HPE6-A85 Sample Questions Answers

The way that STP Spanning Tree Protocol. STP is a network protocol that ensures a loop-free topology for any bridged Ethernet local area network by preventing redundant paths between switches or bridges from creating loops that cause broadcast storms, multiple frame transmission, and MAC table instability. STP creates a logical tree structure that spans all of the switches in an extended network and blocks any redundant links that are not part of the tree from forwarding data packets3. will forward or discard traffic on these ports is as follows:

• STP will elect a root bridge among the two switches based on their bridge IDs, which are composed of a priority value and a MAC address. The switch with the lower bridge ID will become the root bridge and will forward traffic on all its ports.
• STP will assign a role and a state to each port on both switches based on their port IDs, which are composed of a priority value and a port number. The port with the lower port ID will become the designated port and will forward traffic, while the port with the higher port ID will become the alternate port and will discard traffic.
• In this scenario, since both switches have two cables connected between ports 1/1/1 and 1/1/2, there will be two possible paths between them, creating a loop. To prevent this loop, STP will block one of these paths by discarding traffic on one of the ports on each switch.
• Assuming that both switches have the same priority value (default is 32768), the switch with the lower MAC address will have the lower bridge ID and will become the root bridge. The root bridge will forward traffic on both ports 1/1/1 and 1/1/2.
• Assuming that both ports have the same priority value (default is 128), port 1/1/1 will have a lower port ID than port 1/1/2 on both switches because it has a lower port number. Port 1/1/1 will become the designated port and will forward traffic, while port 1/1/2 will become the alternate port and will discard traffic.
• Therefore, the switch with the lower MAC address will discard traffic on one port (port 1/1/2), while the switch with the higher MAC address will also discard traffic on one port (port 1/1/2).

References: 3 https://en.wikipedia.org/wiki/Spanning_Tree_Protocol

The RADIUS message that you should look for to ensure a successful connection via 802.1X is Access-Accept. This message indicates that the RADIUS server has authenticated and authorized the supplicant (the device that wants to access thenetwork) and has granted it access to the network resources. The Access-Accept message may also contain additional attributes such as VLAN ID, session timeout, or filter ID that specify how the authenticator (the device that controls access to the network, such as a switch) should treat the supplicant’s traffic.

The other options are not RADIUS messages because:

• Authorized: This is not a RADIUS message, but a state that indicates that a port on an authenticator is allowed to pass traffic from a supplicant after successful authentication and authorization.
• Success: This is not a RADIUS message, but a status that indicates that an EAP Extensible Authentication Protocol (EAP) is an authentication framework that provides support for multiple authentication methods, such as passwords, certificates, tokens, or biometrics. EAP is used in wireless networks and point-to-point connections to provide secure authentication between a supplicant (a device that wants to access the network) and an authentication server (a device that verifies the credentials of the supplicant). exchange has completed successfully between a supplicant and an authentication server.
• Authenticated: This is not a RADIUS message, but a state that indicates that a port on an authenticator has received an EAP-Success message from an authentication server after successful authentication of a supplicant.

References: https://en.wikipedia.org/wiki/RADIUS#Access-Accept https://www.cisco.com/c/en/us/support/docs/security-vpn/remote-authentication-dial-user-service-radius/13838-10.html https://en.wikipedia.org/wiki/IEEE_802.1X#Port-based_network_access_control https://en.wikipedia.org/wiki/Extensible_Authentication_Protocol#EAP_exchange

QoS Quality of Service (QoS) 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 can improve network performance, reduce latency, increase throughput, and prevent congestion. concept and its definition. Here is my answer:

QoS Concept:

• Best Effort Service
• Class of Service
• Differentiated Services
• WMM ====================== Definition:

d) A method where traffic is treated equally in a first-come, first-served manner a) A method for classifying network traffic at Layer 2 by marking 802.1Q VLAN Ethernet frames with one of eight service classes b) A method for classifying network traffic at Layer 3 by marking packets with one of 64 different service classes c) A method for classifying network traffic using access categories based on the IEEE 802.11e QoS standard

