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Tüm alıştırma soruları

1987 soru

Tüm türler1,987Çoktan seçmeli1,020Çoklu seçim452Sayısal18Eşleştirme229Sıralama203Boşluk doldurma22Kısa cevap43
Soru 1201Soru →

A network engineer is analyzing the forwarding behavior of router R1 for traffic destined to IP address 172.20.16.45172.20.16.45. The router currently has an active OSPFv2 process that learns prefix 172.20.16.0/20172.20.16.0/20 (Administrative Distance 110). Additionally, the administrator configures three IPv4 static routes on R1:

- Command 1: `ip route 172.20.16.0 255.255.240.0 10.0.0.2 115`
- Command 2: `ip route 172.20.16.0 255.255.255.0 10.0.1.2`
- Command 3: `ip route 172.20.16.32 255.255.255.224 10.0.2.2 120`

Assuming all next-hop IP addresses (10.0.0.210.0.0.2, 10.0.1.210.0.1.2, and 10.0.2.210.0.2.2) are reachable via directly connected subnets, which route will router R1 use to forward the packet destined to 172.20.16.45172.20.16.45, and why?

Cevabı ve açıklamayı göster

Cevap: The static route from Command 3 via next-hop 10.0.2.2, because it is installed in the routing table and has the longest prefix match (/27) for the destination IP address.

Cevap

The router forwards the packet via the static route from Command 3 (next-hop 10.0.2.2) because it is installed in the routing table and provides the longest prefix match (/27) for IP address 172.20.16.45.
The correct answer identifies that the static route configured in Command 3 via next-hop 10.0.2.2 is installed in the routing table and selected via the Longest Prefix Match rule. AD comparison only suppresses a route when another protocol offers the exact same destination prefix and mask with a lower AD. Because Command 3 specifies 172.20.16.32/27, no exact match conflict exists with OSPF (172.20.16.0/20) or Command 2 (172.20.16.0/24), allowing Command 3 into the routing table. When forwarding a packet to 172.20.16.45, the router evaluates all installed routes matching the IP address and picks /27 as the longest prefix match.

Adım Adım Çözüm

1
Evaluate Routing Information Base (RIB) installation for each static route based on Administrative Distance (AD).
Command 1 (172.20.16.0/20, AD 115) matches OSPF prefix 172.20.16.0/20 (AD 110). Because OSPF AD < 115, Command 1 is not installed (floating static route). Command 2 (172.20.16.0/24, default AD 1) and Command 3 (172.20.16.32/27, AD 120) have unique prefixes, so AD comparison against OSPF does not prevent their installation.
Administrative Distance is only compared between routes with identical prefix and subnet mask definitions.
2
Determine which installed RIB entries match destination IP 172.20.16.45.
Matching installed routes: OSPF (172.20.16.0/20), Command 2 static route (172.20.16.0/24), and Command 3 static route (172.20.16.32/27).
172.20.16.45 falls within the host ranges of all three installed subnets: /20 (172.20.16.0 - 172.20.31.255), /24 (172.20.16.0 - 172.20.16.255), and /27 (172.20.16.32 - 172.20.16.63).
3
Apply router forwarding decision logic to select the active path for the packet.
Select 172.20.16.32/27 via next-hop 10.0.2.2.
Routers select paths based on the Longest Prefix Match (LPM) rule. A /27 prefix (27 mask bits) is longer and more specific than /24 or /20.

Anahtar Kavram

Routing Table Installation (AD Comparison for Exact Matches) vs Packet Forwarding Logic (Longest Prefix Match)
Soru 1202Soru →

Host-X sends an Ethernet frame destined for Host-Y through a Cisco Catalyst switch. The switch receives the frame on interface FastEthernet0/2. At the time of arrival, Host-X's source MAC address is not present in the switch MAC address table, while Host-Y's destination MAC address is already mapped to FastEthernet0/8. Place the internal processing steps performed by the Layer 2 switch in the correct chronological sequence from first to last.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct chronological sequence begins with receiving the frame on FastEthernet0/2, followed by learning the source MAC address (MAC-X), performing a table lookup for the destination MAC address (MAC-Y), matching MAC-Y to FastEthernet0/8, and finally forwarding the frame solely out interface FastEthernet0/8.
The correct order follows standard Cisco Layer 2 switching logic: 1) Ingress frame reception on interface FastEthernet0/2; 2) Source MAC address inspection and MAC table entry creation for FastEthernet0/2; 3) Destination MAC address table lookup; 4) Identification of egress port FastEthernet0/8; 5) Unicast transmission out FastEthernet0/8.

Adım Adım Çözüm

1
Receive Ingress Frame
The switch physical port FastEthernet0/2 accepts the frame header containing source MAC-X and destination MAC-Y.
Layer 2 processing requires the physical frame to enter an ingress interface first.
2
Source MAC Learning
Source MAC-X is mapped to FastEthernet0/2 in the switch MAC address table.
Switches update or populate their CAM/MAC table based on ingress source MAC addresses.
3
Destination MAC Lookup
The switch queries the MAC address table for destination MAC-Y.
The switch needs to decide whether to flood or unicast-forward the ingress frame based on destination MAC state.
4
Match Egress Port
The lookup resolves MAC-Y to interface FastEthernet0/8.
A matching entry prevents unknown unicast flooding.
5
Unicast Frame Forwarding
The frame is transmitted directly out FastEthernet0/8.
Known unicast destination entries result in single-port forwarding.

