Cabletron Systems Networking Guide Workgroup Solutions
Notice Notice Cabletron Systems reserves the right to make changes in specifications and other information contained in this document without prior notice. The reader should in all cases consult Cabletron Systems to determine whether any such changes have been made. The hardware, firmware, or software described in this manual is subject to change without notice.
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Contents Chapter 1 Introduction Using This Guide ......................................................................................................................... 1-1 Document Organization ............................................................................................................. 1-2 Document Conventions .............................................................................................................. 1-3 Warnings and Notifications ...................................
Contents Chapter 5 Network Design The Role of the Workgroup ........................................................................................................5-2 Workgroup Establishment Criteria ....................................................................................5-3 Selecting Workgroup Technologies ....................................................................................5-9 Creating a Manageable Plan.........................................................................
Contents Appendix A Charts and Tables Workgroup Design Tables .........................................................................................................A-1 Ethernet.................................................................................................................................A-1 Fast Ethernet.........................................................................................................................A-3 Token Ring...................................................
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Chapter 1 Introduction Using This Guide The Cabletron Systems Networking Guide - Workgroup Solutions is intended to provide much of the information necessary to allow Network Managers to design and evaluate workgroup networks using the Cabletron Systems family of standalone and stackable networking products. This guide also provides the methods for associating these workgroups into larger networks or incorporating them into existing facility networks.
Introduction Document Organization The following summarizes the organization of this manual: Chapter 1, Introduction, provides basic information about this document, including the organization and format of the document. Chapter 2, Review of Networking, describes the important design restrictions and characteristics of three basic networking technologies. Chapter 3, The Workgroup Approach, explains the history and product philosophy behind standalone and stackable workgroup networking devices.
Introduction Document Conventions Warnings and Notifications NOTE Note symbol. Calls the reader’s attention to any item of information that may be of special importance. Formats References to chapters or sections within this document are printed in boldface type. References to other Cabletron Systems publications or documents are printed in italic type. Additional Assistance The design of a network is a complex and highly specialized process.
Introduction Related Documentation The following publications may be of assistance to you in the design process. Several of these documents present information supplied in this guide in greater or lesser detail than they are presented here.
Chapter 2 Review of Networking This chapter discusses the defining characteristics of three major Local Area Network (LAN) technologies. Before discussing the selection of networking hardware for workgroup design, an understanding of the major standardized networking technologies available for these designs is necessary. This chapter provides a brief review of the three major networking technologies that are to be treated in this document: Ethernet, Fast Ethernet, and Token Ring.
Review of Networking Ethernet Ethernet is a local area networking technology that was initially developed in the 1970s by the Xerox Corporation. It is based on the principles of workstations being responsible for their own transmissions and operation. It is sometimes referred to as 802.3 networking, in reference to the number of the IEEE standards body which subsumes all Ethernet operations. Ethernet networks provide an operating bandwidth of 10 megabits per second (Mbps).
Review of Networking • AUI Length: The maximum Attachment Unit Interface (AUI) cable length is 50 m for connections from a transceiver to an Ethernet device. The 50 m distance is the allowable maximum for standard AUI, while a maximum length of 16.5 m has been set for office AUI. • Number of Stations per Network: IEEE standards specify that the maximum allowable number of stations per un-bridged network is 1,024, regardless of media type.
Review of Networking This signal path, two end stations and the repeaters between them, is called the network radius. Unlike standard Ethernet networks, Fast Ethernet networks have a maximum network radius that may restrict the lengths of station cabling to less than the maximum allowable distances for single links. Typically, network radius calculations are only important when mixing 100BASE-TX and 100BASE-FX networks. The maximum network radius limits are provided later in this section.
Review of Networking Fast Ethernet networks designed using Class II repeaters may not exceed the following maximum network radii: • Buffered Uplinks: If a buffered uplink is used to make a connection, the allowable length of the buffered uplink itself does not change, but the maximum network radius calculations will change.
