HPE6-A85 Questions and Answers

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

When a wireless client’s countdown timer (also known as a backoff timer) reaches zero during contention-based access periods, and it receives a Transmit Opportunity (TXOP), it has the right to transmit its data frames on the medium. After sending the data frames, it expects an acknowledgment (ACK) from the Access Point (AP) to ensure the frames were received successfully.

To troubleshoot an Aruba CX 6300F switch that is failing to boot correctly, you would typically use the USB-C console port. This port allows you to connect to the switch directly with a console cable and access the boot loader menu, where you can see the available OS images and the ServiceOS for recovery and troubleshooting purposes.

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

OSPF Open Shortest Path First. OSPF is a link-state routing protocol that uses a hierarchical structure to create a routing topology for IP networks. OSPF routers exchange routing information with their neighbors using Hello packets, which are sent periodically on each interface. To establish an adjacency Adjacency is a relationship formed between selected neighboring routers for the purpose of exchanging routing information., OSPF routers must agree on several parameters, including Hello timers, which specify how often Hello packets are sent on an interface. If the Hello timers do not match between neighboring routers, they will not form an adjacency and will not exchange routes. References:https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/osfp/osfp.htm

OAlOps is a feature of Aruba Central that uses artificial intelligence and machine learning to identify recommended steps to resolve network health issues and allows you to share detailed information with support personnel. OAlOps provides insights into network performance, root cause analysis, anomaly detection, proactive alerts, and automated remediation actions. OAlOps also integrates with Aruba User Experience Insight (UXI) sensors to measure and improve user experience across wired and wireless networks. References:https://www.arubanetworks.com/assets/ds/DS_ArubaCentral.pdf

In an AOS-CX switch, if the QoS trust mode is not configured, it is set to none by default. The VoIP phones will mark their traffic with a local-priority value, which, if the QoS trust mode is none, will correspond to CoS map entry 1 by default. The local-priority value of 1 at the branch office likely indicates that the traffic is not being prioritized correctly compared to the corporate office, where a local-priority of 5 suggests a higher level of prioritization for voice traffic.

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.

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

The ideal access switch for a large hospital with distribution racks of over 400 ports in a single VSF stack is the CX 6300. This switch provides the following benefits:

The CX 6300 supports up to 48 ports per switch and up to 10 switches per VSF stack, allowing for a total of 480 ports in a single stack. This meets the requirement of having over 400 ports in a single VSF stack.

The CX 6300 supports high-performance switching with up to 960 Gbps of switching capacity and up to 714 Mpps of forwarding rate. This meets the requirement of having high throughput and low latency for mobile equipment and patient data.

The CX 6300 supports advanced features such as dynamic segmentation, policy-based routing, and role-based access control. These features enhance the security and flexibility of the network by applying different policies and roles to different types of devices and users.

The CX 6300 supports Aruba NetEdit, a network configuration and orchestration tool that simplifies the management and automation of the network. This reduces the complexity and human errors involved in network configuration and maintenance.

The other options are not ideal because:

OCX 6400: This switch is designed for data center applications and does not support VSF stacking. It also does not support dynamic segmentation or policy-based routing, which are useful for network security and flexibility.

OCX 6200: This switch is designed for small to medium-sized businesses and does not support VSF stacking. It also has lower switching capacity and forwarding rate than the CX 6300, which may affect the performance of the network.

OCX 6100: This switch is designed for edge applications and does not support VSF stacking. It also has lower switching capacity and forwarding rate than the CX 6300, which may affect the performance of the network.

References: https://www.arubanetworks.com/assets/ds/DS_CX6300Series.pdf https://www.arubanetworks.com/assets/ds/DS_OC6400Series.pdf https://www.arubanetworks.com/assets/ds/DS_OC6200Series.pdf https://www.arubanetworks.com/assets/ds/DS_OC6100Series.pdf

In the access tracker of ClearPass, after a customer successfully connects to a guest network through a captive portal, the OUTPUT tab should show a role indicating that the user is authenticated, such as "Guest authenticated." This role confirms that the user has passed the authentication process and has been granted access.