Anahtar Kavram

Layer 2 Ethernet Switching Process and MAC Address Table Learning and Forwarding Logic
Soru 1203Soru →

A network architect is designing a wireless solution for a remote branch connected to a main campus via a WAN link. The design requires wireless client data traffic to be switched locally onto the branch switch, while control and management traffic are directed to a centralized Wireless LAN Controller (WLC). Which two statements accurately describe the behavior of the access points at the branch when operating in FlexConnect mode? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The access point maintains a CAPWAP control tunnel to the WLC while switching client data frames locally onto the branch network.; If the WAN link to the central controller fails, the access point enters standalone mode and continues to switch client traffic locally.

Cevap

In FlexConnect mode configured for local switching, the access point maintains a CAPWAP control tunnel to the Wireless LAN Controller for management while bridging client data traffic locally onto the branch VLAN. If WAN connectivity to the controller is lost, the access point transitions to standalone mode to continue switching local traffic for existing clients.
FlexConnect mode is designed for branch office scenarios. It allows the access point to maintain a CAPWAP control tunnel to the centralized Wireless LAN Controller for management purposes while switching client data traffic locally directly onto the branch VLAN. Furthermore, if the WAN link drops and contact with the central controller is lost, FlexConnect access points transition into standalone mode, allowing them to continue switching data locally for existing clients without disruption.

Adım Adım Çözüm

1
Analyze the operational requirements for remote branch access point deployment across a WAN.
The requirement calls for centralized management coupled with local data switching.
FlexConnect mode is specifically designed for branch office environments to prevent client data traffic from unnecessarily consuming WAN bandwidth.
2
Evaluate CAPWAP tunnel separation in FlexConnect local switching mode.
The CAPWAP control plane tunnel terminates at the central controller, whereas client data frames bypass the CAPWAP data tunnel and are bridged directly onto the local Ethernet switch port.
This split-MAC capability allows control functions to remain central while keeping high-volume data traffic local.
3
Determine access point resiliency during controller disconnection.
FlexConnect access points switch from connected mode to standalone mode upon losing WLC heartbeat packets.
Standalone mode ensures business continuity at branch sites by keeping local switching functional.

Anahtar Kavram

Cisco FlexConnect AP Mode Operations and Resiliency
Soru 1204Soru →

A Cisco router receives an Ethernet frame containing an IPv4 packet destined for a remote host. Place the router's forwarding decision steps in the exact chronological order in which they are evaluated from initial packet reception to egress frame transmission.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence starts with extracting the destination IPv4 address, performing the Longest Prefix Match search, resolving ties using Administrative Distance, comparing metrics for remaining identical protocol routes, and finally rewriting Layer 2 headers to forward out the exit interface.
The router processes forwarding logic sequentially: destination IP extraction happens first, followed by selecting candidate routes based strictly on Longest Prefix Match (LPM). If multiple routes share the identical prefix length, Administrative Distance (AD) determines the trusted protocol source. If AD is also equal, metric cost breaks the tie. Once the best path is chosen, Layer 2 header rewriting and egress transmission occur as the final step.

Adım Adım Çözüm

1
Examine incoming packet header.
Destination IP address is retrieved for routing lookup.
The router requires the destination address to query the routing table.
2
Perform Longest Prefix Match (LPM) evaluation.
Routing table entries with the highest number of matching network bits are selected.
LPM is always the primary criterion for route selection, overriding AD and metric.
3
Evaluate Administrative Distance (AD).
The route from the routing protocol with the lowest AD is selected if prefix lengths match.
AD measures route source trustworthiness.
4
Evaluate metric cost.
The route with the lowest metric cost is chosen if prefix lengths and AD are equal.
Metric measures path cost within a single routing protocol instance.
5
Perform egress frame encapsulation and transmission.
New source and destination MAC addresses are populated, ARP/ND is queried if necessary, and the frame is transmitted out the exit interface.
Layer 2 rewrites are required for adjacent next-hop framing.

Anahtar Kavram

Router Forwarding Decision Logic Priority (LPM -> AD -> Metric -> L2 Encapsulation)
Soru 1205Soru →

Match each network topology architecture or deployment model to its defining structural trait or primary operational characteristic.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

Spine-Leaf (Clos) Architecture
Cisco Traditional 3-Tier Campus Architecture
Collapsed Core Architecture
Small Office / Home Office (SOHO) Topology

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Spine-Leaf matches the bipartite topology with two-hop latency and ECMP; Cisco 3-Tier Campus matches the distinct Core, Distribution, and Access layer structure; Collapsed Core matches the combination of core and distribution functions into a single tier; SOHO Topology matches the integrated multifunctional single-device deployment.
Each architecture is mapped accurately to its fundamental design pattern: Spine-Leaf provides non-blocking east-west fabric with ECMP; 3-Tier segregates Core, Distribution, and Access duties; Collapsed Core combines Core and Distribution duties for cost savings; SOHO utilizes an all-in-one appliance.

