Tüm alıştırma soruları

1987 soru

Tüm türler1,987 Çoktan seçmeli1,020 Çoklu seçim452 Sayısal18 Eşleştirme229 Sıralama203 Boşluk doldurma22 Kısa cevap43

A network administrator issues the `show ip route` command on a Cisco router and observes the following partial routing table output:

text
Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 4 subnets, 3 masks
O 10.20.0.0/16 [110/20] via 192.168.12.2, 00:15:10, GigabitEthernet0/0
D 10.20.30.0/24 [90/307200] via 192.168.23.3, 01:42:15, GigabitEthernet0/1
S 10.20.30.128/25 [1/0] via 192.168.34.4, GigabitEthernet0/2
O E2 10.0.0.0/8 [110/20] via 192.168.12.2, 00:05:22, GigabitEthernet0/0

Which TWO statements correctly describe the forwarding behavior and components of this routing table? (Select TWO.)

Geçerli olan tümünü seçin

A packet destined for 10.20.30.140 is egressed via GigabitEthernet0/2 because 10.20.30.128/25 provides the longest prefix match.

The route entry for 10.20.30.0/24 indicates an Administrative Distance of 307200 and a routing metric of 90.

For a packet destined to 10.20.30.150, the router prefers the static route (10.20.30.128/25) over the OSPF route (10.20.0.0/16) primarily due to prefix length rather than administrative distance.

A packet destined for 10.20.30.50 is routed out interface GigabitEthernet0/0 because OSPF has a lower metric than EIGRP.

Cevabı ve açıklamayı göster

Cevap: A packet destined for 10.20.30.140 is egressed via GigabitEthernet0/2 because 10.20.30.128/25 provides the longest prefix match.; For a packet destined to 10.20.30.150, the router prefers the static route (10.20.30.128/25) over the OSPF route (10.20.0.0/16) primarily due to prefix length rather than administrative distance.

Cevap

The router forwards a packet destined for 10.20.30.140 out GigabitEthernet0/2 due to the longest prefix match (/25), and it evaluates prefix length prior to Administrative Distance when choosing between 10.20.30.128/25 and 10.20.0.0/16 for host 10.20.30.150.

Routing table lookups prioritize the Longest Prefix Match (most specific subnet mask). For 10.20.30.140, the /25 route matches and is more specific than /24, /16, or /8, directing traffic to GigabitEthernet0/2. Similarly, prefix specificity overrides administrative distance when comparing non-identical prefix lengths such as /25 versus /16.

Adım Adım Çözüm

Parse the bracketed notation [AD/Metric] for Cisco routing entries.

In [90/307200], Administrative Distance is 90 and the composite metric is 307200.

Distinguishes Administrative Distance from protocol metrics.

Evaluate the IP destination 10.20.30.140 against candidate routing table entries.

Matches 10.0.0.0/8, 10.20.0.0/16, 10.20.30.0/24, and 10.20.30.128/25 (valid host range 10.20.30.129–10.20.30.254).

Identifies all candidate routes containing the destination IP address.

Apply the Longest Prefix Match (LPM) rule.

Selects 10.20.30.128/25 over shorter prefixes (/24, /16, /8), routing out GigabitEthernet0/2.

Prefix length length determines matching priority before administrative distance is ever evaluated for unequal prefixes.

Anahtar Kavram

Routing Table Components and Longest Prefix Match Determination

Soru 1662Soru →

Two Cisco Catalyst switches running Rapid PVST+ are configured with an identical base bridge priority of $4096$ for VLAN $30$ . Which factor ultimately determines which switch is elected as the Root Bridge for VLAN $30$ ?

The switch with the lowest MAC address, because both switches have an identical total Bridge Priority of

4126

The switch with the highest MAC address, because Rapid PVST+ prefers higher physical hardware addresses during tie-breakers.

The switch with the lowest port ID connected to the neighbor, because port IDs break priority ties before MAC addresses are evaluated.

The switch configured first, because Rapid PVST+ retains the active Root Bridge role until an administrative preempt command is issued.

Cevabı ve açıklamayı göster

Cevap: The switch with the lowest MAC address, because both switches have an identical total Bridge Priority of $4126$ .

Cevap

The switch with the lowest MAC address will be elected as the Root Bridge because both switches generate an identical total Bridge Priority of

4126

The correct answer identifies that both switches have a total Bridge Priority of

4126

(

4096

base priority +

30

VLAN ID extension). Because their priorities are equal, the tie-breaker rule dictates that the switch with the lowest MAC address is selected as the Root Bridge.

Adım Adım Çözüm

Calculate the total Bridge Priority for each switch

Total Priority = Base Priority (

4096

) + System ID Extension (

30

) =

4126

Rapid PVST+ automatically adds the VLAN ID to the base priority step.

Compare the total Bridge IDs of both switches

Both switches share the exact same Bridge Priority (

4126

When total priorities match, the election moves to the final component of the Bridge ID.

Apply the Root Bridge tie-breaker rule

The switch with the numerically lowest MAC address wins the Root Bridge election.

In Spanning Tree election criteria, lower numeric values are always preferred.

Anahtar Kavram

Rapid PVST+ Root Bridge Election and System ID Extension Calculation

Soru 1663Soru →

Four Cisco routers (R1, R2, R3, and R4) are connected to a single Layer 2 Ethernet switch on the 10.1.1.0/24 broadcast multi-access network segment. All four routers run OSPFv2 in Area 0 and are powered on simultaneously. Their interface OSPF priorities and OSPF Router IDs are configured as follows:

- R1: Router ID 192.168.100.1, Interface Priority = 0
- R2: Router ID 10.1.1.20, Interface Priority = 100
- R3: Router ID 172.16.50.1, Interface Priority = 100
- R4: Router ID 10.1.1.40, Interface Priority = 10

Which router is elected as the Designated Router (DR) and which router is elected as the Backup Designated Router (BDR) for this multi-access segment?

