32/27. The longest matching prefix is 172.20.100.32/27 because 27 bits is the most specific mask matching the target IP. Therefore, the router forwards the packet to next-hop 10.0.0.3 out interface GigabitEthernet0/2.

Adım Adım Çözüm

1
Determine which routing table prefixes encompass the destination IP address 172.20.100.45.
The prefixes 172.20.0.0/16, 172.20.100.0/24, and 172.20.100.32/27 match destination 172.20.100.45. The prefix 172.20.100.40/30 covers range .40 to .43 and does NOT match .45.
Routing lookup requires identifying all routes whose network mask bits match the destination address.
2
Compare the prefix lengths of all valid candidate routes.
The prefix length /27 is more specific (longer) than /24 and /16.
The router forwarding decision engine strictly follows the Longest Prefix Match (LPM) logic before considering Administrative Distance or Metric.
3
Identify the exit interface and next-hop IP associated with the longest prefix match.
The route entry 172.20.100.32/27 points to next-hop 10.0.0.3 via interface GigabitEthernet0/2.
The candidate route with the longest matching prefix determines the forwarding path.

Anahtar Kavram

Router Forwarding Decision Logic and Longest Prefix Match (LPM)
Soru 1283Soru →

A network administrator is configuring a floating static route on router R1 to reach the destination prefix 2001:db8:acad:10::/642001:\text{db8}:\text{acad}:10::/64. The primary path to this network is currently learned via OSPFv3 with an Administrative Distance of 110. The administrator wants to configure the backup static route using the next-hop neighbor's link-local IPv6 address fe80::2fe80::2 across R1's local interface GigabitEthernet0/1. Which command must be entered on R1 to correctly configure this floating static route?

Cevabı ve açıklamayı göster

Cevap: ipv6 route 2001:db8:acad:10::/64 GigabitEthernet0/1 fe80::2 120

Cevap

The command 'ipv6 route 2001:db8:acad:10::/64 GigabitEthernet0/1 fe80::2 120' is the correct configuration.
The option specifying 'ipv6 route 2001:db8:acad:10::/64 GigabitEthernet0/1 fe80::2 120' uses the valid Cisco IOS syntax for a fully specified static route using a link-local next hop. The local exit interface GigabitEthernet0/1 resolves link-local address ambiguity, and an Administrative Distance of 120 ensures the route functions correctly as a floating static backup to the active OSPFv3 route (AD 110).

Adım Adım Çözüm

1
Identify the mandatory components of an IPv6 static route using a link-local address.
Because IPv6 link-local addresses (fe80::/10) are non-routable outside their local link, Cisco IOS requires both the local exit interface and the link-local next-hop address (fully specified static route).
Without specifying the exit interface, the router cannot determine which local segment contains the target fe80::2 address.
2
Determine the required Administrative Distance for a floating static route.
The primary route is OSPFv3 with AD = 110. The floating static route AD must be greater than 110 (e.g., 120).
Setting an AD higher than the primary routing protocol ensures the static route remains inactive in the routing table until the primary OSPFv3 route fails.
3
Verify Cisco IOS syntax order.
The syntax structure is 'ipv6 route <prefix/length> <exit-interface> <link-local-address> [administrative-distance]'.
The correct command syntax specifies interface GigabitEthernet0/1 followed by next-hop fe80::2 and AD 120.

Anahtar Kavram

Fully Specified IPv6 Static Route and Floating Static Route AD Configuration
Soru 1284Soru →

A network technician is configuring an IPv6 static route on a router to reach network 2001:DB8:5000:10::/642001:\text{DB8}:\text{5000}:10::/64. The technician intends to use the neighbor's link-local address FE80::2\text{FE80}::2 as the next hop. Which Cisco IOS command correctly configures this route using local interface GigabitEthernet0/1?

Cevabı ve açıklamayı göster

Cevap: ipv6 route 2001:DB8:5000:10::/64 GigabitEthernet0/1 FE80::2

Cevap

The command 'ipv6 route 2001:DB8:5000:10::/64 GigabitEthernet0/1 FE80::2' correctly configures the static route.
In Cisco IOS, a fully specified static route using a link-local next-hop address MUST explicitly specify the local exit interface (e.g., GigabitEthernet0/1) prior to the link-local address. This resolves ambiguity because link-local addresses exist on every IPv6-enabled interface.

Adım Adım Çözüm

1
Identify the proper command syntax for IPv6 static routing
Begin with 'ipv6 route' followed by the target destination prefix and length.
Cisco IOS requires 'ipv6 route' for configuring static IPv6 prefixes.
2
Determine interface and next-hop parameter rules for link-local addresses
Include the local exit interface GigabitEthernet0/1 before the next-hop link-local address FE80::2\text{FE80}::2.
Because link-local addresses belong to the FE80::/10\text{FE80}::/10 block and are non-routable outside their local segment, the router must know which exit interface to use to reach the next hop.

