Exam Essentials ( Network+ Chapter 2 )

Exam Essentials
Be able to specify the main features—including speed, access method, topology, and media—of various network technologies, such as 802 standards and FDDI. You should be able to differentiate between the various networking technologies when studying for the exam. Refer to Table 2.3 for help.

Be able to identify a MAC address. A MAC address on a network is a 12-digit hexadecimal number in the format xx:xx:xx:xx:xx:xx, where x is a number from 0 to 9 or a letter from A to F.

Be able to identify the seven layers of the OSI model and describe their functions. 
The seven layers of the OSI model (from the bottom to top—or layer 1 to layer 7) are the Physical layer, Data Link layer, Network layer, Transport layer, Session layer, Presentation layer, and Application layer.

Know how to differentiate between the IP, IPX, NetBEUI, and AppleTalk/AppleTalk over IP protocols when it comes to routing, addressing schemes, interoperability, and naming conventions.
TCP/IP uses the likes of RIP or OSPF as routing protocols, uses a dotted decimal notation (four sets of numbers, each from 0 to 255) for the addressing, is completely interoperable,
and uses DNS for host naming.

IPX, on the other hand, uses IPX RIP and NLSP for routing information, uses a unique 20-digit address (incorporating the MAC address) for the station address, interoperates with several different
operating systems (but not as many as TCP/IP), and uses NDS for host naming.

NetBEUI isn’t routable or as flexible, nor does it have as many features, but it does offer performance on a LAN segment. Addressing and naming are completely automatic (naming does
require a user to enter a computer name).
Finally, AppleTalk does have routing protocols (RTMP) and uses an automatic addressing scheme. It requires only that the user name the computer when enabling AppleTalk. It is by far the simplest protocol, but it has the lowest performance and the least interoperability. Apple-Talk over IP is a form of tunneling for AppleTalk traffic so AppleTalk devices across the Internet can communicate using that public network, but AppleTalk itself is compatible with neither IP nor the Internet.

Be able to explain the issues that must be considered when multiple protocols are running at the same time. When running multiple protocols, not only are you using more memory on a computer, you’re adding a level of complexity to the network that is multiplied by the number of stations  that you add. It is better to run the fewest protocols possible. Some issues you will see include running out of memory, program confusion, stations unable to communicate (each is running a different protocol), and network congestion.

Identify the OSI layers at which hubs, switches, bridges, WAPs, routers, and network interface cards operate. Hubs operate at the Physical layer for the most part. Switches can operate at
many different layers (up to layer 5), but the lowest common denominator for all network switches is OSI layer 2 (Data Link layer). Bridges are relatively simple devices and operate primarily
at the Data Link layer. Routers are more complex devices, but because all they do is route packets, they operate at layer 3 (Network layer). Finally, network interface cards (NICs) operate

at the Physical and Data Link layers.

Review Questions

1. Which layer of the OSI model ensures reliable, end-to-end communications?
A. Network
B. Transport
C. Session
D. Presentation

2. Which layer of the OSI model provides routing functionality?
A. Transport
B. Data Link
C. Physical
D. Network

3. Which layer of the OSI model translates the data from upper-layer protocols into electrical signals and places them on the network media?
A. Physical
B. Transport
C. Data Link
D. Network

4. You are a consultant designing a network for a company with more than 1000 users. Which 802 standard would you implement to ensure that bandwidth would be sufficient and equal without bridging or additional segments?
A. 802.1
B. 802.2
C. 802.3
D. 802.5

5. Which one of the following devices will not propagate broadcasts from one of its interfaces to another?
A. Hub
B. Switch
C. Repeater
D. Router

6. You are installing a Windows XP–based TCP/IP network. You accidentally set workstation B to the same IP address as workstation A. Which workstation(s) will receive an error message?
A. Workstation A
B. Workstation B
C. Neither
D. Both

7. You are installing a Windows XP–based TCP/IP network. You accidentally set workstation B to the same IP address as workstation A. Which workstation(s) will have a valid IP address?
A. Workstation A
B. Workstation B
C. Neither
D. Both

