CompTIA Network+ Exam N10-008 - Lesson 3: Deploying Ethernet Switching

A network engineer is setting up MTU sizes to follow most Ether products. What is the normal IPv4 EtherTypes value (in bytes) A. 1536 B. 1500 C. 1518 D. 64

A. 1536 Most Ethernet products follow the original DIX specification, referred to as Type II frames, and use the field to indicate the type of network layer protocol in the frame. These EtherTypes are values of 1536 or greater. The official IEEE 802.3 standard defines a 2-byte field to specify the size of the data field or payload. The payload can normally be between 46 and 1500 bytes. The maximum size of an Ethernet frame is normally 1518 bytes, excluding the preamble. To comply with CSMA/CD, the minimum length of an Ethernet frame is 64 bytes, so the payload must be at least 46 bytes. If this is not the case, it automatically pads it with redundant data.

A network technician wants to upgrade the company's hub to isolate collision domains from each other. Which solution would help the technician to accomplish this but NOT create separate broadcast domains on each port? A. Bridge B. Switch C. Router D. Hub

A. Bridge An Ethernet bridge works at the data link layer (layer 2), establishing separate physical network segments while keeping all nodes in the same logical network, reducing the number of collisions. An Ethernet layer 2 switch performs a similar function as a bridge, but in a more granular way, and for many more ports than bridges support. Each switch port is a separate collision domain. The router's other interfaces divide the network into three logical subnetworks. These subnets map to layer 2 segments, each implemented using a switch. Hubs have no configuration options. The technician connects the device to a power source and then connects the network cables for the hosts, becoming part of the network segment served by the hub.

A network technician is setting up a connection between switches, but is not establishing a connection. Which of the following would be the most likely cause for it not to work? A. Dual MDI-X ports B. Uplink port C. Crossover cables D. Autonegotiation

A. Dual MDI-X ports When a switch needs to connect to another switch, communications would fail if both interfaces used media dependent interface crossover (MDI-X). Historically (in the days of hubs and very early 10/100 switches), dedicated uplink ports connected to switches. Network administrators used crossover cables in conjunction with dedicated uplink ports to connect switches. Nowadays, network administrators configure most switch interfaces to use auto-MDI/MDIX by default. This means that the switch senses the configuration of the connected device and cable wiring and ensures that an MDI uplink to an MDIX port gets configured.

A systems administrator is setting up servers with standard network interface cards (NICs). Which of the following do most standard NICs support? (Select all that apply.) A. Gigabit Ethernet B. Fast Ethernet C. 10 GbE D. 40 GbE

A. Gigabit Ethernet B. Fast Ethernet Most Ethernet adapters support Gigabit Ethernet, as they are designed for use with copper cabling and are capable of 10/100/1000 operation. Most Ethernet adapters support Fast Ethernet, meaning that they support Gigabit Ethernet, Fast Ethernet, and 10BASE-T. A sysadmin would have to provision for a different kind of adapter for a 10GbE fiber link. Adapters that support 10 GbE come at a considerable price premium over basic Gigabit models. A sysadmin would also have to provision for a different kind of adapter for a 40GbE fiber link. Adapters that support 40 GbE come at a considerable price premium over basic Gigabit models.

A systems administrator is trying to troubleshoot frames moving over a large network medium and wants to set up the most optimal solution. Which of the following should the sysadmin use? A. SPAN port B. Active tap C. Passive tap D. I/G

B. Active tap An active tap is a powered device that performs signal regeneration. Gigabit signaling over copper wire is too complex for a passive tap to monitor. SPAN (switched port analyzer)/mirror port refers to a sensor, attached to a specially configured port on the switch, that receives copies of frames. This method is not completely reliable. A passive tap is a box with ports for incoming and outgoing network cabling and an inductor or optical splitter that physically copies the signal from the cabling to a monitor port. The I/G bit of a MAC address determines whether the frame addresses an individual node (0) or a group (1). The latter is for broadcast and multicast transmissions.

A systems administrator needs to combine multiple 1 Gbps connections to be able to support 2 Gbps connections. What should the administrator set up? A. CAM table B. NIC teaming C. Port security configuration D. Auto-MDI/MDIX

B. NIC teaming Port aggregation combines two or more separate cabled links into a single logical channel. From the host end, this is also known as NIC teaming. A switch learns MAC addresses by reading the source address for a frame. The address mapping normally gets cached in a MAC address table that implements as content addressable memory (CAM). A port security configuration validates the MAC address of end systems that connect to a switch port. In most scenarios, you would not expect the MAC address of servers and workstations to change often. Auto-MDI/MDIX means that the switch senses the configuration of the connected device and cable wiring and ensures that a media dependent interface (MDI) uplink to an MDIX port gets configured.

A help desk operator is trying to identify the vendor for a piece of equipment. What could the help desk operator check to determine the vendor? A. Last six digits of a MAC address B. OUI C. I/G bit of a MAC address D. FCS

B. OUI The first six hex digits of a MAC address (3 bytes or octets), also known as the Organizationally Unique Identifier (OUI), identifies the manufacturer of the adapter. The last six digits of a MAC address are a serial number. An organization can decide to use locally administered addresses in place of the manufacturers' universal coding systems. The I/G bit of a MAC address determines whether the frame addresses an individual node (0) or a group (1). The latter is for broadcast and multicast transmissions. The Cyclic Redundancy Check is also known as the Frame Check Sequence (FCS) and used in collision detection. There is no mechanism for retransmission if damage is detected.

