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1987 soru

Tüm türler1,987Çoktan seçmeli1,020Çoklu seçim452Sayısal18Eşleştirme229Sıralama203Boşluk doldurma22Kısa cevap43
Soru 1361Soru →

Refer to the following command output from Router R1 on a multiaccess Ethernet network:

text
R1# show ip ospf interface GigabitEthernet0/0
GigabitEthernet0/0 is up, line protocol is up
Internet Address 192.168.10.1/24, Area 0
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DROTHER, Priority 0
Designated Router (ID) 3.3.3.3, Interface address 192.168.10.3
Backup Designated Router (ID) 2.2.2.2, Interface address 192.168.10.2

The administrator attempts to force R1 to become the Designated Router (DR) by assigning it the highest Router ID on the segment (10.10.10.10) and resetting the OSPF process. However, R1 remains in the DROTHER state. Why did R1 fail to participate in the DR/BDR election?

Cevabı ve açıklamayı göster

Cevap: The OSPF interface priority on R1 is set to 0, which explicitly excludes the router from participating in DR/BDR elections regardless of its Router ID.

Cevap

R1 cannot become the Designated Router because its OSPF interface priority is configured as 0, which makes the interface ineligible to participate in DR/BDR elections.
In OSPFv2 multiaccess networks (such as Broadcast), DR/BDR elections evaluate interface priority first. A router with an interface priority of 0 is strictly excluded from becoming a DR or BDR and will always remain a DROTHER, regardless of how high its Router ID or interface IP address is.

Adım Adım Çözüm

1
Examine the output of 'show ip ospf interface GigabitEthernet0/0'.
Identify that R1 has an OSPF Priority of 0 and a State of DROTHER.
Interface priority determines DR/BDR election eligibility.
2
Evaluate the effect of OSPF interface priority 0.
Recognize that a priority value of 0 explicitly prevents a router from ever becoming a DR or BDR.
OSPF rules dictate that any interface with priority 0 remains permanently in the DROTHER state regardless of Router ID or interface IP address.

Anahtar Kavram

OSPF Priority 0 Exclusion in DR/BDR Selection
Soru 1362Soru →

An administrator is implementing a floating static route on a Cisco IOS router to act as a backup path for a primary route learned dynamically via internal EIGRP (Administrative Distance 90) to the destination subnet 10.100.50.0/2410.100.50.0/24. The administrator executes the following command:

`ip route 10.100.50.0 255.255.255.0 172.16.1.2 90`

While the primary EIGRP route remains active, traffic destined for 10.100.50.0/2410.100.50.0/24 is unexpectedly load-shared across both the dynamic route and the static route. Which configuration change will ensure that the static route functions exclusively as a backup route?

Cevabı ve açıklamayı göster

Cevap: Reconfigure the static route with an administrative distance greater than 90.

Cevap

Reconfigure the static route with an administrative distance greater than 90.
For a static route to act as a floating backup route, its administrative distance must be configured higher than the administrative distance of the primary route. Since internal EIGRP uses an AD of 90, configuring the static route with an AD of 90 causes both routes to share the same administrative distance, resulting in unexpected dual-path active insertion. Assigning an AD greater than 90 keeps the static route out of the routing table until the primary EIGRP route fails.

Adım Adım Çözüm

1
Analyze the administrative distance of the primary routing protocol.
Internal EIGRP has a default administrative distance of 90.
Administrative distance determines route preference in the Cisco IOS Routing Information Base (RIB).
2
Evaluate the current static route configuration.
The configured static route explicitly sets an administrative distance of 90, matching EIGRP's administrative distance.
When two routes to the exact same prefix have equal administrative distances, the router treats them as equally trustworthy, leading to unexpected traffic load-sharing or tie-breaking behavior.
3
Determine the requirement for a floating static route.
A floating static route must have an administrative distance strictly higher than the primary route's AD (e.g., 91 or 130).
This guarantees the static route remains inactive in the RIB until the primary dynamic route is removed.

Anahtar Kavram

Floating Static Route Administrative Distance Calibration
Soru 1363Soru →

Match each component or prefix notation from a Cisco IOS routing table output to its correct technical characteristic or forwarding behavior.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

Code prefix 'D EX' in: D EX 192.168.50.0/24 [170/2578560] via 10.1.1.2
Bracketed notation '[110/65]' in: O 10.1.4.0/24 [110/65] via 10.1.12.1
Prefix '192.168.10.0/28' vs '192.168.10.0/24' when forwarding to 192.168.10.14
Code prefix 'C' in: C 172.16.1.0/24 is directly connected, GigabitEthernet0/0

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Each routing table notation matches its corresponding definition based on Cisco IOS routing table syntax and path determination rules: 'D EX' matches external EIGRP with AD 170, '[110/65]' matches AD 110 and metric 65, the '/28' prefix matches the Longest Prefix Match rule, and 'C' matches a directly connected network with AD 0.
Each routing table component directly corresponds to Cisco IOS routing table syntax and path determination logic. 'D EX' signifies EIGRP external routes (AD 170); bracketed numbers '[110/65]' display Administrative Distance followed by Metric; destination matching favors the longest subnet mask (/28 over /24); and 'C' represents directly connected routes with an AD of 0.