Review of Networking The transmission and reception of the token determines the amount of time that any station will have to transmit data during its turn, offering a measure of predictability not available in Ethernet or Fast Ethernet. This predictability also allows Token Ring networks to incorporate special error-detection and correction functions which can locate and correct network problems without human intervention.
Review of Networking Token Ring networks can use a variety of physical cabling, including Unshielded Twisted Pair (UTP), Shielded Twisted Pair (STP), or fiber optic cabling. The characteristics of the various cables can directly impact the operational limitations of a Token Ring network which uses a particular media.
Review of Networking • Number of Stations Per 4 Mbps Token Ring: In the same fashion as the limits imposed on cable lengths due to the operating speed of the network and type of cabling used, there are limitations on the number of stations that may be connected to a single ring using active circuitry.
Review of Networking There are other limitations involved in the IEEE 802.5 standard and the various cable specifications that are more detailed and complex. These limitations are covered in detail in the Cabletron Systems Cabling Guide and the Cabletron Systems Token Ring Technology Overview.
Review of Networking 2-10 Token Ring
Chapter 3 The Workgroup Approach This chapter describes the basic operation and design of stackable and standalone devices and the methods used to meet common networking needs with these devices. Standalone and stackable networking devices are specialized and important parts of any end-to-end network design strategy.
The Workgroup Approach Standalones, the Original Networking Devices Standalone devices are the second oldest devices in Local Area Networking, having been developed shortly after transceivers. The basic and most straightforward standalone device is the repeater or concentrator, a device that allows a network signal received on one interface, or port, to be strengthened, regenerated, and sent out another port.
The Workgroup Approach Management of Standalones As standalone devices became more complex, the need to control them became greater. The need to have some form of troubleshooting and control process in place for an eight-port repeater is minimal. In a repeated network where more than 200 users are connected to a single repeater, management capabilities are no longer luxuries, they are a necessity.
The Workgroup Approach Stackables To cope with the limited flexibility and expandability of standalones, the stackable hub, or stackable, was developed. The stackable design allowed a series of devices to act as a single device. With a stackable hub system, five separate devices could act as a single device. From the point of view of network design, this was a master stroke. A single stack, which operated as one big device, could support as many users as four or five standalone repeaters.
The Workgroup Approach How Stacks Work Stackable hubs communicate with one another through proprietary interconnection cables. The cables used in Cabletron Systems’ stackable hub solution are called HubSTACK Interconnect Cables. In Ethernet stackable environments, these cables are short, multistrand cables with special, D-shaped connectors that attach to ports on the backs of the stackable hubs, as shown in Figure 3-3.
The Workgroup Approach HubSTACK Interconnect Cables are connected in a particular sequence, from the OUT port of the first device in the stack to the IN port of the next. This arrangement is repeated from device to device as more stackable hubs are incorporated in the stack, as shown in Figure 3-3.
The Workgroup Approach Initially, Network Designers wishing to make connections from stacks to backbone technologies would be forced to add an additional standalone device to the network at the workgroup area. The addition of a standalone switch, bridge, or router that supported the technology of the stack and the technology of the backbone would allow for the interconnection, or internetworking, of the stack and the backbone.
The Workgroup Approach In addition, stackable and standalone devices are typically available for only the most common of networking media: UTP and STP. In situations where several users connect to the network with UTP, a few make their connections with fiber optics, and there is a handful of existing coaxial cable segments, a solution using stackables would have to provide a series of external transceivers at each location.
Chapter 4 PIMs and BRIMs This chapter deals with the special methods of connecting standalone and stackable devices to one another regardless of cabling media or networking technology. While many network design implementations are simple and straightforward, there are several that must incorporate complexity beyond a single segment, media type, or even a single networking technology.
PIMs and BRIMs The PIMs can be added at any time, allowing a Network Manager to add capabilities for special links at any time. Originally developed for use in the Cabletron Systems Media Interface Module (MIM) line for the MMAC-FNB modular chassis, the PIMs allow a device to support an additional type of cabling in addition to its primary cabling type.