Anahtar Kavram

IPv6 Static Route Link-Local Next-Hop Syntax
Soru 1285Soru →

An engineer is configuring a static route on a Cisco router to reach the destination subnet 2001:db8:a100:12::/642001:\text{db8}:\text{a100}:12::/64 using the neighbor link-local address fe80::fe22:1\text{fe80}::\text{fe22}:1 via local interface GigabitEthernet0/1\text{GigabitEthernet0/1}. Complete the Cisco IOS configuration command by filling in the missing parameters in order.

Aşağıdaki boşlukları doldurun

ipv6 route 2001:db8:a100:12::/64
Cevabı ve açıklamayı göster

Cevap

The complete command is: ipv6 route 2001:db8:a100:12::/64 GigabitEthernet0/1 fe80::fe22:1
In Cisco IOS IPv6 static routing, when a link-local address is designated as the next hop, the command must explicitly include the local exit interface preceding the link-local address. Therefore, the first parameter must specify the interface (GigabitEthernet0/1) and the second parameter must specify the link-local address (fe80::fe22:1).

Adım Adım Çözüm

1
Identify the standard Cisco IOS IPv6 static route command structure for link-local next hops.
The command syntax is: ipv6 route <destination-prefix/prefix-length> <exit-interface> <link-local-next-hop>.
Cisco IOS requires specifying the local exit interface when using an IPv6 link-local address as a next hop because link-local addresses are unique only within the scope of a single link.
2
Fill in the required exit interface parameter for the first blank.
blank_1 is GigabitEthernet0/1 (or acceptable interface abbreviation such as gi0/1 or g0/1).
The exit interface specifies which local link to use to resolve the link-local address.
3
Fill in the next-hop IPv6 link-local address for the second blank.
blank_2 is fe80::fe22:1.
The next-hop link-local address follows the exit interface parameter in a fully specified IPv6 static route.

Anahtar Kavram

IPv6 Fully Specified Static Route
Tahmini Süre:1m 15s
Soru 1286Soru →

An engineer is troubleshooting IPv4 packet forwarding on a Cisco IOS-XE router. The router receives a packet with a destination IP address of 172.16.100.70. Refer to the routing table output below:

text
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

Gateway of last resort is 10.0.0.1 to network 0.0.0.0

S* 0.0.0.0/0 [1/0] via 10.0.0.1
S 172.16.100.0/24 [1/0] via 10.1.1.1
O 172.16.100.64/27 [110/50] via 10.2.2.2
D 172.16.100.64/28 [90/2170112] via 10.3.3.3
C 172.16.100.64/30 is directly connected, GigabitEthernet0/0/0

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

Cevabı ve açıklamayı göster

Cevap: 10.3.3.3

Cevap

The router will forward the packet to next-hop IP address 10.3.3.3.
The router follows the Longest Prefix Match (LPM) algorithm for packet forwarding. For destination 172.16.100.70, the matching routes in the table are 0.0.0.0/0, 172.16.100.0/24, 172.16.100.64/27 (range 172.16.100.64–172.16.100.95), and 172.16.100.64/28 (range 172.16.100.64–172.16.100.79). Among these valid matches, /28 is the most specific mask (longest prefix length). Administrative Distance and metric are only compared when two routes have the exact same prefix length. Therefore, the router chooses the /28 route with next-hop 10.3.3.3.

Adım Adım Çözüm

1
Evaluate all candidate routes in the routing table that encompass destination IP address 172.16.100.70.
The candidate matching routes are 0.0.0.0/0, 172.16.100.0/24, 172.16.100.64/27 (range .64-.95), and 172.16.100.64/28 (range .64-.79). The directly connected 172.16.100.64/30 route covers .64-.67, so it does not match.
Before comparing administrative distance or metric, a router must identify all valid matching prefixes.
2
Apply the Longest Prefix Match (LPM) rule to select the best matching route.
Comparing the prefix lengths of matching routes: /0 < /24 < /27 < /28. The route 172.16.100.64/28 is the longest matching prefix (28 bits).
Cisco routers always prefer the most specific matching prefix (/28 over /27, /24, or /0), regardless of Administrative Distance or routing protocol metric.
3
Identify the next-hop address associated with the winning prefix 172.16.100.64/28.
The route entry for 172.16.100.64/28 specifies 'via 10.3.3.3'.
Packet forwarding uses the next-hop specified by the specific prefix selected by the LPM decision process.