Adım Adım Çözüm

1
Analyze routing table protocol codes
Identify 'D EX' as EIGRP External (AD 170) and 'C' as Connected (AD 0).
Cisco IOS routing tables use specific legend codes to indicate how routes were learned.
2
Interpret numerical brackets [AD/Metric]
Confirm '[110/65]' represents Administrative Distance 110 (OSPF) and a cost metric of 65.
The first number in brackets is always the Administrative Distance and the second is the route metric.
3
Apply forwarding logic to destination lookup
Determine that the /28 route is selected over /24 because 28 matching bits exceeds 24 matching bits.
Longest prefix matching (LPM) is the fundamental rule evaluated before comparing administrative distance or metric.

Anahtar Kavram

Interpretation of Cisco IOS Routing Table Components and Forwarding Decision Logic
Soru 1364Soru →

A network administrator needs to configure an IPv6 static route on router R1 to forward traffic to the remote network 2001:db8:10:20::/642001:\text{db8}:10:20::/64. The next-hop router's interface has a link-local address of fe80::212:79ff:fe34:5678\text{fe80}::212:79\text{ff}:\text{fe34}:5678 connected to R1's local interface GigabitEthernet0/0/1. Which Cisco IOS command correctly provisions this static route?

Cevabı ve açıklamayı göster

Cevap: ipv6 route 2001:db8:10:20::/64 GigabitEthernet0/0/1 fe80::212:79ff:fe34:5678

Cevap

The command 'ipv6 route 2001:db8:10:20::/64 GigabitEthernet0/0/1 fe80::212:79ff:fe34:5678' correctly configures the fully specified IPv6 static route.
The command correctly uses the Cisco IOS syntax for a static route pointing to a link-local address: 'ipv6 route <prefix/length> <exit-interface> <link-local-address>'. Because link-local IPv6 addresses (FE80::/10) are valid only on the local link, the local exit interface must be explicitly stated.

Adım Adım Çözüm

1
Identify the target destination prefix and length.
Destination prefix is 2001:db8:10:20::/642001:\text{db8}:10:20::/64.
The prefix specifies the remote network to be added to the IPv6 routing table.
2
Evaluate the next-hop address type.
The next-hop address fe80::212:79ff:fe34:5678\text{fe80}::212:79\text{ff}:\text{fe34}:5678 is a link-local IPv6 address (starts with FE80::/10).
Link-local addresses require explicit egress interface identification because they are bound to a specific link.
3
Apply Cisco IOS IPv6 static route command syntax for link-local next hops.
Syntax must be: 'ipv6 route <prefix/length> <exit-interface> <link-local-next-hop>'.
Cisco IOS requires the local exit interface (GigabitEthernet0/0/1) immediately following the prefix and preceding the link-local address.

Anahtar Kavram

IPv6 Static Routing with Link-Local Next Hop
Soru 1365Soru →

Complete the Cisco IOS command below to configure a floating static route for the 172.16.100.0/22 network using the next-hop address 10.254.1.2. The route must serve as a floating backup to a primary path learned via internal EIGRP. Enter the dotted-decimal subnet mask in the first blank and the minimum integer administrative distance value required for backup operation in the second blank.

Aşağıdaki boşlukları doldurun

ip route 172.16.100.0 10.254.1.2
Cevabı ve açıklamayı göster

Cevap

blank_1: 255.255.252.0, blank_2: 91
To configure a floating static route in Cisco IOS for the 172.16.100.0/22 prefix, the subnet mask must be specified in dotted-decimal format as 255.255.252.0. Internal EIGRP operates with a default Administrative Distance of 90. To ensure the static route acts strictly as a floating backup—entering the routing table only when the primary EIGRP route is lost—the static route must be assigned an Administrative Distance greater than 90. The minimum integer value that achieves this is 91.

Adım Adım Çözüm

1
Convert the CIDR prefix length /22 to a dotted-decimal subnet mask.
A /22 prefix corresponds to 22 contiguous network bits (11111111.11111111.11111100.00000000), which equals 255.255.252.0.
Cisco IOS IPv4 static route syntax requires the subnet mask in dotted-decimal notation.
2
Identify the default Administrative Distance (AD) of internal EIGRP.
Internal EIGRP has a default AD of 90.
A floating static route must have an AD strictly greater than the primary route's AD to remain inactive in the routing table while the primary path is reachable.
3
Calculate the minimum administrative distance for the floating static route.
The minimum integer value greater than 90 is 91.
Assigning an AD of 91 ensures the static route is floating (inactive) relative to EIGRP (AD 90) but activates immediately if the EIGRP route fails.

Anahtar Kavram

Floating Static Route Configuration and Administrative Distance
Tahmini Süre:2m 0s
Soru 1366Soru →

A network administrator executes the following configuration commands on a Cisco router interface connected to an Ethernet switch:

text
R1(config)# interface GigabitEthernet0/1
R1(config-if)# ip ospf network point-to-point

Prior to this change, GigabitEthernet0/1 was operating under the default Cisco IOS OSPF settings for Ethernet interfaces. Which statement accurately describes the effect of this configuration change on OSPF DR/BDR elections and timer values for GigabitEthernet0/1?

