Which flew in a Layer 3 IPv4 packet header is used to mitigate Layer 3 route loops?
Correct Answer: B
Explanation 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 data transmission, 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
Question 2
Which Protocol Data Unit (PDU) represents the data link layer PDU?
Correct Answer: B
Explanation 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-ove
Question 3
When using the OSPF dynamic routing protocol on an Aruba CX switch, what must match on the neighboring devices to exchange routes?
Correct Answer: A
Explanation 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/o
Question 4
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?
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/arubaos-solutions/lldp/l
Question 5
You are configuring a network with a stacked pair of 6300M switches used for distribution and layer 3 services. You create a new VLAN for users that will be used on multiple access stacks of CX6200 switches connected downstream of the distribution stack You will be creating multiple VLANs/subnets similar to this will be utilized in multiple access stacks What is the correct way to configure the routable interface for the subnet to be associated with this VLAN?
Correct Answer: D
Explanation The correct way to configure the routable interface for the subnet to be associated with this VLAN is to create an SVI Switched Virtual Interface (SVI) Switched Virtual Interface (SVI) is a virtual interface on a switch that represents a VLAN and provides Layer 3 routing functions for that VLAN . SVIs are used to enable inter-VLAN routing , provide gateway addresses for hosts in VLANs , apply ACLs or QoS policies to VLANs , etc . SVIs have some advantages over physical routed interfaces such as saving interface ports , reducing cable costs , simplifying network design , etc . SVIs are usually numbered according to their VLAN IDs (e.g., vlan 10) and assigned IP addresses within the subnet of their VLANs . SVIs can be created and configured by using commands such as interface vlan , ip address , no shutdown , etc . SVIs can be verified by using commands such as show ip interface brief , show vlan , show ip route , etc . in the subnet on the 6300M stack. An SVI is a virtual interface on a switch that represents a VLAN and provides Layer 3 routing functions for that VLAN. Creating an SVI in the subnet on the 6300M stack allows the switch to act as a gateway for the users in that VLAN and enable inter-VLAN routing between different subnets. Creating an SVI in the subnet on the 6300M stack also simplifies network design and management by reducing the number of physical interfaces and cables required for routing. The other options are not correct ways to configure the routable interface for the subnet to be associated with this VLAN because: Create a physically routed interface in the subnet on the 6300M stack for each downstream switch: This option is incorrect because creating a physically routedinterface in the subnet on the 6300M stack for each downstream switch would require using one physical port and cable per downstream switch, which would consume interface resources and increase cable costs. Creating a physically routed interface in the subnet on the 6300M stack for each downstream switch would also complicate network design and management by requiring separate routing configurations and policies for each interface. Create an SVl in the subnet on each downstream switch: This option is incorrect because creating an SVI in the subnet on each downstream switch would not enable inter-VLAN routing between different subnets, as each downstream switch would act as a gateway for its own VLAN only. Creating an SVI in the subnet on each downstream switch would also create duplicate IP addresses in the same subnet, which would cause IP conflicts and routing errors. Create an SVl in the subnet on the 6300M stack, and assign the management address of each downstream switch stack to a different IP address in the same subnet: This option is incorrect because creating an SVI in the subnet on the 6300M stack, and assigning the management address of each downstream switch stack to a different IP address in the same subnet would not enable inter-VLAN routing between different subnets, as each downstream switch would still act as a gateway for its own VLAN only. Creating an SVI in the subnet on the 6300M stack, and assigning the management address of each downstream switch stack to a different IP address in the same subnet would also create unnecessary IP addresses in the same subnet, which would waste IP space and complicate network management. References: https://www.arubanetworks.com/techdocs/AOS-CX/10.05/HTML/5200-7295/index.html https://www.arubanetworks.com/techdocs/AOS-CX/10.05/HTML/5200-7295/cx-noscg/l3-routing/l3-routing-ove https://www.arubanetworks.com/techdocs/AOS-CX/10.05/HTML/5200-7295/cx-noscg/l3-routing/l3-routing-con