Adım Adım Çözüm

1
Analyze the operational requirements of Spine-Leaf (Clos) architecture.
Identify that Spine-Leaf relies on a two-tier fabric where every leaf connects to every spine, using ECMP to route east-west traffic with fixed two-hop latency.
Data center workloads require predictable performance and bandwidth between server racks.
2
Differentiate between 3-Tier and Collapsed Core campus architectures.
Recognize that 3-Tier uses separate Access, Distribution, and Core layers, whereas Collapsed Core combines the Distribution and Core functions onto the same physical switch hardware.
Collapsed Core reduces capital cost for smaller campus sites while retaining boundary control.
3
Identify the defining hardware characteristic of a SOHO topology.
Select the option describing an integrated single-chassis device providing multi-role network services for a small site.
SOHO designs prioritize low cost and simplicity by consolidating routing, switching, AP, and firewall functions.

Anahtar Kavram

Network Topology Architectures and Layer Functions
Soru 1206Soru →

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

text
O 10.20.0.0/16 [110/50] via 172.16.1.1, 01:12:35, GigabitEthernet0/0
D 10.20.10.0/24 [90/307200] via 172.16.2.1, 00:45:10, GigabitEthernet0/1
S 10.20.10.128/25 [1/0] via 172.16.3.1

A packet arrives at the router destined for host IP address 10.20.10.130. Which two statements correctly describe how the router evaluates its routing table components to forward this packet? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The router forwards the packet using the static route (10.20.10.128/25) because /25 is the longest matching prefix for destination 10.20.10.130.; The router evaluates prefix length prior to checking administrative distance or metric when making forwarding decisions.

Cevap

The router selects the static route (10.20.10.128/25) because /25 is the longest matching prefix for destination 10.20.10.130, and the router evaluates prefix length prior to checking administrative distance or metric when making forwarding decisions.
When forwarding a packet, a Cisco router first identifies all routes that match the destination IP address and selects the route with the longest prefix length (most specific subnet mask). Since 10.20.10.128/25 matches destination 10.20.10.130 with 25 matching network bits, it is selected over the /24 and /16 routes. Administrative distance and metrics are only evaluated during route selection when prefix lengths are identical.

Adım Adım Çözüm

1
Compare the destination IP address 10.20.10.130 against all prefix entries in the routing table.
The destination address matches 10.20.0.0/16, 10.20.10.0/24, and 10.20.10.128/25.
Routing forwarding decisions start by identifying all matching routes.
2
Determine the prefix length of each matching route.
The prefix lengths are /16, /24, and /25.
The router applies the longest prefix match rule to find the most specific network path.
3
Select the route with the highest number of matching network bits.
The /25 route (10.20.10.128/25) is chosen regardless of administrative distance or metric values.
Longest prefix match always takes precedence over administrative distance and metric values during forwarding lookup.

Anahtar Kavram

Longest Prefix Match Rule in Cisco Routing Tables
Soru 1207Soru →

A network administrator enables Link Aggregation (LAG) on a Cisco Wireless LAN Controller (WLC) to combine its physical distribution system ports into a single logical interface. How must the connected ports on the upstream switch be configured to establish this link aggregation successfully?

Cevabı ve açıklamayı göster

Cevap: Configured as a static EtherChannel using the command channel-group mode on without dynamic negotiation protocols.

Cevap

The switch ports connected to the Wireless LAN Controller must be configured as a static EtherChannel using the channel-group mode on command.
When Link Aggregation (LAG) is enabled on a Cisco Wireless LAN Controller, all physical distribution system ports are bundled into a single logical channel that carries all VLANs as an 802.1Q trunk. Because the controller does not use dynamic negotiation protocols such as LACP or PAgP, the corresponding connected interfaces on the adjacent switch must be configured as a static EtherChannel using the `channel-group mode on` command.

Adım Adım Çözüm

1
Identify WLC Link Aggregation (LAG) operational characteristics
Determine that Cisco WLC LAG bundles all physical distribution ports into a single logical interface that acts as an 802.1Q trunk.
WLC LAG does not run dynamic link aggregation negotiation protocols (LACP or PAgP).
2
Determine the matching switch port configuration requirements
Select static EtherChannel configuration (channel-group mode on) for all member switch interfaces connected to the WLC.
Because the controller does not transmit negotiation packets, the switch ports must force the EtherChannel into an operational state unconditionally.

Anahtar Kavram

WLC Link Aggregation (LAG) Switchport Configuration
Soru 1208Soru →

Examine the following Cisco IPv4 routing table snippet:

text
Codes: C - connected, S - static, R - RIP, B - BGP, D - EIGRP, O - OSPF
Gateway of last resort is 10.1.1.254 to network 0.0.0.0

S 192.168.100.0/24 [1/0] via 10.1.1.1
D 192.168.100.160/27 [90/2170112] via 10.1.1.2
O 192.168.100.176/28 [110/40] via 10.1.1.3, GigabitEthernet0/0/2
S 192.168.100.180/30 [1/0] via 10.1.1.4
S* 0.0.0.0/0 [1/0] via 10.1.1.254

Which next-hop IP address will the router select to forward an incoming packet destined for host 192.168.100.178?

Cevabı ve açıklamayı göster

Cevap: 10.1.1.3

Cevap

10.1.1.3
When a router receives a packet, it first evaluates all matching routes in the routing table using the Longest Prefix Match (LPM) rule. The destination address 192.168.100.178 matches four routes in the table: 0.0.0.0/0, 192.168.100.0/24, 192.168.100.160/27 (range .160–.191), and 192.168.100.176/28 (range .176–.191). Among these valid matches, 192.168.100.176/28 has the longest subnet mask (/28 = 28 matching bits). Therefore, the router selects this route and forwards the packet to next-hop IP 10.1.1.3.