Anahtar Kavram

Longest Prefix Match (LPM) Rule in Cisco IPv4 Forwarding Logic
Soru 1287Soru →

A network administrator is tasked with configuring a new WPA2-Personal (PSK) wireless network for client connectivity using the Cisco Wireless LAN Controller (WLC) web GUI. Place the steps in the correct order to complete the WLAN deployment from initial creation to saving the final configuration.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct procedural order is: 1) Navigate to WLANs and select Create New, 2) Define Profile Name, SSID, and WLAN ID, 3) Select the Interface/Interface Group and enable Status on the General tab, 4) Configure WPA2-PSK parameters under Security > Layer 2, 5) Enter the PSK passphrase, click Apply, and click Save Configuration.
Configuring a client-facing WLAN on a Cisco AireOS WLC follows a strict sequential process: First, initiate creation under the WLANs menu using Create New. Second, define basic network parameters (Profile Name, SSID, ID) and click Apply to launch the edit view. Third, select the client traffic Interface and check Enabled on the General tab. Fourth, navigate to Security > Layer 2 to specify WPA2 Policy and PSK authentication. Finally, enter the pre-shared key passphrase, click Apply to update running memory, and save the WLC configuration.

Adım Adım Çözüm

1
Initiate WLAN creation
Accesses the preliminary WLAN creation setup window.
You must navigate to WLANs > Create New to start defining a new wireless network.
2
Set WLAN identifiers
Generates the new WLAN instance and opens the full configuration tabs.
The WLC requires a Profile Name, broadcast SSID, and numerical ID before generating the specific WLAN configuration page.
3
Map network interface and enable WLAN
Binds client traffic to the appropriate VLAN interface and sets the administrative state.
Under the General tab, mapping the interface connects clients to the intended subnet, and checking Enabled activates the SSID.
4
Configure Layer 2 WPA2-PSK security parameters
Sets the authentication method to pre-shared key under Layer 2 settings.
WPA2-Personal settings are located specifically under Security > Layer 2 tab > WPA+WPA2 > Auth Key Management > PSK.
5
Enter passphrase, apply configuration, and save state
Commits changes to active memory and saves NVRAM configuration.
Entering the PSK passphrase completes security settings; clicking Apply commits settings to the running configuration, and Save Configuration persists it across reboots.

Anahtar Kavram

WLC GUI WLAN Creation and Client Connectivity Workflow
Tahmini Süre:1m 30s
Soru 1288Soru →

An engineer is troubleshooting IPv4 packet forwarding on a Cisco router. The router receives a packet with a destination IP address of 172.28.64.99172.28.64.99. The active routing table contains the following entries:

text
S 172.28.0.0/16 [1/0] via 10.1.1.1
O 172.28.64.0/20 [110/20] via 10.2.2.2
D 172.28.64.64/26 [90/307200] via 10.3.3.3
B 172.28.64.96/28 [20/0] via 10.4.4.4

Which next-hop IP address will the router use to forward the packet, and what is the primary routing logic behind this decision?

Cevabı ve açıklamayı göster

Cevap: Next-hop 10.4.4.4, because 172.28.64.96/28 provides the longest prefix match for destination 172.28.64.99.

Cevap

The router forwards the packet to next-hop 10.4.4.4 because 172.28.64.96/28 provides the longest prefix match for the destination address 172.28.64.99.
When a router makes a packet forwarding decision, it compares the destination IP address against all routes in the routing table and selects the route with the most specific match (the longest subnet mask length / prefix length). Destination 172.28.64.99 falls into 172.28.64.96/28 (range 172.28.64.96 - 172.28.64.111). Because /28 is the longest matching mask (28 bits), it takes absolute priority over the /26, /20, and /16 matches, directing traffic to next-hop 10.4.4.4.

Adım Adım Çözüm

1
Determine which subnets match the destination IP address 172.28.64.99.
All four routes cover the destination address: 172.28.0.0/16 (172.28.0.0-172.28.255.255), 172.28.64.0/20 (172.28.64.0-172.28.79.255), 172.28.64.64/26 (172.28.64.64-172.28.64.127), and 172.28.64.96/28 (172.28.64.96-172.28.64.111).
Before comparing routing attributes, the router identifies candidate routes whose subnet ranges contain the target IP.
2
Apply the Longest Prefix Match (LPM) rule.
The prefix 172.28.64.96/28 has a mask length of 28 bits, which is greater than /26, /20, or /16.
Routers always prefer the most specific route (longest subnet mask / longest matching prefix) regardless of administrative distance or metric.
3
Identify the next-hop IP associated with the winning route.
The route 172.28.64.96/28 specifies next-hop 10.4.4.4.
The packet is forwarded to the next-hop IP corresponding to the most specific matching prefix entry.

Anahtar Kavram

Longest Prefix Match (LPM) in IP Routing Forwarding Decisions
Soru 1289Soru →

An enterprise network administrator is resolving network initialization delays for workstations connected to access ports on a Cisco Catalyst switch. The administrator decides to configure Cisco PortFast on these access interfaces. How does enabling PortFast alter the IEEE 802.1D Spanning Tree Protocol (STP) port state transition behavior upon link up?

Cevabı ve açıklamayı göster

Cevap: The interface bypasses the Listening and Learning states, transitioning immediately into the Forwarding state.