8. Which device increases the number of collision domains while decreasing the average number of nodes per collision domain?
A. Hub
B. Transceiver
C. Switch
D. NIC

9. Which of the following protocols use a connectionless transport? (Choose all that apply.)
A. HTTP
B. TCP
C. TFTP
D. IP
E. NetBIOS

10. Which protocols use a connection-oriented transport?
A. UDP
B. NetBIOS
C. HTTP
D. TFTP

11. Which name resolution system is implemented with TCP/IP by default?
A. DNS
B. NDS
C. SND
D. WINS

12. Which OSI model layer has both a MAC sublayer and an LLC sublayer?
A. Physical
B. Transport
C. Network
D. Data Link

13. Which OSI model layer is responsible for establishing, maintaining, and breaking down dialog?
A. Application
B. Gateway
C. Session
D. Network

14. Which OSI layer is responsible for formatting data based on a standard syntax and for character- set conversion?
A. Transport
B. Network
C. Presentation
D. Session

15. Which OSI layer is responsible for building and tearing down packets?
A. Network
B. Transport
C. Data Link
D. Physical

16. The two halves of a MAC address are referred to as the 
A. TCP and IP
B. OUI and device ID
C. OUI and IP
D. Device ID and IP

17. Which of the following directory services are hierarchical in design? (Choose all that apply.)
A. Novell NetWare Bindery
B. Microsoft Windows AD
C. Linux password shadow file
D. NT domain

18. You are the administrator of a 100-node Ethernet network. Your users are complaining of slow network speeds. What could you replace your hub with to increase your network throughput?
A. Router
B. Bridge
C. Switch
D. NIC

19. At which OSI model layer do routers primarily operate?
A. Physical
B. Data Link
C. Transport
D. Network

20. Which of the following is a MAC address?
A. 199.165.217.45
B. 00076A:01A5BBA7FF60
C. 01:A5:BB:A7:FF:60

D. 311 S. Park St.

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AppleTalk and AppleTalk over IP

AppleTalk and AppleTalk over IP
When Apple introduced the Macintosh in 1984, the Mac included networking software. This networking software used a protocol known as AppleTalk and a cabling system known as LocalTalk. It is a very simple and elegant protocol in that the computer takes care of most of the configuration. You simply plug it in and it works. Because of its simplicity and popularity with Mac users, and because the Mac users wanted a faster version, Apple developed Apple- Talk version 2 with support for Ethernet (EtherTalk). Figure 2.20 illustrates the interrelationships between these components of AppleTalk, as well as others we’ll discuss. Table 2.5 descibes the protocols shown in Figure 2.20.

FIGURE 2 . 2 0 The AppleTalk protocol model

TABLE 2 . 5 AppleTalk Protocols Defined

Protocol	Description
Datagram Delivery Protocol (DDP)	Delivers data in discrete packets. DDP is unreliable, not acknowledging data delivery or guaranteeing the order of its delivery.
Routing Table Maintenance Protocol (RTMP)	Establishes and maintains routing tables through the exchange of  routing information between routers.
AppleTalk Echo Protocol (AEP)	Provides a way to test for responsiveness and round-trip transmission times. Similar to using ICMP for Pinging remote devices.
AppleTalk Transaction Protocol (ATP)	Provides reliable data transmission, similar to the way in which TCP does so for TCP/IP.
Name Binding Protocol (NBP)	Translates an AppleTalk device name into an AppleTalk network  address.
AppleTalk Data Stream Protocol (ADSP)	Establishes an end-to-end full-duplex session to exchange data between two network applications in which both endpoints have equal control over the communication.
Zone Information Protocol (ZIP)	Maintains AppleTalk internetwork-wide mappings of zone names to network number ranges on routers. While ZIP is primarily implemented by routers, end devices implement a portion of ZIP, allowing them to obtain zone information from a router. A zone is similar, in purpose, to a VLAN in layer 2 switching, unifying nodes by departmental membership or other logical affiliations regardless of their physical LAN segment connectivity.
AppleTalk Session Protocol (ASP)	Establishes reliable sessions that provide for non-duplicate transmissions between an ASP workstation process and an ASP server process. Unlike those formed in ADSP, ASP sessions are asymmetrical in that an ASP server never initiates communication but only responds to communication initiated by the ASP workstation.
Printer Access Protocol	Handles connection setup, maintenance, and termination of reliable transmission of messages to printers.
AppleTalk Filing Protocol (AFP)	Provides the interface between an application and a file server. Allows an application on an AppleTalk workstation to access and manipulate files on an AFP file server, such as an AppleShare server or a Microsoft Windows server running AFP, in the form of Services for Macintosh.