Adım Adım Çözüm

1
Identify all matching candidate routes for destination IP 192.168.100.178.
Candidate matching routes are 0.0.0.0/0, 192.168.100.0/24, 192.168.100.160/27, and 192.168.100.176/28.
Route 192.168.100.180/30 covers range .180-.183 and does NOT match IP .178.
2
Compare the prefix lengths of all valid matching candidate routes.
Prefix lengths are /0, /24, /27, and /28.
Router forwarding logic relies on Longest Prefix Match (LPM) as the primary criteria before Administrative Distance or Metric are evaluated.
3
Select the route with the longest prefix mask.
The route for 192.168.100.176/28 has the longest matching prefix (/28).
192.168.100.176/28 matches 28 bits, which is longer than /27, /24, or /0.
4
Determine the next-hop IP associated with the winning route.
The next-hop IP is 10.1.1.3.
The routing entry specifies 'O 192.168.100.176/28 [110/40] via 10.1.1.3'.

Anahtar Kavram

Router Forwarding Decision Logic (Longest Prefix Match precedence over Administrative Distance and Metric)
Soru 1209Soru →

A network administrator is creating a new WLAN on a Cisco Wireless LAN Controller (WLC) via the web GUI to support corporate users. The WLAN must map client traffic to the dynamic interface associated with VLAN 20 and authenticate clients using WPA2-Enterprise (802.1X) against a central external RADIUS server that has already been globally configured on the controller. Which two configuration actions must the administrator perform within the WLAN configuration tabs in the WLC GUI to successfully complete this setup? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: Under the General tab, select the dynamic interface mapped to VLAN 20 from the Interface/Interface Group dropdown menu and check the Enabled box for Status.; Under the Security > AAA Servers tab, select the pre-configured RADIUS server from the Server 1 dropdown list in the Authentication Servers section.

Cevap

The administrator must map the WLAN to the dynamic interface for VLAN 20 and enable the WLAN status under the General tab, as well as select the pre-configured RADIUS server under the Security > AAA Servers tab.
To complete WLAN client connectivity configuration for WPA2-Enterprise with VLAN tagging: 1) Under the General tab, the WLAN must be associated with the appropriate dynamic interface (VLAN 20) and the Status box must be checked to enable SSID broadcasting and association. 2) Under the Security > AAA Servers tab, the specific external RADIUS server must be bound to the WLAN so authentication traffic is forwarded correctly.

Adım Adım Çözüm

1
Navigate to the WLANs tab in the WLC GUI and edit the target WLAN.
Access the multi-tab configuration interface for the specific WLAN.
WLAN settings are organized into General, Security, AAA Servers, QoS, and Advanced tabs.
2
Select the dynamic interface for VLAN 20 and check the Enabled checkbox under the General tab.
Traffic from clients associating to this WLAN is mapped to VLAN 20, and the WLAN is brought administratively online.
Without enabling Status, the WLAN remains inactive; without binding the dynamic interface, client traffic cannot reach VLAN 20.
3
Navigate to Security > AAA Servers tab and select the globally configured RADIUS server under Authentication Servers.
The WLAN is instructed to send 802.1X authentication requests to the designated external RADIUS server.
Global RADIUS definitions must be explicitly assigned to individual WLANs under the WLAN AAA Servers tab for 802.1X Enterprise security.

Anahtar Kavram

WLC GUI WLAN Client Connectivity and Security Configuration Parameters
Tahmini Süre:2m 0s
Soru 1210Soru →

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

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

Gateway of last resort is not set

O 10.50.16.0/20 [110/50] via 192.168.1.1, 00:04:12, GigabitEthernet0/0
D 10.50.24.0/22 [90/307200] via 192.168.2.2, 00:12:45, GigabitEthernet0/1
S 10.50.25.0/24 [1/0] via 192.168.3.3
O 10.50.25.128/26 [110/30] via 192.168.4.4, 00:01:10, GigabitEthernet0/2

A packet arriving at the router is destined for host address 10.50.25.14010.50.25.140. Which two statements accurately describe how the router processes and forwards this packet? (Select TWO.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The router selects the route entry 10.50.25.128/26 because /26 represents the longest matching prefix for the destination address.; The packet will be forwarded out of interface GigabitEthernet0/2 toward next-hop IP 192.168.4.4.

Cevap

The router selects the route entry for 10.50.25.128/26 because /26 is the longest prefix match for destination IP 10.50.25.140, and consequently forwards the packet out of interface GigabitEthernet0/2 to next-hop 192.168.4.4.
When a router receives an IP packet, it compares the destination IP address against all routing table entries and selects the route with the most specific subnet mask (longest prefix match). Address 10.50.25.14010.50.25.140 matches 10.50.25.128/2610.50.25.128/26 (range 10.50.25.12810.50.25.128 to 10.50.25.19110.50.25.191). Because /26/26 is longer than /24/24, /22/22, and /20/20, the router chooses this route and forwards the traffic via interface GigabitEthernet0/2 to next-hop 192.168.4.4192.168.4.4.