PIMs and BRIMs The suffix of the PIM’s product name, which follows the hyphen, specifies what media type and connector style the PIM provides. Typically any alphabetic characters indicate the media, while numerical characters indicate a special connector type for that media. The “F” in the example shown in Figure 4-2 indicated that the PIM is for fiber optic media, while the “2” further indicates that the PIM provides Straight-Tip, or ST-type connectors. EPIMs EPIMs are Ethernet Port Interface Modules.
PIMs and BRIMs TPIMs TPIMs are Token Ring Port Interface Modules. A TPIM provides a single Token Ring connection. If the Token Ring device the TPIM has been placed in allows it, the TPIM connection can be used as either a station port or a RI/RO port. All TPIMs use active Token Ring circuitry.
PIMs and BRIMs APIMs The Asynchronous Transfer Mode (ATM) Port Interface Modules, or APIMs, are designed to allow connection to differing ATM networks, supporting not only different media, but different speeds of ATM transmission. When selecting an APIM, the Network Designer must ensure that the APIM supports both the required media and the technology to be used.
PIMs and BRIMs Table 4-1 provides basic information regarding the available PIMs and the connectors, media, and technologies they support. Table 4-1.
PIMs and BRIMs Table 4-1.
PIMs and BRIMs Bridge/Router Interface Modules In the same way that Cabletron Systems supplied a method for connecting a single network technology to different types of media, the Bridge/Router Interface Module, or BRIM, allows one networking technology to be connected to either a separate, segmented network or to a completely different networking technology.
PIMs and BRIMs BRIM-F6 The BRIM-F6 is an FDDI bridging device used to connect a standalone device to an FDDI network. The BRIM-F6 provides two user-configurable FPIM slots, allowing the Network Designer to specify and use any type of standard FDDI media for connection to the BRIM. The BRIM can be configured to provide either single attached or dual attached connections to the FDDI network, and can also be configured for dual-homing operation.
PIMs and BRIMs The available BRIMs and the technologies they support are detailed in Table 4-2. This table can be useful for the selection of a BRIM when designing a workgroup requiring a connection to a particular networking technology. Table 4-2.
Chapter 5 Network Design The following chapter discusses some of the more common approaches to workgroup network design. The network design process is the formation of the network from initial concept to the plan of implementation. In this Networking Guide, for the sake of brevity, the process of network design is separated from the process of network configuration.
Network Design As this Networking Guide is concerned with the decisions made regarding networking hardware and not with the administration of networks or the specific uses to which they are put, several aspects of the overall process of network design are not treated in this document, such as the selection of a Network Operating System (NOS), the choice of applications or of workstation types, or other specific decisions generally out of the purview of Cabletron Systems as a provider of networking hardware
Network Design Workgroup Establishment Criteria This section examines some of the methods that may be used to divide the population mass of end users of a network into cohesive and defined workgroups. Geographical Proximity Organizing workgroups by geographical proximity creates workgroups made up of discrete sections of a facility, as shown in Figure 5-1.
Network Design Departmental Organization Corporations, companies, and agencies all separate employees by primary function. No one person “does it all,” and most employees are specialists in the sense that they perform one function or a series of functions that are assigned to them by their job descriptions.
Network Design As the creation of workgroups based on departmental organization mirrors the operation of the company, the expandability of the network is simplified; since departmental growth can often be predicted in stable or growing companies, the network can be designed to allow for simplified expansion in the departments most likely to grow.
Network Design Common Function Segmentation by common function is often used to provide further division of the network within larger overall departments, or to facilitate the use of certain network applications by specific end users common throughout much of the department. An example of this might be the creation of a Documentation workgroup in a corporation within which each department had a dedicated Documentation person handling recording and reporting.
