Free HP HPE6-A85 Practice Exam with Questions & Answers | Set: 2

The Address Resolution Protocol (ARP) is used to map layer-3 IP addresses to layer-2 MAC addresses. When a device on a network wants to communicate with another device, it uses ARP to find the MAC address that corresponds to the IP address it wishes to communicate with, allowing it to construct a frame for the local network.

The reason why you would configure OSPF Open Shortest Path First (OSPF) is a link-state routing protocol that dynamically calculates the best routes for data transmission within an IP network. OSPF uses a hierarchical structure that divides a network into areas and assigns each router an identifier called router ID (RID). OSPF uses hello packets to discover neighbors and exchange routing information. OSPF uses Dijkstra’s algorithm to compute the shortest path tree (SPT) based on link costs and build a routing table based on SPT. OSPF supports multiple equal-cost paths, load balancing, authentication, and various network types such as broadcast, point-to-point, point-to-multipoint, non-broadcast multi-access (NBMA), etc. OSPF is defined in RFC 2328 for IPv4 and RFC 5340 for IPv6. to use the IP address IP address Internet Protocol (IP) address is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. An IP address serves two main functions: host or network interface identification and location addressing. There are two versions of IP addresses: IPv4 and IPv6. IPv4 addresses are 32 bits long and written in dotted-decimal notation, such as 192.168.1.1. IPv6 addresses are 128 bits long and written in hexadecimal notation, such as 2001:db8::1. IP addresses can be either static (fixed) or dynamic (assigned by a DHCP server). 10.1.200.1 as the router ID Router ID (RID) Router ID (RID) is a unique identifier assigned to each router in a routing domain or protocol. RIDs are used by routing protocols such as OSPF, IS-IS, EIGRP, BGP, etc., to identify neighbors, exchange routing information, elect designated routers (DRs), etc. RIDs are usually derived from one of the IP addresses configured on the router’s interfaces or loopbacks, or manually specified by network administrators. RIDs must be unique within a routing domain or protocol instance. is that the loopback interface state Loopback interface Loopback interface is a virtual interface on a router that does notcorrespond to any physical port or connection. Loopback interfaces are used for various purposes such as testing network connectivity, providing stable router IDs for routing protocols, providing management access to routers, etc. Loopback interfaces have some advantages over physical interfaces such as being always up unless administratively shut down, being independent of any hardware failures or link failures, being able to assign any IP address regardless of subnetting constraints, etc. Loopback interfaces are usually numbered from zero (e.g., loopback0) upwards on routers. Loopback interfaces can also be created on PCs or servers for testing or configuration purposes using special IP addresses reserved for loopback testing (e.g., 127.x.x.x for IPv4 or ::1 for IPv6). Loopback interfaces are also known as virtual interfaces or dummy interfaces . Loopback interface state Loopback interface state refers to whether a loopback interface is up or down on a router . A loopback interface state can be either administratively controlled (by using commands such as no shutdown or shutdown ) or automatically determined by routing protocols (by using commands such as passive-interface or ip ospf network point-to-point ). A loopback interface state affects how routing protocols use the IP address assigned to the loopback interface for neighbor discovery , router ID selection , route advertisement , etc . A loopback interface state can also affect how other devices can access or ping the loopback interface . A loopback interface state can be checked by using commands such as show ip interface brief or show ip ospf neighbor . is independent of any physical interface and reduces routing updates.

The loopback interface state is independent of any physical interface because it does not depend on any hardware or link status. This means that the loopback interface state will always be up unless it is manually shut down by an administrator. This also means that the loopback interface state will not change due to any physical failures or link failures that may affect other interfaces on the router.