Cevap

Enabling PortFast on an access interface causes it to bypass the standard 802.1D Listening and Learning states, transitioning immediately into the Forwarding state upon link activation.
Enabling PortFast on a Cisco switch access port allows the interface connected to an end device to bypass the 802.1D Listening (15s) and Learning (15s) states, transitioning immediately to the Forwarding state upon link activation. This eliminates initialization delays that cause host DHCP request timeouts.

Adım Adım Çözüm

1
Analyze standard IEEE 802.1D Spanning Tree Protocol port convergence timers.
Standard 802.1D requires an access port to spend 15 seconds in the Listening state and 15 seconds in the Learning state (totaling 30 seconds) before reaching Forwarding.
These delays prevent transient bridging loops while the switch learns MAC addresses and listens for BPDUs.
2
Determine the impact of Cisco PortFast when configured on edge access ports connected to single end-user hosts.
The port skips Listening and Learning, moving directly to Forwarding upon link up.
Since end-user workstations do not initiate bridging loops, skipping intermediate timers prevents DHCP timeouts and initialization delays.

Anahtar Kavram

STP Port States and PortFast Benefits
Soru 1290Soru →

A Cisco switch receives an Ethernet frame on interface GigabitEthernet0/1 assigned to VLAN 10. The frame features a source MAC address of 0050.56a1.1111 and a destination MAC address of 0050.56b2.2222. The switch MAC address table currently contains an entry for 0050.56b2.2222 associated with interface GigabitEthernet0/3 on VLAN 10, but has no existing entry for 0050.56a1.1111. Which two actions does the switch take upon processing this ingress frame? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: It records an entry in the MAC address table mapping source MAC address 0050.56a1.1111 to interface GigabitEthernet0/1 on VLAN 10.; It forwards the frame directly out interface GigabitEthernet0/3 without transmitting it on any other port.

Cevap

The switch learns the source MAC address by associating 0050.56a1.1111 with ingress port GigabitEthernet0/1 in VLAN 10, and forwards the frame directly out egress port GigabitEthernet0/3 based on the known destination MAC table entry.
Layer 2 switches process Ethernet frames in two distinct phases. First, the switch reads the frame's source MAC address (0050.56a1.1111) and updates its MAC address table by binding that address to ingress port GigabitEthernet0/1 under VLAN 10. Second, the switch checks its MAC table for the destination MAC address (0050.56b2.2222). Since an entry already exists pointing to GigabitEthernet0/3 in VLAN 10, the switch forwards the frame directly out interface GigabitEthernet0/3.

Adım Adım Çözüm

1
Examine incoming frame headers for source MAC address processing.
The switch reads source MAC 0050.56a1.1111 on ingress interface GigabitEthernet0/1 (VLAN 10).
Layer 2 switches inspect the source MAC address of every ingress frame to dynamically build and maintain the MAC address table.
2
Update the MAC address table.
A new dynamic MAC address table entry is created: MAC 0050.56a1.1111 → GigabitEthernet0/1 (VLAN 10).
The source MAC was not previously in the table, so a new mapping is recorded to enable future return traffic forwarding.
3
Examine incoming frame headers for destination MAC lookup.
The switch searches the MAC address table for destination MAC 0050.56b2.2222 in VLAN 10.
Destination lookup determines whether the frame requires point-to-point forwarding or unknown unicast flooding.
4
Forward the frame to the destination interface.
The frame is forwarded directly out GigabitEthernet0/3.
Because destination MAC 0050.56b2.2222 is known in the MAC table on port GigabitEthernet0/3, unicast forwarding is performed without flooding.

Anahtar Kavram

Layer 2 Ethernet switching operates on a two-step process per frame: (1) Learn source MAC address to ingress port mapping, and (2) Forward based on destination MAC address lookup (known unicast forwarding vs. unknown unicast flooding).
Soru 1291Soru →

An engineer is configuring a secondary backup route on core router R1 to reach remote subnet 2001:db8:89ab:2000::/562001:\text{db8}:89\text{ab}:2000::/56 through neighboring router R2. The primary route is learned dynamically via OSPFv3 with an Administrative Distance of 110110. The interconnecting segment between R1 and R2 uses GigabitEthernet0/0/1. R2's interface on this link uses the link-local address fe80::211:22ff:fe33:4455\text{fe80}::211:22\text{ff}:\text{fe33}:4455. Which Cisco IOS command must be configured on R1 to create a valid floating static route with an Administrative Distance of 130130 using R2's link-local address?

Cevabı ve açıklamayı göster

Cevap: ipv6 route 2001:db8:89ab:2000::/56 GigabitEthernet0/0/1 fe80::211:22ff:fe33:4455 130

Cevap

The command 'ipv6 route 2001:db8:89ab:2000::/56 GigabitEthernet0/0/1 fe80::211:22ff:fe33:4455 130' correctly specifies both the exit interface and link-local next-hop address with an Administrative Distance of 130.
When configuring an IPv6 static route using a link-local next-hop address (fe80::/10\text{fe80}::/10), Cisco IOS strictly mandates a fully specified route. This format includes the local exit interface followed by the link-local address of the adjacent router. Appending the value 130 at the end of the syntax correctly sets the Administrative Distance higher than OSPFv3 (110), successfully forming a floating static route.