Network Design Priority Organization Priority organization is a flexible term that refers to the Network Manager assigning devices to workgroups based on specific priorities. As such, it is the most flexible scheme for creating workgroups, because it is based solely on the relative importance of certain network characteristics to individual end users and equipment.
Network Design Priority organization of this manner in a single-segment network involves providing stations in the priority workgroups with qualities of media and network connection based on that priority. For example, the stations in the server farm might have redundant connections to the network in the event that one cable failed, use a media resistant to interference, such as fiber optic cabling, or might be best served by a centralized location.
Network Design Selecting Workgroup Technologies The selection of a network technology at the workgroup level is a very important decision, and one that should be made only after careful consideration and evaluation. Before deciding on a network technology to be used by the workgroups, make sure you are familiar with the operation of each type of technology, the strengths and shortcomings of those technologies, and the special design considerations that each technology imposes on the network.
Network Design Creating a Manageable Plan A well thought-out and carefully designed network is still difficult to troubleshoot if no one else knows how it is organized. There may come a time when the designer of the network is not available, for whatever reason, and troubleshooting or re-configuration needs to be done. It may also become necessary to expand the network to accommodate a growing use of workstations or increases in personnel.
Network Design • Centralization and Control - If you require more control over the networking hardware than you can get from locking it away, you can place many devices in one central location such as a Network Management office. For a small facility, it is entirely possible that all the networking hardware except end user workstations will be located in an office such as this.
Network Design Use a standard, decipherable labeling code for cable and hardware. A label reading L2N5W2C1S243 may look like gibberish now, but if you know that the letter codes indicate locations or conditions of installation, it can be quite helpful. Table 5-1, below, shows the meanings of the codes and numbers of this example. Cable Label: L2N5W2C1S243 Table 5-1.
Network Design Single Points of Failure A single point of failure is any one device, cable or connection that, if it should fail or be removed from the network, would disable all or a sizable part of the network. Most Cabletron Systems hardware seeks to eliminate single points of failure from within the device, by providing for redundant links or the distribution of essential functions among several related devices.
Network Design Isolation and Recovery No matter how much redundancy is designed into a network, and no matter how much the single points of failure are eliminated, the law of averages eventually catches up to any network, and a failure will occur. Once the failure does occur, the isolation and recovery process begins. If a network is designed to eliminate confusing layouts and make the troubleshooting procedure efficient and effective, the amount of time a network is down is reduced.
Network Design Tracking Changes Your network maps will be used for keeping track of a large amount of information, which will naturally change over time. As the network grows or is altered, the devices that make up the network will change, new workgroups will be added, segmented off from larger workgroups or combined with smaller ones. It is, therefore, important to keep track of the changes made to the network, and the network map is a good place to do this.
Network Design The Workgroup as the Network In many cases, the only network that a facility requires is a single workgroup. Depending on the bandwidth, segmentation, and security requirements of any facility, the single workgroup may be all that is needed. In these situations, the only network to be considered is the workgroup. When the only networking concern is the workgroup, issues such as internetworking and inter-workgroup communications are not a part of the initial design strategy.
Network Design What Is a Backbone? A backbone is a network segment or cable which is used to provide for the interconnection of a number of smaller workgroups or self-contained networks. The outlying networks, workgroups, or hubs communicate with one another through the backbone network. The use of a dedicated network acting as a backbone, tying all the separate networks together, is of benefit for several reasons.
Network Design The Distributed Backbone One method of creating a backbone network is to sequentially string all of the workgroup networks or hubs together. Cabling is run from one workgroup hub to the next, providing the necessary connections. This method of configuring a backbone network, as shown in Figure 5-5, may be used with any technology except ATM, which requires a device backbone configuration (detailed later in this chapter). hub hub hub hub 2094n10 Figure 5-5.
Network Design The Collapsed Backbone It is also possible to run cables from a central point, often a network management office or central wiring closet, out to each workgroup network and back. These cabling runs are then terminated at a central point such as a patch panel. The patch panel ports for each of the cable runs can then be connected to one another using jumper cables. As long as technology restrictions are not exceeded, chains and rings of workgroup networks can be created.
