IPv4 Static Routing

89 soru

Soru 1Soru

A network technician is adding a secondary path on Router-HQ to reach the internal subnet 172.16.40.0/24172.16.40.0/24. The primary link currently learns this destination via EIGRP with an administrative distance of 90. To ensure the secondary static path through next-hop IP 10.1.1.210.1.1.2 serves strictly as a backup when the primary link is down, which Cisco IOS command must be configured?

Cevabı ve açıklamayı göster

Cevap: ip route 172.16.40.0 255.255.255.0 10.1.1.2 100

Cevap

The command 'ip route 172.16.40.0 255.255.255.0 10.1.1.2 100' correctly configures a floating static route by specifying an administrative distance higher than the primary routing protocol.
A floating static route functions as a backup path by configuring an administrative distance (AD) higher than the primary active route's protocol. Since the primary route is learned via internal EIGRP (AD 90), assigning an AD of 100 to the static route keeps it out of the active routing table until the EIGRP path becomes unavailable.

Adım Adım Çözüm

1
Identify the primary route's Administrative Distance (AD)
EIGRP internal route has an AD of 90.
Floating static routes rely on AD values to determine precedence.
2
Determine the required AD for a floating static backup route
The floating static route must have an AD strictly greater than 90 (e.g., 100).
Lower administrative distances are preferred in the IP routing table.
3
Construct the Cisco IOS static route command syntax
'ip route <destination> <mask> <next-hop> [administrative-distance]'
Applying this syntax yields 'ip route 172.16.40.0 255.255.255.0 10.1.1.2 100'.

Anahtar Kavram

Floating Static Route Administrative Distance Calibration
Soru 2Soru

A network administrator intends to configure a backup floating static route on router R1 to reach destination network 10.50.0.0/1610.50.0.0/16 in the event that the primary route learned via OSPF fails. The administrator enters the following configuration command on R1:

`ip route 10.50.0.0 255.255.0.0 192.168.12.2 105`

What is the immediate impact of this configuration on router R1's routing table?

Cevabı ve açıklamayı göster

Cevap: The static route becomes the active route in the routing table because its administrative distance of 105 is lower than OSPF's default administrative distance of 110.

Cevap

The static route becomes the active route in the routing table because its administrative distance of 105 is lower than OSPF's default administrative distance of 110.
In Cisco IOS, administrative distance (AD) determines which routing source is preferred when multiple sources provide routes to the same network prefix. OSPF has a default AD of 110. Because the configured static route specifies an AD of 105, which is lower (more trusted) than 110, the static route immediately takes precedence and replaces the OSPF route in the active routing table.

Adım Adım Çözüm

1
Identify default Administrative Distance (AD) values
Default OSPF AD is 110; default Static Route AD is 1.
Administrative distance measures the trustworthiness of a routing information source.
2
Analyze the configured static route parameter
The trailing value `105` in `ip route 10.50.0.0 255.255.0.0 192.168.12.2 105` sets the static route's AD to 105.
Floating static routes require an AD value higher than the primary routing protocol to stay hidden until the primary path fails.
3
Compare AD values to determine routing table selection
105 (configured static) < 110 (OSPF), so the static route is selected and immediately replaces the OSPF route.
When multiple routes to the exact same destination prefix exist, the router installs the route with the lowest administrative distance into the routing table.

Anahtar Kavram

Floating Static Route Administrative Distance Selection
Soru 3Soru

Router R1 learns routes to the remote destination subnet 172.16.50.0/24172.16.50.0/24 via OSPF, which operates with a administrative distance of 110. A network administrator wants to manually configure a backup floating static route toward 172.16.50.0/24172.16.50.0/24 using next-hop IP address 192.168.12.2192.168.12.2. This backup route must remain inactive in the routing table unless the primary OSPF route fails. Which command must be configured on router R1?

Cevabı ve açıklamayı göster

Cevap: ip route 172.16.50.0 255.255.255.0 192.168.12.2 120

Cevap

The command 'ip route 172.16.50.0 255.255.255.0 192.168.12.2 120' correctly configures the floating static route with an administrative distance higher than OSPF.
A floating static route requires an Administrative Distance higher than that of the primary routing protocol. Since OSPF has an AD of 110, setting the static route AD to 120 ensures it will only be installed in the routing table if the OSPF route disappears.

Adım Adım Çözüm

1
Identify the primary dynamic routing protocol and its administrative distance (AD).
OSPF is the primary routing protocol with an AD of 110.
Floating static routes rely on Administrative Distance ranking to remain inactive until primary routes fail.
2
Determine the required AD for the floating static backup route.
The AD of the static route must be configured to a value strictly greater than 110 (such as 120).
Cisco IOS router forwarding logic installs routes with lower AD values into the IP routing table first.
3
Validate Cisco IOS static route syntax including destination, mask, next-hop IP, and AD.
'ip route 172.16.50.0 255.255.255.0 192.168.12.2 120' fulfills all parameters accurately.
The AD parameter is appended at the end of the 'ip route' command string.