      Apple’s Mac OS X and OS X Panther (versions 10.3.x) can communicate with any server running the AFP service, whether over TCP/IP, which is preferred by Apple, or over the legacy Apple- Talk protocol. On Macintosh servers, the AFP service is implemented as AppleShare. You can use IP to connect to Macintosh file services running on Mac OS X Server, AppleShare IP, and Windows 2000 and later servers. AppleShare IP has been an add-on service available since the Mac OS 8 days, necessary for IP connectivity with AFP resources before this functionality became available natively in Mac OS X. Of course, Mac OS X still is capable of communicating with AFP servers over AppleTalk instead of IP, supporting legacy access to older AppleShare servers and Windows NT servers that only provide Mac file services over AppleTalk. However, Apple recommends migrating to TCP/IP as the transport method between clients and AFP servers.

Note:

One note about Mac OS X and AppleTalk: While Mac OS X clients can still use
AppleTalk to communicate with older AppleShare servers, Mac OS X servers
do not support client communication to their Apple File Services (the server’s
instance of AFP) via AppleTalk. While the Mac OS X server advertises its services
over AppleTalk for older clients to be able to show the server in their
Chooser, connection to the server must be via TCP/IP.

Note:

In addition to using AppleTalk for service browsing, you can use Mac OS X
Server’s Server Admin utility to enable Apple File Service browsing via Network
Service Locator (NSL) and Rendezvous. Rendezvous is an IP-based open
service discovery protocol, allowing devices to be added to and removed from
networks without configuration. Rendezvous is mentioned in Chapter 3’s Zero-
Conf discussion. 

Services for Macintosh
Although the Windows 2000 file system is fairly different from the Macintosh file system, files on a Windows 2000 Server machine are accessible by both Windows 2000 clients and Macintosh
clients. Services for Macintosh works in the background on a Windows 2000 Server machine to make this multiclient support possible by establishing an AFP-compatible server service. Files can be made to appear as they usually do for both Macintosh and Microsoft clients. A Microsoft client sees files represented as a directory tree, while a Macintosh client sees files represented as a Macintosh folder. In this environment, files may be stored in shared folders or Macintosh volumes. Macintosh volumes that are shared to the network are seen only by Macintosh clients, not by the Windows 2000 clients. Conversely, in order for a Macintosh
client to gain access to a Microsoft shared folder, the administrator must designate the folder as a Macintosh-accessible volume. 

      For folders that are both a Microsoft shared folder and a Macintosh-accessible volume, both Microsoft clients and Macintosh clients have access to the resource. However, while Microsoft clients see folders and files as they are stored on the server’s hard disk beneath the root of the share, Macintosh clients see the volume as containing Macintosh files and folders.
     The following sections cover AppleTalk’s methods of addressing and naming as well as its ability to be routed over internetworks.

Addressing
Each station on an AppleTalk network uses an address that is 24 bits long. Sixteen of those bits are given to the network, and each network can support 254 nodes. Each network segment can
be given either a single 16-bit network number or a range of 16-bit network numbers. If a network is assigned a range of numbers, that network is considered an Extended AppleTalk network because it can support more than 254 nodes. The node address is automatically assigned by the computer itself.
      In addition to network numbers, AppleTalk networks use areas called zones. Zones allow an administrator to divide a network into logical areas for easier administration and to make it easier

for a user to find resources.