Short But Comprehensive Explanation of Correct Answer Only: The correct match between QoS concept and its definition is as follows:

• Best Effort Service: This is a method where traffic is treated equally in a first-come, first-served manner without any prioritization or differentiation. This is the default service level for most networks and applications that do not have specific QoS requirements or guarantees. Best Effort Service does not provide any assurance of bandwidth, delay, jitter, or packet loss.
• Class of Service: This is a method for classifying network traffic at Layer 2 by marking 802.1Q VLAN Ethernet frames with one of eight service classes (0 to 7). These service classes are also known as IEEE 802.1p priority values or PCP Priority Code Point (PCP) is a 3-bit field in the 802.1Q VLAN tag that indicates the priority level of an Ethernet frame . Class of Service allows network devices to identify and handle different types of traffic based on their priority levels. Class of Service is typically used in LAN Local Area Network (LAN) is a network that connects devices within a limited geographic area, such as a home, office, or building environments where Layer 2 switching is predominant.
• Differentiated Services: This is a method for classifying network traffic at Layer 3 by marking packets with one of 64 different service classes (0 to 63). These service classes are also known as DiffServ Code Points (DSCP) DiffServ Code Point (DSCP) is a 6-bit field in the IP header that indicates the service class of a packet . Differentiated Services allows network devices to identify and handle different types of traffic based on their service classes. Differentiated Services is typically used in WAN Wide Area Network (WAN) is a network that connects devices across a large geographic area, such as a country or continent environments where Layer 3 routing is predominant.
• WMM: This is a method for classifying network traffic using access categories based on the IEEE 802.11e QoS standard. WMM stands for Wi-Fi Multimedia and it is a certification program developed by the Wi-Fi Alliance to enhance QoS for wireless networks. WMM defines four access categories (AC): Voice, Video, Best Effort, and Background. These access categories correspond to different priority levels and contention parameters for wireless traffic. WMM allows wireless devices to identify and handle different types of traffic based on their access categories.

References: https://en.wikipedia.org/wiki/Quality_of_service https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/qos_dfsrv/configuration/xe-16/qos-dfsrv-xe-16-book/qos-dfsrv-overview.html https://www.cisco.com/c/en/us/support/docs/quality-of-service-qos/qos-packet-marking/10103-dscpvalues.html https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/81831-qos-wlan.html https://www.wi-fi.org/discover-wi-fi/wi-fi-certified-wmm

The source that WPA3-Personal uses to generate a different Pairwise Master Key (PMK) each time a station connects to the wireless network is session-specific information (MACs and nonces). WPA3-Personal uses Simultaneous Authentication of Equals (SAE) to replace PSK authentication in WPA2-Personal. SAE is a secure key establishment protocol that uses a Diffie-Hellman key exchange to derive a shared secret between two parties without revealing it to an eavesdropper. SAE involves the following steps:

• The station and the access point exchange Commit messages that contain their MAC addresses and random numbers called nonces.
• The station and the access point use their own passwords and the received MAC addresses and nonces to calculate a shared secret called SAE Password Element (PE).
• The station and the access point use their own PE and the received MAC addresses and nonces to calculate a shared secret called SAE Key Seed (KS).
• The station and the access point use their own KS and the received MAC addresses and nonces to calculate a shared secret called SAE Key Confirmation Key (KCK).
• The station and the access point use their own KCK and the received MAC addresses and nonces to calculate a confirmation value called SAE Confirm.
• The station and the access point exchange Confirm messages that contain their SAE Confirm values.
• The station and the access point verify that the received SAE Confirm values match their own calculated values. If they match, the authentication is successful and the station and the access point have established a shared secret called SAE PMK.

The SAE PMK is different for each session because it depends on the MAC addresses and nonces that are exchanged in each authentication process. The SAE PMK is used as an input for the 4-way handshake that generates the Pairwise Temporal Key (PTK) for encrypting data frames.