Anahtar Kavram

Floating Static Route Administrative Distance Configuration
Soru 4Soru

A network administrator is configuring IPv4 static routing on router R1. Router R1 currently learns the primary route to destination network 192.168.50.0/24192.168.50.0/24 via iBGP, which has an Administrative Distance of 200. The administrator must configure two static routes:
1. A standard static route to reach network 10.100.1.0/2410.100.1.0/24 via next-hop IPv4 address 172.16.1.2172.16.1.2.
2. A backup floating static route to reach network 192.168.50.0/24192.168.50.0/24 via next-hop IPv4 address 172.16.1.2172.16.1.2 that remains inactive until the primary iBGP route fails.

Which two `ip route` commands must the administrator configure on router R1?

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: ip route 10.100.1.0 255.255.255.0 172.16.1.2; ip route 192.168.50.0 255.255.255.0 172.16.1.2 210

Cevap

The commands 'ip route 10.100.1.0 255.255.255.0 172.16.1.2' and 'ip route 192.168.50.0 255.255.255.0 172.16.1.2 210' are correct.
The command 'ip route 10.100.1.0 255.255.255.0 172.16.1.2' is correct because it follows standard IPv4 static route syntax to direct traffic destined for network 10.100.1.0/24 to next-hop address 172.16.1.2. The command 'ip route 192.168.50.0 255.255.255.0 172.16.1.2 210' is correct because a floating static route requires an Administrative Distance higher than the primary route (iBGP AD = 200); setting the AD to 210 ensures it remains inactive until the primary route fails.

Adım Adım Çözüm

1
Identify standard Cisco IOS static route syntax for network 10.100.1.0/24
ip route 10.100.1.0 255.255.255.0 172.16.1.2
Standard IPv4 static routes use the syntax 'ip route <destination-prefix> <subnet-mask> <next-hop-ip>' with a default Administrative Distance of 1.
2
Determine Administrative Distance requirement for the backup floating static route
Target Administrative Distance must be > 200
A floating static route acts as a backup only when its Administrative Distance is configured higher than the primary path's routing protocol (iBGP AD = 200).
3
Select the correct floating static route command
ip route 192.168.50.0 255.255.255.0 172.16.1.2 210
Specifying an Administrative Distance of 210 ensures the static route remains out of the routing table until the iBGP route (AD 200) is lost.

Anahtar Kavram

IPv4 Static Route Syntax and Floating Static Route Administrative Distance Selection
Soru 5Soru

A network administrator is reviewing IPv4 static route syntax and operational characteristics on a Cisco IOS router. Which two statements regarding Cisco IPv4 static routing are correct?

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: A static route configured with an administrative distance higher than a primary dynamic routing protocol serves as a floating static backup route.; Cisco IOS static route syntax requires specifying the destination network mask using dotted-decimal format rather than a wildcard mask.

Cevap

The correct statements are that configuring an administrative distance higher than the primary protocol creates a floating backup route, and that Cisco IOS static routes require dotted-decimal subnet masks.
Configuring a static route with an administrative distance higher than the primary routing protocol creates a floating static route that remains inactive until the primary route fails. Additionally, Cisco IOS 'ip route' command syntax strictly requires dotted-decimal subnet masks for prefix specification.

Adım Adım Çözüm

1
Analyze static route administrative distance mechanics for floating routes.
Lower administrative distance values are preferred in the routing table. To create a backup (floating) route, its administrative distance must be set higher than the primary route source.
If set lower than the primary dynamic protocol (e.g., 90 vs 110 for OSPF), the static route will preempt the primary protocol immediately.
2
Verify Cisco IOS CLI command syntax parameters for static routing.
The correct command format is 'ip route <destination-prefix> <subnet-mask> {next-hop-ip | exit-interface} [distance]'.
Subnet masks in static routes use dotted-decimal format (e.g., 255.255.255.0), and next-hop IP addresses must belong to the neighboring router.

Anahtar Kavram

Cisco IPv4 Static Route Syntax and Floating Static Administrative Distance Calibration
Tahmini Süre:1m 0s
Soru 6Soru

A network administrator needs to configure a floating static route on a Cisco router to act as a backup link for a primary path learned via OSPF (Administrative Distance of 110). Which Administrative Distance value must be assigned to the floating static route to ensure it is used ONLY when the primary OSPF route becomes unavailable?