Adım Adım Çözüm

1
Determine which routing table entries match the destination IP address 10.50.25.140.
All four routes match the destination: 10.50.16.0/20, 10.50.24.0/22, 10.50.25.0/24, and 10.50.25.128/26.
10.50.25.140 falls within the address range of each of these four subnet prefixes.
2
Apply the Longest Prefix Match (LPM) rule to select the best route.
The route 10.50.25.128/26 is chosen because its prefix length (/26) is the most specific.
Prefix length always takes priority over Administrative Distance and routing metrics during route lookup.
3
Identify the forwarding exit interface and next-hop address associated with the winning route.
Next-hop: 192.168.4.4, Exit interface: GigabitEthernet0/2.
The routing table entry specifies these forwarding parameters for 10.50.25.128/26.

Anahtar Kavram

Router Forwarding Decision Logic (Longest Prefix Match)
Soru 1211Soru →

A network administrator is inspecting a host connected to a Cisco switch. The host network interface has a hardware MAC address of `5254.0012.3456`. Assuming IPv6 stateless autoconfiguration uses the standard IEEE EUI-64 format, what is the resulting 64-bit interface identifier?

Cevabı ve açıklamayı göster

Cevap: 5054:00ff:fe12:3456; 5054:00FF:FE12:3456; 5054:ff:fe12:3456; 5054:FF:FE12:3456

Cevap

5054:00ff:fe12:3456
To derive the EUI-64 interface identifier from MAC address `5254.0012.3456`:
1. Split the MAC address: `52:54:00` and `12:34:56`.
2. Insert `FFFE` in the middle: `5254:00FF:FE12:3456`.
3. Invert the 7th bit of the first byte: `0x52` (`0101 0010` in binary) becomes `0x50` (`0101 0000` in binary).

Combining these operations yields the final 64-bit interface identifier `5054:00ff:fe12:3456`.

Adım Adım Çözüm

1
Split the 48-bit MAC address into two 24-bit halves.
Left half: `52:54:00`, Right half: `12:34:56`
EUI-64 insertion occurs directly between the OUI and the vendor-assigned NIC portion.
2
Insert the 16-bit hex value `FFFE` into the middle.
`5254:00FF:FE12:3456`
Inserting `FFFE` expands the 48-bit MAC address into a 64-bit structure.
3
Invert the 7th bit (Universal/Local bit) of the first byte.
First byte `0x52` in binary is `0101 0010`. Inverting the 7th bit yields `0101 0000`, which is `0x50` in hex.
IEEE EUI-64 standards dictate that the 7th bit is flipped (0 becomes 1 for local uniqueness, 1 becomes 0 for universal).
4
Assemble the final 64-bit interface identifier in standard IPv6 hexadecimal notation.
`5054:00ff:fe12:3456`
Combines the modified first byte, remaining MAC components, and inserted `FFFE` into 16-bit colon-separated fields.

Anahtar Kavram

EUI-64 Interface Identifier Derivation
Soru 1212Soru →

Examine the following IPv4 routing table output from a Cisco router:

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 not set

192.168.10.0/24 is subnetted, 3 subnets
O 192.168.10.0/24 [110/20] via 10.1.1.1, 00:05:12, GigabitEthernet0/0
D 192.168.10.0/28 [90/307200] via 10.1.1.2, 00:12:45, GigabitEthernet0/1
S 192.168.10.0/26 [1/0] via 10.1.1.3

The router receives a packet destined for IP address 192.168.10.14. Which next-hop IP address will the router use to forward this packet?

Cevabı ve açıklamayı göster

Cevap: 10.1.1.2

Cevap

The router forwards the packet to next-hop address 10.1.1.2 because 192.168.10.0/28 is the longest prefix match for destination IP address 192.168.10.14.
When a router receives a packet, it compares the destination IP address against all entries in its routing table and selects the route with the most specific match (longest subnet mask length). Destination IP 192.168.10.14 matches the /24, /26, and /28 prefixes. Because /28 is the longest prefix mask (255.255.255.240), the router uses the route pointing to next-hop 10.1.1.2.

Adım Adım Çözüm

1
Evaluate all routing table entries to determine which prefixes contain destination IP 192.168.10.14.
The IP address 192.168.10.14 falls within 192.168.10.0/24 (host range .1 to .254), 192.168.10.0/26 (host range .1 to .62), and 192.168.10.0/28 (host range .1 to .14).
Before comparing protocol metrics or administrative distance, the router must identify all candidate routes matching the destination IP.
2
Apply the Longest Prefix Match (LPM) rule by comparing the subnet mask lengths of matching routes.
The prefix length /28 is longer (more specific) than /26 and /24.
Cisco routers always prefer the route with the longest matching prefix length regardless of administrative distance or metric.
3
Identify the next-hop address associated with the chosen /28 route entry.
The entry 'D 192.168.10.0/28 ... via 10.1.1.2' specifies next-hop 10.1.1.2.
The forwarding decision uses the next-hop IP associated with the longest matching route entry.

Anahtar Kavram

Longest Prefix Match Rule
Soru 1213Soru →

A network engineering team is evaluating topological designs for a expanding enterprise facility. The current infrastructure uses a Collapsed Core topology where distribution and core functions are combined on a single redundant switch pair. As the facility adds multiple new buildings with high port densities and complex policy enforcement requirements, the team considers migrating to a traditional 3-Tier Campus design. Which technical requirement or operational constraint best justifies transitioning to a full 3-Tier architecture?

Cevabı ve açıklamayı göster

Cevap: The quantity of access-layer switches and distribution-layer interconnects exceeds the interface density and processing capacity of a single consolidated switch pair.