The loopback interface state reduces routing updates because it provides a stable router ID for OSPF that does not change due to any physical failures or link failures that may affect other interfaces on the router. This means that OSPF will not have to re-elect DRs Designated Routers (DRs) Designated Routers (DRs) are routers that are elected by OSPF routers in a broadcast or non-broadcast multi-access (NBMA) network to act as leaders and coordinators of OSPF operations in that network. DRs are responsible for generating link-state advertisements (LSAs) for the entire network segment, maintaining adjacencies with all other routers in the segment, and exchanging routing information with other DRs in different segments through backup designated routers (BDRs). DRs are elected based on their router priority values and router IDs . The highest priority router becomes the DR and the second highest priority router becomes the BDR . If there is a tie in priority values , then the highest router ID wins . DRs can be manually configured by setting the router priority value to 0 (which means ineligible) or 255 (which means always eligible) on specific interfaces . DRs can also be influenced by using commands such as ip ospf priority , ip ospf dr-delay , ip ospf network point-to-multipoint , etc . DRs can be verified by using commands such as show ip ospf neighbor , show ip ospf interface , show ip ospf database , etc . , recalculate SPT Shortest PathTree (SPT) Shortest Path Tree (SPT) is a data structure that represents the shortest paths from a source node to all other nodes in a graph or network . SPT is used by link-state routing protocols such as OSPF and IS-IS to compute optimal routes based on link costs . SPT is built using Dijkstra’s algorithm , which starts from the source node and iteratively adds nodes with the lowest cost paths to the tree until all nodes are included . SPT can be represented by a set of pointers from each node to its parent node in the tree , or by a set of next-hop addresses from each node to its destination node in the network . SPT can be updated by adding or removing nodes or links , or by changing link costs . SPT can be verified by using commands such as show ip route , show ip ospf database , show clns route , show clns database , etc . , or send LSAs Link-State Advertisements (LSAs) Link-State Advertisements (LSAs) are packets that contain information about the state and cost of links in a network segment . LSAs are generated and flooded by link-state routing protocols such as OSPF and IS-IS to exchange routing information with other routers in the same area or level . LSAs are used to build link-state databases (LSDBs) on each router , which store the complete topology of the network segment . LSAs are also used to compute shortest path trees (SPTs) on each router , which determine the optimal routes to all destinations in the network . LSAs have different types depending on their origin and scope , such as router LSAs , network LSAs , summary LSAs , external LSAs , etc . LSAs have different formats depending on their type and protocol version , but they usually contain fields such as LSA header , LSA type , LSA length , LSA age , LSA sequence number , LSA checksum , LSA body , etc . LSAs can be verified by using commands such as show ip ospf database , show clns database , debug ip ospf hello , debug clns hello , etc . due to changes in router IDs.

The other options are not reasons because:

The IP address associated with the loopback interface is non-routable and prevents loops: This option is false because the IP address associated with the loopback interface is routable and does not prevent loops. The IP address associated with the loopback interface can be any valid IP address that belongs to an existing subnet or a new subnet created specifically for loopbacks. The IP address associated with the loopback interface does not prevent loops because loops are caused by misconfigurations or failures in routing protocols or devices, not by IP addresses.

The loopback interface state is dependent on the management interface state and reduces routing updates: This option is false because

the loopback interface state is independent of any physical interface state, including the management interface state Management interface Management interface is an interface on a device that provides access to management functions such as configuration, monitoring, troubleshooting, etc . Management interfaces can be physical ports such as console ports, Ethernet ports, USB ports, etc., or virtual ports such as Telnet sessions, SSH sessions, web sessions, etc . Management interfaces can use different protocols such as CLI Command-Line Interface (CLI) Command-Line Interface (CLI) is an interactive text-based user interface that allows users to communicate with devices using commands typed on a keyboard . CLI is one of the methods for accessingmanagement functions on devices such as routers, switches, firewalls, servers, etc . CLI can use different protocols such as console port serial communication protocol Serial communication protocol Serial communication protocol is a method of transmitting data between devices using serial ports and cables . Serial communication protocol uses binary signals that represent bits (0s and 1s) and sends them one after another over a single wire . Serial communication protocol has advantages such as simplicity, low cost, long

Signal to noise ratio (SNR) is a measure that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to the noise power, often expressed in decibels (dB). A high SNR means that the signal is clear and easy to detect or interpret, while a low SNR means that the signal is corrupted or obscured by noise and may be difficult to distinguish or recover1. When the signal from an AP Access Point. AP is a device that allows wireless devices to connect to a wired network using Wi-Fi, or related standards. weakens by being absorbed as it moves through an object, such as a wall or a furniture, the signal power decreases. This reduces the SNR and affects the quality of the wireless connection. The noise power may also increase due to interference from other sources, such as other APs or devices operating in the same frequency band2. Therefore, the correct answer is that SNR decreases when the signal from an AP weakens by being absorbed as it moves through an object. References: 1 https://en.wikipedia.org/wiki/Signal-to-noise_ratio  2 https://documentation.meraki.com/MR/Wi-Fi_Basics_and_Best_Practices/Signal-to-Noise_Ratio_%28SNR%29_and_Wireless_Signal_Strength

