Networking Complete

Networking Complete

by Sybex
     
 
This is the newest version of our popular Networking Complete, designed for all users, from the home networker, to the professional network administrator.

—Packed with information, including sections on TCP/IP, networking hardware and software, network design, network security, and troubleshooting. Also includes discussions on the benefits of sharing

Overview

This is the newest version of our popular Networking Complete, designed for all users, from the home networker, to the professional network administrator.

—Packed with information, including sections on TCP/IP, networking hardware and software, network design, network security, and troubleshooting. Also includes discussions on the benefits of sharing resources, and creating internetworks and extranets.

—Superb value! 1000 pages for only $19.99 US!

Editorial Reviews

bn.com
The Barnes & Noble Review
Networking Complete, Second Edition is a broad, useful overview of networking at a price that's hard to beat. Drawing from the best books in their networking library, Sybex's editors have brought together authoritative coverage of an exceptionally wide range of day-to-day networking techniques and concepts, from network design to maintenance, security to troubleshooting.

Among the highlights: an excellent chapter on preparing for -- and then installing -- a local area network; the principles of network design (written originally for Windows networks but useful in any environment); and two chapters on tracking down network problems (one offering a step-by-step methodology, the other outlining several common scenarios, including ping problems, undelivered email, connectivity trouble, and poor performance. There's also a full chapter on disaster recovery for small-to-midsize companies: planning, effective backups, RAID, clustering, et cetera.

The authors walk you through the basics of building an infrastructure for delivering Internet and intranet services, including setting up DNS, and working with a business ISP. There's also a five-chapter section on security and remote connectivity -- focused primarily on Windows 2000 and NetWare environments, but including some basic guidance for UNIX/Linux servers, as well. Tucked in at the end: a handy 35-page networking glossary.

If you're just starting out with networking, or if you've got a problem to solve and no idea where to start, this book will get you rolling -- and still leave cash in your pocket. (Bill Camarda)

Bill Camarda is a consultant, writer, and web/multimedia content developer with nearly 20 years' experience in helping technology companies deploy and market advanced software, computing, and networking products and services. His 15 books include Special Edition Using Word 2000 and Upgrading & Fixing Networks For Dummies®, Second Edition.

Product Details

ISBN-13:
9780782129144
Publisher:
Sybex, Incorporated
Publication date:
03/01/2001
Series:
Sybex Complete Series
Edition description:
Older Edition
Pages:
912
Product dimensions:
5.86(w) x 8.24(h) x 2.06(d)

Read an Excerpt

Chapter 5: Major Protocol Suites

This chapter provides a detailed discussion of the most important of these suites and takes a look at some other protocols and protocol standards. Although your Networking Essentials exam will not require that you have mastered much of this material, a further understanding of protocol suites broadens your knowledge base as a network administrator.

These are the protocol suites examined in this chapter:

  • NetWare IPX/SPX, Novell NetWare's proprietary pro- tocol suite
  • TCP/IP, the nonproprietary protocols that make up the Internet
  • AppleTalk, Apple Computer's proprietary protocols, which began with the Macintosh

Review of Protocols, Models, and Implementations

A protocol is a set of rules for communication. A simple example of a protocol from the realm of human communications is the different ways of greeting people: should you bow, shake hands, or kiss both cheeks of the person you're greeting? It depends on where you are and whom you are greeting. If you make a mistake,you could be misunderstood.

Although in the data communications world protocols are more complex and precise, the same idea holds true. For example, a protocol may define the shape of a packet that will be transmitted across the network, as well as all the fields within the packet and how they should be interpreted. Obviously, both the sender and receiver must agree on the exact way the packet should be formatted in order for communication to occur.


NOTE
Any protocol product available on the market will necessarily be a protocol implementation, which means any one company's interpretation of the protocol definition or standard. Therefore, one company may interpret a standard in a different way than another, which can cause incompatibility.

A protocol suite is a group of protocols that evolved together, whether created by the same company, as in the case of IBM's SNA, or used in the same environment, such as the Internet protocol suite. Protocol suites have definitions for the interface between protocols that occur at adjacent layers of the OSI model, such as IPX and SPX in the NetWare suite.

NetWare IPX/SPX Protocols

The NetWare protocol suite takes its name from the two main protocols at the network and transport layers of the OSI model: IPX and SPX.