The other options are not sources that WPA3-Personal uses to generate a different PMK each time a station connects to the wireless network because:

• Opportunistic Wireless Encryption (OWE): OWE is a feature that provides encryption for open networks without requiring authentication or passwords. OWE uses a similar key establishment protocol as SAE, but it does not generate a PMK. Instead, it generates a Pairwise Secret (PS) that is used as an input for the 4-way handshake that generates the PTK.
• Simultaneous Authentication of Equals (SAE): SAE is not a source, but a protocol that uses session-specific information as a source to generate a different PMK each time a station connects to the wireless network.
• Key Encryption Key (KEK): KEK is not a source, but an output of the 4-way handshake that generates the PTK. KEK is used to encrypt group keys that are distributed by the access point.

References: https://www.wi-fi.org/discover-wi-fi/wi-fi-certified-6e https://www.wi-fi.org/file/wi-fi-alliance-unlicensed-spectrum-in-the-us https://www.cisco.com/c/en/us/products/collateral/wireless/catalyst-9100ax-access-points/wpa3-dep-guide-og.html https://info.support.huawei.com/info-finder/encyclopedia/en/WPA3.html https://rp.os3.nl/2019-2020/p99/presentation.pdf

• Proves knowledge of the PMK
• Exchanges messages for generating PTK
• Distributes an encrypted GTK to the client
• Sets first initialization vector (IV)

The ideal Aruba access switch for a cost-effective connection to 200-380 clients, printers and APs per distribution rack is the Aruba CX 6200. This switch series is a cloud-manageable, stackable access switch series that is ideal for enterprise branch offices and campus networks, as well as SMBs. The CX 6200 series offers the following benefits:

• Enterprise-class connectivity: The CX 6200 series supports ACLs, robust QoS, and common protocols such as static and Access OSPF routing.
• Power and speed for users and IoT: The CX 6200 series provides built-in 1/10GbE uplinks and 30W to 60W of Class 4 to Class 6 PoE for powering devices such as APs and cameras.
• Scalable growth made simple: The CX 6200 series supports Aruba Virtual Switching Framework (VSF) that allows you to quickly grow your network to eight members in a single stack using high-performance built-in 10G SFP ports.
• Management flexibility: The CX 6200 series supports a choice of management, including cloud-based and on-prem Central, CLI, switch Web GUI and programmability with AOS-CX operating system, and REST APIs.

The other options are not ideal because:

• Aruba CX 6400: This switch series is a high-availability modular switch series that is ideal for versatile edge access to data center deployments. It offers more performance, scalability, and modularity than the CX 6200 series, but it is also more expensive and complex to deploy and manage. It may not be cost-effective for connecting 200-380 clients per distribution rack.
• Aruba CX 6300: This switch series is a layer 3 stackable access and aggregation switch series that offers Smart Rate and High Power PoE. It offers more features and performance than the CX 6200 series, but it is also more expensive and may not be necessary for connecting 200-380 clients per distribution rack.
• Aruba CX 6000: This switch series is a layer 2 access switch series that offers PoE. It offers less features and performance than the CX 6200 series, and it does not support VSF stacking or routing protocols. It may not be sufficient for connecting 200-380 clients per distribution rack.

References: https://www.arubanetworks.com/products/switches/access/ https://www.arubanetworks.com/products/switches/access/6200-series/ https://www.arubanetworks.com/products/switches/access/6400-series/ https://www.arubanetworks.com/products/switches/access/6300-series/ https://www.arubanetworks.com/products/switches/access/6000-series/

A frame is the data link layer PDU that encapsulates the network layer PDU (packet) with a header and a trailer that contain information such as source and destination MAC addresses, frame type, error detection, etc. A frame is transmitted over a physical medium such asEthernet, Wi-Fi, etc. References:https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-overview/networking-basics.htm

