ITC 465 Chapter 2
ST Connector
- fiber optic connector - straight tip - single mode fire optic cable -half twisted bayonet type of lock
LC Connector
- local connector - fiber optic - commonly used between floors on a building - latch like RJ-11
SC Connector
- push pull - fiber optic - common used between floors
What functions are performed by Application layer protocols?
-It facilitates the user to use the services of the network. -It is used to develop network-based applications. -It provides user services like user login, naming network devices, formatting messages, and e-mails, transfer of files etc.
TCP/IP Overview
-Provides a common language or reference point for network professionals. -Divides networking tasks into logical layers for easier comprehension. -Allows specialization of features at different levels. -Aids in troubleshooting. -Promotes standards and interoperability between networks and devices. -Provides modularity in networking features that allows developers to change features without changing the entire approach.
File Transfer Protocol (FTP)
A communications method for transferring data between computers on the Internet
TCP (Transmission Control Protocol)
A connection-oriented, guaranteed-delivery protocol used to send data packets between computers over a network like the Internet.
UDP (User Datagram Protocol)
A connectionless Transport-layer protocol that is one of the protocols in the Internet protocol suite, and is used with IP. It is also known as the Universal Datagram Protocol.
RJ-45
A connector that is slightly larger than an RJ-11 connector and contains eight wires. RJ-45 connectors most commonly attach twisted-pair cables to Ethernet network cards.
Routing Information Protocol (RIP)
A dynamic protocol that uses distance-vector routing algorithms to decipher which route to send data packets.
TCP/IP model
A four-layer data communication model developed by the United States Department of Defense. To some extent, it is similar to the OSI model.
Open Shortest Path First (OSPF)
A link-state protocol that monitors the network for routers that have a change in their link state, meaning they were turned off, turned on, or restarted. This is perhaps the most commonly used interior gateway protocol in large networks.
Broadcast domain
A logical area in a computer network where any node connected to the computer network can directly transmit to any other node in the domain without a central routing device.
Hybrid topology
A physical topology that combines characteristics of more than one simple physical topology.
Internet Protocol (IP)
A set of rules responsible for disassembling, delivering, and reassembling packets over the Internet.
Virtual LAN (VLAN)
A technology that allows scattered users to be logically grouped together even though they may be attached to different switches.
Star topology
A topology with one central node that has each computer or network device attached to the central node. All data first goes into the central node and then is sent out to its destination. (Think of it like a bicycle wheel with spokes.)
Multimode Fiber Optic Cable
A type of fiber-optic cable that has a large core diameter and is susceptible to attenuation due to dispersion.
Single-mode fiber optic cable
A type of fiber-optic cable that has a small core diameter and limited dispersion. It can carry light farther than multimode fiber-optic cable.
Advantages to fiber optic
Able to carry signals much farther than copper
OSI layer Mnemonic
All People Seem To Need Data Processing
Data Encapsulation
App layer: Data (HTTP GET) Transport layer: Segment (Source and Destination Ports) Internet: Packet (Source and Destination IP) Link: frame (Source and Destination MAC)
TCP/IP vs OSI
Application (TCP) -> Application, Session, Presentation (OSI) Transport (TCP) -> Transport (OSI) Internet (TCP) -> Network (OSI) Link Layer (TCO) -> Data Link and Physical (OSI)
OSI layers
Application, Presentation, Session, Transport, Network, Data Link, Physical
Registered port
Assigned by ICANN for a newly created network services. Port number ranges from 1024-49151
__ indicates that a pin is both transmitting and receiving
Bi
Reverse Address Resolution Protocol (RARP) and Bootstrap Protocol (BOOTP)
Both used to discover the IP address of a device with a known MAC address. The latter is an enhancement of the former, and is more commonly implemented.
UTP Cable Categories
Cat 5 (100 mbps; 100 MHz), Cat 5e (1000 Mbps; 100 MHz), Cat 6 (10 gbps; 250 MHz), Cat 6a (10 gbps; 500 MHz), Cat 7 (10 gbps; 600 MHz)
Half-duplex
Communication between two devices whereby transmission takes place in only one direction at a time.
Full duplex
Communication that happens in two directions at the same time.
Data Link layer
Converts bits to bytes and byres to frames, uses MAC addresses, defines logical network topology, specifies media access methods, implements host to host flow control, uses parity and CRC.
Sublayers of Link Layer
Data and Physical
OSI Network Layer
Defines logical address, path determination, routes packets, describes how data is routed, maintains address of neighboring routers, maintains lists of known networks, determines next network point to send data.
Mesh topology
Devices are connected with many redundant interconnections between network nodes.
Physical layer protocol layer
EIA/TIA 232, V.35, Cat6, RJ45
OSI Transport Layer
Enables end to end communication via ports and sockets, and provides transitions to upper and lower layers of the OSI model.