Note:

Although you can have multiple zones on an AppleTalk network, an AppleTalk node can belong to only one zone.

Routing
AppleTalk wasn’t originally designed to be routed over a WAN, but with the release of AppleTalk version 2, Apple included routing functionality with the introduction of the Routing Table Maintenance Protocol (RTMP). RTMP is a distance vector routing protocol, like RIP, for both IP and IPX.

Interoperability
The only computer that comes with AppleTalk installed by default is the Macintosh. Most Windows operating systems are able to use the AppleTalk protocol but require that additional software
be installed. By using AppleTalk over IP, it is possible to tunnel AppleTalk conversations over the very Internet itself. Two AppleTalk speakers can package their AppleTalk packets in
such a way that they are transmissible through IP intermediate systems, being stripped back down to the original AppleTalk packet by the receiving AppleTalk-speaking device.

Naming
AppleTalk uses the Name Binding Protocol (NBP) to associate the name of the computer with its network address. It is broadcast based. Every station broadcasts its name when it comes up on a network. The AppleTalk router on a network will cache these names and respond when a node requests a name resolution; the local router will answer with information it has obtained from this NBP cache.

Note:

If an AppleTalk network doesn’t have a router, each node will perform both its normal NBP requests and any NBP responses to broadcasted requests for its own AppleTalk address.

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Summary ( Chapter 2 )

Summary
In this chapter, you learned about the OSI model and had an introduction to a few of the most popular protocols in use today. You also learned about the seven layers that make up the OSI
model, which are (from top to bottom) the Application, Presentation, Session, Transport, Network, Data Link, and Physical layers. In addition, you learned what each layer’s primary responsibility is and in what layer certain popular protocols function. This chapter also reiterated at which layers certain common devices operate. This chapter included discussions of some of the major protocol suites, including TCP/IP, IPX/SPX, NetBEUI/NetBIOS, and AppleTalk, and how the different protocols of each suite work together. For each protocol, you learned which parts of the protocol stack handle the concepts of addressing, routing, interoperability, and naming. Also in this chapter, you were introduced to popular Data Link technologies, including those
in the 802 standards track of IEEE, such as Ethernet and Token Ring, as well as their media access methodologies, such as CSMA/CD and token passing. On a related note, you were given

the details of the structure and use of the 48-bit MAC address.

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NetBEUI

NetBEUI
NetBEUI is a Network layer protocol designed to provide support for NetBIOS networks. Net- BIOS is a protocol that was developed by IBM (and later enhanced by Microsoft and Novell)
for use with network-aware operating systems like LAN Manager/LAN Server, Windows 9x, and Windows NT, 2000, XP, and 2003. It is a very fast and efficient protocol with low overhead.
Because NetBIOS is small and efficient, it works well on small LANs with between 10 and 200 nodes. The two protocols are often referred to together as NetBEUI/NetBIOS. In the following sections, naming, addressing, routing, and interoperability will be presented for NetBEUI, as it was for IPX/SPX and TCP/IP.

Naming and Addressing
There is very little network addressing with NetBEUI/NetBIOS. Actually, for NetBEUI, naming and addressing are the same thing. Each device, not interface, is configured with a unique name
(called the NetBIOS name) that is used for all communications. It’s simple and quick. The only item that must be configured on the workstation is the name of the workstation. NetBIOS names can be up to 15 characters in length and must adhere to special-character exclusions similar to those listed for IPX/SPX (NetWare).

Routing
Because the NetBEUI/NetBIOS protocol stack does not have an address structure with a hierarchical format and has no network and host boundaries, it is not a routable protocol. Routers
will drop NetBEUI/NetBIOS packets by default. Some routers, however, may be configured to bridge these packets to all segments or to unicast them to a specific IP address, which must be
configured on the receiving interface.