Cevabı ve açıklamayı göster

Cevap: 120

Cevap

The floating static route must be configured with an Administrative Distance greater than 110 (such as 120).
For a static route to function as a floating static route (backup), its Administrative Distance must be configured to a value higher than that of the primary route protocol. Since OSPF has an AD of 110, an AD of 120 ensures the static route remains out of the routing table until the OSPF route fails.

Adım Adım Çözüm

1
Identify the Administrative Distance (AD) of the primary dynamic route.
The primary route is learned via OSPF, which has a default AD of 110.
Routers prefer routes with lower AD values when installing paths into the routing table.
2
Determine the AD requirement for a backup (floating) static route.
The floating static route must have an AD higher than 110 (for example, 120).
Assigning a higher AD keeps the backup route inactive ('floating') until the lower AD primary route disappears from the routing table.

Anahtar Kavram

Floating Static Route Administrative Distance Selection
Tahmini Süre:45s
Soru 7Soru

Branch router R2 needs to reach host devices in the remote subnet 172.20.15.0/24172.20.15.0/24. The next-hop router interface connected to R2 is assigned the IPv4 address 10.1.1.210.1.1.2. Which Cisco IOS command correctly defines this IPv4 static route?

Cevabı ve açıklamayı göster

Cevap: ip route 172.20.15.0 255.255.255.0 10.1.1.2

Cevap

The correct command is 'ip route 172.20.15.0 255.255.255.0 10.1.1.2'.
The correct command adheres precisely to Cisco IOS syntax: 'ip route <destination-prefix> <subnet-mask> <next-hop-ip>'. For a /24/24 destination network of 172.20.15.0172.20.15.0 reached via 10.1.1.210.1.1.2, the proper entry is 'ip route 172.20.15.0 255.255.255.0 10.1.1.2'.

Adım Adım Çözüm

1
Identify the target destination prefix and length.
Destination prefix is 172.20.15.0172.20.15.0 with prefix length /24/24.
Static routing requires specifying the destination network ID.
2
Convert prefix length /24/24 to dotted-decimal subnet mask format.
Mask is 255.255.255.0255.255.255.0.
Cisco IOS global configuration syntax requires dotted-decimal subnet masks for IPv4 static routes.
3
Assemble parameters into Cisco IOS command structure 'ip route <destination> <mask> <next-hop>'.
'ip route 172.20.15.0 255.255.255.0 10.1.1.2'
This matches standard Cisco CLI global configuration syntax.

Anahtar Kavram

IPv4 Static Route Syntax
Soru 8Soru

A network administrator needs to configure a floating static default route on a Cisco IOS router to serve as a backup path to a primary default route learned via OSPF. Which two statements accurately describe the requirements for this configuration? (Select TWO)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: The static route command must specify a destination network of 0.0.0.00.0.0.0 and a subnet mask of 0.0.0.00.0.0.0.; The administrative distance configured for the backup static route must be greater than 110110.

Cevap

To configure a floating static default route as a backup to an OSPF route, the destination address and mask must be configured as 0.0.0.0 0.0.0.0, and the administrative distance must be configured to a value greater than 110.
A static default route requires the destination network 0.0.0.00.0.0.0 and mask 0.0.0.00.0.0.0. To make this static route function as a backup (floating route) to an OSPF-learned route, its administrative distance must be higher than OSPF's default AD of 110110.

Adım Adım Çözüm

1
Identify the destination prefix and mask for a default static route.
A default route matches all traffic using the IPv4 prefix 0.0.0.0 and subnet mask 0.0.0.0.
The default static route syntax requires 'ip route 0.0.0.0 0.0.0.0 {ip-address | exit-interface}'.
2
Determine the required Administrative Distance (AD) for a floating backup route.
Since OSPF has a default AD of 110, the static route AD must be set to 111 or higher.
Cisco routers prefer routes with lower AD values. To ensure the static route is used only when the OSPF route fails, its AD must be higher than the OSPF AD.

Anahtar Kavram

IPv4 Floating Static Default Route Requirements
Soru 9Soru

A network administrator needs to configure an IPv4 static default route on a Cisco router pointing to the next-hop IP address 203.0.113.1. Which Cisco IOS command correctly accomplishes this configuration?

Cevabı ve açıklamayı göster

Cevap: ip route 0.0.0.0 0.0.0.0 203.0.113.1

Cevap

ip route 0.0.0.0 0.0.0.0 203.0.113.1
The correct command uses 'ip route 0.0.0.0 0.0.0.0 203.0.113.1'. In Cisco IOS, a static default route is configured using the prefix 0.0.0.0 and mask 0.0.0.0 followed by either the next-hop IPv4 address or an outbound interface.

