1. Internetworking Flashcards
What does an Internetwork consist of?
- Two or more devices
- Connected via a router
- Logical network addressing scheme (IPV4/6)
What can a hub more accurately be defined as?
A multi-port repeater.
How does a multi-port repeater work?
- Recieves a digital signal.
- Amplifies/regenerates the digital signal.
- Broadcasts out of all other ports.
- Does not inspect the signal.
Why is network segmentation employed?
Network Segmentation reduces congestion within the network.
What do Cisco refer to as microsegmentation?
Microsegmentation is when every host is in a switch port.
How does a switch forward a broadcast?
Switches put out broadcast messages on every port by default.
What is a broadcast domain?
A broadcast domain is a subnet/VLAN in which if a host sends a broadcast message, all other hosts on the same subnet/VLAN will receive it.
How does a router forward a broadcast?
A router does not forward broadcasts by default.
What is a collision domain?
A collision domain is a network segment connected by a shared medium or through repeaters where data packets may collide with one another while being sent.
How are the number of collision domains in a network increased?
Collision domains are increase through the segmentation of a network using switches.
How are the number of broadcast domains increased within an internetwork?
Through the introduction of a router and additional subnets/VLANs.
What is the connection of two or more LANs reffered to as?
An internetwork.
What is the purpose of a Wireless Access Point?
A Wireless Access Point allows for computers to gain wireless access to wired networks
What is the physical function of a wireless access point?
A Wireless Access Point acts as a modulator/demodulator, receiving digital data and transmitting analogue data (and vice versa).
What does Duplex mean?
- The term ‘duplex’ signifies the ability for two points or devices to communicate with each other.
- In a duplex communication system, both points (devices) can transmit and receive information.
What is the difference between Full-Duplex and Half-Duplex?
- Full-duplex communication between two components means that both can transmit and receive information between each other simultaneously.
- In half-duplex systems, the transmission and reception of information must happen alternately. While one point is transmitting, the other must only receive.
How do Wireless Access Points operate?
- Wireless Access Points run at Half-Duplex.
- Using Time Division Duplexing (TDD) and splitting the time divisions very finely, Full-Duplex is emulated.
- This stops self-interference.
What are VOIP Phones?
Voice Over Internet Protocol (VOIP) Phones.
What will be increased if a Wireless Access Point is connected to a switch?
This will expand the collision domain.
What is a Flat network?
A flat network is a large switched network which has a single large broadcast domain.
What is the Cisco Hierarchical Model?
What is a Virtual Local Area Network (VLAN) used for?
A VLAN is used to segment a layer 2 switched network into multiple different broadcast domains.
What is necessary for inter-VLAN routing (IVR)?
A layer 3 switch or router is required for inter-VLAN routing.
What are the layers of the OSI 7 layer model and which protocols and services correspond to these layers?
What does each layer of the OSI model do?
What was the OSI model created for?
The OSI model was created in order to enable different networks to communicate reliably accross disparate systems.
What do the top 3 layers of the OSI model define?
- The top three layers of the OSI model define how the applications within the end stations communicate with each other and the users.
- These layers do not contain information about networking / network addresses.
What do the bottom 4 layers of the OSI model define?
The bottom 4 layers of the OSI model define:
- How data is transmitted end to end.
- How it is transferred through physical mediums.
- How to rebuild a data stream from a transmitting host to a destination hosts’ application.
At which layer do users interact with the computer?
The application layer.
What is the purpose of the presentation layer?
- To present data to the user.
- To handle processing such as encryption.
What is the purpose of the session layer?
To keep different applications’ data separate.
What does the transport layer provide?
The transport layer provides:
- Reliable / Unreliable delivery.
- Error correction before retransmit.
- The segmentation and reassmbly of data in a data stream.
- The reception of all data from higher layers and the combination of it into a single concise data stream.
- The establishment of a logical connection between the sending host and the destination host on the network.
What does the network layer provide?
The network layer provides logical addressing which routers use for path determination.
What does the data link layer provide?
- The combination of packets into bytes. The subsequent comination of bytes into frames.
- Access to media using MAC address.
- Error detection (as opposed to correction).
What does the physical layer provide?
- The movement of bits between devices.
- The specification of voltage, wire speed and pin-out of cables.
What is TCP?
Transmission Control Protocol (TCP) is a connection oriented protocol.
What is UDP?
User Datagram Protocol (UDP) is a connectionless layer protocol.
What steps are required for relaible communication?
- A connection oriented 3-way handshake with a peer device (also known as a call setup)
- Transfer of data
- Termination of connection (which ends the virtual circuit).
