Network Protocols
The Rules of Communications (Again?)
Hosts need to agree on rules of communications so they can talk to each other.
Things defined in the rules of communications...(discussed in Gibbs p. 156-157)
Who’s turn is it to transfer a message?
Can the receiver accept the message?
How to initiate communication?
How to find who you want to talk to?
How to send the message.
How to determine if the receiver received the message
How to end communication.
Agreed upon rules (standards) that define communication between two devices.
Some helpful definitions:
Acknowledgment - proof that a message has been received.
Transaction - group of actions that perform a unit of work you want to complete (for example the successful transmission of a message)
Incomplete transaction - A transaction with unknown results (the sender neither receives an acknowledgment or a request to resend the message to the receiver.
Protocol Suite - a set of protocols used to provide a complete set of communication services.
Introducing the protocols
TCP/IP
TCP/IP (Transmission Control Protocol/Internet Protocol) is the most popular set of protocols used today to connect different computer systems in different physical layer and data link layer environments.
TCP/IP specifies communication above the Data Link layer. This was done on purpose to allow TCP/IP to be used in many different Data Link and Physical topologies. This ability has been one of the major reasons why TCP/IP has been so successful worldwide as a suite of protocols.
TCP/IP includes many, many protocols including:
Telnet
SMTP (Simple Mail Transfer Protocol)
RIP (Router Information Protocol)
OSPF (Open Shortest Path First)
ICMP (Internet Control Message Protocol)
BootP (Bootstrap Protocol)
RARP (Reverse Address Resolution Protocol)
ARP (Address Resolution Protocol)
In this introduction we will only discuss IP and TCP
IP
Defined
IP (Internet Protocol) provides non guaranteed delivery of packets across an internetwork. IP may fragment (packetize) the data it is carrying into smaller parts if necessary and reassemble it at a router or the destination station.
IP moves packets through a internetwork one hop at a time. Each router along the way will make a determination about a packet’s next hop.
Frame Description
Slide and speaker notes
TCP
Defined
TCP (Transmission Control Protocol) is the primary Internet transport protocol. TCP provides acknowledged, flow control transport to a TCP node.
Frame Description
Slide and Speaker Notes
XNS
Defined
XNS (Xerox network system) was designed as a efficient alternative protocol for use on Local Area Networks. Xerox designed XNS to perform less error checking by upper layer protocols making XNS a fast protocol but not as reliable as TCP/IP. Novell’s IPX/SPX is based on XNS.
Discussion of protocol suite
Network Layer
IDP (Internet Datagram Protocol) Provides service similar to IP.
Transport Layer
RIP (Router Information Protocol) Responsible for finding a route from one node to another across an internetwork.
SPP (Sequenced Packet Protocol) Is a reliable data transfer protocol.
PEP (Packet Exchange Protocol) Is a compromise between SPP and IDP.
Session Layer
Courier protocol - Responsible for performing (RPCs) Remote Procedure Calls.
Remote procedure calls allow a process on one computer to make a request for services on another computer. This concept is very useful because programmers do not have to know anything about networking at the lower levels to access data and services on the file server.
Application Layer
Clearinghouse - A directory service that knows about user and device names and can translate them into internetwork addresses. (Functions on session and presentation layers)
File Transfer (like FTP)
Printing services
Summary
Banyan Vines uses XNS
IPX/SPX
IPX
Defined
IPX (Internetwork Packet Exchange) is a connectionless network layer protocol based on XNS’s IDP (Internetwork Datagram Protocol) The primary function of IPX is the delivery of packets from node to node in an internetwork.
Frame Description
Slide and Speaker Notes.
SPX
Defined
SPX (Sequenced Packet Exchange) is Novell’s Transport layer protocol offering acknowledged packet delivery. Common uses of SPX are RCONSOLE (Remote console), Rprinter (Remote printer) and SNA gateway.
Frame Description
Slides and Speaker Notes.
Appletalk
Defined
Appletalk is a suite of proprietary LAN protocols primarily designed to interconnect Apple computers and printers. Appletalk was designed to be easy to use, support small workgroups and cost little.
Protocol suite
Network Layer
DDP (Datagram Delivery Protocol) Responsible for routing message from note to node and delivering it to the appropriate socket.
Socket - A socket it a software address associated with a procedure.
RTMP (Router Table Maintenance Protocol) Maintains information about the internetwork connections and addresses between the various networks.
NBP (Name Binding Protocol) Responsible for name to address translation
ATP (Appletalk Transaction Protocol) Provides acknowledged delivery of packets.
EP (Echo Protocol) Used to test the existence and quality of a connection (similar TCP/IP ping?)
Session Layer
ASP (Appletalk Session Protocol) Insures that packets are sequenced correctly before passing the message to upper layer protocols.
ADSP (Appletalk Data Stream Protocol) Responsible for acknowledged, two-way communications between two nodes.
PAP (Printer Access Protocol) Responsible for access to printer devices.
ZIP (Zone Information Protocol) Responsible for grouping devices on the network into zones.
Zones - An Apple term for grouping devices together for organizational purposes.
Presentation Layer
AFP (AppleTalk File Protocol) Provides MAC and Non-Mac workstations a means to access files on the file server’s shared disk.
Postscript - The page description language used to control Apple printers.
NetBIOS
Defined
NETBIOS (Network Basic Input/Output System)
NetBIOS (Network Basic Input Output System) is the networking protocol used with IBM PC Network Program, Microsoft’s LAN Manager, IBM LAN Server and other PC based networking programs including Microsoft NT and Windows 95. However there are minor differences in each vendor’s implementation of NetBIOS which usually makes different vendor’s products incompatible.
The NetBIOS protocols suite provides session and presentation layer services. It gives NetBios aware applications a way to access network services without concern of how those services are delivered.
NetBios can be implemented on many different systems and can be provided with complete disregard for lower level standards.
The Redirector is an extension of DOS 3.1 or above. It takes requests for remote devices (disk systems and printers) and sends the request using NetBios to the server.
The SMB protocol is used by the NetBios system to perform operating system functions (opening and closing files, reading and writing data and printing functions)