Study Guide Written Lab 1

Written Lab 1.1: OSI Questions

Which layer chooses and determines the availability of communicating partners, along with the resources necessary to make the connection; coordinates partnering applications; and forms a consensus on procedures for controlling data integrity and error recovery?

My answer: Transport layer
- Determine availability of communicating partners: Done through the three-way handshake in TCP so that the Synchronization req is acknowledged by the server?
- Resources necessary to make the connection: Windowing
- Data integrity: Flow Control (basically segments are awknowledged, retransmitted, sequenced in order...)
- Coordination is done through acknowledging segments and making sure they're transmitted in the correct order.
Lab answer: The Application layer is responsible for finding the network resources broadcast from a server and adding flow control and error control (if the application developer chooses).

_{That felt misleading... I feel like the Application layer's purpose can vary from protocol to protocol, and some of the things in the question doesn't always happen in all protocols.
I mean, if you're sending UDP packets through the Internet, then data integrity, coordination, etc. isn't really ensured?
Although this is mentioned in the study guide: "The Application layer is also responsible for identifying and establishing the availability of
the intended communication partner, and determining whether sufficient resources for the
intended communication exist."}
Which layer is responsible for converting data packets from the Data Link layer into electrical signals?

My answer: Physical layer

Lab answer: The Physical layer takes frames from the Data Link layer and encodes the ones and zeros into a digital signal for transmission on the network medium.
At which layer is routing implemented, enabling connections and path selection between two end systems?

My answer: Network layer

Lab answer: The Network layer provides routing through an internetwork and logical addressing.
Which layer defines how data is formatted, presented, encoded, and converted for use on the network?

My answer: Presentation layer

Lab answer: The Presentation layer makes sure that data is in a readable format for the Application layer.
Which layer is responsible for creating, managing, and terminating sessions between applications?

My answer: Session layer

Lab answer: The Session layer sets up, maintains, and terminates sessions between applications
Which layer ensures the trustworthy transmission of data across a physical link and is primarily concerned with physical addressing, line discipline, network topology, error notification, ordered delivery of frames, and flow control?

My answer: Data Link

Lab answer: PDUs at the Data Link layer are called frames. As soon as you see “frame” in a question, you know the answer.
Which layer is used for reliable communication between end nodes over the network and provides mechanisms for establishing, maintaining, and terminating virtual circuits; transport-fault detection and recovery; and controlling the flow of information?

My answer: Transport layer

Lab answer: The Transport layer uses virtual circuits to create a reliable connection between two hosts.
Which layer provides logical addressing that routers will use for path determination?

My answer: Network layer

Lab answer: The Network layer provides logical addressing, typically IP addressing and routing.
Which layer specifies voltage, wire speed, and pinout cables and moves bits between devices?

My answer: Physical layer

Lab answer: The Physical layer is responsible for the electrical and mechanical connections between devices.
Which layer combines bits into bytes and bytes into frames, uses MAC addressing, and provides error detection?

My answer: Data Link layer

Lab answer: The Data Link layer is responsible for the framing of data packets.
Which layer is responsible for keeping the data from different applications separate on the network?

My answer: Application layer

Lab answer: The Session layer creates sessions between different hosts' applications.

_{I guess that makes sense: "Session layer basically keeps different applications' data separate from other applications' data."}
Which layer is represented by frames?

My answer: Data Link layer

Lab answer: The Data Link layer frames packets received from the network layer.
Which layer is represented by segments?

My answer: Transport layer

Lab answer: The Transport layer segments user data.
Which layer is represented by packets?

My answer: Network layer

Lab answer: The Network layer creates packets out of segments handed down from the Transport layer.
Which layer is represented by bits?

My answer: Physical layer

Lab answer: The Physical layer is responsible for transporting ones and zeros in a digital signal.
Put the following in order of encapsulation:

My answer: Bits [ Frame [ Packet [ Segment ] ] ]

Lab answer: Segments, packets, frames, bits
Which layer segments and reassembles data into a data stream?

My answer: Transport layer

Lab answer: Transport
Which layer provides the physical transmission of the data and handles error notification, network topology, and flow control?

My answer: Data Link

Lab answer: Data Link
Which layer manages device addressing, tracks the location of devices on the network, and determines the best way to move data?

My answer: Network layer

Lab answer: Network
What is the bit length and expression form of a MAC address?