R3 is elected as DR, and R2 is elected as BDR.

R1 is elected as DR, and R3 is elected as BDR.

R2 is elected as DR, and R3 is elected as BDR.

R3 is elected as DR, and R1 is elected as BDR.

Cevabı ve açıklamayı göster

Cevap: R3 is elected as DR, and R2 is elected as BDR.

Cevap

R3 is elected as Designated Router (DR), and R2 is elected as Backup Designated Router (BDR).

The correct response identifies R3 as DR and R2 as BDR. In OSPFv2 broadcast multi-access networks, any router with an interface priority of 0 is strictly excluded from becoming a DR or BDR (relegated to DROTHER status). Thus, R1 is ineligible despite having the highest Router ID. Among the eligible routers (R2, R3, and R4), R2 and R3 share the highest priority (100). The tie is broken by comparing Router IDs; R3 (172.16.50.1) is higher than R2 (10.1.1.20), making R3 the DR. R2 is then elected as BDR because its priority (100) is higher than R4's priority (10).

Adım Adım Çözüm

Filter out disqualified routers based on OSPF interface priority.

R1 has an OSPF priority of 0, which makes it ineligible to participate in DR/BDR elections (it remains DROTHER). Eligible candidates are R2 (Priority 100), R3 (Priority 100), and R4 (Priority 10).

An interface priority of 0 explicitly prevents a router from becoming a DR or BDR regardless of its Router ID.

Determine the Designated Router (DR) using priority and Router ID rules.

R2 and R3 have the highest priority value (100). Comparing Router IDs, R3's Router ID (172.16.50.1) is numerically higher than R2's Router ID (10.1.1.20). R3 is selected as DR.

OSPF DR election first chooses the candidate with the highest priority. If priorities tie, it chooses the candidate with the highest Router ID.

Determine the Backup Designated Router (BDR) from the remaining eligible candidates.

Remaining candidates are R2 (Priority 100) and R4 (Priority 10). R2 has the higher priority, so R2 is selected as BDR.

After DR selection, the BDR is chosen using the same highest-priority and highest-Router-ID criteria among remaining eligible routers.

Anahtar Kavram

OSPFv2 DR/BDR Election Precedence and Priority 0 Disqualification

Soru 1664Soru →

A network technician is provisioning host interfaces within the enterprise block assigned as $10.80.192.0/22$ . Which of the following IPv4 addresses are valid, usable host addresses within this specific subnetwork? (Select TWO.)

Geçerli olan tümünü seçin

10.80.192.1

10.80.195.250

10.80.192.0

10.80.195.255

10.80.196.1

Cevabı ve açıklamayı göster

Cevap: $10.80.192.1$ ; $10.80.195.250$

Cevap

The addresses

10.80.192.1

and

10.80.195.250

are the valid usable host addresses within the

10.80.192.0/22

subnetwork.

The prefix

/22

yields a subnet mask of

255.255.252.0

, providing

2^{10} - 2 = 1022

usable host addresses per subnet. The subnet boundaries run from network ID

10.80.192.0

to broadcast address

10.80.195.255

. Thus, the valid host range spans from

10.80.192.1

through

10.80.195.254

. Both

10.80.192.1

and

10.80.195.250

fall strictly inside this range.

Adım Adım Çözüm

Determine the subnet mask from prefix length

Prefix

/22

corresponds to a subnet mask of

255.255.252.0

Converting

/22

to binary gives 22 network bits and 10 host bits (

11111111.11111111.11111100.00000000

Calculate block size and network boundary

Block size in the 3rd octet is

256 - 252 = 4

. The subnet starts at

10.80.192.0

and ends right before

10.80.196.0

The 3rd octet increments in multiples of 4 (

0, 4, 8, \dots, 192, 196

). Network ID is

10.80.192.0

Identify broadcast address and usable host range

Broadcast address is

10.80.195.255

. Usable host range is

10.80.192.1

10.80.195.254

Usable host addresses are all IP values between the network ID and the broadcast ID.

Evaluate choices against the usable range

10.80.192.1

and

10.80.195.250

lie within

[10.80.192.1, 10.80.195.254]

10.80.192.0

is the network ID,

10.80.195.255

is the broadcast ID, and

10.80.196.1

is in the next subnet.

Only IP addresses inside the calculated host range can be assigned to devices.

Anahtar Kavram

IPv4 Subnet Boundaries and Host Address Ranges

Soru 1665Soru →

An administrator inspects the OSPFv2 interface settings on router HQ-R1 and observes a Hello interval of 10 seconds and a Dead interval of 40 seconds on interface GigabitEthernet0/1 (10.0.12.1/24, Area 0). On the directly connected router BR-R1 interface GigabitEthernet0/1 (10.0.12.2/24), OSPFv2 is configured in Area 0 with a Hello interval of 15 seconds and a Dead interval of 60 seconds. What is the outcome of the OSPFv2 neighbor relationship between HQ-R1 and BR-R1?

The routers fail to establish a neighbor relationship, and neither router accepts the other as a valid neighbor.

The routers progress to the EXSTART state but remain stuck because timer parameters cannot be negotiated.

The routers reach the 2-WAY state and elect a Designated Router, but cannot exchange Database Descriptor packets.