NOTE
NetWare was first developed by Novell,Inc., in the early 1980s. Its design was based on a network developed by Xerox at its Palo Alto Research Center (PARC) called Xerox Network System (XNS).

The NetWare IPX/SPX protocol suite provides file, print, message, and application services. This architecture is server-centric because workstations make requests for file services or other services from the server. To the user at a workstation, all resources appear local to that workstation. For example, saving a file to a file server on the network is simply a matter of saving it to drive F (or another mapped drive) in the same way it would be saved to the user's C hard drive.

The NetWare protocols are modular; you can use them with many different hardware configurations. You can also use other protocols, such as TCP/IP and AppleTalk, with NetWare, making it very flexible. NetWare, therefore, is not limited to its proprietary protocols,IPX and SPX. Allowing additional protocols provides more interoperability with other computer systems.

The NetWare protocol suite can be mapped to the OSI model as shown in Figure 5.1. The following sections discuss the NetWare protocols, organized by their function with respect to the OSI model.

Figure 5.1: The NetWare protocol suite mapped to the OSI model

NetWare Lower-Layer Protocols

NetWare normally runs over standard lower-layer protocols, such as Ethernet (IEEE 802.3) and Token Ring (IEEE 802.5). The lower-layer protocol discussed here, MLID, is a proprietary standard for network interface card drivers.

MLID (Multiple Link Interface Driver)

The MLID protocol operates at the MAC sublayer of the OSI model's data link layer. It is concerned with medium access and uses these methods:

  • Contention
  • Token passing
  • Polling
The MLID is a standard for network drivers. Each type of network board has a unique MLID driver. The MLID is implemented in software. A common example is the DOS file called NE2000.COM, written for the Novell/Eagle NE2000 network card.

The MLID is also called the network driver or LAN driver. Its job is to communicate directly with the hardware network card. The MLID is independent of upper-layer protocols because of the LSL (link support layer) module at the LLC sublayer of the data link layer, which acts as an interface between the MLID and network layer protocols.

The interaction between the MLID, LSL, and other components is specified by the ODI (Open Data-link Interface) specification, a Novell standard for modular network communications. The ODI specification allows you to easily configure client software using the same programs, regardless of the type of network board used. With this architecture only the MLID changes; before ODI, you needed to create a customized version of the IPX driver for each network card.

NetWare Middle-Layer Protocols

NetWare's middle-layer protocols include the following:
  • IPX: Used for transporting packets
  • RIP and NLSP: Routing protocols
  • SPX: Runs at the transport layer and adds connection-oriented service when added reliability is required

IPX (Internetwork Packet Exchange)

Novell's main network layer protocol is IPX. It deals with addressing (the logical network and service addresses), route selection, and connection services. IPX provides connectionless datagram service, which means that data is sent over the whole network segment rather than across a direct connection.IPX is based on the IDP (Internetwork Datagram Protocol) of XNS (Xerox Network System).

Because of its connectionless nature, IPX is not suitable for some types of network communications. Most of the communication on a network, including workstation connections and printing, uses the SPX protocol, described later in this chapter. Simple IPX is used for broadcast messages, such as error notifications and time synchronization.

IPX performs dynamic route selections based on RIP tables, which contain a list of identified and reachable networks. In NetWare 4.1, IPX is usually implemented by the IPXODI.COM program, which follows the ODI specification. Earlier NetWare versions used a program called IPX.COM. As discussed in the section "MLID (Multiple Link Interface Driver)" earlier in this chapter,before ODI, a custom version of IPX was required for each type of network card and settings.

RIP (Routing Information Protocol)

RIP is the default protocol NetWare uses for routing. RIP uses the distance-vector route discovery method to determine hop counts. The hop count is the number of intermediate routers a packet must cross to reach a particular device.

RIP functions at the network layer of the OSI model, although it has a service address assigned to it. Because it is a distance-vector routing protocol, RIP periodically broadcasts routing table information across the internetwork. This can create a bottleneck when the information must be transmitted over wide area links. For WANs, you should use a link-state routing protocol instead,such as NLSP.

NLSP (Network Link Services Protocol)

NLSP is another routing protocol that functions at the network layer. NLSP uses the link-state route discovery method to build routing tables. It is based on an OSI routing protocol called IS-IS (Intermediate System-to-Intermediate System)....

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