Cevabı ve açıklamayı göster

Cevap: OSPF DR and BDR elections are suppressed on the interface, while the default Hello timer remains 10 seconds.

Cevap

OSPF DR and BDR elections are suppressed on the interface, while the default Hello timer remains 10 seconds.
On Cisco routers, Ethernet interfaces default to the Broadcast network type, which elects a Designated Router (DR) and Backup Designated Router (BDR) and uses a 10-second Hello interval. Manually overriding the network type with `ip ospf network point-to-point` instructs OSPF to treat the link as a direct point-to-point connection. As a result, DR and BDR elections are completely suppressed on that interface. Because the standard Hello interval for OSPF Point-to-Point interfaces is also 10 seconds, the Hello timer remains unchanged.

Adım Adım Çözüm

1
Identify default OSPF parameters for Ethernet media.
By default, Cisco IOS assigns the OSPF network type 'Broadcast' to Ethernet interfaces, which uses a 10-second Hello timer (40-second Dead timer) and elects a DR/BDR.
Ethernet is multi-access media, requiring DR/BDR to reduce adjacency count.
2
Analyze the impact of the 'ip ospf network point-to-point' command.
Configuring 'point-to-point' changes the network type to Point-to-Point, which does NOT elect a DR/BDR on the interface.
Point-to-Point networks assume only two routers exist on the link, rendering designated routers unnecessary.
3
Determine timer adjustments associated with the Point-to-Point network type.
The Point-to-Point network type in OSPFv2 defaults to a 10-second Hello timer and 40-second Dead timer.
Both Broadcast and Point-to-Point OSPF network types share the same default 10-second Hello / 40-second Dead timer interval.

Anahtar Kavram

OSPFv2 Network Types and DR/BDR Suppression
Soru 1367Soru →

An enterprise router R1 learns the internal destination network 10.50.0.0/1610.50.0.0/16 dynamically via OSPF (default Administrative Distance of 110). A network administrator needs to manually configure two IPv4 static routes on R1:
1. A secondary backup (floating) static route to reach 10.50.0.0/1610.50.0.0/16 via the next-hop IP address 192.168.12.2192.168.12.2.
2. A default static route to forward all non-matching IPv4 traffic to the upstream ISP router at next-hop IP 203.0.113.1203.0.113.1.

Which TWO commands must be configured on router R1 to achieve these routing requirements? (Select TWO.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: ip route 10.50.0.0 255.255.0.0 192.168.12.2 130; ip route 0.0.0.0 0.0.0.0 203.0.113.1

Cevap

The correct commands are 'ip route 10.50.0.0 255.255.0.0 192.168.12.2 130' to establish a floating static route with an Administrative Distance higher than OSPF (110), and 'ip route 0.0.0.0 0.0.0.0 203.0.113.1' to establish a standard default static route using the prefix 0.0.0.0/0.
To create a floating static route, the Administrative Distance specified at the end of the 'ip route' command must be higher than that of the primary routing source. Since OSPF has an AD of 110, setting an AD of 130 guarantees the route will only be installed in the Routing Information Base (RIB) if the primary OSPF route disappears. Additionally, a default static route requires matching any IP address, configured with destination network 0.0.0.0 and subnet mask 0.0.0.0 pointing to the next-hop router address.

Adım Adım Çözüm

1
Determine the primary route's Administrative Distance (AD) for network 10.50.0.0/16.
OSPF has a default AD of 110.
Floating static routes must have an AD strictly greater than the active dynamic protocol's AD to remain inactive until primary route failure.
2
Validate the floating static route syntax and AD parameter.
The command syntax 'ip route 10.50.0.0 255.255.0.0 192.168.12.2 130' specifies an AD of 130, which is higher than 110.
AD 130 ensures the static route remains floating in backup mode until OSPF drops the path.
3
Formulate the default static route syntax for all unrouted traffic.
A default route uses destination prefix 0.0.0.0 and subnet mask 0.0.0.0 followed by the next-hop IP 203.0.113.1.
The prefix 0.0.0.0 0.0.0.0 matches any IPv4 address with a 0-bit prefix length.

Anahtar Kavram

Floating Static Routes and Default Static Route Syntax
Soru 1368Soru →

A network engineer is analyzing the rapid convergence mechanism of Rapid PVST+ (IEEE 802.1w) on a point-to-point link between two Cisco Catalyst switches. Place the steps of the Rapid PVST+ Proposal-Agreement handshake sequence in the correct chronological order from first event to final event.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct order of events in the Rapid PVST+ Proposal-Agreement handshake sequence is: 1) The upstream switch transmits a BPDU with the Proposal bit set. 2) The downstream switch selects the port as its new Root Port and blocks non-edge Designated Ports (synchronization). 3) The downstream switch sends an Agreement BPDU back to the upstream switch. 4) The upstream switch immediately transitions its Designated Port to the Forwarding state.
Rapid PVST+ (IEEE 802.1w) achieves rapid convergence on point-to-point links through an active handshake sequence between switch ports. First, the upstream switch transmits a proposal BPDU on its Designated Port. Second, the downstream switch recognizes the superior BPDU, adopts the receiving interface as its Root Port, and blocks all non-edge Designated Ports to synchronize the switch topology. Third, once synchronized, the downstream switch responds with an Agreement BPDU on its new Root Port. Finally, the upstream switch receives this agreement and immediately transitions its Designated Port to the Forwarding state without waiting for legacy forward delay timers.

