1. What is the difference between host and end systems.

1. What is the difference between host and end systems.

No difference

2. What is the packet switches?

?

3. End systems communicate by network of… and … /

Communication link, switches

4. What is the IETF: Internet Engineering Task Force

The Internet Engineering Task Force (IETF) develops and promotes voluntary Internet standards, in particular the standards that comprise the Internet protocol suite (TCP/IP). It is an open standards organization, with no formal membership or membership requirements. All participants and managers are volunteers, though their work is usually funded by their employers or sponsors.

The IETF started out as an activity supported by the US federal government, but since 1993 it has operated as a standards development function under the auspices of the Internet Society, an international membership-based non-profit organization.

5. Rfc

A Request for Comments (RFC) is a publication of the Internet Engineering Task Force (IETF) and the Internet Society, the principal technical development and standards-setting bodies for the Internet.

An RFC is authored by engineers and computer scientists in the form of a memorandum describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems. It is submitted either for peer review or simply to convey new concepts, information, or (occasionally) engineering humor. The IETF adopts some of the proposals published as RFCs as Internet standards.

6. What is the server application And client application

7. DSL

Digital subscriber line (DSL; originally digital subscriber loop) is a family of technologies that provide internet access by transmitting digital data using a local telephone networkwhich uses the Public switched telephone network. In telecommunications marketing, the term DSL is widely understood to mean asymmetric digital subscriber line (ADSL), the most commonly installed DSL technology. DSL service is delivered simultaneously with wired telephone service on the same telephone line. This is possible because DSL uses higherfrequency bands for data. On the customer premises, a DSL filter on each non-DSL outlet blocks any high frequency interference, to enable simultaneous use of the voice and DSL services.

8. HFC: hybrid fiber coax

Hybrid fibre-coaxial (HFC) is a telecommunications industry term for a broadband network that combines optical fiber and coaxial cable. It has been commonly employed globally by cable television operators since the early 1990s.

9. Propagation delay: all delays!

/propagation =the length of time taken for the quantity of interest to reach its destination.

, processing = the time it takes routers to process the packet header

, queue = the time a job waits in a queue until it can be executed

, transmission = the amount of time required to push all of the packet's bits into the wire

10. What’s a protocol?(network)

protocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, receipt

11. Internet protocol stack

— application: supporting network applications

— FTP, SMTP, HTTP

— transport: process-process data transfer

— TCP, UDP

— network: routing of datagrams from source to destination

— IP, routing protocols

— link: data transfer between neighboring network elements

— Ethernet, 802.111 (WiFi), PPP

— physical: bits “on the wire”

12. End to end delay

D = transmittion + processing + queue + propogation

13. Differences between Packet switching and circuit switching

Definitions: Packet-switched networks move data in separate, small blocks -- packets -- based on the destination address in each packet. When received, packets are reassembled in the proper sequence to make up the message. Circuit-switched networks require dedicated point-to-point connections during calls.

Circuit-switched networks and packet-switched networks have traditionally occupied different spaces within corporations. Circuit-switched networks were used for phone calls and packet-switched networks handled data. But because of the reach of phone lines and the efficiency and low cost of data networks, the two technologies have shared chores for years.

In modern circuit-switched networks, electronic signals pass through several switches before a connection is established. And during a call, no other network traffic can use those switches.

In packet-based networks, however, the message gets broken into small data packets that seek out the most efficient route as circuits become available. Each packet may go a different route; its header address tells it where to go and describes the sequence for reassembly at the destination computer

14. R = Link bandwith, La= packet length. La/R = 0(small delay), 1(delay large), >1(more work arriving)

15. TCP UDP

TCP is more reliable, UDP is faster. UDP = no connection between client and server + no handshaking, TCP always connection between client and server.

16. P2P ARCHITECTURE

peers request service from other peers, provide service in return to other peers

17. Internet apps: application, transport protocols

application

e-mail

remote terminal access

Web

file transfer

streaming multimedia

Internet telephony

Application

layer protocol

SMTP [RFC 2821]

Telnet [RFC 854]

HTTP [RFC 2616]

FTP [zRFC 959]

HTTP (e.g., YouTube),
RTP [RFC 1889]

SIP, RTP, proprietary

(e.g., Skype)

Дата добавления: 2015-11-04