Adım Adım Çözüm

1
Identify the standard Cisco IOS syntax for IPv4 static routing.
The standard syntax is 'ip route <destination-prefix> <subnet-mask> {ip-address | exit-interface}'.
Cisco IOS requires explicit declaration of the target network prefix, subnet mask, and forwarding target.
2
Determine the prefix and mask required for a static default route.
A default route matching all IPv4 destinations uses network prefix 0.0.0.0 and subnet mask 0.0.0.0.
The prefix 0.0.0.0/0 matches any IPv4 address when no more specific match exists in the routing table.
3
Append the specified next-hop IP address.
Combining the default prefix/mask with next-hop IP 203.0.113.1 yields 'ip route 0.0.0.0 0.0.0.0 203.0.113.1'.
The next-hop IP address designates the forwarding address of the adjacent router.

Anahtar Kavram

IPv4 Static Default Route Configuration
Soru 10Soru

A network engineer is configuring router R1 to reach destination network 172.16.10.0/24172.16.10.0/24. The primary path must use next-hop IP address 192.168.12.2192.168.12.2 with standard default static priority. A backup path must use next-hop IP address 10.0.0.210.0.0.2 and function as a floating static route that only enters the routing table if the primary path is unavailable. Which TWO commands must be configured on R1 to meet these requirements? (Select two.)

Geçerli olan tümünü seçin

Cevabı ve açıklamayı göster

Cevap: ip route 172.16.10.0 255.255.255.0 192.168.12.2; ip route 172.16.10.0 255.255.255.0 10.0.0.2 10

Cevap

The correct commands are 'ip route 172.16.10.0 255.255.255.0 192.168.12.2' for the primary path and 'ip route 172.16.10.0 255.255.255.0 10.0.0.2 10' for the backup floating path.
The command specifying next-hop 192.168.12.2 without an explicit administrative distance correctly creates the primary static route with the default Administrative Distance of 1. The command specifying next-hop 10.0.0.2 with an explicit administrative distance of 10 correctly creates a floating static route, because its higher administrative distance keeps it out of the routing table until the primary route disappears.

Adım Adım Çözüm

1
Identify the proper Cisco IOS IPv4 static route command structure.
The correct command format is 'ip route <destination-prefix> <subnet-mask> <next-hop-ip> [administrative-distance]'.
Cisco IOS requires a subnet mask (not a wildcard mask) and optional administrative distance parameter.
2
Configure the primary static route.
'ip route 172.16.10.0 255.255.255.0 192.168.12.2' is generated.
When no administrative distance is specified at the end of the command, Cisco IOS assigns a default Administrative Distance of 1.
3
Configure the backup floating static route.
'ip route 172.16.10.0 255.255.255.0 10.0.0.2 10' is generated.
A floating static route must have an Administrative Distance higher than the primary route (in this case, 10 > 1) so it remains inactive in the RIB until the primary route fails.

Anahtar Kavram

IPv4 Static Route Syntax and Administrative Distance for Floating Static Routes
Soru 11Soru

Which Cisco IOS command configures an IPv4 floating static route to destination network 172.20.0.0/16172.20.0.0/16 through next-hop IP address 10.0.0.210.0.0.2 so that it serves as a backup to a primary route learned via Internal EIGRP (Administrative Distance of 9090)?

Cevabı ve açıklamayı göster

Cevap: ip route 172.20.0.0 255.255.0.0 10.0.0.2 130

Cevap

ip route 172.20.0.0 255.255.0.0 10.0.0.2 130 correctly configures the backup floating static route with an administrative distance higher than the primary EIGRP route.
The command correctly uses the standard subnet mask format for destination network 172.20.0.0/16 and sets an administrative distance of 130. Because 130 is greater than EIGRP's administrative distance of 90, the router keeps this static route inactive in reserve until the primary EIGRP route is lost.

Adım Adım Çözüm

1
Identify the proper Cisco IOS static route command syntax.
Syntax is: ip route <destination-prefix> <subnet-mask> <next-hop-ip> [distance]
Cisco IOS requires a subnet mask (255.255.0.0) rather than a wildcard mask.
2
Determine the required Administrative Distance (AD) for a floating static route.
The AD must be greater than 90 (the AD of Internal EIGRP).
Routes with lower AD values are preferred in the routing table. To act as a backup, the static route must have a higher AD so it is only installed when the primary route goes down.
3
Select the command matching both syntax and AD requirements.
ip route 172.20.0.0 255.255.0.0 10.0.0.2 130
130 is greater than 90 and the syntax uses the valid subnet mask format.