Network Design • Simplified Troubleshooting - Workgroups can be bypassed by simply reconfiguring a single patch panel. This can easily isolate a problem segment for troubleshooting, and keeps the backbone network from being kept in a fault condition. • Moderate Control - The isolation of workgroups and the reorganization of the backbone network is simplified with the collapsed backbone, but the system does not incorporate any management features beyond the physical connections of facility cabling.
Network Design • Simplified Troubleshooting - The device collapsed backbone, by connecting the workgroups through a manageable device, provides not only simplified troubleshooting, but the ability to detect some backbone faults before they become network failures. • Extensive Control - The device collapsed backbone provides the highest level of network control. Workgroups and devices on the backbone can be included or bypassed with the click of a mouse or through the use of a terminal session.
Network Design 5-22 The Workgroup in the Larger Network
Chapter 6 Ethernet This chapter describes in detail the processes and decisions involved in designing an Ethernet workgroup using Cabletron Systems products. Once the proposed network has been broken into a number of workgroups, it is necessary to begin designing the actual solutions for those workgroups and selecting hardware for use in them. The information that follows details the procedures used to determine the Cabletron Systems networking hardware necessary for specific types of workgroup networks.
Ethernet Ethernet Workgroup Devices The following sections describe the various Cabletron Systems networking devices that may be used in an Ethernet workgroup implementation. These Ethernet devices are divided into two categories - shared Ethernet devices and switched Ethernet devices. Shared Ethernet devices are those which connect all stations and links to a single Ethernet collision domain.
Ethernet Type The type column describes what functions the device in question performs. There are three basic types of devices covered by this table. Repeaters are standalone Ethernet multiport repeaters. They count as a single repeater hop for purposes of calculating maximum network size or propagation delay. Stackables are Ethernet repeaters that may stand alone or be connected to other stackable devices of the same type to form a single Ethernet stack, which acts as one repeater domain.
Ethernet Switched Devices Ethernet segmentation and switching designs require some slightly different information and decisions. Several of the important factors to consider when selecting a segmentation-based workgroup scheme are listed along with the Cabletron Systems Ethernet switch products in Table 6-2, below. Table 6-2.
Ethernet Ethernet Workgroup Design When designing a new workgroup, one of the first tasks to be confronted is the selection of a technology and an approach to the network. These selections are based on the organization of the workgroups, as discussed in Chapter 5, Network Design, the scale (or population) of the workgroups, and the anticipated bandwidth requirements of each workgroup or each station in the workgroup.
Ethernet Abstracting the Design Process There are a series of logical stages that must be kept in mind when designing a network for any location, including the relatively simple home office. The first parts of the design process involve the decisions relating to the technology and media to be used in the workgroup. The complex nature of these questions can be intimidating to a new Network Designer, but the importance of good planning in these initial stages cannot be underestimated.
Ethernet Some Cabletron networking devices, through their support of PIMs and BRIMs, will support a small number of connections using different media. For example, an Ethernet network which is made up primarily of 10BASE-T links has a single multimode fiber optic connection to a distant building. If a standalone or stackable device which supports EPIMs is selected for the network in the main location, an EPIM-F2 can be added to the device, eliminating the need for an expensive external transceiver.
Ethernet In an effort to provide some measure of differentiation between the varying levels of expense, the design tables which list a series of possible selections in a particular category attempt to organize the networking devices presented in ascending order of expense. In many cases, the difference between the list prices of some networking devices is quite small, so this arrangement of products should be considered an estimation aid only.
Ethernet The table below shows the selection field of Cabletron Systems shared Ethernet workgroup devices. This is the same table that was displayed at the beginning of this chapter. During the course of the design example, sections of the table shown will be removed to indicate the gradual reduction of choices as the needs of the network are compared to the capabilities of the devices.