Adım Adım Çözüm

1
Identify the initial proposal transmission.
The upstream switch sends a BPDU with the Proposal bit set.
Rapid PVST+ uses explicit handshake messages rather than timer-based transitions on point-to-point links. The process starts when a switch sends a Proposal BPDU out of a Designated Port.
2
Determine the downstream switch state synchronization.
The downstream switch selects the port as Root Port and puts non-edge Designated Ports into Discarding.
To prevent transient Layer 2 loops while agreeing to the new topology, the downstream switch performs synchronization by isolating (discarding on) all non-edge Designated ports.
3
Identify the agreement response mechanism.
The downstream switch sends an Agreement BPDU back on its new Root Port.
Once all interfaces are verified synchronous, the downstream switch confirms loop-free readiness by transmitting an Agreement BPDU.
4
Determine the final port state transition.
The upstream switch transitions its Designated Port directly into Forwarding.
Upon receiving the Agreement BPDU, the upstream switch immediately moves its Designated Port to Forwarding without waiting for traditional 15-second Listening/Learning timers.

Anahtar Kavram

Rapid PVST+ Proposal-Agreement Handshake Convergence
Soru 1369Soru →

An enterprise network team is allocated the IPv4 address block 10.240.16.0/2010.240.16.0/20 to provision subnets for remote branch offices. Each branch subnet must support at least 60 usable host addresses. What is the maximum number of equal-sized subnets that can be created from this address block?

Cevabı ve açıklamayı göster

Cevap: 64

Cevap

The maximum number of equal-sized subnets that can be created is 64.
To support 60 usable host addresses, a subnet requires 6 host bits because 26−2=622^6 - 2 = 62 usable addresses (25−2=302^5 - 2 = 30 is insufficient). A subnet with 6 host bits corresponds to a prefix length of /26 (32−6=2632 - 6 = 26). Subtracting the original block prefix (/20) from the subnet prefix (/26) yields 6 borrowed subnet bits. Calculating 262^6 gives 64 maximum equal-sized subnets.

Adım Adım Çözüm

1
Calculate required host bits for 60 usable hosts
6 host bits (26−2=62≥602^6 - 2 = 62 \ge 60)
Network and broadcast addresses are reserved and cannot be assigned to hosts, requiring subtraction of 2 from total addresses.
2
Determine target prefix length
Prefix length of /26
Subtracting 6 host bits from the 32 bits of an IPv4 address results in a 26-bit network prefix.
3
Calculate borrowed subnet bits
6 subnet bits
The difference between the new prefix (/26) and the allocated prefix (/20) represents the borrowed bits (26−20=626 - 20 = 6).
4
Calculate total usable subnets
64 subnets
The formula 2s2^s, where ss is the number of borrowed bits, gives 26=642^6 = 64 available subnets.

Anahtar Kavram

IPv4 Subnetting and Host Requirement Sizing
Soru 1370Soru →

A network engineer wants to configure a floating static route to serve as a backup to a primary route learned via OSPF, which has an Administrative Distance of 110. Which Administrative Distance value should be specified in the static route command so that it is only installed in the routing table when the OSPF route fails?

Cevabı ve açıklamayı göster

Cevap: 120

Cevap

The correct administrative distance is 120 because a floating static route must have an administrative distance higher than the primary routing protocol (OSPF AD 110) to remain inactive until the primary route fails.
A floating static route acts as a backup route and is configured with an Administrative Distance higher than that of the primary routing protocol. Since OSPF has an AD of 110, setting the static route's AD to 120 keeps it out of the routing table until the primary OSPF route becomes unavailable.

Adım Adım Çözüm

1
Identify the Administrative Distance (AD) of the primary routing protocol.
The primary route is learned via OSPF, which has a default AD of 110.
Administrative Distance determines route trustworthiness, where a lower AD value is preferred.
2
Determine the required AD relationship for a floating (backup) static route.
The floating static route must be configured with an AD strictly greater than 110.
If the static route has a lower or equal AD, it will be preferred over or compete with the primary OSPF route.
3
Select the valid option that satisfies the backup requirement.
An AD of 120 is greater than 110 and represents standard backup static routing behavior.
120 is higher than 110, ensuring the route stays in floating status until the OSPF route fails.

Anahtar Kavram

Floating Static Route Administrative Distance Configuration
Soru 1371Soru →

A network engineer needs to capture raw 802.11 wireless frames over the air on a specific channel to troubleshoot client connectivity failures in a manufacturing warehouse. The dedicated access point used for this operation must stop serving wireless clients and send all captured 802.11 traffic directly to a remote network analyzer tool such as Wireshark. Which Cisco Access Point mode must be configured to accomplish this objective?