Anahtar Kavram

IPv4 Floating Static Route Configuration and Administrative Distance Selection
Tahmini Süre:45s
Soru 12Soru

A network engineer needs to configure a floating static route on a Cisco router to serve as a backup path for the destination network 172.28.32.0/21172.28.32.0/21. The primary path to this network is currently learned via OSPF, which operates with an Administrative Distance of 110. Which Cisco IOS command correctly configures the floating static route so that it only enters the routing table if the primary OSPF route fails?

Cevabı ve açıklamayı göster

Cevap: ip route 172.28.32.0 255.255.248.0 10.200.1.2 120

Cevap

ip route 172.28.32.0 255.255.248.0 10.200.1.2 120
The correct command specifies 'ip route 172.28.32.0 255.255.248.0 10.200.1.2 120'. A /21 subnet mask corresponds to 255.255.248.0. Since the primary route is learned via OSPF with an Administrative Distance (AD) of 110, a backup (floating) static route must be configured with an AD greater than 110 (such as 120). This keeps the route out of the routing table until the primary OSPF route is withdrawn.

Adım Adım Çözüm

1
Determine the subnet mask representation for the prefix /21
A /21 network mask consists of 21 contiguous binary 1s: 11111111.11111111.11111000.00000000, which evaluates to 255.255.248.0 in dotted-decimal notation.
Cisco IOS IPv4 static route command syntax requires the netmask parameter in dotted-decimal format.
2
Identify the administrative distance (AD) of the primary dynamic routing protocol
OSPF has a default Administrative Distance of 110.
To create a floating static route, the static route must have an AD strictly greater than the primary route protocol's AD.
3
Select an Administrative Distance value for the floating static route
An AD of 120 is higher than 110, ensuring the route stays inactive in the routing table until OSPF fails.
Lower AD values are preferred by Cisco IOS. Setting the AD to 120 keeps the static route inactive (floating) while OSPF is active.
4
Construct the full Cisco IOS static route command
'ip route 172.28.32.0 255.255.248.0 10.200.1.2 120'
Matches the syntax: 'ip route <prefix> <mask> <next-hop-ip> [distance]'.

Anahtar Kavram

IPv4 Floating Static Route Configuration and Administrative Distance Selection
Soru 13Soru

An enterprise router learns the remote network 10.50.0.0/1610.50.0.0/16 via OSPF, which has a default administrative distance of 110. A network administrator must configure a floating static backup route to reach destination 10.50.0.0/1610.50.0.0/16 using next-hop IP address 192.168.12.2192.168.12.2. The backup route must only enter the routing table if the primary OSPF path fails. Which Cisco IOS command correctly configures this floating static route?

Cevabı ve açıklamayı göster

Cevap: ip route 10.50.0.0 255.255.0.0 192.168.12.2 120

Cevap

The command 'ip route 10.50.0.0 255.255.0.0 192.168.12.2 120' correctly configures the floating static route.
A floating static route acts as a backup path and must remain dormant in the routing table until the primary path fails. Since the primary path is installed by OSPF with an Administrative Distance of 110, the backup static route must be assigned an Administrative Distance higher than 110 (e.g., 120). The command 'ip route 10.50.0.0 255.255.0.0 192.168.12.2 120' fulfills this requirement.

Adım Adım Çözüm

1
Identify the primary routing protocol and its Administrative Distance (AD).
The primary route to 10.50.0.0/1610.50.0.0/16 is learned via OSPF, which has an AD of 110.
Floating static routes rely on AD comparison to remain inactive until primary routes fail.
2
Determine the required AD for the backup floating static route.
The floating static route must have an AD greater than 110 (such as 120).
Lower AD values are preferred by the router forwarding logic; a higher AD ensures the route stays out of the routing table while OSPF is active.
3
Construct the Cisco IOS static route command syntax.
'ip route 10.50.0.0 255.255.0.0 192.168.12.2 120'
Syntax requires destination prefix, subnet mask, next-hop IP, and the explicit administrative distance metric at the end.

Anahtar Kavram

Floating Static Route Administrative Distance Selection
Tahmini Süre:1m 30s
Soru 14Soru

A network engineer is configuring a backup path on router HQ-R1 to reach the corporate subnet 172.20.40.0/22172.20.40.0/22. The primary route to this prefix is currently learned via Internal EIGRP with a default administrative distance of 90. The backup connection uses a point-to-point Ethernet link where HQ-R1 local interface GigabitEthernet0/1 is assigned IP address 198.51.100.1/30198.51.100.1/30 and the remote peer router interface is assigned 198.51.100.254/30198.51.100.254/30.

Which Cisco IOS command must be configured on HQ-R1 to ensure the static route acts as a floating backup route that only enters the routing table if the primary EIGRP route fails?