The routers successfully form a FULL adjacency, but routes learned with non-default timers receive an infinite metric.

Cevabı ve açıklamayı göster

Cevap: The routers fail to establish a neighbor relationship, and neither router accepts the other as a valid neighbor.

Cevap

The routers fail to establish a neighbor relationship because OSPF Hello and Dead timer intervals must match on directly connected interfaces.

For two routers to form an OSPFv2 neighbor adjacency, several parameters in their Hello packets must match: Area ID, Subnet Mask, Hello Interval, Dead Interval, Stub Area Flag, and Authentication. Because HQ-R1 has a Hello/Dead timer configuration of 10s/40s while BR-R1 has 15s/60s, the Hello packets received by each router fail validation and are discarded, preventing any neighbor relationship from forming.

Adım Adım Çözüm

Analyze OSPF Hello packet parameter requirements for neighbor adjacency.

Identified that Hello interval, Dead interval, Area ID, Subnet Mask, and Authentication parameters must match in Hello packets.

OSPF routers drop incoming Hello packets if any mandatory Hello packet fields do not match the local configuration.

Compare the configured OSPF timer values between HQ-R1 and BR-R1.

HQ-R1 uses Hello/Dead of 10s/40s while BR-R1 uses Hello/Dead of 15s/60s.

The mismatched Hello (10s vs 15s) and Dead (40s vs 60s) intervals prevent packet validation.

Determine the resulting OSPF neighbor state.

No neighbor state is formed.

Because Hello packets are dropped upon receipt, neither router moves past the Down state for this peer.

Anahtar Kavram

OSPFv2 Mandatory Neighbor Adjacency Parameters

Soru 1666Soru →

A network administrator configures the IP address of an external DNS server on a Cisco IOS router using the command `ip name-server 10.1.1.1`. However, when attempting to ping a remote server by its hostname (`ping server1.example.com`), the router immediately fails to resolve the name and no DNS query packets are transmitted. Which command must be entered in global configuration mode to enable the router to perform DNS queries for hostname resolution?

ip domain lookup

ip dns server

ip domain name example.com

ip helper-address 10.1.1.1

Cevabı ve açıklamayı göster

Cevap: ip domain lookup

Cevap

The command `ip domain lookup` must be configured in global configuration mode to enable Cisco IOS DNS hostname resolution.

The `ip domain lookup` command globally enables the DNS host name resolution feature on a Cisco IOS router. Without this command enabled, the router will not generate DNS request packets to configured DNS servers specified by `ip name-server`.

Adım Adım Çözüm

Identify the role of the Cisco IOS device in name resolution

The router is acting as a DNS client trying to resolve hostnames to IP addresses for local CLI operations.

Configuring `ip name-server` defines the destination DNS server IP address, but the DNS lookup process must be globally enabled on the device.

Determine the global command required to enable client DNS lookups

Executing `ip domain lookup` enables the IP DNS client feature in Cisco IOS.

If DNS lookup is disabled (via `no ip domain lookup`), Cisco IOS will not initiate DNS queries over UDP port 53 even if valid name servers are defined.

Anahtar Kavram

Cisco IOS DNS Client Configuration and Hostname Resolution Mechanics

Soru 1667Soru →

A network engineer is configuring an IPv4 static route on router HQ to reach the destination subnet $172.16.40.0/24$ . Router HQ connects to the next-hop router over an Ethernet broadcast multi-access segment via interface GigabitEthernet0/1. The engineer enters the command `ip route 172.16.40.0 255.255.255.0 GigabitEthernet0/1` without specifying the next-hop IP address. Which operational issue will occur on router HQ as a result of configuring only the exit interface on a multi-access link?

The router treats the destination network as directly connected and sends an ARP request for every destination IP address in the 172.16.40.0/24 subnet, causing ARP table bloat and performance degradation.

The router assigns an administrative distance of 255 to the route, rendering it unusable and removing it from the IPv4 routing table.

The route is rejected by Cisco IOS syntax validation because an administrative distance value is required whenever an interface parameter is used.

The router drops packets matching the route because recursive lookup logic is automatically disabled on Layer 3 GigabitEthernet interfaces.

Cevabı ve açıklamayı göster

Cevap: The router treats the destination network as directly connected and sends an ARP request for every destination IP address in the 172.16.40.0/24 subnet, causing ARP table bloat and performance degradation.

Cevap

Specifying only an exit interface on a broadcast multi-access link (like Ethernet) causes the router to treat the remote prefix as directly connected. When forwarding traffic, the router issues an ARP request for every individual destination IP within that prefix. This relies heavily on proxy ARP from the next-hop router, causing unnecessary ARP broadcast traffic and consuming significant Memory/CPU resources due to ARP cache growth.

Adım Adım Çözüm

Analyze static route exit interface behavior on broadcast networks.

When a static route specifies only a multi-access exit interface (such as Ethernet), Cisco IOS assumes the destination network resides directly on that interface segment.

Directly connected interface routes prompt the router to attempt Layer 2 MAC address resolution for every individual target destination IP address.

Evaluate layer 2 address resolution mechanics (ARP).

Router HQ generates an ARP request broadcast for each unique IP address in the

172.16.40.0/24

network.

Without a explicit next-hop IP specified in the route, the router relies on proxy ARP from the neighboring router, creating large ARP tables and high broadcast overhead.