Transport Layer
Enables host to send and receive error corrected data packets or messages over a network component, allowing multiplexing
Frame type
Ethernet frame size is 64 to 1518 bytes
Media Access
Ethernet uses Carrier Sense Multiple Access/Collision Detection (CSMA/CD) to control access to the transmission medium. Devices use the following process to send data: 1) Because all devices have equal access to the transmission media (multiple access), a device with data to send, first listens to the transmission medium to determine if it is free (carrier sense). 2) If it is not free, the device waits a random time and listens again to the transmission medium. When it is free, the device transmits its message. 3) If two devices transmit at the same time, a collision occurs. The sending devices detect the collision (collision detection) and send a jam signal. 4) Both devices wait a random length of time before attempting to resend the original message. The process of waiting before attempting to resend is called a backoff.
TCP/IP Protocol Suites
FTP, TFPT, HTTP, SMTP, SMP, Telnet, NFS, VoIP, DNS, TCP, UDP, IP, ICMP, ARP, BOOTP, DHCP
OSI Presentation Layer
Formats ddata into a compatible form for receipt by the Application layer or the destination system. Specifically, the Presentation layer ensures: formatting and translation of data, negotiation of data transfer, compatibility with host, encapsulation of data, restoration of data
FTP
Generic method of transferign files
OSI Application Protocols
HTTP(S), (T)FTP, SNMP, Telnet
What are MAC addresses? How are they used by the Link layer?
Hosts are uniquely identified at the link layer using a media access control address. "Mac"
OSI Network protcols
IP and AppleTalk
Network transmission
If necessary, the data is transferred to various routers, which forward the data to the appropriate network. The source and destination network addresses are used to determine whether the hosts reside on the same network or on different networks. If they reside on the same network, the data can be sent directly to the destination host. The Address Resolution Protocol (ARP) is used to determine the MAC address of the host using the destination IP address If the sending and receiving hosts reside on different networks, the packets must be forwarded from router to router until they reach the appropriate destination network and host. The source IP address of each packet in the transmission is the IP address of the sending system and the destination IP address is the IP address of the receiving system. However, the frames can't be sent directly to the receiving system because it is not on the same network and ARP can only be used on the local subnet.
MAC layer
In the OSI model, the lower of the two sublayers of the data link layer. It is defined by the IEEE as being responsible for interaction with the physical layer
Network File System (NFS)
It consists of several protocols that enable users on various platforms to seamlessly access files from remote file systems.
What does the application layer do?
It contains high-level protocols used by processes (applications) running on a host for network communications. The Application layer integrates network functionality into the host operating system and enables network services. The Application layer does not include specific applications that provide services, but rather provides the capability for services to operate on the network.
How does TCP negotiate a connection with a remote host?
It uses a three-way handshake.
OSI Presentation protocols
JPEG, BMP, TIFF, PICT, MPEG, WMV, AVI, ASCII, MIDI, WAV
Data Link layer protocls
LAN (802.2, 802.3, and 802.11) WAN (PPP, MLPPP, ISDN)
Simple Network Management Protocol (SNMP)
Lets network hosts exchange configuration and status information. This information can be gathered by management software and used to monitor and manage the network.
Session layer
Manages data sessions which data is transferred. Functions may include: separating data streams, management of communication sessions, maintenance of communication sessions, management of multiple sessions, assignment of session ID, dialog control, termination of communication sessions, and coordination of requests.
Physical layer
Moves bits across media via cables, connectors, and pin positions. Specifies electrical signals and defines the physical topology.
Session layer protocols
NFS, ASP, SQL, RPC, X Window
Unshielded Twisted Pair (UTP)
Networking cable that has four twisted pairs of copper wire and a flexible outer coating.
Cat 5e and above ethernet specification
Pin 1: Bi+ Pin 2: Bi- Pin 3: Bi+ Pin 4: Bi+ Pin 5: Bi- Pin 6: Bi- Pin 7: Bi+ Pin 8: Bi-
Cat 5 (and below) ethernet specifications
Pin 1: Tx+ Pin 2: Tx- Pin 3: Rx+ Pin 4: Unused Pin 5: Unused Pin 6: Rx- Pin 7: Unused Pin 8: Unused
What role does port assignments play in application-to-application communications?
Ports allow a network host with a single IP address to provide multiple services, each sending and receiving data on its own port.
Ethernet frame
Premable, D.Mac, S.Mac, Type, Packet, Pad, FCS
Logical Link Control
Providers an interface between the MAC layer and upper-layer protocols are defined by 802.2 committee. Includes: Orderly delivery of frames through sequencing, ensuring error-free exception of messages by retransmitting, converts data into an acceptable form for the upper layers, removing faming info from the packet and forwarding the messages to the network layer, provides a way for upper layers of OSI to use any MAC layer protocol, and defines Service Access Points (SAPs) by tracking and managing different protocols.