The main characteristic of the 6 GHz band that is true among the given options is that in North America, the 6 GHz band offers more 80 MHz channels than there are 40 MHz channels in the 5 GHz band. This characteristic provides more spectrum availability, less interference, and higher throughput for wireless devices that support Wi-Fi 6E Wi-Fi Enhanced (Wi-Fi 6E) is an extension of Wi-Fi 6 (802.11ax) standard that operates in the newly available unlicensed frequency spectrum around 6 GHz in addition to existing bands below it. Some facts about this characteristic are:

In North America, there are up to seven non-overlapping channels available in each of three channel widths (20 MHz, 40 MHz, and 80 MHz) in the entireunlicensed portion of the new spectrum (5925–7125 MHz). This means there are up to 21 non-overlapping channels available for Wi-Fi devices in total.

In comparison, in North America, there are only nine non-overlapping channels available in each of two channel widths (20 MHz and 40 MHz) in the entire unlicensed portion of the existing spectrum below it (2400–2483 MHz and 5150–5825 MHz). This means there are only up to nine non-overlapping channels available for Wi-Fi devices in total.

Therefore, in North America, there are more than twice as many non-overlapping channels available in each channel width in the new spectrum than in the existing spectrum below it.

Specifically, there are more than twice as many non-overlapping channels available at 80 MHz width (seven) than at 40 MHz width (three) in the existing spectrum below it.

The other options are not true because:

Less RF signal is absorbed by objects in a 6 GHz WLAN: This option is false because higher frequency signals tend to be more absorbed by objects than lower frequency signals due to higher attenuation Attenuation is a general term that refers to any reduction in signal strength during transmission over distance or through an object or medium . Therefore, RF signals in a 6 GHz WLAN would be more absorbed by objects than RF signals in a lower frequency WLAN.

The 6 GHz band is fully backward compatible with existing bands: This option is false because Wi-Fi devices need to support Wi-Fi 6E standard to operate in the new spectrum around 6 GHz . Existing Wi-Fi devices that do not support Wi-Fi 6E standard cannot use this spectrum and can only operate in existing bands below it.

Low Power Devices are allowed for indoor and outdoor usage: This option is false because Low Power Indoor Devices (LPI) are only allowed for indoor usage under certain power limits and registration requirements . Outdoor usage of LPI devices is prohibited by regulatory authorities such as FCC Federal Communications Commission (FCC) is an independent agency of United States government that regulates communications by radio, television, wire, satellite, and cable across United States . However, outdoor usage of Very Low Power Devices (VLP) may be allowed under certain power limits and without registration requirements.

References: https://www.wi-fi.org/discover-wi-fi/wi-fi-certified-6e https://www.wi-fi.org/file/wi-fi-alliance-spectrum-needs-study https://www.cisco.com/c/en/us/products/collateral/wireless/spectrum-expert-wi-fi/prod_white_paper0900aecd807395a9.html https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/82068-power-levels.html https://www.wi-fi.org/file/wi-fi-alliance-unlicensed-spectrum-in-the-us

The correct command to add a static route to a class-c-network 10.2.10.0 via a gateway of 172.16.1.1 is ip-route 10.2.10.0/24 172.16.1.1 . This command specifies the destination network address (10.2.10.0) and prefix length (/24) and the next-hop address (172.16.1 .1) for reaching that network from the switch. The other commands are either incorrect syntax or incorrect parameters for adding a static route.References:https://www.arubanetworks.com/techdocs/AOS-CX_10_04/NOSCG/Content/cx-noscg/ip-routing/static-routes.htm

To add a static route in network devices, including Aruba switches, the correct command format generally includes the destination network, subnet mask (or CIDR notation for the mask), and the next-hop IP address. The command "ip route 10.2.10.0/24 172.16.1.1" correctly specifies the destination network "10.2.10.0" with a class C subnet mask indicated by "/24", and "172.16.1.1" as the next-hop IP address. This command is succinct and follows the standard syntax for adding a static route in many network operating systems, including ArubaOS-CX. The other options either have incorrect syntax or include additional unnecessary parameters that are not typically part of the standard command to add a static route.

In a 2.4GHz WLAN environment, channels 1, 6, and 11 are recommended for use simultaneously to avoid co-channel interference because these channels do not overlap with each other. Each of these channels is separated by enough frequency space to ensure that the signals do not interfere, which is not the case with other channel combinations.