Cevabı ve açıklamayı göster

Cevap: ip route 172.20.40.0 255.255.252.0 198.51.100.254 95

Cevap

The correct command is `ip route 172.20.40.0 255.255.252.0 198.51.100.254 95`, which specifies the destination network, valid subnet mask, remote next-hop IP, and an administrative distance higher than Internal EIGRP (90).
The correct command properly formats the /22 mask as 255.255.252.0, uses the remote neighbor's interface IP (198.51.100.254) as the next hop, and sets an administrative distance of 95. Because 95 is higher than Internal EIGRP's administrative distance of 90, the router keeps this route out of the active routing table until the EIGRP route fails.

Adım Adım Çözüm

1
Convert the CIDR prefix length /22 to dotted-decimal subnet mask format.
A /22 prefix corresponds to 22 binary ones (11111111.11111111.11111100.00000000), which evaluates to 255.255.252.0.
Cisco IOS static routing syntax requires a valid IPv4 subnet mask following the destination network prefix.
2
Identify the correct next-hop IP address for static route forwarding.
The next-hop IP address must be the neighbor router's IP address on the point-to-point link, which is 198.51.100.254.
Configuring a local interface IP address as a next hop is invalid because a router cannot forward packets to its own local interface.
3
Determine the required Administrative Distance (AD) for a floating static route.
Select an administrative distance value strictly greater than 90 (e.g., 95).
Internal EIGRP has a default AD of 90. To act as a floating backup, the static route's AD must be higher than the active primary routing protocol so that it remains untrusted until the primary route drops from the routing table.

Anahtar Kavram

Floating Static Route Administrative Distance Configuration
Tahmini Süre:1m 30s
Soru 15Soru

An engineer configures a next-hop IPv4 static route on a Cisco router using the command `ip route 10.1.2.0 255.255.255.0 192.168.12.2`. Place the processing steps in the correct sequential order from first to last that the router performs when forwarding an incoming packet destined for 10.1.2.4510.1.2.45.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence for packet forwarding with a next-hop static route is: First, match the packet destination IP 10.1.2.4510.1.2.45 to the static route entry pointing to next-hop 192.168.12.2192.168.12.2. Second, perform a recursive lookup in the routing table for 192.168.12.2192.168.12.2 to find the outgoing interface. Third, look up the MAC address of 192.168.12.2192.168.12.2 in the ARP table. Fourth, encapsulate the packet into a Layer 2 frame and transmit it out the egress interface.
When a static route specifies only a next-hop IPv4 address (recursive static route), the router must first identify the static route via longest-prefix match. Next, it performs a recursive RIB lookup on the next-hop IP address to determine the exit interface. After identifying the exit interface, it performs an ARP table lookup to find the next-hop MAC address, and finally encapsulates and transmits the frame.

Adım Adım Çözüm

1
Evaluate incoming packet destination IP against routing table entries.
The destination address 10.1.2.4510.1.2.45 matches static route 10.1.2.0/2410.1.2.0/24 with next-hop 192.168.12.2192.168.12.2.
Routing decisions begin with a longest-prefix match lookup in the RIB.
2
Perform recursive routing lookup for next-hop IP address 192.168.12.2192.168.12.2.
The router identifies the directly connected network prefix and egress interface used to reach 192.168.12.2192.168.12.2.
Static routes configured solely with a next-hop IP require a recursive lookup to identify the exit interface.
3
Resolve Layer 2 destination hardware address via ARP cache lookup for 192.168.12.2192.168.12.2.
The target next-hop MAC address is retrieved for frame header construction.
Ethernet interfaces require the next-hop MAC address to format the data-link layer encapsulation.
4
Encapsulate IPv4 packet into Layer 2 Ethernet frame and send out the egress interface.
The packet is transmitted on the physical wire.
All forwarding requirements (interface and Layer 2 rewrite info) are complete.

Anahtar Kavram

IPv4 Static Route Recursive Lookup & Forwarding Process
Tahmini Süre:1m 30s
Soru 16Soru

An enterprise router R1 learns a primary path to the remote network 172.16.50.0/24172.16.50.0/24 dynamically through OSPF with an Administrative Distance of 110. A network administrator needs to configure a floating static backup route to 172.16.50.0/24172.16.50.0/24 via the next-hop IPv4 address 10.0.12.210.0.12.2. Which TWO statements accurately describe the requirements and operational behavior of this IPv4 static route configuration? (Select two.)

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Cevap: The floating static route command must specify an administrative distance value greater than 110 (such as 120) so that it is installed in the routing table only if the primary OSPF route fails.; When configured using only the next-hop IPv4 address 10.0.12.210.0.12.2, the router must perform a recursive lookup in the routing table to resolve the outbound interface.