A network technician has set up a link where the cable length exceeds the distance limitation and may not achieve the required speed or be unreliable. What should the network technician use in this case? A. Media converter B. Repeater C. MDI D. Hub

B. Repeater Repeaters overcome distance limitations by boosting the signal somewhere along the cable run. A repeater works at the physical layer (Layer 1) of the OSI model and is transparent concerning the rest of the network infrastructure. Where a repeater connects two cable segments of the same type, a media converter transitions from one cable type to another. Media converters also work at the Physical layer of the OSI model. When Ethernet gets wired with a hub, there needs to be a means of distinguishing the interface on an end system with the hub. The end system interface is known as medium dependent interface (MDI). A hub acts like a multiport repeater so that every port receives transmissions sent from any other port.

A network technician wants to upgrade the company's hub to avoid collisions. Which solution would help the technician accomplish this to the fullest extent? A. Router B. Switch C. Bridge D. Hub

B. Switch An Ethernet layer 2 switch performs a similar function as a bridge, but in a more granular way, and for many more ports than bridges support. Each switch port is a separate collision domain. The router's other interfaces divide the network into three logical subnetworks. These subnets map to layer 2 segments, each implemented using a switch. An Ethernet bridge works at the data link layer (layer 2), establishing separate physical network segments while keeping all nodes in the same logical network, reducing the number of collisions. Hubs have no configuration options. The technician connects the device to a power source and then connects the network cables for the hosts, becoming part of the network segment served by the hub.

A server administrator needs to allow a server to instruct the switch to pause traffic temporarily to avoid overwhelming its buffer and causing it to drop frames. What should the server administrator set up? A. Jumbo frames B. Port mirroring C. Flow control D. Port aggregation

C. Flow control IEEE 802.3x flow control allows a server to instruct the switch to pause traffic temporarily to avoid overwhelming its buffer and causing it to drop frames. A jumbo frame is one that supports a data payload of up to around 9,000 bytes. This reduces the number of frames that need to be transmitted. Port mirroring copies all packets sent to one or more source ports to a mirror (or destination) port. Port aggregation means combining two or more separate cabled links into a single logical channel. From the host end, this can also be called NIC teaming.

A network administrator is setting up connection points for multiple devices to connect. Which of the following cannot be configured? A. Bridge B. Switch C. Hub D. Router

C. Hub Hubs have no configuration options. The technician connects the device to a power source and then connects the network cables for the hosts, becoming part of the network segment served by the hub. An Ethernet bridge works at the data link layer (layer 2), establishing separate physical network segments while keeping all nodes in the same logical network, reducing the number of collisions. An Ethernet layer 2 switch performs a similar function as a bridge, but in a more granular way, and for many more ports than bridges support. Each switch port is a separate collision domain. The router's other interfaces divide the network into three logical subnetworks. These subnets map to layer 2 segments, each implemented using a switch.

A network architect is assessing network performance. Which of the following is part of the CSMA/CD protocol to identify collisions early? (Select all that apply.) A. CRC B. FCS C. Preamble D. SFD

C. Preamble D. SFD The preamble is for clock synchronization and as part of the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol to identify collisions early. The Start Frame Delimiter (SFD) is also used for clock synchronization and as part of the CSMA/CD protocol to identify collisions early. The error checking field contains a 32-bit (4-byte) checksum called a Cyclic Redundancy Check (CRC). The CRC is calculated based on the contents of the frame. The Cyclic Redundancy Check is also known as the Frame Check Sequence (FCS). There is no mechanism for retransmission if the damage is detected, nor is the CRC completely accurate at detecting damage.

A networking project manager needs switches that can connect together and operate as a group. Which of the following should the project manager use? A. Managed B. Modular C. Stackable D. Rack-mounted

C. Stackable Stackable means that switches can connect together and operate as a group. The sysadmin can manage the switch stack as a single unit. On a corporate network, switches are most likely to be managed. This means the sysadmin can configure the switch settings. If a managed switch is left unconfigured, it functions the same as an unmanaged switch does. A modular switch has slots for plug-in cards, meaning a sysadmin can configure them with different numbers and types of ports. The design on most larger switches allows them to fit in the standard-size racks used to hold networking equipment.

A networking administrator is trying to power off a Cisco switch, but it is not working. The administrator needs to be in which mode to perform this task? A. Global configuration B. User C. Autonegotiate D. Enable

D. Enable Privileged EXEC mode (or enable mode) allows the user to reboot or shut down the appliance and to backup and restore the system configuration. Global configuration mode allows the user to write configuration updates. This is important to consider when automatically pushing out configuration updates as well. User EXEC mode is a read-only mode where commands can report the configuration, show system status, or run basic troubleshooting tools. Autonegotiate is not a user mode, but the network administrator sets the port on the switch to autonegotiate speed (10/100/1000) and full- or half-duplex operation.

A cable operator needs to transition from one cable type to another. Which of the following would best help? A. MDI B. Repeater C. Hub D. Media converter

D. Media converter Where a repeater connects two cable segments of the same type, a media converter transitions from one cable type to another. Media converters also work at the Physical layer of the OSI model. When Ethernet gets wired with a hub, there needs to be a means of distinguishing the interface on an end system with the hub. The end system interface is known as medium dependent interface (MDI). Repeaters overcome distance limitations by boosting the signal somewhere along the cable run. A repeater works at the physical layer (Layer 1) of the OSI model and is transparent concerning the rest of the network infrastructure. A hub acts like a multiport repeater so that every port receives transmissions sent from any other port.