Cisco Network Ch 6 & 7
What is the special value assigned to the first 24 bits of a multicast MAC address transporting an IPv4 packet?
01-5E-00 FF-00-5E FF-FF-FF 01-00-5E
Ethernet frame size
64 bytes and the expected maximum is 1518 bytes, Any frame less than 64 bytes in length is considered a "collision fragment" or "runt frame" and is automatically discarded by receiving stations. Frames with more than 1500 bytes of data are considered "jumbo" or "baby giant frames".
What are the two sizes (minimum and expected maximum) of an Ethernet frame? (Choose two.)
64bytes min and 1,518 bytes max
Which statement is true about MAC addresses?
A NIC only needs a MAC address if connected to a WAN. The first three bytes are used by the vendor assigned OUI. The ISO is responsible for MAC addresses regulations.
transmitting node
A transmitting node creates a logical summary of the contents of the frame, known as the cyclic redundancy check (CRC) value. This value is placed in the frame check sequence (FCS) field to represent the contents of the frame. In the Ethernet trailer, the FCS provides a method for the receiving node to determine whether the frame experienced transmission errors.
What Layer 2 function does a router perform?
Accepts a frame from a medium De-encapsulates a frame Re-encapsulates to a new frame
Full-duplex communication
Both devices can simultaneously transmit and receive on the shared media at same time
Legacy LAN Topologies
Bus - All end systems are chained to each other and terminated in some form on each end. Infrastructure devices such as switches are not required to interconnect the end devices. Legacy Ethernet networks were often bus topologies using coax cables because it was inexpensive and easy to set up. Ring - End systems are connected to their respective neighbor forming a ring. The ring does not need to be terminated, unlike in the bus topology. Legacy Fiber Distributed Data Interface (FDDI) and Token Ring networks used ring topologies.
Which data link layer media access control method does Ethernet use with legacy Ethernet hubs?
CSMA/CD determinism turn taking token passing
What method is used to manage contention-based access on a wireless network?
CSMA/CD priority ordering CSMA/CA token passing There are two basic access control methods for shared media: contention-based access and controlled access. In contention-based multi-access networks, all nodes are operating in half-duplex. There is a process if more than one device transmits at the same time. Examples of contention-based access methods include: CSMA/CD for bus-topology Ethernet LANs and CSMA/CA for WLANs.
Which organization defines standards for the network access layer (i.e., the OSI physical and data link layers)?
Cisco IANA IEEE IETF
There are two basic access control methods for shared media:
Contention-based access & Controlled access
Which part of an Ethernet Frame uses a pad to increase the frame field to at least 64 bytes?
Data Field Preamble EtherType
Which statement describes the half-duplex mode of data transmission?
Data that is transmitted over the network can only flow in one direction. Data that is transmitted over the network flows in one direction at a time. Data that is transmitted over the network flows in one direction to many different destinations simultaneously. Data that is transmitted over the network flows in both directions at the same time.
Which part of an Ethernet Frame describes the higher-layer protocol that is encapsulated?
EtherType Preamble Start of Frame Delimiter Frame Check Sequence
Data link layer protocols include:
Ethernet 802.11 Wireless Point-to-Point Protocol (PPP) High-Level Data Link Control (HDLC) Frame Relay
data encapsulation includes the following:(mac sublayer)
Ethernet frame - This is the internal structure of the Ethernet frame. Ethernet Addressing - The Ethernet frame includes both a source and destination MAC address to deliver the Ethernet frame from Ethernet NIC to Ethernet NIC on the same LAN. Ethernet Error detection - The Ethernet frame includes a frame check sequence (FCS) trailer used for error detection.
Which part of an Ethernet Frame notifies the receiver to get ready for a new frame?
Frame Check Sequence Preamble Data field
Half-duplex communication
Half-duplex allows only one device to send or receive at a time on the shared medium
Three basic parts of a frame
Header Data Trailer
Physical topology
Identifies the physical connections and how end devices and intermediary devices (i.e, routers, switches, and wireless access points) are interconnected. The topology may also include specific device location such as room number and location on the equipment rack. Physical topologies are usually point-to-point or star.
Which two engineering organizations define open standards and protocols that apply to the data link layer? (Choose two.)
Institute of Electrical and Electronics Engineers (IEEE) Internet Assigned Numbers Authority (IANA) International Telecommunication Union (ITU) Electronic Industries Alliance (EIA) Internet Society (ISOC)
Which function or operation is performed by the LLC sublayer?
It communicates with upper protocol layers. It is responsible for media access control. It adds a header and trailer to a packet to form an OSI Layer 2 PDU.
What are two services performed by the data link layer of the OSI model? (Choose two.)
It fragments data packets into the MTU size. It determines the path to forward packets. It accepts Layer 3 packets and encapsulates them into frames. It provides media access control and performs error detection. It monitors the Layer 2 communication by building a MAC address table.
Which two functions or operations are performed by the MAC sublayer? (Choose two.)
It is responsible for Media Access Control. It performs the function of NIC driver software. It adds a header and trailer to form an OSI Layer 2 PDU. It handles communication between upper and lower layers. It adds control information to network protocol layer data.
Which two characteristics describe Ethernet technology? (Choose two.)
It is supported by IEEE 802.3 standards. It is supported by IEEE 802.5 standards. It typically uses an average of 16 Mbps for data transfer rates. It uses unique MAC addresses to ensure that data is sent to the appropriate destination. It uses a ring topology.
What will a host on an Ethernet network do if it receives a frame with a unicast destination MAC address that does not match its own MAC address?
It will discard the frame. It will forward the frame to the next host. It will remove the frame from the media.