Anahtar Kavram

Directly Attached Static Routes on Multi-Access Ethernet Links

Tahmini Süre:1m 30s

Soru 1668Soru →

An enterprise client workstation attempts to access an external web application at `app.partner.example.net` for the first time. Arrange the steps of the complete DNS resolution process in the correct chronological order, starting from the client's initial lookup request to the final IP address retrieval.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence begins with the client host checking its local resolver cache and hosts file, followed by sending a recursive query to the local internal DNS resolver. The internal resolver then performs iterative queries starting at the root server, proceeding to the .net TLD server, and finally querying the authoritative server for partner.example.net before caching the record and returning the resolved IP address to the client.

The proper sequence follows standard operating system and DNS protocol operational order: local client cache and hosts file check -> client recursive query to the local internal DNS resolver -> internal resolver iterative query to the root name server -> root referral to the TLD server -> TLD referral to the domain authoritative server -> authoritative answer returned, cached by the internal resolver, and forwarded to the client.

Adım Adım Çözüm

Check local OS resolution mechanisms.

The host OS scans the local `hosts` file and client DNS cache for `app.partner.example.net`.

Local lookup prevents unnecessary network overhead if the IP address is already known locally.

Transmit recursive query from client host to configured DNS server.

A UDP port 53 recursive query is sent to the internal enterprise DNS resolver.

The client delegates name resolution responsibility entirely to its configured local DNS server.

Initiate iterative resolution from the DNS root hierarchy.

The internal DNS server queries a DNS root hint server (`.`).

When resolving an un-cached external FQDN, the recursive resolver starts lookups at the root zone.

Process root referral response.

The root server responds with NS and glue A records for the `.net` TLD servers.

Root servers maintain delegation points for top-level domains.

Query TLD name server for domain authority.

The `.net` TLD server provides NS records pointing to authoritative servers for `partner.example.net`.

TLD servers maintain delegations for secondary registered domains under their top-level domain.

Fetch definitive record from authoritative server and respond to client.

The authoritative server responds with the `A` record, which the internal server caches and forwards to the requesting client.

Only authoritative name servers hold the master resource records for the targeted domain.

Anahtar Kavram

DNS Lookup and Name Resolution Roles in Enterprise Networks

Tahmini Süre:2m 0s

Soru 1669Soru →

A network engineer is tasking a Cisco IOS router with Port Address Translation (PAT) to enable Internet access for internal endpoints on the $192.168.20.0/24$ network using the public IPv4 address assigned to interface GigabitEthernet0/0/1. Which two configuration steps are required on the router to accomplish this requirement? (Select two.)

Geçerli olan tümünü seçin

Define an IPv4 Access Control List (ACL) that permits traffic originating from the internal

192.168.20.0/24

subnet.

Execute the global configuration command `ip nat inside source list <ACL> interface GigabitEthernet0/0/1 overload`.

Execute the global configuration command `ip nat inside source list <ACL> interface GigabitEthernet0/0/1` without the `overload` keyword.

Define an Access Control List (ACL) matching destination range

172.32.0.0/12

to classify private local endpoints.

Cevabı ve açıklamayı göster

Cevap: Define an IPv4 Access Control List (ACL) that permits traffic originating from the internal $192.168.20.0/24$ subnet.; Execute the global configuration command `ip nat inside source list <ACL> interface GigabitEthernet0/0/1 overload`.

Cevap

To configure interface-based PAT (overload) on Cisco IOS, an administrator must define an ACL identifying the inside local host network and bind that ACL to the outside WAN interface using `ip nat inside source list <ACL> interface <interface-id> overload`.

Configuring interface-based Port Address Translation (PAT) requires creating an ACL that permits internal host addresses (

192.168.20.0/24

) and linking that ACL to the egress interface with `ip nat inside source list <ACL> interface GigabitEthernet0/0/1 overload`. The `overload` keyword is mandatory to enable layer 4 port tracking so multiple hosts can share one IP.

Adım Adım Çözüm

Identify the internal host network requiring translation.

Internal subnet is identified as

192.168.20.0/24

An Access Control List (ACL) must be configured to match traffic coming from

192.168.20.0/24

Bind the matching ACL to the external interface using PAT.

The command `ip nat inside source list <ACL> interface GigabitEthernet0/0/1 overload` is configured.

The `overload` keyword allows multiple internal hosts to share the single interface IP address by tracking unique L4 port numbers.

Anahtar Kavram

Port Address Translation (PAT) interface overload configuration

Soru 1670Soru →

Arrange the Cisco Hot Standby Router Protocol (HSRP) router states in the correct sequential order from initial interface startup to the active forwarding role.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence of HSRP state transitions from startup to active forwarding is: Initial state, Listen state, Speak state, Standby state, and Active state.

HSRP router state transitions follow a strict logical progression: Initial (startup), Listen (receives Hello packets), Speak (sends Hello packets and joins election), Standby (selected as candidate backup), and Active (forwards virtual IP traffic).

Adım Adım Çözüm

Identify the initialization state.

The router starts in the Initial state.

An interface must be enabled and initialized before any protocol messages are processed.

Determine the discovery phase.

The router transitions to the Listen state.

In the Listen state, the router receives Hello packets from existing group members without sending its own.

Identify the election participation phase.

The router moves to the Speak state.

The router sends periodic Hello messages to compete for active or standby router roles.

Determine the backup role assignment.

The router enters the Standby state.

The router is designated as the candidate to take over if the active router fails.

Identify the primary forwarding role.

The router reaches the Active state.

The elected router actively forwards frames destined to the virtual MAC and virtual IP address.

Anahtar Kavram

HSRP Router State Machine Sequence

Soru 1671Soru →

A network administrator is evaluating the protocol mechanics and default operational behaviors of HSRPv2 and VRRPv2 across an enterprise distribution layer. Which two statements accurately describe the functional differences in preemption, virtual IP assignment, or virtual MAC addressing between HSRP and VRRP? (Select two.)