Adım Adım Çözüm

1
Identify the mandatory components of an IPv6 static route using a link-local address as the next hop.
Because link-local addresses (fe80::/10\text{fe80}::/10) are shared across multiple local links, Cisco IOS requires a fully specified route syntax: 'ipv6 route <prefix/mask> <exit-interface> <link-local-next-hop> [AD]'.
Without the local exit interface, the router cannot determine which physical or logical link to use to reach the target link-local address.
2
Verify Administrative Distance manipulation for floating static route capability.
The primary path is learned via OSPFv3 with AD = 110110. Setting the static route AD to 130130 ensures it remains inactive in the IPv6 routing table until the primary OSPFv3 route disappears.
Floating static routes require an Administrative Distance higher than the active primary routing protocol.
3
Validate the exact command string structure.
The target prefix is 2001:db8:89ab:2000::/562001:\text{db8}:89\text{ab}:2000::/56, the local exit interface is GigabitEthernet0/0/1, the next-hop link-local address is fe80::211:22ff:fe33:4455\text{fe80}::211:22\text{ff}:\text{fe33}:4455, and the metric parameter is 130.
This matches the exact fully specified static route configuration requirements in Cisco IOS.

Anahtar Kavram

Fully Specified IPv6 Static Routes and Link-Local Next-Hop Requirements
Soru 1292Soru →

An enterprise is deploying a Collapsed Core network topology for a newly acquired medium-sized facility. Which two architectural traits or design implications characterize a Collapsed Core topology when compared to a traditional three-tier campus design? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The functional responsibilities of high-speed backbone routing and distribution-layer security/policy enforcement are consolidated into a single physical switch tier.; Capital outlay and operational complexity are minimized by reducing the total required physical switch count and inter-tier cabling.

Cevap

A Collapsed Core topology combines the core and distribution layer functions into a single pair of switches, reducing hardware expenditure and operational complexity while combining routing boundaries and policy enforcement.
A Collapsed Core design combines core-layer transport and distribution-layer routing and security policy controls into the same physical switches. This architectural reduction significantly lowers hardware costs, rack space, power requirements, and management overhead for environments that do not require a separate dedicated core tier.

Adım Adım Çözüm

1
Analyze the structural difference between Three-Tier and Collapsed Core architectures.
A traditional three-tier network contains distinct Core, Distribution, and Access layers. Collapsed Core merges Core and Distribution functions into one tier.
Understanding tier consolidation clarifies which functional boundaries overlap.
2
Evaluate the operational benefits of tier consolidation.
Eliminating a dedicated core hardware tier saves capital costs and lowers switch count and cabling complexity.
This identifies cost and deployment advantages characteristic of smaller or medium enterprise sites.
3
Evaluate Layer 2 loop considerations in redundant topologies.
Dual-homed uplinks from access switches to two collapsed core switches still form Layer 2 physical loops, requiring STP.
Consolidating tiers does not eliminate broadcast loops on redundant Layer 2 trunks.

Anahtar Kavram

Collapsed Core Architecture Traits and Considerations
Tahmini Süre:1m 15s
Soru 1293Soru →

A network engineer is configuring static routes on a Cisco IOS router to establish connectivity across an enterprise IPv6 infrastructure. Which two statements correctly describe valid IPv6 static route configuration syntax and operational requirements on Cisco IOS?

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: When specifying a link-local IPv6 address as the next-hop, the local exit interface must also be explicitly specified in the static route command.; A floating static IPv6 route is configured by manually assigning an administrative distance that is higher than the administrative distance of the primary route.

Cevap

The two correct statements are: specifying a link-local next-hop address requires defining the local exit interface in the command, and configuring a floating static IPv6 route requires setting an administrative distance higher than that of the primary route.
The statement specifying that a link-local next-hop requires the local exit interface is correct because link-local addresses are non-unique across different interface links. The statement describing floating static routes is correct because setting an administrative distance higher than the active dynamic protocol or primary static route keeps the backup route inactive until the primary route fails.

Adım Adım Çözüm

1
Analyze link-local address scoping rules in Cisco IOS static routing.
Link-local addresses (FE80::/10) are link-dependent and non-routable beyond their local segment. Consequently, Cisco IOS requires specifying the egress interface when using a link-local next-hop address.
Without specifying the egress interface, the router cannot determine which local link segment to transmit packets to reach the FE80:: next-hop.
2
Evaluate the administrative distance mechanism for floating static routes.
A floating static route uses a artificially high administrative distance (e.g., AD of 130 backing up OSPF with AD of 110).
The router installs the route into the IPv6 RIB only if lower AD routes for the destination prefix become unavailable.
3
Verify EUI-64 generation rules and global unicast next-hop syntax options.
EUI-64 requires both FFFE insertion and flipping the 7th bit. Global unicast next-hop static routes can be configured recursively without defining an egress interface.
Global unicast addresses are globally unique and can be resolved recursively via the routing table.