My answer: It's 48 bit address.
The first 24 bytes are the organizationally unique identifier. It's usually the organization that manufactured the NIC, the IEEE issues one to them.
Bit 47 (I/G): 0 means it belongs to a real manufacturer, 1 means you can assume its broadcast or multicast
Bit 46 (G/L or U/L): 0 means the address was globally administered, 1 means it was locally administered
Remaining 22 bits of 24: Identifies the organization

The last 24 bits identify the card and are assigned by the organization making the NIC

Lab answer: 48 bits (6 bytes) expressed as a hexadecimal number
_{So That's what they mean by expression form... huh}

Written Lab 1.2: Defining the OSI Layers and Devices

This device sends and receives information about the Network layer.

My answer: Router

Lab answer: Router
This layer creates a virtual circuit before transmitting between two end stations.

My answer: Transport layer

Lab answer: Transport
This layer uses service access points.

My answer: Data Link (802.2 SNAP and SAP)

Lab answer: Data Link (LLC sublayer)
This device uses hardware addresses to filter a network.

My answer: Switch

Lab answer: Bridge or Switch
Ethernet is defined at these layers.

My answer: Data Link

Lab answer: Data Link AND Physical

_{Should have seen the 's' on layers. I thought they only meant one.}
This layer supports flow control and sequencing.

My answer: Data Link AND Transport layer

Lab answer: Transport

_{Not a fan of this question because Data Link DOES do that at the LLC sublayer (The LLC
can also provide flow control and sequencing of control bits.)}
This device can measure the distance to a remote network.

My answer: Router

Lab answer: Router
Logical addressing is used at this layer.

My answer: Network layer

Lab answer: Network
Hardware addresses are defined at this layer.

My answer: Data Link

Lab answer: Data Link (MAC sublayer)
This device creates one big collision domain and one large broadcast domain.

My answer: Hub

Lab answer: Hub
This device creates many smaller collision domains, but the network is still one large broadcast domain.

My answer: Switch

Lab answer: Switch or Bridge
This device breaks up collision domains and broadcast domains.

My answer: Router

Lab answer: Router

Written Lab 1.3: Identifying Collision and Broadcast Domains

A - Hub

My answer: 1 Collision Domain, 1 Broadcast Domain

Lab answer: Hub: One collision domain, one broadcast domain

B - Bridge

My answer: 2 Collision Domains, 1 Broadcast Domain

Lab answer: Bridge: Two collision domains, one broadcast domain

C - Switch

My answer: 4 Collision Domains, 1 Broadcast Domain

Lab answer: Switch: Four collision domains, one broadcast domain

D - Router

My answer: 3 Collision Domains, 3 Broadcast Domains

Lab answer: Router: Three collision domains, three broadcast domains

Study Guide Written Lab 1

Written Lab 1.1: OSI Questions

Which layer chooses and determines the availability of communicating partners, along with the resources necessary to make the connection; coordinates partnering applications; and forms a consensus on procedures for controlling data integrity and error recovery?

Which layer is responsible for converting data packets from the Data Link layer into electrical signals?

At which layer is routing implemented, enabling connections and path selection between two end systems?

Which layer defines how data is formatted, presented, encoded, and converted for use on the network?

Which layer is responsible for creating, managing, and terminating sessions between applications?

Which layer ensures the trustworthy transmission of data across a physical link and is primarily concerned with physical addressing, line discipline, network topology, error notification, ordered delivery of frames, and flow control?

Which layer is used for reliable communication between end nodes over the network and provides mechanisms for establishing, maintaining, and terminating virtual circuits; transport-fault detection and recovery; and controlling the flow of information?

Which layer provides logical addressing that routers will use for path determination?

Which layer specifies voltage, wire speed, and pinout cables and moves bits between devices?

Which layer combines bits into bytes and bytes into frames, uses MAC addressing, and provides error detection?

Which layer is responsible for keeping the data from different applications separate on the network?

Which layer is represented by frames?

Which layer is represented by segments?

Which layer is represented by packets?

Which layer is represented by bits?

Put the following in order of encapsulation:

Which layer segments and reassembles data into a data stream?

Which layer provides the physical transmission of the data and handles error notification, network topology, and flow control?

Which layer manages device addressing, tracks the location of devices on the network, and determines the best way to move data?

What is the bit length and expression form of a MAC address?

Written Lab 1.2: Defining the OSI Layers and Devices

This device sends and receives information about the Network layer.

This layer creates a virtual circuit before transmitting between two end stations.

This layer uses service access points.

This device uses hardware addresses to filter a network.

Ethernet is defined at these layers.

This layer supports flow control and sequencing.

This device can measure the distance to a remote network.

Logical addressing is used at this layer.

Hardware addresses are defined at this layer.

This device creates one big collision domain and one large broadcast domain.

This device creates many smaller collision domains, but the network is still one large broadcast domain.

This device breaks up collision domains and broadcast domains.

Written Lab 1.3: Identifying Collision and Broadcast Domains

A - Hub

B - Bridge

C - Switch

D - Router