Geçerli olan tümünü seçin

VRRP permits configuring the virtual IP address to match the physical IP address assigned to an interface, whereas HSRP requires the virtual IP address to be an unassigned address within the local subnet.

VRRP enables preemption by default for participating routers, whereas HSRP requires preemption to be explicitly configured on candidate standby routers.

HSRPv2 uses the well-known MAC address prefix range 0000.5E00.01xx, whereas VRRPv2 utilizes 0000.0C9F.Fxxx for virtual gateway addressing.

Assigning an active router's physical IPv4 address as the HSRP virtual IP address is supported in HSRPv2 and automatically elevates the router priority to 255.

Cevabı ve açıklamayı göster

Cevap: VRRP permits configuring the virtual IP address to match the physical IP address assigned to an interface, whereas HSRP requires the virtual IP address to be an unassigned address within the local subnet.; VRRP enables preemption by default for participating routers, whereas HSRP requires preemption to be explicitly configured on candidate standby routers.

Cevap

The correct statements are that VRRP permits configuring the virtual IP address to match a physical IP address (IP address owner) while HSRP requires a unique IP, and VRRP enables preemption by default whereas HSRP requires explicit preemption configuration.

VRRP supports IP address ownership, allowing the virtual IP address to be identical to the primary physical IP address of an interface (which automatically assigns priority 255 to that router). HSRP does not support this and mandates that the virtual IP address must be an unused IP on the subnet. Additionally, VRRP preemption is enabled by default, whereas HSRP requires manual preemption configuration.

Adım Adım Çözüm

Analyze virtual IP assignment rules for HSRP vs VRRP

VRRP supports IP address ownership where the Master router's physical interface IP is used as the virtual IP (priority becomes 255). HSRP requires the virtual IP to be a separate, distinct IP address not assigned to any physical interface in the subnet.

Determines the validity of virtual IP configuration options.

Analyze default preemption mechanics across both protocols

VRRP has preemption enabled by default with a default priority of 100. HSRP has preemption disabled by default, meaning a higher-priority router will not take over the Active role unless 'standby preempt' is explicitly configured.

Identifies procedural configuration differences for failover behavior.

Verify virtual MAC address allocations for HSRPv2 and VRRPv2

VRRPv2 uses

0000.5E00.01xx

. HSRPv1 uses

0000.0C07.ACxx

, and HSRPv2 uses

0000.0C9F.Fxxx

Evaluates MAC range precision to rule out inverted options.

Anahtar Kavram

HSRP vs VRRP Operational & Architectural Comparison

Soru 1672Soru →

A network engineer is configuring link aggregation (LAG) on a Cisco Wireless LAN Controller (WLC) to connect to a Cisco Catalyst switch stack. The WLC distribution system ports are connected to ports GigabitEthernet1/0/1 through GigabitEthernet1/0/4 on the switch stack.

Which behavior accurately describes how the Wireless LAN Controller manages interface traffic and link failures when LAG is enabled?

All distribution system ports are combined into a single logical port channel, and if an individual physical link fails, traffic is dynamically redistributed across the remaining active links without interrupting wireless traffic.

Each distribution system port acts as a dedicated primary interface for a specific WLAN, and link failures require manual failover reassignment of the affected WLAN to an operational backup port.

The controller negotiates active and standby links using LACP, keeping two ports active while holding two ports in a standby state until an active link fails.

Untagged AP management frames are dropped by the switch trunk unless each physical distribution port is configured with a unique native VLAN setting across the member ports.

Cevabı ve açıklamayı göster

Cevap: All distribution system ports are combined into a single logical port channel, and if an individual physical link fails, traffic is dynamically redistributed across the remaining active links without interrupting wireless traffic.

Cevap

When Link Aggregation (LAG) is enabled on a Wireless LAN Controller, all physical distribution system ports are combined into a single logical EtherChannel trunk. Traffic across all configured WLANs and management interfaces is load-balanced across the active links. If any physical port in the bundle experiences a failure, the controller and upstream switch immediately re-route traffic over the remaining operational member links without dropping client sessions or requiring manual intervention.

Adım Adım Çözüm

Identify the operational characteristics of Link Aggregation (LAG) on a Wireless LAN Controller.

Enabling LAG merges all physical distribution system ports into a single logical EtherChannel/port-channel interface.

Bundling ports provides both increased aggregate throughput and full link redundancy for all controller-managed VLANs.

Analyze how traffic distribution and fault tolerance function within the unified LAG bundle.

If a physical link within the LAG fails, the WLC immediately redistributes client and management traffic over the remaining operational links.

Redistribution happens transparently at Layer 2 without requiring manual remapping of WLANs or AP management interfaces.

Anahtar Kavram

WLAN Infrastructure Connections and LAG Operation

Tahmini Süre:1m 0s

Soru 1673Soru →

A network engineer executes the `show interfaces FastEthernet0/10 switchport` command on a Cisco Catalyst switch to verify port settings after assigning it to a departmental network. The partial output displays the following parameters:

Name: Fa0/10
Switchport: Enabled
Administrative Mode: dynamic auto
Operational Mode: static access
Access Mode VLAN: 40 (FINANCE)

Which interface configuration command must the engineer enter on FastEthernet0/10 to statically force the interface into access mode and disable Dynamic Trunking Protocol (DTP) negotiation?

switchport mode access

switchport access vlan 40

switchport trunk native vlan 40

switchport nonegotiate

Cevabı ve açıklamayı göster

Cevap: switchport mode access

Cevap

The command 'switchport mode access' statically configures the interface into access mode and disables DTP dynamic trunk negotiation.

