Client Server 1 Flashcards
collection of individual networks, connected by intermediate networking devices, that functions as a single large network.
intranetwork
evolved around the PC revolution.
LAN
interconnect LANs with geographically dispersed users to create connectivity
WAN
Physical Network Components
- router
- cable
- switching equipments
- transport stack
Transport Stack examples
- TCP/IP
- NetBIOS
- IPX
- DECNet
- AppleTalk
- APPC
conceptual framework which breaks down the complexity of networking into seven layers
OSI
OSI 7 layers
- Application
- Presentation
- Session
- Network
- Data Link
- Physical
- Transport
deal with application issues and generally are implemented only in software
upper layer
handle data transport issues.
lower layer
Concerned with the physical, mechanical and electrical characteristics of the network hardware – cables, voltages, etc
physical layer
Concerned with the error-free delivery of data
Data Link Layer
Organizes raw bit stream into groupings of bits
frames
Transfers frames between devices on a single network
Data Link Layer
The Institute of Electrical and Electronics Engineers (IEEE) has subdivided the data link layer into two sublayers
Logical Link Control (LLC) and
Media Access Control (MAC).
Organizes raw bit stream into groupings of bits, called frames
Data Link Layer
sub-layer defines the relationship at the hardware level between Physical Layer devices, like Network Adapter Cards, and the Data Link Layer
Media Access Control
sub-layer defines the relationship between the MAC sub-layer and Data Link Layer devices and drivers
Logical Link Layer
Handles routing between networks and timely delivery of data
Network Layer
Packets include a header which includes network addresses for the source and destination
Network Layer
Organizes frames from the Data Link Layer into packets
Network Layer
Responsible for delivering data reliably
Transport Layer
Transport Layer Operations (4)
- Building up and tearing down connections
- packet sequencing
- acknowledgements
- flow control
Provides mechanisms to establish and maintain communications between applications.
session layer
session layer operations
- Access authentication (for example, logging into a server)
- Session Management
- Verification that adequate disk space is available for a request
- Notifying a user that a printer is offline
Responsible for formatting, representing and translating data
presentation layer
presentation layer operations
- ASCII to EBCDIC translation
- Compression of data
- Encryption of data
Provides interface between the network and the application software
Application Layer
Umbrella committee
IEEE 802.1
Umbrella committee
IEEE 802.2
Defines Ethernet and its variations, including 10Base5, 10Base2, 10BaseT and 100BaseT
IEEE 802.3
Defines Token Ring
IEEE 802.5
Provides the physical and electrical connection required to access the networkcabling.
physical layer
Provides the processing to assemble or disassemble the bit stream on the cable into frames suitable for the Media Access Method* in use
data link layer
- Operates at the Physical and Data LinkLayers of the ISO Reference Model
- Media-dependent (physical connector)
- Media Access Method-dependent (Ethernet vs Token Ring, etc.)
- Protocol-independent (i.e. an Ethernet NIC can simultaneously connect to a LAN server running IPX/SPX and to a UNIX host running TCP/IP)
Network Interface Card (NIC)
- Amplifies and rebroadcasts a signal
- Extends the distance a signal may be run reliably over a cable
- Makes no decisions based on signal content
repeater
- Used as a concentrator to join multiple workstations with a single link to the rest of the LAN
- Functions as a multi-port repeater
- Signals received on any port are immediately retransmitted to all other ports on the hub.
- Increases the number of connectable devices
- Operates at the OSI Physical Layer (Level 1)
hub
* Personal hub
* Stack hubs
- Looks at destination address of a frame and internally establishes a logical connection with the port connected to the destination node.
- Other ports on the switch have no part in the connection
- Result: Each port on the switch corresponds to an individual collision domain, and network collision is avoided.
- Operates at the OSI Data Link Layer (Level 2)
- Essentially an intelligent hub
switch
- Operate at the Data Link layer
- Establish logical connections between ports based on MAC addresses
- Used to segment existing network into small collision domains
Layer 2 switch based on bridging technology
- Used to divide a network into mutually isolated segments
- Operates at the Data Link Layer (layer 2) of the ISO Reference Model
- Physical media-dependent; usually media access layer dependent
- Protocol-independent above the Data Link Layer
bridge
- Operate at the Network Layer
- Establish logical connections between ports based on network addresses
- Used to connect different networks into an internetwork
Layer-3 (based on routing technologies) (aka routing or multilayer switches)
- Used to connect one network to another
- Operates at the Network Layer (layer 3) of the ISO Reference Model
- Media-independent
- Protocol-dependent above the Data Link Layer
- Works with packets and their logical addresses
router
- Some protocols (e.g. TCP/IP, IPX/SPX) have packets that include the Network Layer logical addresses needed by routers
- Others (e.g. NetBEUI) do not, and are non-routed/non-routable protocols
Routed/Routable protocols