Interoperability
Only a few operating systems run NetBEUI/NetBIOS. The operating systems for IBM and Microsoft are the primary supporters of this protocol. Windows 9x, NT, and 2000/2003 and LAN Manager and OS/2 support NetBEUI/NetBIOS. These operating systems can therefore communicate using
 NetBEUI/NetBIOS. The Macintosh operating system, however, does not support NetBEUI natively, nor do the latest implementations of Microsoft Windows, but you can add it back in, which, unless a strong case exists in favor of doing so, is highly frowned upon due to compatibility issues.

Note:

Note that the Apple Filing Protocol should be your certification focus and the
overall structure of the AppleTalk suite of protocols is provided for context.

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The Presentation Layer

The Presentation Layer
The Presentation layer does what you might think it does: It changes the look, or presentation, of the data from the lower layers into a format that the upper-layer processes can work with.
Among other services, the Presentation layer deals with encryption, data compression, and network redirectors. 
      In addition, the Presentation layer deals with character-set translation. Not all computer systems use the same table to convert binary numbers into text. Most standard computer systems use the American Standard Code for Information Interchange (ASCII). Mainframe computers (and some IBM networking systems) use the Extended Binary Coded Decimal Interchange Code (EBCDIC) and Unicode, which is popular on the Internet as one character set that assigns a
unique number to every character regardless of the language or the operating system used to display the character. The three are totally different. Protocols at the Presentation layer can translate
between the three.

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The OSI Model’s Upper Layers

The OSI Model’s Upper Layers
The upper layers of the OSI model deal with less esoteric concepts. Even though we’re still discussing computer networking, the top three layers (Session, Presentation, and Application)
seem easier to understand. Because the Network+ exam doesn’t cover the upper layers (and many times these top three layers are grouped together), the following sections will give only a brief overview.

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The Session Layer

The Session Layer
Protocols that operate at the Session layer of the OSI model are responsible for establishing, maintaining, and breaking sessions, or dialogs. This is different from the connection services provided at
the Transport layer because the Session layer operates at a higher level and looks at the bigger picture— the entire conversation, not just one sentence. Many gateways operate at the Session layer.
Novell’s Service Advertisement Protocol (SAP) is a Session layer protocol, as well as NetBIOS.

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The Application Layer

The Application Layer
Now, you might be thinking, “This layer is for my programs, right?” Wrong. The Application layer defines several standard network services that fall into categories such as file transfer, print access, and e-mail relay. The applications that access these network services are located above the Application layer and are not even part of the layered model.

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Upper-Layer Devices

Upper-Layer Devices
There are only a few upper-layer devices, none of which operate at any specific layer. Because they perform a range of functions for the network, they fall into the class of devices known as
gateways. A gateway translates one type of network data into another. Gateways can be either hardware or software, but the most popular way to run a gateway is as a software program on
a dedicated computer.
     There are many, many types of gateways, but the one most people think of is an e-mail gateway. E-mail gateways translate e-mail messages from one type of e-mail system so that they can
be transmitted on another (for example, from GroupWise e-mail to SMTP mail for the Internet).

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Networking Protocols

Networking Protocols
Now that you have a basic understanding of the OSI model and its related concepts, you can use these concepts to understand how the major protocols work and how each of the protocols
within each protocol stack maps to the OSI model, thus describing its function. 
     In the following sections, you will learn about four major protocol stacks and how each one handles the concepts of addressing, routing, interoperability, and naming:

• TCP/IP
• IPX/SPX
• NetBEUI
• AppleTalk/AppleTalk over IP

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TCP/IP

TCP/IP

Transmission Control Protocol/Internet Protocol (TCP/IP) is the protocol suite of choice today. It, like other protocols suites, is used to allow local network devices to communicate over a network.

However, TCP/IP is used not only on LANs, but also over WANs and the Internet. Actually, TCP/IP is the only protocol suite in use on the Internet.