Cevap

The floating static route must be configured with an administrative distance greater than 110 (such as 120) to remain inactive while OSPF is up, and specifying only a next-hop IP address requires the router to perform a recursive routing lookup to resolve the exit interface.
For a static route to function as a floating backup, its Administrative Distance must be configured higher than the primary route's protocol AD (110 for OSPF). Additionally, static routes configured with only an IP next-hop rely on recursive lookup logic to identify the outgoing interface.

Adım Adım Çözüm

1
Analyze the Administrative Distance (AD) requirement for floating static routes.
OSPF has an AD of 110. Standard static routes have an AD of 1. To make a static route act as a floating backup, its AD must be manually set higher than the active protocol (e.g., AD > 110).
The Cisco IOS routing table installs the route with the lowest Administrative Distance when multiple sources offer routes to the exact same prefix.
2
Evaluate router forwarding lookup behavior for next-hop static routes.
Specifying only the next-hop IPv4 address (10.0.12.210.0.12.2) obligates the router to recursively search the routing table to match 10.0.12.210.0.12.2 against directly connected egress interfaces.
Without an explicitly named local exit interface, the control plane must resolve how to reach the next-hop address.
3
Evaluate Longest Prefix Match rules against Administrative Distance.
A default route (0.0.0.0/00.0.0.0/0) is less specific than a /24 route. Longest prefix matching occurs prior to AD comparison, so a /24 route always beats a /0 default route.
Prefix length is the primary criterion in IPv4 forwarding decisions.

Anahtar Kavram

Floating Static Route Administrative Distance and Recursive Next-Hop Lookup
Soru 17Soru

A network administrator is configuring an IPv4 static route on router R1 to reach the remote network 10.10.40.0/2410.10.40.0/24 across an Ethernet multiaccess segment. After issuing the command `ip route 10.10.40.0 255.255.255.0 GigabitEthernet0/0`, the administrator observes high CPU utilization and a large ARP table on R1 because the router attempts to resolve ARP for every individual destination host address in the remote network. Which command modification correctly resolves this issue while maintaining reachability?

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Cevap: Specify the next-hop IPv4 address instead of specifying only the Ethernet exit interface.

Cevap

Specify the next-hop IPv4 address instead of specifying only the Ethernet exit interface.
When a static route on a broadcast multiaccess link (like Ethernet) points solely to an exit interface without a next-hop IP address, the router considers all host addresses in the destination subnet directly connected. Consequently, for every destination packet, the router broadcasts an ARP request on the local segment. Specifying the next-hop IPv4 address ensures the router sends packets to the specific neighbor router's MAC address, preventing ARP flooding and excessive memory usage.

Adım Adım Çözüm

1
Analyze the static route syntax and multiaccess interface behavior.
Configuring `ip route` on a multiaccess Ethernet link with only an exit interface causes the router to assume the destination prefix is directly attached to that Ethernet segment.
Because Ethernet is a multiaccess medium with multiple potential devices, the router must send an ARP request for every single destination IP address in the prefix if no next-hop IP is specified.
2
Determine the solution for multiaccess static route next-hop resolution.
Including the next-hop IPv4 address (e.g., `ip route 10.10.40.0 255.255.255.0 192.168.1.2` or combining next-hop IP and exit interface) allows R1 to resolve ARP only for the next-hop router's IP address.
This avoids generating ARP requests for remote host IPs and prevents ARP table exhaustion and excessive CPU load.

Anahtar Kavram

Next-Hop IPv4 Address vs. Exit Interface in Multiaccess Static Routes
Tahmini Süre:1m 30s
Soru 18Soru

A network engineer is configuring an IPv4 static route on router R1 to reach destination network 172.20.40.0/24172.20.40.0/24. The path connects through an Ethernet broadcast multi-access interface (GigabitEthernet0/1) to the next-hop router address 10.0.12.210.0.12.2. Which command configures a fully specified static route that prevents recursive lookup overhead while avoiding excessive Address Resolution Protocol (ARP) table expansion on the multi-access segment?

Cevabı ve açıklamayı göster

Cevap: ip route 172.20.40.0 255.255.255.0 GigabitEthernet0/1 10.0.12.2

Cevap

The command 'ip route 172.20.40.0 255.255.255.0 GigabitEthernet0/1 10.0.12.2' correctly configures a fully specified static route.
The correct command uses the syntax 'ip route 172.20.40.0 255.255.255.0 GigabitEthernet0/1 10.0.12.2'. By providing both the local exit interface and the specific next-hop IPv4 address, the router creates a fully specified route. This prevents recursive table lookup overhead (associated with next-hop IP only) and avoids excessive ARP requests for individual destination IPs (associated with exit interface only on multi-access media).