The output indicates that the administrative mode is currently 'dynamic auto', meaning the port is dynamically operating in access mode only because the connected neighbor is not actively negotiating a trunk. Executing 'switchport mode access' under interface configuration mode statically forces the interface into access mode, overriding DTP dynamic negotiation.

Adım Adım Çözüm

Analyze the CLI output for administrative versus operational state.

The administrative mode is currently set to 'dynamic auto' (default on many Cisco Catalyst switches), while the operational mode is currently operating as 'static access' because the connected endpoint is not attempting DTP negotiation.

An interface in 'dynamic auto' mode is willing to become a trunk if the neighboring device actively requests it (e.g., dynamic desirable or trunk mode).

Determine the required CLI command to hardcode static access mode.

Entering interface configuration mode and executing 'switchport mode access' explicitly locks the administrative mode to static access.

Hardcoding access mode turns off DTP negotiation attempts to form a trunk, improving security and port stability.

Anahtar Kavram

Disabling DTP Negotiation and Statically Hardcoding Access Ports

Tahmini Süre:1m 0s

Soru 1674Soru →

A client workstation is configured to obtain IPv4 addressing dynamically. Arrange the four messages exchanged during the standard DHCP lease process (DORA) in chronological order from first to last.

Öğeleri doğru sıraya koymak için sürükleyin

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Cevap

The chronological sequence of the IPv4 DHCP operation is DHCPDISCOVER, DHCPOFFER, DHCPREQUEST, and DHCPACK.

The standard IPv4 DHCP lease negotiation process follows the four-step DORA sequence: Discover (client broadcast), Offer (server response), Request (client selection broadcast), and Acknowledge (server confirmation).

Adım Adım Çözüm

Identify the initial client discovery broadcast.

DHCPDISCOVER is sent first by the client.

The client has no assigned IP address and must broadcast to discover active DHCP servers.

Identify the server offer response.

DHCPOFFER is sent second by the server.

A server receiving the discovery broadcast offers an available IP address and subnet parameters.

Identify the client acceptance broadcast.

DHCPREQUEST is sent third by the client.

The client broadcasts its intent to accept the specific offer, allowing unselected servers to release their reserved offers.

Identify the server final acknowledgment.

DHCPACK is sent fourth by the server.

The server acknowledges the request and locks in the IP lease parameters for the client.

Anahtar Kavram

DHCP DORA Process (Discover, Offer, Request, Acknowledge)

Soru 1675Soru →

An enterprise network engineer observes that a Cisco IOS device attempting to resolve a hostname receives a DNS response from the DNS server with the Truncation (TC) bit set in the DNS header. Which action does the client device perform to obtain the complete set of resource records?

It initiates a TCP connection to the DNS server on port 53 and re-issues the lookup request.

It retransmits the identical UDP query to the secondary configured DNS server address on port 53.

It sends an ICMP Packet Too Big message back to the DNS server to request IP layer packet fragmentation.

It aborts the DNS lookup process and sends a local subnet broadcast query using Link-Local Multicast Name Resolution.

Cevabı ve açıklamayı göster

Cevap: It initiates a TCP connection to the DNS server on port 53 and re-issues the lookup request.

Cevap

The client device initiates a TCP connection to the DNS server on port 53 and re-issues the lookup request.

Standard DNS transactions utilize UDP port 53 due to lower overhead. However, basic UDP DNS responses are restricted to a maximum size of 512 bytes. If the answer exceeds this size limit, the DNS server sets the Truncation (TC) bit in the DNS header. When a client receives a response with the TC bit set, it recognizes that data was omitted and re-issues the query over a TCP connection to port 53, allowing the full set of resource records to be transferred reliably.

Adım Adım Çözüm

Analyze standard DNS transport protocol limits.

Standard DNS resolution operates over UDP port 53 with a maximum message size limit of 512 bytes to minimize network overhead.

UDP provides fast name resolution without requiring connection setup state.

Identify the purpose of the DNS Truncation (TC) bit.

When a DNS response payload exceeds 512 bytes, the responding DNS server sets the TC bit to 1 in the DNS response header.

This signals to the client that the returned data was truncated and incomplete.

Determine the RFC-compliant DNS client behavior upon receiving a truncated response.

The client opens a reliable TCP connection to the same DNS server on port 53 and re-sends the query.

TCP streaming handles large payloads by managing segmentation and reliable delivery without the 512-byte restriction.

Anahtar Kavram

DNS Transport Protocols and Truncation Mechanics (UDP vs TCP Port 53)

Tahmini Süre:1m 30s

Soru 1676Soru →

A network administrator is configuring Cisco HSRP group 5 on interface GigabitEthernet0/0 of a primary router. The interface is assigned the physical IPv4 address 10.1.10.2/24. When executing the command `standby 5 ip 10.1.10.2`, the router rejects the configuration. Which statement correctly explains why Cisco IOS rejects this command?

HSRP requires the virtual IPv4 address to be unique and not match the physical IP address of any participating router interface.

VRRP protocol rules automatically enforce that the primary master router must use its own physical IP address as the virtual IP address in HSRP.

HSRP virtual IPv4 addresses must be configured from a separate, non-overlapping IP subnet than the physical interface IP address.

HSRP group numbers must match the host portion of the interface physical IPv4 address before the virtual IP command is accepted.

Cevabı ve açıklamayı göster

Cevap: HSRP requires the virtual IPv4 address to be unique and not match the physical IP address of any participating router interface.