Cevabı ve açıklamayı göster

Cevap: Sniffer mode

Cevap

Sniffer mode is the dedicated AP mode used to capture raw 802.11 frames on a specified channel and forward them to a remote packet analyzer tool like Wireshark.
Sniffer mode dedicates the access point radio to listening on a specific channel, capturing raw 802.11 frames, and encapsulation-tunneling those captured frames to a designated IP address running a network packet analyzer such as Wireshark.

Adım Adım Çözüm

1
Identify the primary operational requirement in the scenario.
The AP must capture raw 802.11 over-the-air frames on a dedicated channel and forward them to a packet analyzer (Wireshark) without servicing clients.
Troubleshooting complex 802.11 Layer 2 issues requires dedicated frame-level capture capabilities.
2
Evaluate Cisco AP modes against the required capability.
Sniffer mode turns the AP into a dedicated wireless packet capture device tied to a designated channel and target analyzer IP address.
Other modes either continue to service clients (FlexConnect, Local) or perform non-streaming security monitoring functions (Monitor, Rogue Detector).

Anahtar Kavram

Cisco Lightweight AP Operational Modes and Sniffer Mode Functionality
Soru 1372Soru →

A Cisco router initializes an OSPFv2 process without a manually configured router ID. The router currently has the following operational interfaces:

- Loopback0: 10.10.10.1/3210.10.10.1/32
- Loopback10: 10.20.20.1/3210.20.20.1/32
- GigabitEthernet0/1: 192.168.100.1/24192.168.100.1/24

What IP address will OSPFv2 automatically select as the router ID?

Cevabı ve açıklamayı göster

Cevap: 10.20.20.1

Cevap

10.20.20.1
When an explicit OSPF router ID is not configured using the 'router-id' command, OSPFv2 selects the highest IPv4 address among all active loopback interfaces. Because loopback interfaces take priority over physical interfaces, the router compares 10.10.10.1 and 10.20.20.1, choosing 10.20.20.1 as the router ID.

Adım Adım Çözüm

1
Check if a manual OSPF router ID is configured.
No manual router ID is specified under the OSPF process.
Explicit configuration taking highest precedence is absent.
2
Evaluate active loopback interfaces.
Two active loopback interfaces exist: Loopback0 (10.10.10.110.10.10.1) and Loopback10 (10.20.20.110.20.20.1).
OSPF criteria prioritize active loopback interface IP addresses over active physical interface IP addresses.
3
Determine the highest IP address among active loopback interfaces.
10.20.20.110.20.20.1 is numerically higher than 10.10.10.110.10.10.1.
10.20.20.110.20.20.1 is chosen as the router ID.

Anahtar Kavram

OSPFv2 Router ID Election Order
Tahmini Süre:45s
Soru 1373Soru →

A network administrator initializes an OSPFv2 routing process on a Cisco router without explicitly configuring an OSPF router ID under the router configuration mode. The router displays the following interface status and IP address assignments:

- Loopback0: IP address 10.10.10.1/32, status up, line protocol up
- Loopback1: IP address 192.168.1.1/32, status administratively down, line protocol down
- GigabitEthernet0/0: IP address 172.16.1.1/24, status up, line protocol up
- GigabitEthernet0/1: IP address 192.168.100.1/24, status up, line protocol up

Which IP address will OSPFv2 select as the router ID when the routing process starts?

Cevabı ve açıklamayı göster

Cevap: 10.10.10.1

Cevap

The router will select 10.10.10.1 (Loopback0) as the OSPFv2 Router ID.
OSPFv2 determines its Router ID using a strict three-tier precedence: (1) manual configuration via the 'router-id' command, (2) the highest IPv4 address among active (up/up) loopback interfaces, and (3) the highest IPv4 address among active non-loopback physical interfaces. Because Loopback0 (10.10.10.1) is operational (up/up) and Loopback1 is administratively down, Loopback0 provides the highest active loopback IP address, overriding all physical interface IPs.

Adım Adım Çözüm

1
Check for manual configuration
No explicit 'router-id' command was configured under the OSPF process.
Manual configuration always takes highest precedence.
2
Evaluate loopback interfaces
Loopback0 (10.10.10.1) is up/up. Loopback1 (192.168.1.1) is administratively down.
Only active (up/up) interfaces are considered for router ID election.
3
Apply tie-breaking rules for loopback vs physical interfaces
Loopback0 is the only active loopback interface, so its IP address 10.10.10.1 is selected as the Router ID.
Active loopback interfaces are preferred over active physical interfaces regardless of numerical IP address values.

