HP HP Certifications HPE6-A85 Questions & Answers

• Question 31:

  You are in a meeting with a customer where you are asked to explain the network redundancy feature Multiple Spanning Tree (MSTP). What is the correct statement for this feature?

  A. MSTP configuration ID revision by default as current MSTP root priority

  B. MSTP configuration ID name by default using switch IMC address

  C. MSTP configuration ID name by default using switch serial number

  D. MSTP configuration ID revision by default as switch serial number

  Correct Answer: B

  Explanation: 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/ar ubaos-solutions/mstp/mstp.htm

• Question 32:

  What are two advantages of a UXl? (Select two.)

  A. A UXl can be used without any internet connection

  B. A UXl helps to calculate the best WiFi channels in a remote location

  C. A UXl behaves like a client/user

  D. A UXl measures the Wi-Fi coverage of all APs in the given location.

  E. A UXl can check different applications, such as HTTP VOIP or Office 365.

  Correct Answer: CE

  Explanation: A UXI (User Experience Insight) is a device that simulates user behavior and tests network performance from the user perspective. It can check different applications, such as HTTP, VOIP, or Office 365, and measure metrics

  such as latency, jitter, packet loss, and throughput.

  References:https://www.arubanetworks.com/products/networking/user-experience-insight/

• Question 33:

  You need to drop excessive broadcast traffic on ingress to an ArubaOS-CX switch What is the best technology to use for this task?

  A. Rate limiting

  B. DWRR queuing

  C. QoS shaping

  D. Strict queuing

  Correct Answer: A

  Explanation: 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

• Question 34:

  What is 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?

  A. ip-route 10.2.10.0/24 172.16.1.1

  B. ip route 10.2.10.0.255.255.255.0 172.16.1.1 description aruba

  C. ip route 10.2.10.0/24.172.16.11

  D. ip route-static 10.2 10.0.255.255.255.0 172.16.1.1

  Correct Answer: A

  Explanation: 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

• Question 35:

  What are the main characteristics of the 6 GHz band?

  A. Less RF signal is absorb by objects in a 6 GHz WLAN.

  B. In North America, the 6 GHz band offers more 80 MHz channels than there are 40 MHz channels in the 5 GHz band.

  C. The 6 GHz band is fully backward compatible with the existing bands.

  D. Low Power Devices are allowed for indoor and outdoor usage.

  Correct Answer: B

  Explanation: 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 entire unlicensed portion of the new spectrum (5925?125 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?483 MHz and 5150?825 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 6Estandard 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

• Question 36:

  What does WPA3-Personal use as the source to generate a different Pairwise Master Key (PMK) each time a station connects to the wireless network?

  A. Session-specific information (MACs and nonces)

  B. Opportunistic Wireless Encryption (OWE)

  C. Simultaneous Authentication of Equals (SAE)

  D. Key Encryption Key (KEK)

  Correct Answer: A

  Explanation: 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

• Question 37:

  When measuring signal strength, dBm is commonly used and 0 dBm corresponds to 1 mW power.

  What does -20 dBm correspond to?

  A. .-1 mW

  B. .01 mw

  C. 10 mW

  D. 1mW

  Correct Answer: B

  Explanation: dBm is a unit of power that measures the ratio of a given power level to 1 mW. The formula to convert dBm to mW is: P(mW) = 1mW * 10^(P(dBm)/10). Therefore, - 20 dBm corresponds to 0.01 mW, as follows: P(mW) = 1mW * 10^(-20/10) = 0.01 mW

  References:https://www.rapidtables.com/convert/power/dBm_to_mW.html

• Question 38:

  

  Based on the given topology, what is the requirement on an Aruba switch to enable LLDP messages to be received by Switch 1 port 1/1/24. when Router 1 is enabled with LLDP?

  A. LLDP is enabled by default

  B. global configuration lldp enable

  C. int 1/1/24, lldp receive

  D. int 1/1/24, no cdp

  Correct Answer: C

  Explanation: 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/ar ubaos-solutions/lldp/lldp.htm

• Question 39:

  When using an Aruba standalone AP you select "Native VLAN" for the Client VLAN Assignment In which subnet will the client IPs reside?

  A. The same subnet as the mobility controller

  B. The same subnet as the Aruba ESP gateway

  C. The same subnet as the mobility conductor

  D. The same subnet as the access point

  Correct Answer: D

  Explanation: When using an Aruba standalone AP, selecting "Native VLAN" for the Client VLAN Assignment means that the clients will get their IP addresses from the same subnet as the access point's IP address. This is because the access point acts as a DHCP server for the clients in this mode.

  References:https://www.arubanetworks.com/techdocs/Instant_86_WebHelp/Content/instan t-ug/iap-dhcp/iap-dhcp.htm

• Question 40:

  Which feature can network administrators use to centralized RF planning and optimization service when using an Aruba mobility master architecture?

  A. Airwave

  B. Client Match

  C. AirMatch

  D. Client Wave

  Correct Answer: C

  Explanation: 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