Cevap

The transition to a 3-Tier architecture is justified when the volume of access switches and interconnections exceeds the port density, backplane performance, and policy processing capacity of a collapsed distribution/core pair.
In expanding campus networks, a Collapsed Core topology can become a bottleneck due to limited physical uplink ports, buffer sizes, and control-plane processing under high policy loads. Transitioning to a traditional 3-Tier design adds a dedicated Core layer that interconnects multiple distribution blocks, providing scalable throughput and switch port availability.

Adım Adım Çözüm

1
Analyze the functional limits of a Collapsed Core topology.
Collapsed Core combines the Core and Distribution layers into a single switch pair, which works well for small to medium environments but encounters scaling limits as port counts and routing policies grow.
Understanding architectural boundaries is essential for network design scaling.
2
Evaluate the benefits of introducing a dedicated Core tier in a 3-Tier design.
A 3-Tier design separates the Distribution layer (which handles routing, ACL policies, and VLAN aggregation) from the Core layer (which focuses strictly on ultra-fast, unthrottled packet forwarding).
Decoupling roles prevents a single tier from suffering hardware port exhaustion or CPU overload.

Anahtar Kavram

Cisco 3-Tier Campus vs Collapsed Core Architectural Scaling
Tahmini Süre:1m 30s
Soru 1214Soru →

A network engineer is operating a remote branch office where Lightweight Access Points are deployed in FlexConnect mode with local switching and central authentication. If the WAN link connecting the branch AP to the central Wireless LAN Controller (WLC) fails, how does the AP process existing connected client data traffic and new 802.1X client authentication attempts?

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Cevap: Existing client data traffic continues to be bridged locally, but new 802.1X client authentication attempts fail.

Cevap

Existing client data traffic continues to be bridged locally, but new 802.1X client authentication attempts fail.
When a FlexConnect AP configured for local switching loses CAPWAP connectivity to its controlling WLC, it enters standalone mode. Existing clients using local switching continue to have their data traffic bridged directly onto the local network interface. However, because authentication is set to central authentication, the AP cannot process new 802.1X client requests without WLC access to reach the RADIUS server, causing new authentications to fail.

Adım Adım Çözüm

1
Analyze the FlexConnect mode configuration parameters.
The AP is operating with local switching for data frames and central authentication for control/security operations via the WLC.
FlexConnect separates the data plane and control plane according to configured WLAN profiles.
2
Evaluate the impact of WAN link failure on existing active client sessions.
Data traffic for already authenticated clients is switched directly to the local Ethernet switch port of the AP without passing through the CAPWAP data tunnel.
Local switching allows the AP to continue forwarding client VLAN traffic locally during WLC standalone mode.
3
Evaluate the impact of WAN link failure on new 802.1X authentication requests.
New authentication requests fail because central authentication relies on the active CAPWAP control tunnel to reach the central WLC and RADIUS infrastructure.
Without active CAPWAP control connectivity or configured local backup authentication methods, the AP cannot process 802.1X EAP exchanges.

Anahtar Kavram

FlexConnect Standalone Mode Operations for Central Authentication and Local Switching
Tahmini Süre:2m 0s
Soru 1215Soru →

A Cisco switch receives an Ethernet frame on a port configured as an 802.1Q trunk link. In what sequential order does the switch process this incoming frame from initial ingress parsing to its final forwarding decision?

Öğeleri doğru sıraya koymak için sürükleyin

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Cevap

The correct sequence begins with inspecting the ingress frame header for an 802.1Q tag, assigning the VLAN ID based on tag presence or native VLAN configuration, checking the VLAN against the allowed VLAN list, and finally forwarding or dropping the frame.
When a frame arrives on an 802.1Q trunk interface, the switch performs ingress processing in a strict order: First, it examines the Ethernet header to detect whether an 802.1Q tag (EtherType 0x8100) is present. Second, it determines the internal VLAN ID—reading the 12-bit VLAN ID for tagged frames or mapping untagged frames to the interface's configured native VLAN. Third, it checks whether that VLAN ID is included in the interface's allowed VLAN list. Fourth, if the VLAN is permitted, the switch looks up the MAC table and forwards the frame to destination ports in that VLAN; if the VLAN is disallowed, the frame is dropped.

Adım Adım Çözüm

1
Parse frame header for 802.1Q tag
Determines if an 802.1Q EtherType (0x8100) and 4-byte tag exist within the frame.
The switch must identify encapsulation formatting before reading VLAN metadata.
2
Assign internal VLAN ID
Tagged frames are assigned the 12-bit VLAN ID from the tag; untagged frames are assigned to the port's native VLAN.
All ingress frames inside an 802.1Q switch must be mapped to a specific internal VLAN context.
3
Verify allowed VLAN status
The target VLAN ID is checked against the list defined by 'switchport trunk allowed vlan'.
Filtering rules must confirm that the trunk interface allows traffic for that specific VLAN.
4
Execute switching decision
The frame is switched toward matching destination interfaces or dropped if the VLAN is pruned.
The MAC address table lookup and allowed VLAN check dictate final egress behavior.

