Term
| What does IETF stand for? |
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Definition
| Internet Engineering Task Force |
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Definition
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Term
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Definition
| Frequency-division Multiplexing |
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| What does Wi-Fi stand for? |
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Definition
| A slang way of saying Wireless Local Area Network. (WLAN) Some say Wi-fi stands for wireless fidelity but it doesn't actually stand for anything. |
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Definition
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Term
| What does SMTP stand for? |
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Definition
| Simple Mail Transfer Protocol |
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Term
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Definition
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Term
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Definition
| A protocol controls the sending and receiving of information within the internet. Run on end-systems. |
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Term
| What is the difference between a host system and an end-system? |
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Definition
| They are both the same thing.. Includes PCs, workstations, Web Servers, mail servers, Internet connected PDAs, WebTVs, etc. |
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Term
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Definition
| TCP, IP, UDP, SMTP, FTP, HTTP, Skype, 802.11 |
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Term
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Definition
| Time Division Multiplexing |
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Term
| What are the 5 layers in the Internet? |
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Definition
1. Application
2. Transport
3. Network
4. Data Link
5. Physical |
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Term
| What does store-and-forward mean? |
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Definition
| The entire packet must arrive at router before it can be transmitted on next link |
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Term
| What's the difference between packet switching and circuit switching? |
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Definition
-Packet switching allows more users to use network.
-Circuit switching has circuit-like (guaranteed) performance
-Packet switching is simpler, no call setup
-Packet switching has resource sharing
-Packet switching has packet delay and loss. Needs more work, protocols needed for reliable data transfer, congestion control |
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Term
| How do packet loss and packet delay occur? |
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Definition
-When packet arrival rate to link (temporarily) exceeds output link capacity.
-Packets queue, wait for turn. |
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Term
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Definition
-Time waiting at output link for transmission.
-Depends on congestion level of router. |
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Term
| What is nodal processing delay? |
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Definition
-Checking for bit errors.
-Determine output link.
-Typically < msec |
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Term
| What is transmission delay? |
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Definition
Time needed to transmit L-bit packet into link
-L:packet length (bits)
-R:link bandwidth (bps)
-dtrans = L/R |
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Term
| What is propagation delay? |
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Definition
-d:length of physical link
-s:propagation speed in medium (~2x10^8 m/sec)
-dprop = d/s
-Very different from transmission delay calculation. |
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Term
| What is the traceroute program? |
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Definition
| Provides delay measurement from source to router along end-end Internet path towards destination. |
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Term
| What does the traceroute program output? |
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Definition
for all i(routers):
-sends three packets that will reach router i on path towards destination
-router i will return packets to sender
-sender times interval between transmission and reply.
(Outputs 3 different delay measurements from every router between two host machines) |
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Term
| What is end-to-end throughput? |
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Definition
| End-to-end throughput is the rate (bits/time unit) at which bits transferred between sender/receiver(One end to another end). |
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Term
| What is the instantaneous end-to-end throughput? |
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Definition
| rate at given point in time |
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Term
| What is the average end-to-end throughput? |
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Definition
Rate over longer period of time.
If it takes T seconds for a host to receive a file with F bits, then the avg throughput is F/T bps. |
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Term
| Explain the application layer. |
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Definition
Supporting network applications.
-Uses FTP, SMTP, and HTTP |
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Term
| Explain the transport layer. |
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Definition
Process-process data transfer.
-TCP, UDP |
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Term
| Explain the network layer. |
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Definition
Routing of datagrams from source to destination.
-IP, routing protocols |
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Term
| Explain the Data link layer. |
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Definition
Data transfer between neighboring network elements.
-Ethernet, 902.111 (WiFi), PPP |
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Term
| Explain the Physical layer. |
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Definition
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Term
| What layer's packets are called messages? |
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Definition
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Term
| What layer's packets are called segments? |
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Definition
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Term
| What layer's packets are called datagrams? |
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Definition
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Term
| What layer's packets are called frames? |
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Definition
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Term
| What are typical protocols for the application layer? |
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Definition
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Term
| What are typical protocols for the transport layer? |
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Definition
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Term
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Definition
| Also called Link Transmission Rate, how fast data is pushed to the communication link. |
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Term
| Bandwidth vs. end-to-end throughput |
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Definition
| Bandwidth describes data transmission capacity of a communication link, but end-to-end throughput describes the average rate at which data is transmitted between the sender (one end) and the receiver (the other end). |
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Term
| What are the possible Application Architectures, or structure of applications using the internet? |
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Definition
-client-server
-peer-to-peer (P2P) |
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Term
| What is client-server architecture? |
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Definition
Server: Always-on host, permanent IP address, data centers for scaling.
