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CHAPTER 3
PROTOCOLS
MIDTERM
PROTOCOL: the rules a network uses to transfer data. Protocols ensure that data is transferred whole, in sequence, and without error from one node on the network to another. Networks that use more than one protocol are called multiprotocol networks.
ROUTABLE: protocols that can span more than one LAN segment are routable, because they carry Network layer and addressing information that can be interpreted by a router.
TCP/IP: one of the most common protocols in use due to its low cost and its ability to communicate between a multitude of dissimilar platforms. It is routable and flexible. The TCP/IP core protocols operate in the Transport layer of the OSI model, where they provide communications between the hosts on a network.
TCP: (Transport Control Protocol) belongs in the Transport layer of the TCP/IP suite and provides reliable data delivery services. TCP is connection-oriented, this means it requires a connection to be established between communicating nodes before it will transmit data. TCP sits on top of the IP protocol and compensates for IP’ reliability deficiencies with its checksum, flow control and sequencing information.
IP: (Internet Protocol) belongs in the Internet layer of the TCP/IP model and that corresponds with the network layer of the OSI. IP provides information about how and where data should be delivered. IP is the subprotocol that enables TCP/IP to internetwork- that is to transverse more than one LAN segment and more than one type of network through a router.
UDP: (User Datagram Protocol) sits in the Transport layer, between the Internet layer and the Application layer of the TCP/IP model. UDP is a connectionless transport service. It offers no error checking and no assurance that packets will be received in the correct sequence. UDP’s lack of sophistication actually makes it more efficient than TCP and useful in situations where data must be transferred quickly; such as live audio or video transmissions over the Internet.
ARP: (Addressing Resolution Protocol) belongs to the Internet layers of the TCP/IP model, which corresponds with the application layer and the presentation layer of the OSI model. It contains the MAC address of a host, or node, then creates a local database that maps the MAC address to the hosts IP (logical) address.
TELNET: a terminal emulating protocol used to log on to a remote host using the TCP/IP protocol. Telnet resides in the Application layer of the TCP/IP suite that corresponds with the Presentation and Application layers of the OSI model.
FTP: (File Transfer Protocol) an application layer protocol used to send and receive files via TCP/IP.
SMTP: (Simple Mail Transfer Protocol) the protocol responsible for moving messages from one e-mail server to another over the internet and other TCP/IP-based networks.
SNMP (Simple Network Management Protocol): the protocol responsible for moving messages form one e-mail server to another over the internet and other TCP/IP-based networks.
IPADDRESS: a logical address used in TCP/IP networking. This unique 8-bit number is divided into four groups of octets, or 8 bit bytes, that are separated by periods. An IP address contains 2 types of information: network and host.
The class A, B or C determines the first set of numbers or octet.
Class A; 1-126
Class B: 127-191 (127 is reserved for loop back addresses ONLY!)
Class C: 192-223
LOOP BACK ADDRESS: the address 127.0.0.1 is a loop back address. This means when you try to contact this IP address you are actually pinging your own computer. This address is useful for troubleshooting problems with a workstation’s TCP/IP communications.
3 CATEGORIES OF ADDRESSING
FIREWALL: a specialized device (typically a router, but possibly only a PC running special software) that selectively filters or blocks traffic between networks. A firewall may be strictly hardware-based or it may involve a combination of both hard and software.
HOST (TCP/IP): a computer connected to a network that uses the TCP/IP protocol.
STATIC IP ADDRESS: An IP address that is manually assigned to a device.
DHCPLDynamic Host Configuration Protocol) an application layer protocol in the TCP/IP suite that manages the dynamic distribution of IP addresses on a network. Using DHCP to assign IP address can nearly eliminate duplicate-addressing problems.
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95/98 START, RUN, WINIP.CFG
IPX/SPX: CREATED BY XEROX USED BY NETWARE: (Internet Packet Exchange/Sequenced Packet Exchange) required for interoperability with LAN’s running NetWare versions 3.2 or lower, it can also be used with LANs running higher versions of the NetWare operating system. Similar to TCP/IP IPX/SPX is a suite of protocols that reside at different layers of the OSI model. It also carries network-addressing information, which means it is routable. The core protocols provide services at the Transport and Network layers of the OSI model.
IPX CONNECTIONLESS: operates at the Network layer of the OSI model.
SPX CONNECTION OREINTED: belongs to the Transport layer of the OSI model.
IPX ADDRESS CONTAINS 2 PARTS. The network address and the node address. The network address must be an 8 bit hexadecimal address, which means that each of its bits can have a value of either 0-9 or a-f. The second part of an IPX address, the node address is equal to the devices MAC address.
NETBIOS; (Network Basic Input Output System) is a protocol originally designed by IBM to provide Transport and Session layer services for applications running on small homogenous networks. To transmit data between tow network nodes Net BIOS needs to know how to reach each workstation. For this reason network admin must assign a Net BIOS name to each workstation.
NETBEUI: Microsoft adopted NetBIOS as it foundation protocol and added and application layer component on top of NetBIOS and renamed it NetBEUI. It is fast and efficient protocol that consumes few network resources, provided excellent error correction, and requires little configuration. It can support only 254 connections, however, and does not allow for good security. Further more, Since NetBEUI lacks a Network layer, it is nonroutable and therefore not suitable for large networks.
APPLETALK: this is a protocol suite used to interconnect Macintosh computers. An AppleTalk network is separated into logical groups of computers called AppleTalk zones. Each network can contain multiple zones, but each node can belong to only one zone. Zones enable users to share file and print resources.
ADDRESSING: apple talk uses node Ids and network numbers to identify computers on a network. A node-ID is a unique 8- or 16-bit number that identifies a computer on an AppleTalk network. AppleTalk assigns a node ID to each workstation when the workstation connects to the network.
INSTALL PROTOCOLS, BINDING: The process of assigning one network component to work with another.