Network Layer
Provides data routing paths for network communication. Primary responsibilities are logical connection setup, data forwarding routing, and delivery error reporting.
Well known port
Ranges from 0 to 1023. Assigned for specific protocols and services
Link layer protocols
Responsible for describing the physical layout of the network and how messages are electrically transmitted. It is used to move information between hosts by controlling how individual bits are transmitted and received on the network medium. Does this by identifying MAC address of the host.
Physical Link Layer
Responsible for the communication of raw, unstructured streams of data over a physical medium
Internet layer protocols
Routing (forwarding packets to multiple networks), via the following protocols: IP, ARP, ICMP, and IGMP.
Application Layer
Specifies shared communication protocols and interface methods used by hosts in a network
Transport layer protocols
TCP and UDP
Dynamic Port
TCP/IP ports in the range of 49,152 through 65,535, which are open for use without requiring administrative privileges on a host or approval from IANA.
How does the TCP protocol differ from the UDP protocol?
TCP: Connection-oriented. Handshake as a means of verification. UDP: Connectionless, but is faster and can send larger files
Simple Mail Transfer Protocol (SMTP)
The Internet standard protocol for transferring e-mail messages from one computer to another.
Destination host de-encapsulation
The data received is de-encapsulated on the destination host by moving from the bottom layer of the TCP/IP or OSI model to the top: 1) The Link layer converts bits received on the network medium into frames and passes them to the Internet layer. 2) The Internet layer extracts the packets from the frames and passes them to the Transport layer. 3) The Transport layer receives packets and uses sequencing and error control information to request retransmission of any missing or damaged packets. 4) The Transport layer uses sequencing information to convert the packets into segments and passes them to the Application layer. 5) The Application layer uses the appropriate Application layer protocol to convert the segments back into the original data stream from the application on the source host.
Source host encapuslation
The data to be transferred is encapsulated on the sending host from the top layer of the TCP/IP or OSI model to the bottom.
What functions are provided by the Internet layer?
The internet layer is responsible for forwarding packets multiple networks. This is called "routing".
What is the purpose of a network model?
To display a flexible approach to representing connected objects and their relationship.
Data Link Layer
Transfers data in-between notes on a network segment across a physical layer.
TFTP
Transfers files without authentication
__ is for transmitting and __ is for receiving
Tx and Rx
MAC (Media Access Control) address
Unique 48-bit address assigned to each network card. IEEE assigns blocks of possible addresses to various NIC manufacturers to help ensure that the address is always unique. The Data Link layer of the OSI model uses MAC addresses to locate machines.
Address Resolution Protocol (ARP)
Used to get the MAC address of a host from a known IP address. ARP is used within a subnet to get the MAC address of a device on the same subnet as the requesting device.
Disadvantages of fiber optics
Very expensive and difficult to work with
Port Categories
Well known, registered, dynamic
Auto-MDIX
a feature that detects the type of cable, and configures the interfaces to allow the connection
Internet Group Management Protocol (IGMP)
a protocol for defining host groups. All group members can receive broadcast messages intended for the group (called multicasts). Multicast groups can be composed of devices within the same network or across networks (connected with a router).
Voice over Internet Protocol (VoIP)
a protocol optimized for the transmission of voice through the internet or other packet switched networks.
Domain Name System (DNS)
a system that is distributed throughout the internetwork to provide address/name resolution.
Telnet
allows an attached computer to act as a dumb terminal, with data processing taking place on the TCP/IP host computer. It is still widely used to provide connectivity between dissimilar systems.
Dynamic Host Configuration Protocol (DHCP)
allows dynamic IP address allocation so users do not have to have a preconfigured IP address to use the network
TCP/IP layers
application, transport, internet, network access
HTTP
by web browsers and web servers to exchange files, such as web pages, through the World Wide Web and intranets.
Destination address
identifies the receiving host's MAC address.
Source Address
identifies the sending host's MAC address.
OSI Application Layer
integrates network functionality into the host operating system and enables network services. The Application layer does not include specific applications that provide services, but rather provides the capability for services to operate on the network. These services include: Interface, Communication, File services, Print services, Message services, Application services, Application services, Database services
Transport Layer processes
responsible for error checking and reliable delivery. The Transport layer provides various functions with both TCP and UDP and their characteristics. Transport layer also uses ports for app-to-app communication between hosts
Preamble
set of alternating ones and zeros terminated by two ones (11), which mark it as a frame.
Application layer processes
the source host send data to other processes running on a destination host at the Application layer. For example, a web browser on a client system can send an HTTP GET request to the web service running on a network server to request that it send a particular web page.
Fiber optic
thin, flexible fibers of glass capable of transmitting light signals
Type
two bytes and specifies the network/internet layer protocol being used.
Internet Control Message Protocol (ICMP)
works closely with IP in providing error and control information that helps move data packets through the internetwork.