The status of “ALFOE” means that LACP Link Aggregation Control Protocol (LACP) is a network protocol that provides dynamic negotiation of link aggregation between two devices. LACP allows multiple physical links to be combined into a single logical link for increased bandwidth, redundancy, and load balancing. LACP is defined in IEEE 802.3ad standard. is working fine with no problems when checking LACP with “show lacp interfaces”. The status of “ALFOE” is an acronym that stands for:

• A: Active - The interface is actively sending LACP packets to negotiate link aggregation with the peer device.
• L: Link Up - The interface has physical connectivity with the peer device.
• F: Aggregatable - The interface can be aggregated with other interfaces into a single logical link.
• O: Synchronized - The interface has successfully negotiated link aggregation parameters with the peer device and can transmit or receive traffic on the logical link.
• E: Collecting/Distributing - The interface is collecting incoming traffic from the peer device and distributing outgoing traffic to the peer device on the logical link.

The other options are not correct because:

• The interface on the local switch is configured as static-LAG: This option is false because static-LAG does not use LACP to negotiate link aggregation. Static-LAG requires manual configuration of link aggregation parameters on both devices and does not have any status indicators.
• LACP is not configured on the peer side: This option is false because if LACP is not configured on the peer side, the status of the interface would be “ALF–” instead of “ALFOE”. This means that the interface would not be synchronized or collecting/distributing with the peer device.
• LACP is in a synchronizing process: This option is false because if LACP is in a synchronizing process, the status of the interface would be “ALF-O” instead of “ALFOE”. This means that the interface would not be collecting/distributing with the peer device.

References: https://www.arubanetworks.com/techdocs/AOS-CX_10_08/NOSCG/Content/cx-noscg/lag/lag-overview.htm https://www.arubanetworks.com/techdocs/AOS-CX_10_08/NOSCG/Content/cx-noscg/lag/lag-lacp.htm https://www.arubanetworks.com/techdocs/AOS-CX_10_08/NOSCG/Content/cx-noscg/lag/lag-lacp-status.htm

Multiple Pre-Shared Key (MPSK) is a feature that allows device-specific or group-specific passphrases to securely add headless devices to the WLAN Wireless Local Area Network. WLAN is a wireless computer network that links two or more devices using wireless communication to form a local area network (LAN) within a limited area such as a home, school, computer laboratory, campus, or office building. . MPSK enhances the WPA2 PSK Wi-Fi Protected Access 2 Pre-Shared Key. WPA2 PSK is a method of securing your network using WPA2 with the use of the optional Pre-Shared Key (PSK) authentication, which was designed for home users without an enterprise authentication server. mode by allowing different PSKs for different devices on the same SSID Service Set Identifier. SSID is a case-sensitive, 32 alphanumeric character unique identifier attached to the header of packets sent over a wireless local-area network (WLAN). The SSID acts as a password when a mobile device tries to connect to the basic service set (BSS) — a component of the IEEE 802.11 WLAN architecture. . MPSK passwords can be generated or user-created and are managed by ClearPass Policy Manager12. References: 1 https://blogs.arubanetworks.com/solutions/simplify-iot-authentication-with-multiple-pre-shared-keys/  2 https://www.arubanetworks.com/techdocs/ClearPass/6.8/Guest/Content/AdministrationTasks1/Configuring-MPSK.htm

 LLDP Link Layer Discovery Protocol. LLDP is a vendor-neutral link layer protocol used by network devices for advertising their identity, capabilities, and neighbors on a local area network. is enabled by default on Aruba switches, but it can be disabled on a per-port basis using the no lldp command. To enable LLDP messages to be received by Switch 1 port 1/1/24, you need to enter the interface configuration mode for that port and use the lldp receive command. References:https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/lldp/lldp.htm

The 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 recover3. To calculate the SNR in dB, we can use the following formula:

SNR (dB) = Signal power (dBm) - Noise power (dBm)

In this question, we are given that the noise floor measures -90 dBm (0.000000001 milliwatts) and the receiver’s signal strength is -65 dBm (0.000316 milliwatts). Therefore, we can plug these values into the formula and get:

SNR (dB) = -65 dBm - (-90 dBm) SNR (dB) = -65 dBm + 90 dBm SNR (dB) = 25 dBm

Therefore, the correct answer is that the SNR is 25 dBm.