Anahtar Kavram

IPv6 Static Routing Syntax and Next-Hop Resolution
Soru 1294Soru →

A Cisco router interface GigabitEthernet0/0/0 has the burned-in MAC address 1866.da34.5678. The interface is configured with the command `ipv6 enable` to automatically derive its IPv6 link-local address using stateless address autoconfiguration (SLAAC) and the IEEE EUI-64 process. Which IPv6 address will be assigned to the interface?

Cevabı ve açıklamayı göster

Cevap: fe80::1a66:daff:fe34:5678

Cevap

fe80::1a66:daff:fe34:5678
The address fe80::1a66:daff:fe34:5678 correctly follows the IEEE EUI-64 interface identifier derivation by inserting FFFE into the middle of MAC address 1866.da34.5678, inverting the 7th bit of the first byte (changing 18 to 1A in hexadecimal), and prefixing it with the link-local scope fe80::.

Adım Adım Çözüm

1
Split the 48-bit MAC address into two 24-bit halves and insert FFFE in the middle.
The MAC address 1866.da34.5678 (18:66:DA:34:56:78) becomes 1866:DAFF:FE34:5678.
EUI-64 standard requires expanding a 48-bit MAC address into a 64-bit interface identifier by placing FFFE between the Organizationally Unique Identifier (OUI) and the NIC-assigned extension.
2
Invert the 7th bit (Universal/Local bit) of the first byte.
The first byte 0x18 (binary 00010000) becomes 0x1A (binary 00011010). The expanded interface identifier becomes 1A66:DAFF:FE34:5678.
IEEE EUI-64 rules dictate that the 7th bit of the interface identifier must be inverted (0 indicates local scope, 1 indicates globally unique/universal).
3
Combine the IPv6 link-local prefix with the calculated 64-bit interface identifier.
Prefix fe80:: + 1a66:daff:fe34:5678 = fe80::1a66:daff:fe34:5678.
The `ipv6 enable` command dynamically creates a link-local address starting with the fe80::/10 prefix.

Anahtar Kavram

IPv6 EUI-64 Interface Identifier Derivation
Soru 1295Soru →

A network engineer is implementing Link Aggregation (LAG) using IEEE 802.3ad LACP between a Cisco Catalyst 9800 Series Wireless Controller and an upstream Cisco Catalyst 9300 switch stack. Place the following implementation and verification steps in the correct chronological order required to establish the infrastructure link.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct implementation sequence begins with configuring the physical switch interfaces with LACP mode active, configuring trunking parameters on the resulting switch Port-channel interface, configuring the WLC uplink EtherChannel bundle, verifying Layer 2 bundle operation with 'show etherchannel summary', and finally validating WLC management reachability and CAPWAP tunnel stability.
Establishing a Link Aggregation connection between a Cisco Catalyst 9800 WLC and an upstream switch requires a structured bottom-up approach. First, physical switch ports must be assigned to the LACP channel group ('channel-group 10 mode active'). Second, the resulting logical Port-channel interface must be configured with 802.1Q trunking and VLAN parameters. Third, the controller-side interfaces must be bundled into the corresponding uplink EtherChannel. Fourth, the engineer must verify Layer 2 LACP negotiation using 'show etherchannel summary' to ensure the channel state is 'SU' and member interfaces display 'P'. Finally, end-to-end control plane operation is verified by testing WLC management reachability and AP CAPWAP tunnel stability.

Adım Adım Çözüm

1
Define switch member ports
Physical switch ports are associated into channel-group 10 using active LACP negotiation.
Assigning physical member ports creates the logical Port-channel interface on the switch.
2
Configure switch Port-channel interface
The Port-channel interface is set to switchport mode trunk with designated native and allowed VLANs.
Applying trunk configuration to the logical Port-channel ensures consistent trunking behavior across all bundled physical member links.
3
Configure WLC uplink LAG bundle
Controller physical ports are grouped into an uplink EtherChannel bundle.
With the switch ready to negotiate, the controller side is enabled for link aggregation.
4
Verify EtherChannel protocol status
Switch CLI displays 'SU' (Layer 2, In-use) for Port-channel 10 and 'P' (Bundled) for all member ports.
Verifying LACP status ensures physical links negotiated properly without misconfigurations such as mode mismatches or suspended ports.
5
Verify network access and CAPWAP operation
Management traffic reaches the WLC IP and AP CAPWAP tunnels operate successfully over the aggregated link.
End-to-end verification validates overall infrastructure connectivity and wireless control plane operation.