Anahtar Kavram

OSPFv2 Router ID election precedence logic
Soru 1374Soru →

A network administrator is configuring static routing on Cisco router Branch-R1 to reach remote subnet 2001:db8:3c4d:15::/642001:\text{db8}:3\text{c4d}:15::/64. The routing design requires a primary path using next-hop global unicast address 2001:db8:3c4d:12::22001:\text{db8}:3\text{c4d}:12::2, and a floating static backup path using link-local next-hop address fe80::2\text{fe80}::2 reachable via interface GigabitEthernet0/0/1. Which two commands must be configured on Branch-R1 to fulfill these requirements? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: ipv6 route 2001:db8:3c4d:15::/64 2001:db8:3c4d:12::2; ipv6 route 2001:db8:3c4d:15::/64 GigabitEthernet0/0/1 fe80::2 130

Cevap

The correct commands are 'ipv6 route 2001:db8:3c4d:15::/64 2001:db8:3c4d:12::2' for the primary route and 'ipv6 route 2001:db8:3c4d:15::/64 GigabitEthernet0/0/1 fe80::2 130' for the floating static backup route.
For the primary path, specifying the destination IPv6 prefix and the global unicast next-hop address provides sufficient forwarding information to the routing table. For the backup path, using a link-local IPv6 address requires a fully specified route format that explicitly includes the exit interface (GigabitEthernet0/0/1), combined with an administrative distance greater than 1 (such as 130) so that it functions as a floating backup route.

Adım Adım Çözüm

1
Identify the proper syntax for a primary IPv6 static route using a global unicast next-hop address.
The command syntax is 'ipv6 route <destination-prefix/prefix-length> <global-unicast-next-hop>'. This maps to 'ipv6 route 2001:db8:3c4d:15::/64 2001:db8:3c4d:12::2'.
Global unicast addresses are uniquely identifiable across interfaces, so specifying an exit interface is optional.
2
Identify the mandatory components when configuring a fully specified IPv6 static route with a link-local next-hop address.
Because link-local addresses (fe80::/10) are reused across multiple physical links, Cisco IOS demands both the local exit interface and the link-local address.
Without the local exit interface, the router cannot determine which physical link to transmit packets on to reach fe80::2.
3
Determine the administrative distance requirement for a floating static route.
Assign an administrative distance higher than the primary route's default AD of 1 (e.g., 130).
A higher administrative distance ensures the route remains inactive in the IPv6 routing table until the primary route fails.

Anahtar Kavram

IPv6 Static Route Syntax and Link-Local Next-Hop Requirements
Soru 1375Soru →

Match each physical network cabling or interface standard on the left with its corresponding physical characteristic or specification on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Öğeler

Single-Mode Fiber (SMF) OS2
Multimode Fiber (MMF) OM3
Category 6 UTP (10GBASE-T)
Rollover Cable

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Single-Mode Fiber (SMF) OS2 matches the 9 µm core diameter specification for long-haul links; Multimode Fiber (MMF) OM3 matches the 50 µm core supporting 10 Gbps up to 300 m; Category 6 UTP (10GBASE-T) matches 10 Gbps support up to 55 m; Rollover Cable matches reversing pin connections for console access.
Each physical media type has distinct physical properties: Single-Mode Fiber (OS2) uses a 9 µm core to eliminate modal dispersion over long distances; Multimode Fiber (OM3) uses a laser-optimized 50 µm core to achieve 10 Gbps over 300 m; Category 6 UTP supports 10 Gbps up to 55 m; and Rollover Cable completely flips the pin connections (pin 1 to pin 8) for out-of-band console access.

Adım Adım Çözüm

1
Analyze Single-Mode Fiber (SMF) OS2 characteristics.
Identify that SMF features a small 9 µm core for long-range links with zero modal dispersion.
SMF core size allows only one mode of light propagation, enabling distances of 10 km or more.
2
Analyze Multimode Fiber (MMF) OM3 characteristics.
Identify that OM3 fiber uses a laser-optimized 50 µm core rated for 10 Gbps up to 300 meters.
OM3 fiber is engineered for 850 nm VCSEL lasers to extend 10G reach beyond older OM1/OM2 fibers.
3
Evaluate Category 6 UTP copper constraints for 10GBASE-T.
Match Category 6 UTP to 10 Gbps transmission capped at 55 meters.
Category 6 UTP can support 10 Gbps up to 55 meters, whereas Category 6A extends this reach to 100 meters.
4
Identify the purpose and pinout structure of a Rollover Cable.
Match Rollover Cable to reversing pin connections for switch console management.
Rollover cables flip all 8 pins (pin 1 to 8, 2 to 7) to map DB-9/USB serial adapters to RJ-45 Cisco console ports.

Anahtar Kavram

Physical interface cabling specifications, core diameters, distance limits, and pinout roles in Cisco enterprise networks.
Soru 1376Soru →

A network administrator needs to configure a backup floating static route for destination network 10.30.0.0/16 via next-hop IP 192.168.10.2. The primary route to this destination is learned via internal EIGRP, which has a default administrative distance of 90. What is the minimum administrative distance value that must be specified at the end of the command to ensure the route acts as a backup?

Aşağıdaki boşlukları doldurun

`Router(config)# ip route 10.30.0.0 255.255.0.0 192.168.10.2 `
Cevabı ve açıklamayı göster

Cevap

91
To configure a floating static route, the administrative distance (AD) appended to the end of the `ip route` command must be higher than the AD of the primary route. Because internal EIGRP has an administrative distance of 90, the minimum integer value required to make the static route act as a backup is 91.

