Title: Networks and Telecommunications
1Networks and Telecommunications
2Telecommunications Media
- Twisted pair (RJ-11 RJ-45)
- Advantages
- Disadvantages
- Coax
- Fiber-optic
3Communication channels their capacities
4Capacities of other communication media
5Telephone company connection choices
6Telecommunications Media-wireless
- Microwave
- Satellite
- Cellular
- Infrared laser
7Transmission Modes
- Simplex
- Half-duplex
- Full-duplex
- Echoplex (re-x-mit for check)
8The signal
- Analog
- Digital
- Modems
- Serial vs. parallel
- Asynchronous vs. synchronous (character vs. block
per unit time!)
9Networks
- A computer network is a collection of computers
- and other devices that communicate to share data,
- hardware and software.
- LANs
- topologies
- protocols (polling vs. contention vs. token)
- WANs
- PBXs
- gateways vs. bridges (dissimilar vs. similar)
10What sort of resources does a LAN provide?
Network nodes include workstations printers,
and servers.
11Networks
- Logging in
- Network administrators
- Workstation gains access to the server when the
server hard drive is mapped to a drive letter. - Drive mapping - network term for assigning a
drive letter to a network server disk drive. - many use the letter F
12LANs
- When you start a program that is stored on a LAN,
the program is copied to your workstations RAM,
then runs normally. - With proper licensing, many users on the same
network can use the same program simultaneously,
also known as sharing. - Sharing is effective because
- less disk storage space required
- easier to update software
- less expensive
13LAN topologies
- Ring
- Bus
- Star
- Hierarchical
- Hybrid
14LANs
- File locking
- To access other printers on a network,
- install its driver software.
- Default printer
- Another way to select a different printer is from
within an application
15LAN Hardware
- Hubs
- To connect workstations
- together and then
- to the server
- Server types
- dedicated servers
- non-dedicated servers
- print servers
- application servers
- host computers
16Dedicated file server
- Which of the servers processes my data?
- Dedicated server delivers programs and data files
to workstations. - It does not process data or run programs for
workstations.
17Dedicated file server
18Non-dedicated file server
- Which of the servers processes my data?
- A non-dedicated file server is a computer on a
network that performs a dual role as both file
server and workstation processes the data - also called peer-to-peer capability
- Print server - receives files from workstations
and forwards them to a specific network printer - A print server manages a print queue, a holding
area for files waiting to be printed.
19Non-dedicated file server
20Application server
- A computer that runs a specific application
software package also processes data - also referred to as client/server architecture
- An application server splits processing between
the workstation (client) and the network
(server).
21Application server
An application server typically runs database
software and performs database functions as
requested by the workstations.
22Host computers
- A minicomputer or a mainframe with attached
terminals. - all processing takes place on the host
- terminals only display results of processing
- also known as a time-sharing system
- MSCDs Clem is a host computer (see Pine, Clems
own mail system, or Pico, Clems own editor) - Terminal emulation software connects a
microcomputer to a host (see Telnet)
23Network software
- Network operating system (NOS) software
- manages network resources
- controls flow of data
- maintains security
- tracks user accounts
- Network operating system has two components
- network server software
- network client software
24Network Operating System (NOS)
- Network server software (on file server)
- controls file access from the servers hard disk
- manages print queue
- tracks user data e.g. IDs and passwords
- Network client software (on workstation)
- gathers login information
- handles drive mapping
- directs printouts to network printer
25LANs
- Can single user s/w be installed on networks?
- Is it legal? Depends.
- Do single user s/w have network capabilities?
26Can two or more people work together on the same
data file?
- Groupware is an application software that
supports collaborative work by managing - schedules
- shared documents
- intra-group communications
- based on information-centered model
- Workflow software
- electronically routes documents from one person
to another - sequences routing in a specific order
- it is based on a process-centered model
27End Networks and Telecommunications