Anahtar Kavram

WLAN Infrastructure LAG and Switch EtherChannel Implementation Sequence
Tahmini Süre:2m 0s
Soru 1296Soru →

An network engineer is analyzing various IPv4 routing table entries on a Cisco IOS-XE router. Match each routing table code or bracketed component on the left with its correct operational description on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

Bracketed notation [120/4] in an entry starting with 'R'
Bracketed notation [170/2578560] in an entry starting with 'D EX'
Prefix source code and symbol 'S*'
Prefix source code 'C'

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Bracketed notation [120/4] matches the RIP route description with AD 120 and metric 4. Bracketed notation [170/2578560] matches the External EIGRP route with AD 170 and composite metric. Code 'S*' matches the static candidate default route. Code 'C' matches the directly connected network with AD 0.
Each matching pair correctly identifies the Cisco IOS routing table syntax: bracketed notation [AD/Metric], protocol codes ('C' for connected, 'S' for static, 'D EX' for external EIGRP, 'R' for RIP), and special flags such as '*' for candidate default routes.

Adım Adım Çözüm

1
Analyze bracketed notation format [AD/Metric]
Identify that the first integer inside brackets is Administrative Distance (trustworthiness) and the second integer is the routing protocol metric (cost).
Cisco IOS routing tables consistently structure route preference metrics as [Administrative Distance / Metric].
2
Evaluate protocol code 'R' and bracket [120/4]
Match with RIP protocol attributes (AD 120, hop count metric 4).
RIP routes use AD 120 and measure metric in hop counts.
3
Evaluate protocol code 'D EX' and bracket [170/2578560]
Match with External EIGRP route attributes.
Internal EIGRP uses AD 90, but external redistributed EIGRP routes ('D EX') use AD 170 and 32-bit composite metric values.
4
Evaluate static default indicator 'S*'
Match with static candidate default route.
'S' stands for static and '*' designates candidate default.
5
Evaluate connected code 'C'
Match with directly connected interface route (AD 0).
'C' represents connected routes directly assigned to router interfaces.

Anahtar Kavram

Routing Table Components and Administrative Distance
Tahmini Süre:2m 0s
Soru 1297Soru →

An administrator is configuring a wireless network using the Cisco Wireless LAN Controller (WLC) web interface. The WLAN profile has been created and mapped to the proper client interface, but wireless clients are unable to automatically detect the network name during passive scanning. However, clients can connect successfully when the network name is entered manually. Which configuration setting under the WLANs > Edit 'General' tab must be selected to resolve this issue?

Cevabı ve açıklamayı göster

Cevap: Broadcast SSID

Cevap

Broadcast SSID
Enabling the Broadcast SSID check box under the WLAN General tab causes the WLC to instruct APs to include the network name (SSID) in 802.11 beacon management frames. This allows client devices performing passive scans to discover and display the wireless network in their list of available networks.

Adım Adım Çözüm

1
Identify the symptom described in the scenario.
Clients cannot detect the wireless network via passive scanning, but can connect if the SSID is configured manually.
This indicates that beacon frames sent by the Access Point are hiding the SSID parameter.
2
Locate the appropriate setting in the WLC GUI.
Navigate to WLANs > Edit for the specified WLAN profile, under the General tab.
Basic WLAN parameters like SSID name, profile name, global status, and broadcast settings are located on the General tab.
3
Select the setting that enables SSID advertisement in beacon frames.
Check the Broadcast SSID check box.
Enabling Broadcast SSID ensures the network name is transmitted in beacon frames for client discovery.

Anahtar Kavram

WLC GUI WLAN General Tab Configuration
Soru 1298Soru →

A Cisco router receives an IPv4 packet destined for a remote host. Place the sequential steps of the router's forwarding decision logic in the correct order from first to last.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence begins with extracting the packet's destination IP address, applying Longest Prefix Match to identify candidate routes, comparing Administrative Distance for equal-length prefix ties, comparing metric/cost for intra-protocol ties, and completing Layer 2 encapsulation for egress transmission.
When forwarding an IP packet, a Cisco router follows a precise hierarchy: it extracts the destination address, evaluates all matching routing table entries to find the Longest Prefix Match (most specific subnet mask), breaks ties between different routing protocols using Administrative Distance (lowest wins), breaks ties within the same protocol using Metric/Cost (lowest wins), and finally resolves the Layer 2 next-hop rewrite for frame transmission.