Anahtar Kavram

802.1Q Ingress Frame Processing Logic
Tahmini Süre:1m 30s
Soru 1216Soru →

Refer to the following partial routing table output from router R1:

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

Gateway of last resort is 192.168.5.2 to network 0.0.0.0

S* 0.0.0.0/0 [1/0] via 192.168.5.2
B 10.140.0.0/16 [20/0] via 192.168.4.2, 01:22:00, GigabitEthernet0/0/0
S 10.140.24.0/24 [1/0] via 192.168.3.2
O 10.140.24.0/25 [110/20] via 192.168.1.2, 00:14:22, GigabitEthernet0/0/1
D 10.140.24.64/28 [90/307200] via 192.168.2.2, 00:05:10, GigabitEthernet0/0/2

Router R1 receives an IP packet addressed to 10.140.24.6710.140.24.67. Which egress interface and next-hop IP address will R1 use to forward this packet?

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Cevap: Interface GigabitEthernet0/0/2 with next-hop IP address 192.168.2.2

Cevap

Interface GigabitEthernet0/0/2 with next-hop IP address 192.168.2.2
When a router makes a packet forwarding decision, it evaluates all matching routing table entries using the Longest Prefix Match (LPM) rule first. For destination IP 10.140.24.6710.140.24.67, the matching prefixes are /0/0, /16/16, /24/24, /25/25, and /28/28. The /28/28 prefix (10.140.24.64/2810.140.24.64/28) is the most specific match. Therefore, R1 forwards the packet to next-hop 192.168.2.2192.168.2.2 out interface GigabitEthernet0/0/2.

Adım Adım Çözüm

1
Evaluate all candidate routes in the routing table to find which subnets contain the target IP 10.140.24.6710.140.24.67.
Candidate matching routes are: 0.0.0.0/00.0.0.0/0, 10.140.0.0/1610.140.0.0/16, 10.140.24.0/2410.140.24.0/24, 10.140.24.0/2510.140.24.0/25 (range .0–.127), and 10.140.24.64/2810.140.24.64/28 (range .64–.79).
Before comparing administrative distance or metric, a router determines all routes that mathematically match the destination address.
2
Determine the prefix length (number of subnet mask bits) for each matching candidate route.
0.0.0.0/00.0.0.0/0 has prefix length /0; 10.140.0.0/1610.140.0.0/16 has prefix length /16; 10.140.24.0/2410.140.24.0/24 has /24; 10.140.24.0/2510.140.24.0/25 has /25; 10.140.24.64/2810.140.24.64/28 has /28.
The fundamental forwarding rule (Longest Prefix Match) dictates that the route with the highest number of matching network bits is chosen.
3
Select the route with the longest prefix match.
The route 10.140.24.64/2810.140.24.64/28 has the longest prefix length (/28 > /25 > /24 > /16 > /0).
The router selects 10.140.24.64/2810.140.24.64/28 pointing to next-hop 192.168.2.2192.168.2.2 via exit interface GigabitEthernet0/0/2. Administrative distance is not evaluated across routes with different prefix lengths.

Anahtar Kavram

Longest Prefix Match Rule
Tahmini Süre:1m 30s
Soru 1217Soru →

A network administrator is provisioning a routed Layer 3 EtherChannel bundle between a core switch and a distribution switch using the Link Aggregation Control Protocol (LACP). Which two configuration requirements or operational conditions must be met for the Layer 3 EtherChannel bundle to successfully form and forward traffic? (Select two.)

Geçerli olan tümünü seçin

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Cevap: The 'no switchport' command must be executed on both the logical port-channel interface and all physical member interfaces before configuring an IP address on the port-channel.; At least one side of the connection must have its member interfaces configured in LACP 'active' mode to actively send LACP control packets.

Cevap

The two correct requirements are: executing the 'no switchport' command on both the logical port-channel and physical member interfaces before assigning an IP address to the port-channel, and ensuring that at least one switch is set to LACP 'active' mode to initiate LACP negotiations.
To operationalize a Layer 3 EtherChannel, all member interfaces and the logical port-channel interface must be configured with 'no switchport' to disable Layer 2 switching before assigning an IP address to the port-channel. Additionally, LACP negotiation requires at least one end to actively transmit LACP frames by using 'active' mode.

Adım Adım Çözüm

1
Verify Layer 3 port conversion requirements
Confirm that physical member ports and the port-channel interface must have switchport functionality disabled using 'no switchport'.
Layer 3 EtherChannels act as routed interfaces. The logical port-channel interface holds the IP address, and member ports must be converted to routed ports to participate.
2
Evaluate LACP negotiation mode rules
Identify valid LACP mode pairings: active-active or active-passive.
LACP active mode sends LACP frames proactively, whereas passive mode only listens and responds. If both sides are passive, no frames are sent and the EtherChannel will not form.

Anahtar Kavram

Layer 3 EtherChannel Configuration and LACP Mode Negotiation Rules
Soru 1218Soru →

A network engineer is configuring a high-security WLAN on a Cisco Wireless LAN Controller (WLC) via the web GUI to support modern client devices using WPA3-Personal (SAE) key management. Under the WLANs > Edit > Security > Layer 2 tab, the engineer selects WPA3 Policy but leaves the Protected Management Frames (PMF) setting at 'Disabled'. When attempting to save and enable the WLAN, the WLC displays a configuration error and refuses to save the profile. Which setting change in the WLC GUI is mandatory to resolve this error?