Aruba AirMatch is a feature that optimizes RF Radio Frequency. RF is any frequency within the electromagnetic spectrum associated with radio wave propagation. When an RF current is supplied to an antenna, an electromagnetic field is created that then is able to propagate through space. performance and user experience by using machine learning algorithms and historical data to dynamically adjust AP power levels, channel assignments, and channel width. AirMatch performs live firmware upgrades on Aruba APs by partitioning all the APs based on RF neighborhood data and minimizing the impact on clients. AirMatch uses a rolling upgrade process that upgrades one partition at a time while ensuring that adjacent partitions are not upgraded simultaneously. References: https://www.arubanetworks.com/assets/ds/DS_AirMatch.pdf https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/arm/AirMatch.htm

AirMatch is a feature that provides centralized RF planning and optimization service for Aruba wireless networks. It uses cloud-based algorithms and machine learning to optimize the RF performance and user experience.References:https://www.arubanetworks.com/assets/ds/DS_AirMatch.pdf

In Aruba networks, the recommended Virtual Switching Framework (VSF) topologies include the daisy chain plus Multi-Active Detection (MAD) and the ring topology. The daisy chain topology with MAD provides a straightforward and effective way to connect multiple switches in a series while ensuring there is a mechanism in place (MAD) to detect and handle situations where more than one switch in the VSF might become active simultaneously. The ring topology offers redundancy by creating a looped connection pattern among the VSF members, enhancing network resilience and reliability.

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

A MAC address is divided into two parts: the Organizationally Unique Identifier (OUI) and the Network Interface Controller (NIC) serial number. The OUI is the first three octets of the MAC address and is unique to the manufacturer. The NIC serial number is the last three octets and is unique to the device itself. Therefore, for the MAC address B8-31-B5-80-41-4F, the OUI is B8-31-B5, and the NIC serial number is 80-41-4F.

In Aruba Central during group creation, users can define various configuration groups to manage settings for multiple devices. A Security group allows you to apply consistent security settings across devices, and a Template group enables you to apply pre-defined configurations to devices. These groups help streamline the deployment and management of network devices in Aruba Central.

TCP 3-Way Handshake sequence is:

Step 1: The initiating host sends a packet with no data to the target host with a SEQ=1 and sets the SYN flag to 1.

Step 2: The target host responds with a packet with ACK=2, SEQ=8, and the SYN and ACK flags set to 1.

Step 3: The initiating host sends a packet with SEQ=2, ACK=9, and the ACK flag set to 1.

Step 4: A normal-controlled connection is established.

References: https://en.wikipedia.org/wiki/Transmission_Control_Protocol https://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/13788-3.html

Virtual Router Redundancy Protocol (VRRP) is a network protocol that provides automatic assignment of available Internet Protocol (IP) routers to participating hosts. VRRP sends its messages over multicast for communication among routers for the election process of the master and advertisement of the virtual IP address.

In the context of Aruba networks, a Microbranch environment is managed using a group persona that aligns with the functionality required. ArubaOS 10 Branch Gateway Group Persona would be the correct device type and group persona for managing a Microbranch environment, as it would provide the necessary features and controls for branch networking requirements.

To troubleshoot an Aruba CX 6200 switch that is failing to boot correctly, accessing the switch via the RJ-45 console port on any of its member switches provides direct access to the switch's console for troubleshooting. This method allows a network technician to interact with the boot process, view boot messages, and access boot options, including the selection of different OS images or ServiceOS for recovery purposes.

Layer: 1) Physical layer Phase of Message Processing: d) Organize the data into bits

Layer: 2) Data Link layer Phase of Message Processing: c) Organize the data into frames

Layer: 3) Network layer Phase of Message Processing: b) Organize the data into packets

Layer: 4) Transport layer Phase of Message Processing: a) Organize the data into segments

The OSI model divides the networking process into seven layers, each representing a different step of the transmission chain. Each layer has its own function and is responsible for well-defined tasks. User data passes sequentially from the highest layer down through the lower layers until the device transmits it externally. The lowest layer, the physical layer, converts the data into bits that can be sent over a physical medium. The second layer, the data link layer, organizes the bits into frames that can be transmitted over a link between two nodes. The third layer, the network layer, organizes the frames into packets that can be routed across a network of nodes. The fourth layer, the transport layer, organizes the packets into segments that can provide reliable and error-free communication between two end points12. References: 1 https://www.linode.com/docs/guides/introduction-to-osi-networking-model/  2 https://en.wikipedia.org/wiki/OSI_model

For an 80m distance between wiring closets, using SFP+ transceivers is appropriate as they can support longer distances than standard copper interfaces. Ports 1/1/51 and 1/1/52 are typically reserved for uplinks on Aruba CX 6200F 48G switches and can support SFP+ transceivers, making them suitable for a redundant link-aggregation port configuration.