Note:

You’ll learn more about TCP/IP in Chapter 3, “TCP/IP Fundamentals.”

In the following sections, TCP/IP addressing, routing, interoperability, and naming concepts will be presented. This is a consolidation of similar information from other parts of the chapter

with a few additional points of interest.

Addressing

As mentioned earlier in the chapter, each host is given (either manually or automatically) a dotted decimal IP address in the format xxx.xxx.xxx.xxx, where xxx is a number from 0 to 255.

Note:

There are several addressing rules, which you will learn more about in Chapter 3.

Because addressing is a Network layer concept, the protocols that deal with addressing can be found at this layer. The Address Resolution Protocol (ARP) is responsible for resolving an IP
address to the MAC address of the receiving host. The MAC address is a Data Link layer address hard-coded to each network interface by the manufacturer. When a TCP/IP packet is sent, at some point a router will need to determine exactly which device the packet is intended for. On Ethernet networks, the router will use an ARP request broadcast. Any device that wants a specific physical
address will send an ARP broadcast on to the immediate link with the IP address of the interface for which it wants the MAC address in the packet header. The device whose interface has the
matching IP address will respond with its interface’s MAC address. Whenever a device sends an ARP request and receives a response, it notes that resolution in a table known as the ARP cache.
When a router receives packets and needs to send them to a particular device on one of its own segments, it examines the IP address of the destination, looks up the MAC address of that device’s interface using ARP, and forwards the packet via Ethernet to the intended destination.

Note:

You’ll learn more about ARP in Chapter 3.

Routing

On TCP/IP networks, routing is a fairly involved process. In order to send a packet through an internetwork (like the Internet), the router must have three pieces of information:

• The IP address of the sender
• The IP address of the destination
• The IP address of the next router to which the packet should be sent

The first two are part of the IP datagram being sent, but the router must figure out the last item itself. The router uses information it receives from other routers about what IP networks their interfaces are members of, as well as other networks they have learned about from their neighbors, in order to build a logical “map” of the network (called a routing table). Then the router can determine the best way to get the datagram to its destination and send the information on to the next router.

   Routers build routing tables using dynamic routing protocols, such as RIP and Open Shortest Path First (OSPF), or by having static routes entered manually. The major difference between the two dynamic routing protocols mentioned is that RIP is a distance vector routing protocol and OSPF is a link state routing protocol. The difference between them is pretty simple. Distance vector protocols (like RIP) are used by routers to gather information about the hosts connected to them and to build a table of the addresses and the segment they are on (called a routing table). The router then sends out this information to all the routers it is connected to. All of the routers that receive this information add the route information to their own routing tables and continute to propagate them. Approximately every 30 seconds (varies depending on the protocol), distance vector protocol routers will re-advertise their entire routing table, with each interface having its own independent timer. Eventually, all routers in the internetwork know about

all the other routers and the networks they serve.

      Link state routing protocols (like OSPF) work slightly differently. Whereas IP RIP routers will advertise their entire routing table every 30 seconds, a link state router will send out to its “neighbors” only the changes to its routing table, as they occur. Additionally, link state routers have a more directed relationship with their neighbors. Instead of blindly advertising all of their

information to their neighbors, link state protocols (like OSPF) prefer to more intentionally send updates only to a specific list of addresses via unicast or multicast.

Interoperability

Of all the protocols listed in this chapter, no protocol is more flexible or more interoperable than TCP/IP. As the Internet gained popularity, everyone wanted to “get on the Net.” As such,

almost every computer had to have two things: a web browser and some form of TCP/IP connection. Therefore, every computer that is connected to the Internet is running TCP/IP in one way or another. Many companies use the TCP/IP protocol suite to communicate with one another over the Internet. Additionally, because of this phenomenon, every operating system has some form of TCP/IP

protocol stack and, as such, can communicate with other operating systems on some fundamental level.

Naming

TCP/IP hosts are named according to the DNS convention. DNS is a service that resolves FQDNs to IP addresses. For instance, you can use friendly names like www.trainsolutions.com to refer to

computers instead of unfriendly IP addresses like 192.168.24.31.

