Flashcards
203Full
Flashcards do conjunto (101)
- 1What is Telegraphy, the type of connection it uses1 - Sending an signal transmitting of information which was encoded
2 - Send data via message switching
3 - Uses Connection-less - 2What is Telephony, what it uses and the type of connection it uses1 - The ability to transmit voice
2 - Uses Circuit switching
3 - Connection oriented - 3What are Connection-less and Connection Oriented1 - Connection-less is that if you send multiple message, may take a different route
2 - Connection oriented is a service - 4What is Message switching1 - No dedicated lines between sender and reciever
2 - If you send multiple messages, they may take different routes to reach destination - 5What is Circuit switching1 - Dedicated line between sender and receiver
2 - Establish a connection, talk, then you close
3 - All the information is on the same line
4 - Provides Connection Oriented Service - 6Name and Describe the 3 Phases of Circuit Switched Systems1 - Call set-up - establish a call
2 - Communicate - Send/Receive information
3 - Tear-down - When you hang up
Kys Alex ty. - 7What is a Protocol1 - Use this to communicate
2 - Gets all possible events and actions in a system
3 - Exact detail of message sent - 8Protocol in Independent Systems1 - Protocols must be complete
2 -Little errors could cause failure to network - 9In Simple Terms, what is Addressing1 - How to make sure communication ends up in the right place
- 10What is a Hierarchical Addresses1 - Prefix of Numbers allows us to have a location for a given address
2 - 0161 - Manny on the map - 11What is a Flat Address and an Example of this1 - Given an address we have no idea where the device is
2 - An example of this is a MAC Address. - 12What are Connection-Oriented-Systems1 - Connection setup/teardown
2 - If a failure occurs, may not be possible to continue
3 - - 13How do Connection-Less Systems get to their destinations1 - Using packet switching
- 14What is Packet Switching1 - Each transmission is an independent packet of data
2 - Each packet is like an addressed envelope - 15What is a simple diagram of a Packet, and what does each part contain1 - Header - Holds the address
2 - Payload - Holds the data - 16What is Statistical Multiplexing1 - Allow resource demand to exceed supply
2 - Queue packets until available link capacity - 17What are the 2 modes for Packet switching1 - Datagram
2 - Virtual Circuit - 18What is a Datagram and the type of connection it is used for1 - Applications aware of packet structure
2 - Used for connection-less - 19What is Virtual Circuit and the type of connection it is used for1 - Applications unaware of packet
2 - Used for a non-physical connection - 20What is the path selection for a datagram1 - Each packet is considered as a seperate message
2 - Datagrams are like postcards - 21What is inside the Header of a datagram1 - Destination (32 bits)
2 - Sender (32 bits) - so we know where to reply to
3 - Length (16 bits)
4 - Type (16 bits) - The type of what the information os - 22What is the path selection for virtual circuits1 - Emulate connection oriented over connectionless network
2- Each packet contains a connection tag - used for path selection - 23What is the Application view and the different examples of each one1 - Service Provided to Application
2 - Data-Grams - Connection less
3 - Virtual Circuits Connection Oriented - 24What is the Physical view1 - How underlying network operate
2 - Packet switching Connection Less
3 - Circuit Switching Connection Oriented - 25What is Communication Protocols1 - How and when Data is transmitted
- 26Describe what a layer is1 - Provides service to the layer above
2 - Abstract complexity - 27What are Reference Models1 - Specifying communication function across layers
2 - OSI -7 layers
3 - Internet Model- 5 layers - 28From Top to Bottom, Name the layers in the OSI Model1 - Application
2 - Presentation
3 - Session
4 - Transport
5 - Network
6 - Data Link
7 - Physical - 29From Top to bottom, what are the layers of the Internet Model1 - Application
2 - Transport
3 - Network
4 - Link
5 - Physical - 30Define the Physical Layer and examples of this1 - Mechanical and electrical specification
2 - Plugs and sockets
3 - we use symbols - 31What is the Data Link layer1 - Frame based transmission
2 - Sends and receives bytes to and from Host
