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80 Cards in this Set
- Front
- Back
Possible structure of applications: |
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Characteristics of a server on a client-server architecture |
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Characteristics of clients on a client-server architecture |
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Peer-to-Peer Architecture |
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What is a process? |
Program running within a host |
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Within the same host, processes communicate using ______________ |
inter-process communication |
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Processes in different hosts communicate by exchanging ________ |
messages |
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Client Process |
Process that initiates communication |
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Server Process |
Process that waits to be contacted |
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Sockets |
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To receive messages process must have ___________ |
identifier |
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Does the IP address of a host on which process runs suffice for identifying the process? |
No. many processes can be running on same host. |
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Identifier includes |
both the IP address and port numbers associated with process on host |
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App-layer protocol defines |
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Open protocols |
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Proprietary protocols |
e.g., Skype |
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What transport service does an app need? |
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TCP Service |
Reliable transport between sending and receiving process Flow control: sender won't overwhelm receiver Congestion control: throttle sender when network overloaded Does not provide: timing, minimum throughput guarantee, security Connection-oriented: setup required between client and server processes |
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UDP Service |
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When to use UDP? |
When you want live communications and don't care if there are some glitches. (e.g. Streaming videos, Skype) |
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SSL |
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HTTP is stateless |
Server maintains no information about past client requests |
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HTTP uses TCP |
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Non-persistent HTTP |
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Persistent HTTP |
Multiple objects can be sent over a single TCP connection between client, server |
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RTT (Round Trip Time) |
Time for a small packet to travel from client to server and back |
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HTTP Response Time in Non-persistent HTTP |
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Two types of HTTP messages |
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True or False: Non-persistent and stateless mean the same thing |
False |
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True or False: HTTP is in-band protocol |
True |
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True or False: Web cache is used heavily in SMPT protocol |
False |
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True or False: UDP is used heavily as the supporting transport protocol for music downloads |
False |
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True or False: FTP uses one TCP link in its operation |
False |
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HTTP POST method |
Input is uploaded to server in entity body |
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HTTP URL method |
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HTTP HEAD method |
Asks server to leave requested object out of response |
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HTTP PUT method |
uploads file in entity body to path specified in URL field |
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HTTP DELETE method |
Deletes file specified in the URL field |
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Status code appears in _____ line in server-to-client response message |
First |
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Four components of cookies |
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Describe how cookies are used in HTTP |
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What cookies can be used for |
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How to keep "state" in a protocol |
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Goal of Web caches |
Satisfy client request without involving origin server |
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Why Web Caching? |
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What is a web cache? |
A mechanism for the temporary storage (caching) of web documents, such as HTML pages and images, to reduce bandwidth usage, server load, and perceived lag. |
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Goal of Conditional GET |
Don't send object if cache has up-to-date cached version |
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FTP |
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3 Major Components of Electronic Mail |
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User Agent in Electronic Mail |
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Mail servers in Electronic Mail |
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SMTP |
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3 phases of transfer for SMTP |
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True or False: SMTP uses persistent connections |
True |
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HTTP vs SMTP |
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POP3 Protocol |
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POP3 "download-and-keep": |
copies of messages on different clients |
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True or False: POP3 is stateless across sessions |
True |
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IMAP |
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DNS (Domain Name System) |
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DNS Services |
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Why not centralize DNS? |
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DNS: root name servers |
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Top-level domain (TLD) servers |
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Authoritative DNS servers |
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Local DNS name server |
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Two types of DNS queries |
iterative query recursive query |
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Once name servers learns mapping, it _________ mapping |
caches |
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DNS records type=A |
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DNS records type=NS |
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DNS records type=CNAME |
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DNS records type=MX |
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True or False: DNS query and reply messages both have the same format |
True |
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DNS: distributed database storing ________ ________ |
resource records (RR) |
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File Distribution time: Client-server Server transmission: |
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File Distribution time: Client-server Client: |
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File Distribution time: P2P Server transmission: |
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File Distribution time: P2P client: |
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File Distribution time: P2P clients: |
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Distributed Hash Table |
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