Adım Adım Çözüm

1
Extract Destination IPv4 Address
The destination IP address is identified from the incoming IPv4 packet header.
The destination address is required to query the routing table.
2
Apply Longest Prefix Match (LPM)
Routes with the longest/most specific matching prefix length (subnet mask) are isolated.
LPM is the primary rule of IP routing decision logic and overrides Administrative Distance and Metric.
3
Evaluate Administrative Distance (AD)
If candidate routes have identical prefix lengths, the route with the lowest AD is selected.
AD determines the believability of different routing sources.
4
Evaluate Protocol Metric / Cost
If candidate routes are from the same routing protocol and share equal prefix lengths, the path with the lowest metric is chosen.
Metric measures path efficiency within a single routing protocol.
5
Encapsulate and Forward Frame
The router looks up the next-hop IP in the ARP table, constructs a new Layer 2 header, and sends the frame out the exit interface.
Layer 2 rewrite completes the packet forwarding action at the data plane.

Anahtar Kavram

Router Forwarding Decision Logic Sequence
Soru 1299Soru →

A network administrator is configuring access interfaces on a Cisco Catalyst switch connected directly to workstations. To prevent DHCP address negotiation timeouts caused by Spanning Tree Protocol (STP) initialization delays, the administrator applies the `spanning-tree portfast` command. Which two operational traits accurately describe the behavior of an interface configured with PortFast? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The interface bypasses the Listening and Learning states, transitioning immediately to the Forwarding state upon link activation.; The switch suppresses Topology Change Notifications (TCNs) for the interface when its link state toggles.

Cevap

Enabling PortFast on an access interface causes it to immediately transition to the STP Forwarding state (bypassing Listening and Learning states) and suppresses Topology Change Notifications (TCNs) when the link status changes.
PortFast provides two primary operational advantages on edge interfaces: it skips the 802.1D Listening and Learning states to enter Forwarding instantly upon link activation, and it suppresses Topology Change Notifications (TCNs) when host connectivity toggles.

Adım Adım Çözüm

1
Analyze standard 802.1D STP convergence delays.
Standard 802.1D transitions through Blocking -> Listening (15s) -> Learning (15s) -> Forwarding, taking 30 seconds total before data forwarding begins.
This delay causes end-user devices (like workstations seeking DHCP leases) to experience timeouts before the port reaches Forwarding state.
2
Identify the state transition behavior of PortFast.
PortFast places the access interface immediately into the Forwarding state upon link up, bypassing Listening and Learning.
Edge ports connected to single host devices cannot create Layer 2 loops upon initialization.
3
Identify the topology notification impact of PortFast.
Link state changes on PortFast ports do not trigger Topology Change Notifications (TCNs).
Edge end-user devices turning on or off do not change the core Layer 2 forwarding topology, avoiding unnecessary clearing of switch MAC address tables.

Anahtar Kavram

STP PortFast operational behavior and TCN suppression on access ports
Soru 1300Soru →

A Cisco Catalyst switch receives an Ethernet frame on interface FastEthernet0/10. The frame has a source MAC address of 0011.2233.4455 and a destination MAC address of 00aa.bbcc.dd88. The switch MAC address table already contains an active dynamic entry for 0011.2233.4455 mapped to interface FastEthernet0/10, but contains no entry for 00aa.bbcc.dd88. Interfaces FastEthernet0/10 through FastEthernet0/15 are active access ports assigned to VLAN 10, while interface FastEthernet0/16 is an access port assigned to VLAN 20. Which action does the switch perform upon receiving this frame?

Cevabı ve açıklamayı göster

Cevap: Refreshes the aging timer for MAC 0011.2233.4455 on FastEthernet0/10 and floods the frame out interfaces FastEthernet0/11 through FastEthernet0/15.

Cevap

The switch refreshes the aging timer for the existing source MAC entry on interface FastEthernet0/10 and floods the frame out all other active interfaces in VLAN 10 (FastEthernet0/11 through FastEthernet0/15).
When a switch receives a frame, it inspects the source MAC address to update or refresh its MAC address table entry. Next, it looks up the destination MAC address. Because the destination MAC is not in the table, the switch treats the frame as an unknown unicast frame and floods it out all operational interfaces in the same VLAN (VLAN 10), except for the receiving interface (FastEthernet0/10).

Adım Adım Çözüm

1
Examine the source MAC address and update the MAC address table.
The source MAC address 0011.2233.4455 is already mapped to interface FastEthernet0/10. The switch resets/refreshes the aging timer for this entry.
MAC learning occurs on every incoming frame. If the entry exists on the correct port, its aging timer is reset.
2
Examine the destination MAC address to determine the forwarding decision.
The destination MAC address 00aa.bbcc.dd88 is not present in the MAC address table (unknown unicast).
Switches use MAC table lookup for unicast forwarding. Absence of an entry triggers unknown unicast flooding.
3
Identify the target egress interfaces for flooding.
The frame is flooded out FastEthernet0/11 through FastEthernet0/15. It is excluded from FastEthernet0/10 (ingress port) and FastEthernet0/16 (different VLAN).
Flooding is constrained within the ingress VLAN boundary and strictly avoids reflecting traffic back out the receiving interface.

Anahtar Kavram

Layer 2 Unknown Unicast Flooding and MAC Table Aging
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