The field in a Layer 3 IPv4 packet header that is used to mitigate Layer 3 route loops is Time To Live (TTL). TTL is an 8-bit field that indicates the maximum number of hops that a packet can traverse before being discarded. TTL is set by the source device and decremented by one by each router that forwards the packet. If TTL reaches zero, the packet is dropped and an ICMP Internet Control Message Protocol (ICMP) Internet Control Message Protocol (ICMP) is a network protocol that provides error reporting and diagnostic functions for IP networks. ICMP is used to send messages such as echo requests and replies (ping), destination unreachable, time exceeded, parameter problem, source quench, redirect, etc. ICMP messages are encapsulated in IP datagrams and have a specific format that contains fields such as type, code, checksum, identifier, sequence number, data, etc. ICMP messages can be verified by using commands such as ping , traceroute , debug ip icmp , etc . message is sent back to the source device. TTL is used to mitigate Layer 3 route loops because it prevents packets from circulating indefinitely in a looped network topology. TTL also helps to conserve network resources and avoid congestion caused by looped packets.

The other options are not fields in a Layer 3 IPv4 packet header because:

Checksum: Checksum is a 16-bit field that is used to verify the integrity of the IP header. Checksum is calculated by the source device and verified by the destination device based on the values of all fields in the IP header. Checksum does not mitigate Layer 3 route loops because it does not limit the number of hops that a packet can traverse.

Protocol: Protocol is an 8-bit field that indicates the type of payload carried by the IP datagram. Protocol identifies the upper-layer protocol that uses IP for datatransmission, such as TCP Transmission Control Protocol (TCP) Transmission Control Protocol (TCP) is a connection-oriented transport layer protocol that provides reliable, ordered, and error-checked delivery of data between applications on different devices . TCP uses a three-way handshake to establish a connection between two endpoints , and uses sequence numbers , acknowledgments , and windowing to ensure data delivery and flow control . TCP also uses mechanisms such as retransmission , congestion avoidance , and fast recovery to handle packet loss and congestion . TCP segments data into smaller units called segments , which are encapsulated in IP datagrams and have a specific format that contains fields such as source port , destination port , sequence number , acknowledgment number , header length , flags , window size , checksum , urgent pointer , options , data , etc . TCP segments can be verified by using commands such as telnet , ftp , ssh , debug ip tcp transactions , etc . , UDP User Datagram Protocol (UDP) User Datagram Protocol (UDP) is a connectionless transport layer protocol that provides

ICMP (Internet Control Message Protocol) is used by network devices to send error and operational information related to IP communications. It is used to send messages like "destination unreachable" or "time exceeded" when there are issues in IP communication

In Aruba Central, during the creation of a device configuration group, users can define various types of groups to manage and apply configurations to devices centrally. Among the options, "Template group" and "Default group" are valid types. A "Template group" allows the definition of configuration settings in a template format, which can be applied to multiple devices or device groups, ensuring consistency and efficiency in configurations across the network. A "Default group" is typically a predefined group in Aruba Central that applies a basic or initial set of configurations to devices that are not assigned to any other specific group. This helps in initial provisioning and management of devices. The other options, such as "Security group," "UIgroup," and "ESP group," are not standard group types defined in Aruba Central for device configuration purposes.

The best technology to use for dropping excessive broadcast traffic on ingress to an ArubaOS-CX switch is rate limiting. Rate limiting is a feature that allows network administrators to control the amount of traffic that enters or leaves a port or a VLAN on a switch by setting bandwidth thresholds or limits. Rate limiting can be used to prevent network congestion, improve network performance, enforce service level agreements (SLAs), or mitigate denial-of-service (DoS) attacks. Rate limiting can be applied to broadcast traffic on ingress to an ArubaOS-CX switch by using the storm-control command in interface configuration mode. This command allows network administrators to specify the percentage of bandwidth or packets per second that can be used by broadcast traffic on an ingress port. If the broadcast traffic exceeds the specified threshold, the switch will drop the excess packets.