There are two parts to a DNS name: the host name (e.g., www) and the domain name (e.g., trainsolutions.com). Each of these components is separated by a period. Typically, you would assign a host name that says what the computer’s function is (e.g., www for a web server). The domain name, on the other hand, is usually the name of the company in which the computer resides, or some related name, followed by .com, .edu, .net, or any other top-level

domain suffix.

Note:

You’ll learn more about DNS in Chapter 3.

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IPX/SPX

IPX/SPX
When Novell NetWare was introduced, it was designed to be a server platform for a local area and wide area networks. To that end, Novell designed a protocol stack that was very efficient
over local area networks and that would also work on wide area networks. That protocol stack was the Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX).
In the following sections similar information to that presented for TCP/IP will be presented so that you may compare similar features, including addressing, routing, and naming, between
the two.

 Addressing
IPX is the Network layer protocol that handles addressing and routing for the IPX/SPX protocol stack. IPX addressing is actually very simple. It takes the 12-digit hexadecimal address because
that is the address for the individual node on that network segment. The network segment is referred to by its own unique 8-digit hexadecimal address. For example, the address
0001ABF3:12AB341FF414 would correspond to an interface with a MAC address of 12-AB- 34-1F-F4-14 on the network segment labeled 0001ABF3. Every network segment is assigned its own, unique IPX network address. Since the MAC address is burned in to the NIC at the factory and, for the most part, shouldn’t be changed, it doesn’t have to be configured. The only configuration
that must be done is to assign the IPX network address and configure the server with that address.

Note:

In addition to a station address, routers are given an internal IPX address. This address uniquely identifies a router to the rest of a network. NetWare servers always have an internal IPX address because they can function as routers.

Routing
Most routers that route TCP/IP traffic can also route IPX traffic (although they may require additional software or configuration). IPX/SPX is a routable protocol stack because its address
strucure is hierarchical, with a network portion and a node portion. As a result and to increase functionality, IPX/SPX has routing protocols designed into it. The routing protocols for IPX/SPX are RIP and NLSP. IPX RIP is very similar to the RIP protocol in TCP/IP in that it is the distance vector routing protocol for IPX. Similarly, NLSP is the link state routing protocol for IPX/SPX. Both work similarly to their TCP/IP counterparts. RIP uses broadcasts of the entire IPX routing tables to keep all IPX routers updated, although every 60 seconds, not 30 as with IP RIP, and just as OSPF
does, NLSP sends out only the changes to the routing tables and then only to a select group of network addresses. NLSP is actually based on another link state routing protocol, ISO’s Intermediate
Sytem to Intermediate System (IS-IS).

Interoperability
IPX/SPX isn’t as ubiquitous as TCP/IP (which can even be found running on Coke machines), but it holds its own when it comes to allowing many different platforms to talk. Windows 9x,
NT, Me, 2000, XP, and2003 as well as NetWare, and a few versions of Linux come “out of the box” with support for communicating with other entities via the IPX/SPX protocol stack,
although Microsoft calls its completely compatible version NWLink. Before the popularity explosion of the Internet in the mid-1990s, the IPX/SPX protocol stack was the only protocol
stack many companies would run.
     The only downside to interoperability using IPX/SPX is that many versions of Unix and other high-end operating systems like OS/400 don’t come with built-in support for the IPX/SPX protocol stack or even with an option for support.


Naming
Really, the only devices that have names are the NetWare servers. Generally speaking, you can name a NetWare server anything you want, as long as you follow these rules:

• The name must not include any of the “illegal” characters, including a period (.), a comma (,), a plus sign (+), an equal sign (=), and a backslash (\).
• Names must have fewer than 64 characters.
• Names are not case sensitive.

These names are resolved using either Bindery Services or Novell Directory Services.

Note:

These will be discussed more in Chapter 5, “Major Network Operating Systems.”

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