Adım Adım Çözüm

1
Identify the administrative distance (AD) of the primary routing protocol.
Internal EIGRP has a default Administrative Distance of 90.
Floating static routes rely on administrative distance values to determine route preference in the Cisco IOS routing table.
2
Determine the required administrative distance for the backup static route.
The floating static route must have an AD strictly greater than 90.
A route with a lower AD is always preferred. Standard static routes have a default AD of 1, which would override EIGRP if not changed.
3
Calculate the minimum integer value.
The lowest integer greater than 90 is 91.
Setting the AD to 91 ensures EIGRP is preferred under normal operations while allowing the static route to take over if EIGRP fails.

Anahtar Kavram

Floating Static Route Administrative Distance Configuration
Soru 1377Soru →

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

Gateway of last resort is 192.168.10.1 to network 0.0.0.0

S* 0.0.0.0/0 [1/0] via 192.168.10.1
D 172.20.0.0/16 [90/307200] via 10.1.1.2, 02:14:10, GigabitEthernet0/0
O 172.20.100.0/24 [110/20] via 10.2.2.2, 01:45:12, GigabitEthernet0/1
R 172.20.100.32/27 [120/2] via 10.3.3.2, 00:12:05, GigabitEthernet0/2

When the router receives an IP packet with a destination address of 172.20.100.50172.20.100.50, to which next-hop IP address and interface will the router forward the packet?

Cevabı ve açıklamayı göster

Cevap: 10.3.3.2 via GigabitEthernet0/2, because 172.20.100.32/27 provides the longest matching subnet mask for the destination IP address.

Cevap

The router forwards the packet to next-hop 10.3.3.2 via interface GigabitEthernet0/2 because 172.20.100.32/27 is the longest prefix match.
When a router makes a forwarding decision, it evaluates all matching routes in the routing table and selects the route with the most specific (longest) subnet mask. The destination IP 172.20.100.50 matches four routes in the routing table: 0.0.0.0/0, 172.20.0.0/16, 172.20.100.0/24, and 172.20.100.32/27 (range 172.20.100.32 to 172.20.100.63). Because /27 has the highest number of matching network bits, the router selects 172.20.100.32/27 and forwards the packet to next-hop 10.3.3.2 out GigabitEthernet0/2.

Adım Adım Çözüm

1
Identify all candidate routes matching the destination IP address 172.20.100.50172.20.100.50.
0.0.0.0/00.0.0.0/0 (/0), 172.20.0.0/16172.20.0.0/16 (/16), 172.20.100.0/24172.20.100.0/24 (/24), and 172.20.100.32/27172.20.100.32/27 (/27) all cover 172.20.100.50172.20.100.50.
The range for 172.20.100.32/27172.20.100.32/27 is 172.20.100.32172.20.100.32 to 172.20.100.63172.20.100.63, which includes host .50.50.
2
Compare the prefix lengths of all matching routes.
Prefix lengths are /0, /16, /24, and /27.
The router forwarding engine always selects the matching route with the most specific (longest) prefix mask.
3
Select the route with the maximum prefix length.
Route 172.20.100.32/27172.20.100.32/27 has the longest prefix match (/27).
Administrative Distance (AD) and metric are ignored when routes have different prefix lengths; Longest Prefix Match (LPM) takes strict priority.

Anahtar Kavram

Longest Prefix Match (LPM) Rule
Soru 1378Soru →

A Cisco router's IPv4 routing table contains the following entries:

text
Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 5 subnets, 3 masks
O 10.180.0.0/14 [110/65] via 192.168.12.2, 00:04:12, GigabitEthernet0/0/1
D 10.180.0.0/16 [90/307200] via 192.168.10.2, 01:15:04, GigabitEthernet0/0/0
S 10.180.32.0/19 [1/0] via 192.168.15.1, GigabitEthernet0/0/3
O IA 10.180.40.0/22 [110/120] via 192.168.14.2, 00:10:05, GigabitEthernet0/0/2

When a packet destined for IP address 10.180.42.100 arrives at the router, which route entry will the router select to forward the packet?

Cevabı ve açıklamayı göster

Cevap: The OSPF inter-area route to 10.180.40.0/22 because it provides the longest prefix match for the destination address.

Cevap

The router will select the OSPF inter-area route to 10.180.40.0/22 because 10.180.42.100 matches that route with a /22 prefix length, which is the longest matching prefix.
The destination address 10.180.42.100 matches multiple entries in the routing table. Cisco routers evaluate forwarding decisions using the Longest Prefix Match rule, which prioritizes the route with the longest subnet mask length regardless of administrative distance or metric. The route 10.180.40.0/22 covers range 10.180.40.0 to 10.180.43.255, giving a 22-bit matching prefix, which is longer than /19, /16, or /14.