Which data link sublayer works with the upper layers to add application information for delivery of data to higher level protocols?
LLC or MAC
What is another name for the OSI data link layer?
Layer 1 Layer 2 Layer 3 side note-The data link protocol is responsible for NIC-to-NIC communications within the same network. The data link layer prepares the encapsulated data (usually an IPv4 or IPv6 packet) for transport across the local media by encapsulating it with a header and a trailer to create a frame.
The media access control method used depends on which two criteria?
Layer 3 IP protocol Media sharing Topology Transport layer protocol Type of data
What identifier is used at the data link layer to uniquely identify an Ethernet device?
MAC address sequence number TCP port number UDP port number Explanation- Ethernet frames are identified at the data link layer by their MAC addresses, which are unique to each NIC. IP addresses are used at the network layer, and TCP and UDP port numbers are used at the transport layer
Which data link sublayer controls the network interface through software drivers?
MAC or LLC
The IEEE 802 LAN/MAN data link layer consists of which two sublayers? (Choose two.)
Media Link and Logical Link Control
What kind of network would use point-to-point, hub and spoke, or mesh topologies?
PAN LAN WLAN WAN
Which part of an Ethernet frame detects errors in the frame?
Preamble Start of Frame Delimiter Frame Check Sequence
What is the responsibility of the MAC sublayer?
Provides the method to get the frame on and off the media
Logical topology
Refers to the way a network transfers frames from one node to the next. This topology identifies virtual connections using device interfaces and Layer 3 IP addressing schemes.
What happens to runt frames received by a Cisco Ethernet switch? (less than 64 bytes)
The frame is dropped. The frame is returned to the originating network device. The frame is broadcast to all other devices on the same network. The frame is sent to the default gateway.
What is true concerning physical and logical topologies?
The logical topology is always the same as the physical topology. Physical topologies are concerned with how a network transfers frames. Physical topologies display the IP addressing scheme of each network. Logical topologies refer to how a network transfers data between devices.
What statement describes a characteristic of MAC addresses?
They must be globally unique. They are only routable within the private network. They are added as part of a Layer 3 PDU. They have a 32-bit binary value.
What is the function of the last field in a data link layer frame?
To determine whether the frame experienced transmission errors To identify special flow control services such as quality of service (QoS) To identify the beginning and end limits of the frame To identify the Layer 3 protocol in the data field
Which topology displays networking device layer IP addresses?
aerial topology IP address topology logical topology physical topology
What is auto-MDIX?
an Ethernet connector type a feature to automatically determine speed and duplex a feature that detects Ethernet cable type
What type of address is 01-00-5E-0A-00-02?
an address that reaches one specific host an address that reaches every host in the network an address that reaches a specific group of hosts
Which layer of the OSI model is responsible for specifying the encapsulation method used for specific types of media?
application transport data link physical
What attribute of a NIC would place it at the data link layer of the OSI model?
attached Ethernet cable IP address MAC address RJ-45 port TCP/IP protocol stack
Which LAN topology is a hybrid topology?
bus extended star ring star
A technician has been asked to develop a physical topology for a network that provides a high level of redundancy. Which physical topology requires that every node is attached to every other node on the network?
bus hierarchical mesh-In a true mesh topology every node has a connection to every other node in the network. ring star
Which media access control method is used in legacy Ethernet LANs?
carrier sense multiple access/collision annoyance carrier sense multiple access/collision avoidance carrier sense multiple access/collision destruction carrier sense multiple access/collision detection
What is a function of the MAC sublayer? (Choose three.)
controls access to the media checks for errors in received bits uses CSMA/CD or CSMA/CA to support Ethernet technology communicates between software at the upper layers and the device hardware at the lower layers allows multiple Layer 3 protocols to use the same network interface and media
Which lists the Layer 2 and Layer 3 address fields in the correct order?
destination NIC address, source NIC address, source IP address, destination IP address source NIC address, destination NIC address, source IP address, destination IP address destination NIC address, source NIC address, destination IP address, source IP address source NIC address, destination NIC address, destination IP address, source IP address
What does the data link layer add to a Layer 3 packet to create a frame? (Choose two.)
flags sequence number header trailer
Which duplex communication method is used in WLANs?
half-duplex simplex full-duplex
Which network device makes forwarding decisions based on the destination MAC address that is contained in the frame?
hub switch router
What are the two sublayers of the OSI model data link layer? (Choose two.)
internet physical LLC transport MAC network access
multiaccess network
is a network that can have two or more end devices attempting to access the network simultaneously.
MAC Sublayer
is responsible for data encapsulation and accessing the media.
What type of physical topology can be created by connecting all Ethernet cables to a central device?
ring star mesh
Which network device has the primary function to send data to a specific destination based on the information found in the MAC address table?
switch router
Accessing the Media(mac sublayer)
the IEEE 802.3 MAC sublayer includes the specifications for different Ethernet communications standards over various types of media including copper and fiber.
What addressing information is recorded by a switch to build its MAC address table?
the destination Layer 2 address of outgoing frames the source Layer 3 address of outgoing packets the source Layer 2 address of incoming frames
Although CSMA/CD is still a feature of Ethernet, why is it no longer necessary?
the virtually unlimited availability of IPv6 addresses the use of CSMA/CA the use of full-duplex capable Layer 2 switches the development of half-duplex switch operation the use of Gigabit Ethernet speeds
Which is a function of the Logical Link Control (LLC) sublayer?
to define the media access processes that are performed by the hardware to provide data link layer addressing to identify which network layer protocol is being used to accept segments and package them into data units that are called packets