The other options are not technologies for dropping excessive broadcast traffic on ingress because:

DWRR queuing: DWRR stands for Deficit Weighted Round Robin, which is a queuing algorithm that assigns different weights or priorities to different traffic classes or queues on an egress port. DWRR ensures that each queue gets its fair share of bandwidth based on its weight while avoiding starvation of lower priority queues. DWRR does not drop excessive broadcast traffic on ingress, but rather schedules outgoing traffic on egress.

QoS shaping: QoS stands for Quality of Service, which is a set of techniques that manage network resources and provide different levels of service to different types of traffic based on their requirements. QoS shaping is a technique that delays or buffers outgoing traffic on an egress port to match the available bandwidth or rate limit. QoS shaping does not drop excessive broadcast traffic on ingress, but rather smooths outgoing traffic on egress.

Strict queuing: Strict queuing is another queuing algorithm that assigns different priorities to different traffic classes or queues on an egress port. Strict queuing ensures that higher priority queues are always served before lower priority queues regardless of their bandwidth requirements or weights. Strict queuing does not drop excessive broadcast traffic on ingress, but rather schedules outgoing traffic on egress.

References: https://en.wikipedia.org/wiki/Rate_limiting https://www.arubanetworks.com/techdocs/AOS-CX_10_08/NOSCG/Content/cx-noscg/qos/storm-control.htm https://www.arubanetworks.com/techdocs/AOS-CX_10_08/NOSCG/Content/cx-noscg/qos/dwrr.htm https://www.arubanetworks.com/techdocs/AOS-CX_10_08/NOSCG/Content/cx-noscg/qos/shaping.htm https://www.arubanetworks.com/techdocs/AOS-CX_10_08/NOSCG/Content/cx-noscg/qos/strict.htm

LACP is a protocol that allows multiple physical links to be aggregated into a single logical link for increased bandwidth and redundancy. LACP must be configured on both ends of the link for it to work properly. In this case, EDGE1 has LACP configured on its uplink port-channel 1, but CORE1 does not have LACP configured on its corresponding port-channel 1. This causes a mismatch and prevents the link from coming up.References:https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-overview/lacp.htm

When checking the status of LACP (Link Aggregation Control Protocol) with the command "show lacp interfaces," various flags indicate the state of the LACP negotiation. "ALFOE" indicates different states for each letter: A (Activity), L (Link), F (Aggregation), O (Synchronization), and E (Collecting). In this context, the O flag is particularly of interest. If the O flag is not set (meaning the synchronization is not achieved), it typically suggests that LACP is not configured or not functioning correctly on the peer side, hence the link is not operational as part of an LACP channel.

AAA Authentication, Authorization, and Accounting (AAA) Authentication, Authorization, and Accounting (AAA) is a framework that provides security services for network access control . AAA consists of three components:

Authentication: The process of verifying the identity of a user or device that wants to access the network based on credentials such as username and password , certificates , tokens , etc . Authentication can use different protocols such as PAP , CHAP , EAP , RADIUS , TACACS+ , etc .

Authorization: The process of granting or denying access to network resources based on the identity and privileges of a user or device . Authorization can use different methods such as ACLs , RBAC , MAC , DAC , etc .

Accounting: The process of recording and reporting the activities and usage of network resources by users or devices . Accounting can use different formats such as syslog , SNMP , NetFlow , etc .

service. Here is my answer:

The correct match for each AAA service with its definition is:

Accounting: C. Tracking user activity on the network

Authentication: D. Who can access the network based on credentials/certificates

Authorization: B. Control users access on the network

The other options are not correct matches because:

A list of rules that specifies which entities are permitted or denied access: This option is a definition of an access control list (ACL) Access Control List (ACL) Access Control List (ACL) is a list of rules that specifies which entities are permitted or denied access to a network resource such as a router , switch , firewall , server , etc . ACLs can be based on different criteria such as source and destination IP addresses , port numbers , protocol types , time of day , etc . ACLs can be applied to different interfaces or directions such as inbound or outbound .ACLs can be verified by using commands such as show access-lists , show ip access-lists , debug ip packet , etc . , not an AAA service.

Who can access the network based on credentials/certificates: This option is a definition of authentication, not authorization. Authorization is the process of granting or denying access to network resources based on the identity and privileges of a user or device, not based on credentials/certificates.

References: https://en.wikipedia.org/wiki/AAA_(computer_security) https://www.cisco.com/c/en/us/support/docs/security-vpn/remote-authentication-dial-user-service-radius/13838-10.html