Adım Adım Çözüm

1
Determine which routing table entries match the destination IP 10.180.42.100.
Destination 10.180.42.100 falls into 10.180.0.0/14 (10.180.0.0 - 10.183.255.255), 10.180.0.0/16 (10.180.0.0 - 10.180.255.255), 10.180.32.0/19 (10.180.32.0 - 10.180.63.255), and 10.180.40.0/22 (10.180.40.0 - 10.180.43.255). All four routes are valid matches.
Before making forwarding decisions, the router identifies all routes matching the destination IP address.
2
Compare the prefix lengths of all matching routes to apply the Longest Prefix Match rule.
The prefix lengths are /14, /16, /19, and /22. The longest (most specific) prefix length is /22.
The fundamental routing lookup logic in Cisco IOS prefers the route with the most specific mask (longest subnet mask / highest number of prefix bits).
3
Select the route corresponding to the longest prefix match.
The entry 'O IA 10.180.40.0/22 [110/120] via 192.168.14.2' is selected.
Administrative Distance and metric are completely ignored when comparing routes of different prefix lengths.

Anahtar Kavram

Longest Prefix Match Rule in Cisco Routing Tables
Soru 1379Soru →

A network engineer configures SLAAC on a dual-stack Cisco IOS router interface with a burned-in MAC address of `a036.9f12.3456`. Based on standard IEEE EUI-64 calculations, which IPv6 link-local address is automatically assigned to this interface?

Cevabı ve açıklamayı göster

Cevap: fe80::a236:9fff:fe12:3456

Cevap

The automatically assigned link-local address is fe80::a236:9fff:fe12:3456.
The correct answer derives the link-local address by taking the MAC address a036.9f12.3456, inserting FFFE in the middle (a036.9fff.fe12.3456), and inverting the 7th bit of the first byte from 0 to 1 (0xA0 binary 10100000 -> 0xA2 binary 10100010). Combining this 64-bit interface identifier with the link-local prefix FE80:: results in fe80::a236:9fff:fe12:3456.

Adım Adım Çözüm

1
Split the MAC address into two 24-bit halves.
High-order OUI: a0:36:9f; Low-order NIC ID: 12:34:56.
EUI-64 formatting requires inserting a 16-bit payload into the middle of a standard 48-bit MAC address.
2
Insert the hexadecimal value FFFE between the two halves.
a0:36:9f:ff:fe:12:34:56.
IEEE EUI-64 expansion rule inserts FFFE (11111111 11111110 binary) at the midpoint.
3
Invert the 7th bit (Universal/Local bit) of the first byte.
First byte 0xA0 (10100000 binary) becomes 0xA2 (10100010 binary), yielding interface ID a236:9fff:fe12:3456.
In EUI-64 interface identifiers derived from IEEE MAC addresses, the 7th bit is flipped to indicate universal scope when set to 1.
4
Combine the calculated 64-bit interface ID with the link-local prefix fe80::/10.
fe80::a236:9fff:fe12:3456.
IPv6 link-local autoconfiguration appends the EUI-64 interface ID to fe80::/10.

Anahtar Kavram

Generating an IPv6 EUI-64 interface identifier from a 48-bit MAC address requires inserting FFFE into the middle of the MAC address, flipping the 7th bit (Universal/Local bit) of the first octet, and prepending the fe80::/10 prefix for link-local addresses.
Soru 1380Soru →

A network administrator needs to configure a secondary floating default route on router Edge-2 toward an upstream ISP. The primary default route is learned dynamically via OSPFv3 with a administrative distance of 110. The backup route must forward all unmatched traffic out local interface GigabitEthernet0/1 to the ISP router's link-local next-hop address fe80::250:56ff:fea1:2b3c using an administrative distance of 130. Complete the global configuration command required on router Edge-2 to create this fully specified floating default static route.

Aşağıdaki boşlukları doldurun

ipv6 route GigabitEthernet0/1 fe80::250:56ff:fea1:2b3c
Cevabı ve açıklamayı göster

Cevap

The first blank requires '::/0' to designate the default IPv6 prefix, and the second blank requires '130' to set the administrative distance for the floating static route.
An IPv6 default static route uses the prefix '::/0'. When using a link-local address (fe80::/10) as a next-hop, Cisco IOS requires specifying the local exit interface alongside the link-local address because link-local addresses are scope-bound to a specific link. To make the static route a floating backup path behind OSPFv3 (AD 110), an administrative distance parameter of 130 is added to the end of the global configuration command syntax: 'ipv6 route <prefix/length> <exit-interface> <next-hop-address> [administrative-distance]'.

Adım Adım Çözüm

1
Identify the destination prefix notation for an IPv6 default static route.
The default route covering all IPv6 destinations is represented by '::/0'.
In IPv6 prefix notation, ::/0 represents all possible IPv6 destinations, equivalent to 0.0.0.0 0.0.0.0 in IPv4.
2
Verify link-local next-hop syntax requirements.
The exit interface GigabitEthernet0/1 precedes the link-local address fe80::250:56ff:fea1:2b3c.
Link-local addresses (fe80::/10) are only unique on the local link segment. Cisco IOS mandates specifying the egress interface when using a link-local address as a next-hop.
3
Determine the administrative distance needed for floating route behavior.
Append '130' to the end of the command.
To float behind an active OSPFv3 route (AD 110), the static route's administrative distance must be higher than 110. The scenario specifies an AD of 130.

Anahtar Kavram

IPv6 Fully Specified Floating Static Default Route Syntax
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