Cevap

HSRP requires the virtual IPv4 address to be unique and not match the physical IP address of any participating router interface.

In HSRP, the virtual IPv4 address shared by the redundancy group must be a unique IP address in the local subnet that is not assigned as the physical interface address of any member router. When a network administrator attempts to assign an existing physical IP as the HSRP virtual IP, Cisco IOS rejects the command.

Adım Adım Çözüm

Analyze the HSRP virtual IP address configuration rule in Cisco IOS.

In HSRP (both v1 and v2), the virtual IP address must be a separate, unused IP address within the local primary IP subnet.

Cisco IOS explicitly blocks assigning a router's physical interface IP address as the HSRP virtual IP address to avoid ARP and routing conflicts.

Compare HSRP behavior with VRRP.

Unlike VRRP (which permits an IP Address Owner where the virtual IP matches the physical IP), HSRP rejects physical IP assignment.

Understanding protocol differences prevents misconfiguration errors on Cisco routers.

Anahtar Kavram

HSRP Virtual IP Address Assignment Rules

Soru 1677Soru →

Match each OSPFv2 interface scenario or configuration on the left to its corresponding election behavior or timer characteristics on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

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Cevap

The correct pairings are: 1) GigabitEthernet interface with 'ip ospf network point-to-point' matches 'Uses 10-second Hello / 40-second Dead timers and dynamically forms adjacencies without electing a DR or BDR.'; 2) Ethernet interface with 'ip ospf priority 0' matches 'Remains in the DROTHER state and is completely excluded from participating in DR/BDR elections regardless of Router ID.'; 3) Frame Relay main interface with default OSPF network type matches 'Defaults to Non-Broadcast (NBMA) mode using 30-second Hello / 120-second Dead timers and requires manual unicast neighbor statements.'; 4) Interface with priority 200 added to a segment with an active DR (priority 100) matches 'Does not preempt the operational DR upon initialization, assuming BDR or DROTHER status until an election event occurs.'

Each OSPF network type and interface parameter dictates distinct neighbor discovery methods, timer values, and election roles. Converting a broadcast interface to point-to-point maintains 10-second timers while removing DR/BDR election. Setting priority to 0 explicitly forces a DROTHER state. Default Frame Relay main interfaces employ NBMA mode with 30-second timers requiring unicast neighbor commands. Finally, introducing a high-priority router to a segment with an existing active DR honors OSPF's non-preemptive election rule.

Adım Adım Çözüm

Analyze OSPF network type override on broadcast interfaces.

Configuring 'ip ospf network point-to-point' on a broadcast interface (such as GigabitEthernet) instructs OSPF to treat the link logically as point-to-point. This retains the 10/40 second timers but suppresses DR/BDR election.

Point-to-point interfaces only connect two routers, making DR/BDR election unnecessary.

Evaluate the effect of interface priority 0.

An OSPF interface priority of 0 explicitly disqualifies the router interface from becoming a DR or BDR, locking its state into DROTHER.

Priority 0 is a reserved value designed specifically to prevent specific routers from taking on DR/BDR responsibilities.

Determine default behavior on Non-Broadcast Multi-Access (NBMA) media.

Frame Relay main interfaces default to the Non-Broadcast (NBMA) OSPF network type, which has 30-second Hello / 120-second Dead timers and does not send multicast Hello packets.

NBMA interfaces support multiple access without native broadcast/multicast capability, requiring static unicast neighbor configuration.

Analyze non-preemptive DR/BDR election mechanics.

When a router boots or connects to an existing multi-access network with an established DR, it accepts the existing DR and BDR regardless of its own interface priority.

DR/BDR elections in OSPF are non-preemptive to maintain routing stability and prevent unnecessary adjacency updates.

Anahtar Kavram

OSPFv2 Network Types, Timers, Priority Exclusions, and Non-preemptive Election Behavior

Soru 1678Soru →

A network administrator is evaluating First Hop Redundancy Protocols (FHRP) for deployment across campus gateways. Which two statements correctly describe default operational characteristics of HSRPv1 compared to VRRPv2?

Geçerli olan tümünü seçin

VRRP enables router preemption by default, whereas HSRP requires preemption to be explicitly configured under interface settings.

HSRP permits configuring an active router's physical IP address as the group virtual IP address, whereas VRRP strictly forbids matching the virtual IP with an interface IP.

HSRP designates redundancy roles as Active and Standby, whereas VRRP uses Master and Backup to define router states.

VRRP sends periodic master advertisement messages to IPv4 multicast address 224.0.0.2, whereas HSRPv1 sends hello messages to 224.0.0.18.

Cevabı ve açıklamayı göster

Cevap: VRRP enables router preemption by default, whereas HSRP requires preemption to be explicitly configured under interface settings.; HSRP designates redundancy roles as Active and Standby, whereas VRRP uses Master and Backup to define router states.

Cevap

VRRP enables preemption by default while HSRP requires explicit preemption configuration, and HSRP uses Active/Standby role terminology while VRRP uses Master/Backup.

VRRP has preemption enabled by default and uses Master/Backup role terminology, whereas HSRP has preemption disabled by default and uses Active/Standby role terminology.

Adım Adım Çözüm

Evaluate preemption default settings for HSRP and VRRP

VRRP preemption is enabled by default; HSRP preemption is disabled by default.

By protocol specification, VRRP automatically preempts lower-priority master routers unless preemption is manually disabled, whereas HSRP requires interface preemption syntax.

Examine operational role terminology across both protocols

HSRP uses Active and Standby; VRRP uses Master and Backup.