3 - Basic error checking - 32What is the Network Layer1 - Uses packets which are formed from one or more layers
2 - independent host to host transmissions
3 - introduces network addresses and routable addresses
4 - Allows us to communicate
5 - Provide network independent message service - 33What is the transport layer1 - Uses segments - formed from 1 or more packets
2 - user oriented global addressing scheme - 34What is Upper Layer Architecture1 - Session, Presentation and Application
2 - Provide user oriented services - 35What is the Session Layer1 - Provides value added services
2 - Ability to restart a connection at agreed point - 36Presentation Layer1 - Data representation
2 - Compression
3 - Encryption - 37What is the Application Layer1 - Application of the Internet such as FTP, DNS
- 38What are the Characteristics of the Physical Layer1 - Mechanical - size of the plug
2 - Electrical - specifies voltage
3 - Functional - desfines pin allocation
4 - Procedural - defines rules for using switching functions - 39Elements of the Physical Layer1 - Bit - propagates between transmitter receiver pairs
2 - Physical link - line between transmitter and reciever - 40Example of Guided Media1 - Twisted pair - insulated copper wires
- 41Example of Unguided Media1 - Radio - No physical wire
- 42What is DIgital transmission1 - How bits are transferred across a physical medium
- 43What is Binary Encoding, Pros and Cons and what you do1 - Using binary number
2 - 1 Is mapped high
3 - 0 is mapped low
4 - Pros - Simple and cheap
5 - Cons - No self CLocking feature - 44What is Manchester Encoding, Pros and Cons and what you do1 - Using the transition of numbers
2 - Transition of 1 > 0 = High to Low
3 - Transition of 0 > 1 = Low to High
4 - Good for self clockign feature
5 - Only using half of the bandwidth utilisation - 45Differential Manchester Encoding, Pros and Cons, and what you do1 - When there is a one, You do a Z, until it hits another 1. When it hits another 1, it flips it.
2 - Pros is good self clocking feature
2 - Cons is that is complex - 46What is Multiplexing and the Types1 - Multiple conversations over one cable
2 - Frequency Division MultiPlexing
3 - Time Division multiplexing - 47What is Frequency Division Multiplexing1 - Band is split between the user
2 - Each user is allocated frequency
3 - Eg TV - 48What is Time Division MultiPlexing1 - User has a time slot
2 - During time, user has full bandwidth
EG Skype (VOIP) - 49Types of Time Division Multiplexing1 - Synchronous
2 - Asynchronous - 50What is Synchronous TDM and Pros and Cons1 - fixed slot allocation
2 - Sender can only send in one allocation
3 - Pros - Easy to implement
4 - Cons - Waste resources - 51What is Asynchronous, and Pros and Cons of it1 - Packets are processed upon arrival time
2 - Pros - optimal bandwidth usage
3 - cons - additional processing - 52What is a Data Link Layer1 - Access networks and how frames are sent across individual networks eg LAN
- 53What is Framing1 - Blocks of frames which are exchanged
2 - Node a sent across to node B
3 - Node b collections and deposits in memory - 54What is Error Detection1 - To detect an error and correcting these to
- 55Why do we need error Detection in Link Layers1 - Errors can be introduced in to frames
- 56What is Parity Checking1 - Single Bit Parity - Detect single bit errors
2 - 2D bit parity - detect and correct single bit errors - 57What is Checksum1 - To detect error in a packet ( Used in transport layer only)
2 - - 58What is the Cyclic Redudancy Check1 - View data bits as a binary number
2 - Implement a function, if a non zero remainder, then an error, else its fine - 593 Functions of Data link layer1 - Framing - Ids the start and the end of a message
2 - Error control - detects and corrects transmission errors
3 - Media access control - controls when computers transmit - 60What is Media Access Control1 - Point 2 point Connection - uses simple 2 way handshake
2 - Shared media - Used for LANS - 612 types of Links1 - Point to Point - point 2 point link between ehternet switch, host
2 - broadcast - shared wire or medium - 62What are multiple access protocols1 - Single shared broadcast channels
2 - Determines how nodes share channel
3 - - 63What is Slotted aloha and Pros and Cons for it1 - When node obtains frame, wait for next and transmit.
