Card Set Information
Resources a network makes available to its users including applications and the data provided by these applications.
Methods and rules of communication.
Using the same network to deliver multiple types of communication services, such as video, voice and fax.
Unified communications (UC)
The centralized management of multiple network-based communications. E.g. intraoffice phone, long distance phone, cell phone, voice mail, fax, text messages.
Video teleconference (VTC)
Allow people to communicate with video and voice.
Primarily uses point-to-point model
Skype and Google Talk are examples.
Delay sensitive / Loss tolerant
You don't want to hear breaks or buffering in A/V in a movie, this is delay sensitivity
Video transmissions are Loss Tolerant.
Disadvantages of peer to peer networks
Network Operating Systems are responsible for...
Managing data and other resources for a number of clients.
Ensuring that only authorized users access the network.
Control which types of files a user can open and read.
Restricting when and from where users can access the network.
Dictating which rules computers will use to communicate.
Sometimes supplying applications and data files to clients.
Client-server network advantages
User accounts and passwords to network are assigned in one place.
Access to multiple shared resources can be centrally granted to a user or group.
Problems on the network can be monitored, diagnosed and often fixed from one location.
Difference between a Switch and Router?
Switch belongs to one network.
Router belongs to more than one.
What are the Layers in the OSI model?
: Application Layer
: Presentation Layer
: Session Layer
: Transport Layer
: Network Layer
: Data Link Layer
: Physical Layer
Protocol Data Unit (PDU)
A group of bits moving from one layer of the OSI to another.
: L7PDU: Payload or Data
: L4PDU: Segment (TCP) or Datagram (UDP)
: L3PDU: Packet
: L2PDU: Frame
: L1PDU: Bit
Layer 7: Application Layer
Describes the interface between two applications on separate computers.
Application programs that provide services to a user. E.g. browser and web server using HTTP
Utility Programs that provide services to the system. E.g. SNMP that monitors and gathers information about network traffic.
Layer 6: Presentation Layer
Responsible for reformatting, compressing, and encrypting data for an application to be able to read it.
Layer 5: Session Layer
Describes how data between applications is synced and recovered if messages don't arrive intact.
Layer 4: Transport Layer
Responsible for transporting Application layer payloads from one application to another.
Transmission Control Protocol (TCP)
User Datagram protocol (UDP)
Uses the port number
Divides messages into smaller segments if they are too large.
Adds header information to Segments or Datagrams.
Transmission Control protocol
Connection oriented protocol
Makes a connection, checks whether data was received, resends if not.
User Datagram Protocol
Connectionless protocol / Best effort protocol
Not guaranteed delivery
used for broadcasting, streaming, network traffic monitoring
Adding header information to PDUs
Transport Layer 4
Network Layer 3
Data Link Layer 2
Layer 3: Network Layer / Internet Layer
Responsible for moving messages from one note to another until they reach their destination.
IP (Internet Protocol) is the principle protocol used.
Identifies sending and receiving hosts by IP address.
Routing protocols include...
ICMP (Internet Control Message protocol)
ARP (Address Resolution Protocol)
Adds header information to packets.
Applies to Layer 3
: Network Layer
If a packet is larger than the maximum size for the network, the Network Layer will divide it into smaller packets.
Layer 2: Data Link Layer / Link Layer
Protocols used here are programmed into the firmware of the NIC or other hardware.
Example protocols used are...
Adds Header and trailer information to frames.
header information contains the MAC address of the source and destination NICs.
Data Link Layer Address
Media Access Control
Unique address on ever NIC
Layer 1: Physical Layer
Responsible for sending bits via wired or wireless transmission.
: Wavelengths in the air
Ethernet with Twisted Pair
: Voltage on copper wire
Ethernet with Fiber Optic Cable
Similar to OSI model but with only 4 layers.
Application, presentation, and Session Layers are combined into Application Layer.
Physical Layer is ignored.
Material Safety Data Sheet (MSDS)
Explains how to properly handle substances such as chemical solvelts and how to dispose of them.
Network Troubleshooting Steps
Identify problem and symptoms
Establish a theory of probably cause
Test your theory to determine cause
Establish a plan to resolve the problem
Implement the solution or escalate the problem
Verify functionality and implement preventive measures
Document findings, actions, and outcomes
Organizationally Unique Identifier (OUI)
First 24 bits (6 hex characters) of a MAC address that identifies the manufacturer of the NIC.
Assigned by IEEE.
Last 24 bits (6 hex characters) of a MAC address that identifies the NIC.
Based on model and manufacture date.
A computer, router, or other device that a host uses to access another network.
The default gateway is the gateway that nodes turn to first for access to the outside world.
32 bit number that helps computers find each other.
The bits are used to indicate what portion of an IP address is the network portion and what part if the host portion.
Using this information, a computer can know if a remote computer with a given IP address is on its own or a different network.
Responsible for tracking computer names and their IP addresses.
The IP Address plus port number.
Assigned by IANA to well known protocols and programs.
: FTP-DATA / TCP / File transfer
: FTP / TCP / File transfer control
: SSH / TCP / Secure shell
: TELNET / TCP
: SMTP / TCP
: DNS / TCP & UDP
: DHCPv4 / UDP / Client to Server
: DHCPv4 / UDP / Server to Client
: TFTP / UDP / Trivial FTP
: HTTP / TCP & UDP
: POP3 / TCP
: NTP / UDP / Network Time Protocol
: NetBIOS / TCP & UDP / Legacy support
: IMAP / TCP
: SNTP / TCP & UDP
: HTTPS / TCP
: SMB / TCB / Server message Block
: DHCPv6 / UDP / Client to Server
: DHCPv6 / UDP / Server to Client
: H.323 / TCP / Packet-based Multimedia Communications Systems
: MGCP / TCP & UDP / Media Gateway Control Protocol
: RDP / TCP / Remote Desktop
: RTP / UDP / Real-time Transport Protocol
: RTCP / UDP / Real-time Transport Control Protocol
: SIP / UDP / Session Initiaion Protocol, not encrypted
: SIP / UDP / Encrypted SIP
Used by network users and processes that are not considered standard.
Must be registered with IANA.
Dynamic & private ports
Can be used without restriction.
Class A IP Addresses
1.x.y.z to 126.x.y.z
126 possible networks or licences
16 million possible IP addresses in each network
Class B IP Addresses
128.0.x.y to 191.255.x.y
16,000 possible networks or licenses
65,000 possible IP addresses in each network
Class C IP Addresses
192.0.0.x to 223.255.255.x
2 million possible networks or licenses
254 possible IP addresses in each network
Reserved IP Addresses
: Used for broadcast messages by TCP/IP sent to every node ont he network
: Currently unassigned
: Loopback address