Karteikarten
Datakommunikation
Karten in diesem Stapel (24)
- 1What are they used for and what is the difference: UDP vs TCPBoth TCP and UDP are protocols used for sending bits of data - known as packets - over the Internet. When sending packets with UDP you can't be sure if the package actually arrive and you don't really care about it. TCP is used when you do care that all the packages do arrive.
Exempel:
UDP - Livestreams
TCP - Överföring av filer - 2What is layer one in OSI-model and its use?Physical layer.
The task of the physical layer is to couple the flow of ones and zeros to the right at each point (node) in the network where they can move in two or more directions.
The physical layer is "stupid" and only tracks instructions from the next layer of the OSI model, the data link storage.
Compare with a railroad switch that controls the trains left or right according to received signals, but without "knowing" where the train is on its way or what it's loaded with.) - 3What is an Autonoumus System(AS) in the Internet?Within the Internet, an autonomous system (AS) is a collection of connected Internet Protocol (IP) routing prefixes under the control of one or more network operators on behalf of a single administrative entity or domain that presents a common, clearly defined routing policy to the Internet.
An IPS is an example (internet provide service) - 4Identify the class, and the bits used for network id and host id of the end system, by looking at the following IP address 110.1.1.8.Class = A
Network = 2^8 , 110.
Host = 2^24, 1.1.8.
The class is know by taking the first number "110" and convering it to a 8 bits of 32 bits.
110 to byte = 0110 1110
Class A = Start with 0
B = Start with 1 then 0 and so on.
There are class A to E.
Class A takes 8 bits, B 16, C 24 and D all (Multicast adress) - 5Explain the objective of tracert administartion utilityTracert(Traceroute) is a command line utility that measures the speed and route data takes to a destination server. It works by sending several test packets of data to a specified destination address, and records each intermediate router or link passed by the data on it's journey.
- 6What are the functions of a Media player?Handle UI.
Decompress Data.
Remove Jitter.
Handle Transmissions Errors. - 7What is the major drawback of stop-and-wait ARQ protocol?Stop and Wait protocol. disadvantages of stop-and-wait: fairly slow: the sender can send at most one new packet per RTT. not robust: if the ack can get lost, when the receiver gets a packet, the receiver cannot tell if it is a retransmission or a new packet.
- 8What is the objective of UDP ports?UDP stands for User Datagram Protocol. Using this method, the computer sending the data packages the information into a nice little package and releases it into the network with the hopes that it will get to the right place. What this means is that UDP does not connect directly to the receiving computer like TCP does, but rather sends the data out and relies on the devices in between the sending computer and the receiving computer to get the data where it is supposed to go properly. This method of transmission does not provide any guarantee that the data you send will ever reach its destination. On the other hand, this method of transmission has a very low overhead and is therefore very popular to use for services that are not that important to work on the first try. A comparison you can use for this method is the plain old US Postal Service. You place your mail in the mailbox and hope the Postal Service will get it to the proper location. Most of the time they do, but sometimes it gets lost along the way.
- 9What is the main difference between the functionalities of two devices: a switch and a router?Routers and switches are both computer networking devices that allow one or more computers to be connected to other computers, networked devices, or to other networks. The functions of a router, switch and hub and are all different, even if at times they are integrated into a single device.
Routers connect two or more logical subnets, which do not necessarily map one-to-one to the physical interfaces of the router. The term layer 3 switch often is used interchangeably with router, but switch is really a general term without a rigorous technical definition. In marketing usage, it is generally optimized for Ethernet LAN interfaces and may not have other physical interface types. - 10True or False Primarily objective of the OSI Layer 3 is to avoid congestion in the local areanetwork.False, the main objective of layer 3 Network to enable communication between nodes in the different networks.
- 11True or False IP is a routing protocol, which computes the shortest paths between the nodes in the Internet.It's a host and network interface identification and an location adress.
- 12True or False HTML is the protocol for theexchange of HTTPHTTP(Hyper text transfer protocol) is the transfer protocol of Hypertext. HTML is a type of Hypertext therefore False.
- 13True or False When the public key cryptography is applied for the authentication of the sender, then its private key should be made known to the receiver in advance.False, a private key is always a private key.
- 14True or False IP is a Layer 3 protocol, which is executed by the routers and the hosts to maintain their routing tables.False
- 15True or False Primarily objective of a Layer 1 is to transmit packets between the nodes directly connected by a cable.False,
transform raw bits into a form that is suitable for transmission between physical medium - 16True or False “Ping” to the host in the same local area network returns “Destination host unreachable” message. This means that the ARP protocol has not managed to identify the MAC address of the host.True, if the local network router cannot find the IP the ARP protocol can't combine the MAC and IP to the host
- 17True or False Autonomous system is a segment of the network, which is isolated from other segments by a firewall.False, AS is a segment handle by the IPS or network host taht specifiy special rules and not the firewall.
- 18True of False Often the PHP is used to develop e-commerce applications.True, yes many applications use PHP to gather data from databases and more functions.
- 19A public key cryptography is more computationally secure than a traditional symmetric key cryptography.True, We know that a public key cryptography does things that symmetric key cryptography cannot do but it does so at a hefty price like more maths, more code, more complexity, bigger objects, more power from CPU requried.
- 20Explain why a typical computer has both the IP and the MAC addresses. Is not IP address enough to identify it in the Internet?INTE DUBBELKOLLAT
MAC and IP are on two different layers in the OSI-model, some protocol still rely on the MAC adress. - 21Identify the class, and the bits used for network id and host id of the end system, by looking up the following IP address 129.1.4.4.Klass B
16 Network 16 Host - 22Explain the objective of the ARP protocol.To connect the MAC and IP adress.
- 23What is the main difference between routing within a datagram network and routing within virtual-circuit network?VCN is when you have a predecided path on the network while Datagram network
has no predefined path (contactless network) - 24Explain TDMA, RMA, CDMA, FDMATDMA(Time Divide Multiple Access)
CDMA(Code DMA)
Different times and different frequencies
FDMA(Frequency Divide multiple access)
is the process of dividing one channel or bandwidth into multiple individual bands, each for use by a single user Each individual band or channel is wide enough to accommodate the signal spectra of the transmissions to be propagated. The data to be transmitted is modulated on to each subcarrier, and all of them are linearly mixed together.
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- Beschreibung
- Engineering Karteikarten am Datakommunikation, erstellt von Martin Myhrman am 29/10/2018.
- Erstellt von
- Martin Myhrman
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