2 - If no collision = sucess
3 - If collision = retransmit
4 - Pros - Easy to implement
5 - Cons - Idle slots - 64What is Unslotted Aloha1 - No Synchronization required
2 - When first arrives, transmit immediately
3 - Collision probability increased - 65What is CSMA1 - Carriable - signal used to carry data
2 -CSMA - listens before transmit
3 - if someone else is talking, stop - 66What is CSMA/CD1 - Collision detection CSMA
2 - 2 nodes may not hear each other - 67What is Ethernet1 - Most common used link layer
- 68Frame Structure of Ethernet1 - Preamble - 7 bytes to sync receiver sender
2 - dest addr -
3 - src addr -
4 - Data
5 - CRC - 69Ethernet Switches1 - Relay frames at the link layer
2 - store and forward ethernet frames
3 - self learning
4 - dont have mac addresses - 70What is a switch forwarding table1 - Each switch has a table entry
2 - switch learns which host can be reached through which interfaces - 71What is a Virtual Network1 - Having a network without physically having one
2 - Single broadcast domain
Illuminati Confirmed - 72What are the differences between Switches and Routers1 - Both are store and forward - routers example network layer headers. siwtches example link layer headers
2 - both have forwarding tables - routers compute tables. Switches learn forwarding - 73What is Traffic Isolation1 - Frames to and from port 1-8 can only go to them ports
- 74What is Connectionless network protocol1 - Allows us to transmit information between web pages
2 - best effort - packets may be lost
3 - packets may be duplicated or delayed - 75Key Internet Design Decisions1 - Test Before Release
2 - Simplicity - Avoid unnecessary features
3 - Modularity - Protocol stack of independent layers
4 - Heterogeneity - allow different network hardware
5 - Spread load as evenly as possible - 76What is IPv41 - Current Generation of protocol
- 77What is the IP Packet Header Length1 - Length of bit of information that you are sending across the netwrok
- 78What is the Diffeserv in an IP Paclet1 - Allows people to grade the traffic sending
- 79What is the Length in the IP packet1 - Length of whole IP Packet in bytes, includes the ip header and the payload
- 80What causes Fragmentation1 - If a length is 1500 and we try to send more than that, we have fragmentation
- 81Transparent Fragmentations1 - If network cant carry the data you are sending
2 - send it across using multiple bots - 82Non transparent fragmentations1 - if you fragment a packet, you leave it fragmented until the end system de frags it
2 - If you lose fragments, then you wil have to send the whole thing again - 83Fragmentation Identifier1 - Sending host uses incrementing in each packet
2 - Receiver with same ID belong to same source packet - 84Fragmentation Offset1 - indication of each fragmentation starts in each packet
2 - tells receiver where each fragment sits in the original packet - 85Time to live1 - Time to live for a packet
2 - When = 0 the packet is discarded - 86IPV4 Addresses1 - 32 Bit /4 byte Identifier
2 - Value stored in header field are those 4 values put together
3 - 127.0 - network identifier
4 - 0.1 - host identifier - 87What are private Addresses1 - You cannot announce these outside your organisation
2 - These addresses are meaningless outside an organisation - 88What are special addresses1 - These are to do with communicating with more than one device at a time
- 89Multi-Cast Addresses1 - Packets are delivered to a group of interested devices
Used in media or distribution services - 90BroadCast Addresses1 - For delivery to all devices on a local network
2 - Every device on your network will get a copy fo the acpket
3 - Good for broadcasting messages - 91Special Addresses1 - Used where we dont know what addresses we are dealing with
- 92ICMP - Internet COntrol Message1 - Routers can send error messages to source devices
2 - Used to reports errors back to source - 93Using Traceroute1 - Finding a path
2 - Need to find single path to destination - 94Linking network and data link layer1 - ethernet address = data link layer
2 - ip address = network layer
3 - network layer - end to end
4 - data link layers - address end point on same physical link hop by - 95What is ARP Cache1 - Table of which says this IP address is this mac address
- 96Gratious ARP1 - Sent on address configuration
2 - puts values in tables - 97PRos and COns with ARP1 - pros they are simple
2 - easily spoof addresses and fake replies - 98What is MPLS, pros and cons1 - Multi protocol label switching
2 - high speed ip forwarding using fixed length label
3 - pros are that it is flexible - 99MPLS Routing vs IP Routing1 - MPLS routing - path to destination can based on source and dest address
2 - IP routing - path to destination determined by detinsation address alone - 100What is DHCP1 - Getting your ip address
2 - allows a computer to join a network without having an ip address address - 101What does DHCP do1 - Assigns a unique ip address
2 - Used by isps t
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- FlashCards sobre 203Full, criado por Shez F em 28-04-2017.
- Criado por
- Shez F
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