Adım Adım Çözüm

1
Identify the static route requirement for a broadcast multi-access network (Ethernet).
On Ethernet links, specifying only an exit interface causes the router to treat all destination IP addresses as directly connected, issuing ARP requests for every destination host.
Ethernet is a multi-access network requiring Layer 2 MAC address resolution.
2
Evaluate the difference between directly attached, next-hop, and fully specified static routes.
A fully specified static route includes both the local exit interface (GigabitEthernet0/1) and the next-hop IP address (10.0.12.2).
This eliminates the need for recursive routing lookups while pinpointing the exact Layer 2 next-hop neighbor.
3
Verify Cisco IOS syntax ordering and subnet mask formatting.
The correct syntax order is 'ip route <prefix> <mask> <exit-interface> <next-hop-ip>'.
Dotted-decimal subnet masks must be used instead of wildcard masks.

Anahtar Kavram

Fully Specified IPv4 Static Route Syntax on Multi-access Networks
Tahmini Süre:1m 15s
Soru 19Soru

A network administrator configures a static route using only a next-hop IP address. Place the operational steps in the correct order that a Cisco IOS router performs to process and forward a packet using this recursive static route.

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Cevap

The correct sequence of packet forwarding steps for a recursive static route is: 1) Evaluate destination against routing table for longest prefix match, 2) Identify matching static route and extract next-hop IP, 3) Perform recursive lookup to resolve next-hop IP to an exit interface, 4) Query ARP table for next-hop MAC address on that interface, 5) Encapsulate frame and forward out the exit interface.
When an IPv4 static route is configured using only a next-hop IP address, Cisco IOS must resolve the outgoing interface by performing a second (recursive) lookup in the routing table. First, the router matches the packet destination address to the static route entry. Second, it extracts the next-hop IP. Third, it recursively resolves that next-hop IP to a connected interface. Fourth, it uses ARP on that interface to determine the next-hop MAC address. Finally, it encapsulates the packet and forwards it out the interface.

Adım Adım Çözüm

1
Examine incoming packet destination
Longest match matching the static route prefix is found
Cisco IOS routing logic always evaluates the destination IPv4 address against all known routes using longest prefix matching first.
2
Extract next-hop IP address
Next-hop IPv4 address identified
Static routes configured in the format 'ip route prefix mask next-hop-ip' do not explicitly define the outgoing interface.
3
Perform recursive routing lookup
Exit interface and directly connected network identified
The router must locate a connected or dynamic route entry that covers the next-hop IP address to find the exit interface.
4
Resolve Layer 2 address
Next-hop MAC address obtained from ARP cache
For multi-access Ethernet interfaces, the router requires the destination MAC address of the next-hop gateway.
5
Frame encapsulation and transmission
Packet successfully transmitted
The packet is encapsulated with the local exit interface source MAC and next-hop destination MAC address.

Anahtar Kavram

Recursive Static Route Lookup and Packet Forwarding Process
Soru 20Soru

A Cisco router relies on OSPF (administrative distance 110) to reach destination network 192.168.10.0/24192.168.10.0/24. A backup path is connected via next-hop IPv4 address 10.0.0.210.0.0.2. The network engineer must configure a floating static route so that traffic uses this secondary link only when the primary OSPF path becomes unavailable. Which command correctly configures this backup static route?

Cevabı ve açıklamayı göster

Cevap: ip route 192.168.10.0 255.255.255.0 10.0.0.2 120

Cevap

The command 'ip route 192.168.10.0 255.255.255.0 10.0.0.2 120' correctly configures the floating static route.
The command specifying 'ip route 192.168.10.0 255.255.255.0 10.0.0.2 120' uses proper Cisco IOS syntax with a subnet mask and assigns an administrative distance of 120. Because 120 is higher than OSPF's administrative distance of 110, the route will stay out of the routing table until the OSPF route is lost.

Adım Adım Çözüm

1
Identify the primary routing protocol's Administrative Distance (AD)
OSPF has an AD of 110.
Floating static routes must have an AD strictly higher than the primary routing protocol to remain inactive while the primary route is present in the routing table.
2
Verify Cisco IOS static route command syntax
Syntax: 'ip route <destination-network> <subnet-mask> <next-hop-ip> [distance]'.
Cisco static routes require a dotted-decimal subnet mask (e.g., 255.255.255.0) rather than a wildcard mask.
3
Select the correct Administrative Distance value
An AD of 120 is greater than 110.
Setting the AD to 120 ensures the static route remains floating in backup state until the primary OSPF route (AD 110) fails.

Anahtar Kavram

Floating Static Route Administrative Distance
Tahmini Süre:1m 15s
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