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Cevap: Set Protected Management Frames (PMF) to Required under the Security > Layer 2 tab

Cevap

Set Protected Management Frames (PMF) to Required under the Security > Layer 2 tab
Under the Wi-Fi Alliance WPA3 specification, Protected Management Frames (PMF / IEEE 802.11w) are strictly mandatory. When configuring a WLAN on a Cisco Wireless LAN Controller via the web GUI (WLANs > Edit > Security > Layer 2), selecting WPA3 Policy forces the administrator to set Protected Management Frames to 'Required'. Leaving PMF set to 'Disabled' results in an immediate GUI validation failure because the controller enforces WPA3 security standard compliance.

Adım Adım Çözüm

1
Identify the mandatory prerequisite for WPA3 operation on Cisco WLCs
Recognize that the Wi-Fi Alliance WPA3 specification mandates IEEE 802.11w Protected Management Frames (PMF).
PMF prevents management frame spoofing attacks such as deauthentication and disassociation attacks.
2
Locate the PMF configuration field in the WLC GUI
Navigate to WLANs > Edit > Security > Layer 2 tab where WPA+WPA2/WPA3 parameters reside.
PMF is a Layer 2 security mechanism configured on the same sub-tab as WPA3 Policy.
3
Adjust the PMF parameter to satisfy WPA3 policy validation
Change Protected Management Frames dropdown from Disabled to Required.
Selecting WPA3 Policy without enabling PMF as Required generates a WLC GUI validation error when applying changes.

Anahtar Kavram

WLC GUI Layer 2 Security and WPA3 PMF Prerequisite Configuration
Tahmini Süre:2m 0s
Soru 1219Soru →

A network engineer is provisioning interface IP addresses for a server cluster assigned to the 172.16.140.0/22172.16.140.0/22 IPv4 subnet. Which two IP addresses are valid usable host addresses within this subnet?

Geçerli olan tümünü seçin

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Cevap: 172.16.141.255; 172.16.143.254

Cevap

The addresses 172.16.141.255 and 172.16.143.254 are valid usable host addresses for the 172.16.140.0/22 subnet.
For the network block 172.16.140.0/22, the subnet spans 172.16.140.0 to 172.16.143.255. The unusable boundary addresses are 172.16.140.0 (network ID) and 172.16.143.255 (broadcast ID). Any address strictly between these boundaries (172.16.140.1 to 172.16.143.254) is usable. Consequently, 172.16.141.255 (where host bits are binary 01 11111111) and 172.16.143.254 are both valid usable host addresses.

Adım Adım Çözüm

1
Determine the subnet mask and block size from CIDR prefix /22
A /22 prefix corresponds to mask 255.255.252.0. The third octet block size is 256 - 252 = 4.
Prefix length of 22 leaves 10 host bits (32 - 22 = 10). 2 bits in the 3rd octet and 8 bits in the 4th octet belong to host portion.
2
Calculate the network and broadcast boundaries for 172.16.140.0/22
Network Address: 172.16.140.0; Broadcast Address: 172.16.143.255.
140 is a multiple of 4 (4 * 35 = 140). The next subnet begins at 172.16.144.0, so the broadcast address is 172.16.143.255.
3
Determine the usable host IP address range
Usable host range: 172.16.140.1 through 172.16.143.254.
Usable host addresses are all IPs between the network address and broadcast address.
4
Evaluate candidate options against the usable host range
172.16.141.255 and 172.16.143.254 both fall inside the valid range 172.16.140.1 - 172.16.143.254.
172.16.140.0 is the network IP and 172.16.143.255 is the broadcast IP, leaving 172.16.141.255 and 172.16.143.254 as valid usable host IPs.

Anahtar Kavram

IPv4 Usable Host Range in Non-Octet Boundary Subnets (/22 Prefix)
Soru 1220Soru →

Complete the Cisco IOS command by entering the missing administrative distance value to configure a floating static route.

Aşağıdaki boşlukları doldurun

An engineer is configuring a backup IPv6 static route to network 2001:db8:40::/64 via next-hop 2001:db8:10::2. The route must remain inactive in the routing table unless the primary OSPFv3 route (administrative distance 110) fails.

Complete the command below by filling in a valid administrative distance value in :

`Router(config)# ipv6 route 2001:db8:40::/64 2001:db8:10::2 `
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Cevap

Any integer from 111 through 254 (for example, 130) that is greater than the OSPFv3 administrative distance of 110.
A floating static route requires an Administrative Distance (AD) higher than the routing protocol it backs up. Since OSPFv3 has a default AD of 110, any integer value between 111 and 254 (such as 120, 130, or 150) placed at the end of the `ipv6 route` command correctly configures the floating static route.

Adım Adım Çözüm

1
Identify the primary route's Administrative Distance (AD).
The primary route uses OSPFv3, which has a default AD of 110.
Floating static routes rely on a higher AD than the active routing protocol so they are only installed when the primary route fails.
2
Determine the valid range for the floating static route AD.
The AD must be strictly greater than 110 and less than 255 (valid Cisco IOS AD range for static routes is 1–254).
An AD of 255 makes a route unroutable/untrustworthy, while an AD of 110 or less would cause the static route to preempt or equal-cost load-share with OSPFv3.
3
Place the AD parameter in the Cisco IOS IPv6 static route syntax.
The syntax is `ipv6 route <prefix/length> <next-hop> [administrative-distance]`.
The final optional position in the command specifies the administrative distance.

Anahtar Kavram

IPv6 Floating Static Route Administrative Distance Configuration
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