Clients: Communicate with server, may be intermittently connected, may have dynamic IP addresses, do not communicate directly with each other. Facebook, YouTube, Gmail. |
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Term
| What is P2P Architecture? |
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Definition
| There is no always-on server, arbitrary end systems directly communicate from eachother, peers request service from other peers, provide service in return to other peers, peers are intermittently connected and change IP addresses. BitTorrent, uTorrent, Bitcoin |
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Term
| What is self scalability? |
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Definition
| In p2p architecture, new peers bring new service capacity, as well as new service demands. |
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Term
| What's the difference between Transmission Control Protocol(TCP) services and User Datagram Protocol User Datagram Protocol(UDP) services? |
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Definition
| Transmission Control Protocol(TCP) provides a reliable transport, flow control, and congestion control. User Diagram Protocol(UDP) does not provide any of these. |
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Term
| What services does Transmission Control Protocol(TCP) provide? |
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Definition
| TCP provides reliable transport, flow control, congestion control, does not provide, and is connection-oriented. |
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Term
| What services does User Datagram Protocol(UDP) provide? |
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Definition
| UDP provides unreliable data transfer. |
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Term
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Definition
UDP is simpler so some systems that have limited capabilities (e.g. embedded systems prefer to use UDP)
UDP has less latency: the cost of establishing a TCP connection is sometimes excessive: If I just want to urgently send you a packet, I don't want to lose time of establishing a TCP connection.
The retransmission mechanism of TCP can be a nuisance for nearly real time systems: If I transmit video, I don't want the image to freeze while TCP is retransmitting. If a video packet is lost, that's a pity, you will have some pixelation of your image, but you will soon get the next UDP packet and the image will recover. |
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Term
| What kind of transport layer protocol does HTTP(streaming multimedia) use? |
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Definition
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Term
| What kind of transport layer protocol does SMTP(e-mail) use? |
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Definition
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Term
| What kind of transport layer protocol does Telnet(remote terminal access) use? |
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Definition
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Term
| What kind of transport layer protocol does HTTP(Web) use? |
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Definition
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Term
| What kind of transport layer protocol does FTP(file transfer) use? |
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Definition
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Term
| What kind of transport layer protocol does SIP, RTP, proprietary(i.e Skype)[Internet telephony] use? |
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Definition
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Term
| What are some transport service requirements? |
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Definition
| File-transfer, Email, and Web must be reliable so they use TCP. Congestion control and flow control are also necessary for Email and file-ttransfer. UDP would be ideal for multimedia applications, because a video will freeze using TCP when it has to retransmit for a package, but UDP will only pixelate the image till the next packet is sent. |
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Term
| Hypertext Transport Protocol(HTTP) port number? |
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Definition
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Term
| File Transfer Protocol(FTP) port number? |
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Definition
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Term
| What 2 connections does FTP use? |
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Definition
| 2 TCP connections: a control connection(transmitting commands) and a data connection(transmitting data) |
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Term
| What does Simple Mail Transfer Protocol(SMTP) do? |
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Definition
| Runs between mail servers and between mail client and mail server for message sending. |
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Term
| What do Mail Access Protocols do? |
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Definition
| Between mail server and mail client for message retrieving, using Post Office Protocol(POP3), Internet Mail Access Protocol(IMAP), and Hypertext Transfer Protocol(HTTP) |
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Term
| What important services does Domain Name Server(DNS) provide? |
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Definition
-hostname to IP address translation
-host aliasing
-mail server aliasing
-load distribution |
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Term
| What are the four types of Domain Name System(DNS) records? |
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Definition
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Term
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Definition
| Name Server Lookup. Usable on most PCs to obtain name server information for Domain Name System(DNS) by querying Domain Name System(DNS). |
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Term
C:\> nslookup
Default Server: resolver1.opendns.com
Address: 208.67.222.222
\>
What is this showing? |
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Definition
| This nslookup shows the DNS server configured on the PC in use for look-ups. |
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Term
| What is HTTP Response Status Code: 200? |
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Definition
200 = OK
-Request succeeded, requested object later in this msg |
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Term
| What is HTTP Response Status Code: 202? |
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Definition
202 = Accepted
-The request has been accepted for processing, but the processing has not been completed. |
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Term
| What is HTTP Response Error Code: 301? |
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Definition
302 = Moved Permanently
-Requested object moved, new location specified later in this msg (Location:) |
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Term
| What is HTTP Response Error Code: 304? |
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Definition
304 = Not Modified
If the client has performed a conditional GET request and access is allowed, but the document has not been modified, the server SHOULD respond with this status code. |
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Term
| What is HTTP Response Error Code: 403? |
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Definition
403 = Forbidden
The server understood the request, but is refusing to fulfill it. Authorization will not help and the request SHOULD NOT be repeated. |
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Term
| What is HTTP Response Error Code: 404? |
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Definition
404 = Not Found
-Requested document not found on this server. |
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Term
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Definition
-authorization
-shopping carts
-recommendations
-user session state(Web e-mail) |
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Term
| How does the cookie mechanism work? |
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Definition
| They permit sites to learn a lot about you. You may supply names and e-mail to sites. |
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