References: 3 https://en.wikipedia.org/wiki/Signal-to-noise_ratio

MSTP Multiple Spanning Tree Protocol. MSTP is an IEEE standard protocol for preventing loops in a network with multiple VLANs. MSTP allows multiple VLANs to be mapped to a reduced number of spanning-tree instances. configuration ID consists of two parameters: name and revision. The name is a 32-byte ASCII string that identifies the MSTP region, which is a group of switches that share the same configuration ID and VLAN-to-instance mapping. The revision is a 16-bit number that indicates the version of the configuration ID. By default, the MSTP configuration ID name is set to the switch IMC address, which is a unique identifier derived from the MAC address Media Access Control address. MAC address is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment. of the switch. References:https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/mstp/mstp.htm

Features: 1) Clustered Instant Access Points Aruba OS version: a) Aruba OS 8

Features: 2) Dynamic Radius Proxy Aruba OS version: a) Aruba OS 8

Features: 3) Scales to more than 10,000 devices Aruba OS version: b) Aruba OS 10

Features: 4) Unifies wired and wireless management Aruba OS version: a) Aruba OS 8 

Features: 5) Wireless controllers Aruba OS version: a) Aruba OS 8

ArubaOS is the operating system for all Aruba Mobility Controllers (MCs) and controller-managed wireless access points (APs). ArubaOS 8 delivers unified wired and wireless access, seamless roaming, enterprise grade security, and a highly available network with the required reliability to support high density environments1. Some of the features of ArubaOS 8 are:

• Clustered Instant Access Points: This feature allows multiple Instant APs to form a cluster and share configuration and state information. This enables seamless roaming, load balancing, and fast failover for clients2.
• Dynamic Radius Proxy: This feature allows an MC to act as a proxy for RADIUS authentication requests from clients or APs. This simplifies the configuration and management of RADIUS servers and reduces the network traffic between MCs and RADIUS servers3.
• Wireless controllers: Aruba wireless controllers are devices that centrally manage and control the wireless network. They provide functions such as AP provisioning, configuration, security, policy enforcement, and network optimization.

ArubaOS 10 is the next-generation operating system that works with Aruba Central, a cloud-based network management platform. ArubaOS 10 delivers greater scalability, security, and AI-powered optimization across large campuses, branches, and remote work environments. Some of the features of ArubaOS 10 are:

• Scales to more than 10,000 devices: ArubaOS 10 can support up to 10,000 devices per cluster, which is ten times more than ArubaOS 8. This enables customers to scale their networks without compromising performance or reliability.
• Unifies wired and wireless management: ArubaOS 10 provides a single platform for managing both wired and wireless devices across the network. Customers can use Aruba Central to configure, monitor, troubleshoot, and update their devices from anywhere.

Both ArubaOS 8 and ArubaOS 10 share some common features, such as:

• Unifies wired and wireless management: Both operating systems provide unified wired and wireless access for customers who use Aruba switches and APs. Customers can use a single interface to manage their entire network infrastructure1 . References: 1 https://www.arubanetworks.com/resource/arubaos-8-fundamental-guide/ 2 https://www.arubanetworks.com/techdocs/Instant_86_WebHelp/Content/instant-ug/iap-maintenance/cluster.htm 3 https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-overview/dynamic-radius-proxy.htm https://www.arubanetworks.com/products/networking/controllers/ https://www.arubanetworks.com/products/network-management-operations/arubaos/ https://blogs.arubanetworks.com/solutions/making-the-switch/ https://www.arubanetworks.com/products/network-management-operations/aruba-central/