This aligns with RFC standards for VRRP compared to Cisco proprietary HSRP conventions.

Anahtar Kavram

First Hop Redundancy Protocols (HSRP and VRRP) default behavior comparison

Soru 1679Soru →

A network engineer is implementing SNMP telemetry across an enterprise routing infrastructure. The network management system (NMS) must perform scheduled status polling while also receiving confirmed alerts for critical interface state changes. Which TWO statements correctly describe the operational mechanisms and transport ports used by SNMP in this environment?

Geçerli olan tümünü seçin

SNMP Informs require the receiving network management station to return an explicit Response PDU to the agent over UDP port 162 to acknowledge delivery.

SNMP Traps achieve reliable delivery by establishing a connection over TCP port 162, which handles frame sequencing and retransmissions.

SNMP polling requests, such as GetRequest and SetRequest, are transmitted by the NMS to the managed device agent listening on UDP port 161.

SNMP agent polling operations sent from the NMS to query device MIB objects are directed to UDP destination port 162 on the managed router.

Cevabı ve açıklamayı göster

Cevap: SNMP Informs require the receiving network management station to return an explicit Response PDU to the agent over UDP port 162 to acknowledge delivery.; SNMP polling requests, such as GetRequest and SetRequest, are transmitted by the NMS to the managed device agent listening on UDP port 161.

Cevap

The correct statements are that SNMP Informs require the receiving network management station to return an explicit Response PDU to the agent over UDP port 162, and that SNMP polling requests (such as GetRequest and SetRequest) are transmitted by the NMS to the managed device agent listening on UDP port 161.

The statements confirming that SNMP Informs demand an explicit Response PDU acknowledgement over UDP port 162 and that NMS polling requests target UDP port 161 on managed agents are technically accurate. SNMP agents listen for incoming requests on UDP port 161. When asynchronous events occur, agents send Traps or Informs to the NMS on UDP port 162. While Traps are unacknowledged, Informs mandate a Response PDU back from the NMS to confirm receipt.

Adım Adım Çözüm

Identify transport port usage for SNMP polling versus notifications.

Managed agents listen for NMS requests (Get/Set) on UDP port 161, while NMS trap/inform receivers listen for notifications on UDP port 162.

SNMP separates request-response agent traffic from asynchronous trap/inform notification traffic by port number.

Evaluate the delivery mechanism difference between Traps and Informs.

Both Traps and Informs use UDP transport (port 162). Traps are unacknowledged, while Informs require the manager to send a Response PDU back to the agent.

Informs provide application-layer reliability over UDP without relying on TCP connections.

Anahtar Kavram

SNMP Transport Ports and Trap vs. Inform Mechanics

Soru 1680Soru →

Four Cisco routers (R1, R2, R3, and R4) are connected to a single Layer 2 Ethernet switch on the 192.168.1.0/24 subnet and configured for OSPFv2 single-area routing in Area 0. R1 and R2 have their OSPF interface priorities set to 100 and 50, respectively. R3 and R4 both have their OSPF interface priorities configured as 0. All routers are booted simultaneously and reach steady-state OSPF convergence. What is the expected OSPF neighbor state between R3 and R4 when executing the `show ip ospf neighbor` command on R3?

2WAY/DROTHER, because routers configured with a priority of 0 only build full adjacencies with the DR and BDR on broadcast multi-access networks.

FULL/DROTHER, because all OSPF routers on the same broadcast multi-access segment automatically establish full neighbor relationships with every router.

INIT/DROTHER, because setting an interface priority to 0 prevents a router from processing incoming OSPF Hello packets from other non-DR routers.

EXSTART/DROTHER, because routers with an interface priority of 0 are barred from negotiating Master/Slave parameters during database description exchange.

Cevabı ve açıklamayı göster

Cevap: 2WAY/DROTHER, because routers configured with a priority of 0 only build full adjacencies with the DR and BDR on broadcast multi-access networks.

Cevap

The expected OSPF neighbor state between R3 and R4 is 2WAY/DROTHER because DROTHER routers on a broadcast multi-access network form full adjacencies only with the DR and BDR, remaining in the 2-WAY state with each other.

On a broadcast multi-access network (such as Ethernet), OSPF reduces protocol overhead by electing a Designated Router (DR) and Backup Designated Router (BDR). Routers configured with an interface priority of 0 (DROTHERs) build FULL neighbor adjacencies only with the DR and BDR. Between two DROTHER routers (in this scenario, R3 and R4), bidirectional communication is established via Hello packets, so their neighbor relationship settles permanently in the 2-WAY state (displayed as 2WAY/DROTHER). This is normal operating behavior.

Adım Adım Çözüm

Analyze the network type and OSPF priorities.

The network segment is Ethernet (broadcast multi-access). R1 (priority 100) becomes DR, R2 (priority 50) becomes BDR, while R3 and R4 (priority 0) become DROTHERs.

Setting the OSPF interface priority to 0 disqualifies a router from being elected as DR or BDR.

Determine OSPF adjacency rules on multi-access networks.

DROTHER routers form FULL adjacencies exclusively with the DR and BDR. Between two DROTHER routers (R3 and R4), the neighbor relationship stops at the 2-WAY state.

Limiting FULL adjacencies to DR/BDR minimizes Link State Advertisement (LSA) flooding and memory overhead on shared network segments.

Anahtar Kavram

OSPF Neighbor States and DR/BDR Adjacency Requirements on Multi-Access Networks

Tahmini Süre:1m 30s

ÖncekiSayfa 84 / 100Sonraki

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