Ethernet Type Max Management Media Port Count PIMs/BRIMs MR9T-E repeater NONE UTP 8 1 EPIM SEH-22/32 stackable NONE UTP 12 1 EPIM SEH-24/34 stackable NONE UTP 24 2 EPIMs SEH-22FL stackable NONE Multimode Fiber Optics 12 1 EPIM Product The media selected for the network is inexpensive Category 3 UTP jumper cabling. The low cost, durability, and ready availability of UTP makes it by far the preferred media for this installation.
Ethernet The Network Designer checks the Cabletron Systems Networking Solutions Product Guide to examine the characteristics and full description of the MR9T. Deciding that the product will fit well into the installation, the Network Designer makes a call to the Cabletron Systems Sales Department and works out the details with a Sales Representative. MR9T 2094n14 Figure 6-2.
Ethernet The small office location is an ideal place to examine the suitability of stackable networking devices. As these locations fall into a space between tiny workgroups and full-scale facility networks, they are the target location for stackables. The sections below describe the important criteria that need to be examined when selecting a networking solution for a small office location. In many cases, these criteria are exactly the same as those treated in the home office section discussed previously.
Ethernet Expandability The simplicity and fluidity of expansion in a small office setting is of paramount importance. Every small office wants to expand, even if it is an addition of nothing more than a few additional networked computers. The ability to quickly and efficiently increase the number of available ports in the small office network must factor into any selection of devices for installation.
Ethernet Design Example The following example follows a Network Designer’s selection process for a small office Ethernet network. As in the previous example, the Network Designer has already decided upon a networking technology (Ethernet) and a media type (10BASE-T) for the network. The location being considered is a combined warehouse and business office for a wholesale pottery distributor. The 27 users in the facility will be connected to one another through a single-segment Ethernet network.
Ethernet Table 6-3. Shared Ethernet Workgroup Devices Type Max Management Media Port Count PIMs/BRIMs SEHI-22/32 stack base SNMP UTP 12 1 EPIM SEHI-24/34 stack base SNMP UTP 24 2 EPIMs SEHI-22FL stack base SNMP Multimode Fiber Optics 12 1 EPIM MicroMMAC-22/32E stack base RMON UTP 12 1 EPIM 1 BRIM MicroMMAC-24/34E stack base RMON UTP 24 2 EPIMs 1 BRIM Product As the network will be using UTP cabling, the SEHI-22FL can be removed from the selection field.
Ethernet through an interconnect cable and have a stack providing 36 ports. This entire stack will act as a single repeater, and the management functions that are included in the SEHI-24 will be applied also to the SEH-22 in the stack.
Ethernet FDDI Backbone 2094n17 Figure 6-5. FDDI Backbone Internetworking The main difference between the small office and the remote office is that a provision must be made to accommodate a connection to a different networking technology. In the case of Cabletron Systems workgroup products, this process has been simplified by the inclusion of BRIM capabilities into the MicroMMAC stackable bases and the ESX and NBR Ethernet switches.
Ethernet Design Example For an example of remote office workgroup configuration, we will build upon the previous small office example. Let us assume that there has been no growth of the small office network, but the pottery distributor has been purchased by a larger, nationwide chain of distributors. The facility itself will not be changing appreciably, but the facility will need a Wide Area Network connection to the regional headquarters in a neighboring state.
Ethernet Office Stations (21) To Main Office SEH-24 MicroMMAC-24 with BRIM-W6 Servers (3) Business Office WAN (56K) 2094n18 Figure 6-6. Ethernet Remote Office Implementation The High-End Department The high-end department is a workgroup with specialized needs, demanding high reliability or high throughput to each and every station. The high-end department typically consists of the most demanding users on the network, and connections between them must be fast, reliable, and predictable.
Ethernet Management In a network using any form of segmentation, whether it is bridging, switching, or routing, management functionality is a part of the devices needed to create the network. Without some form of management, segmentation decisions can not be made by the devices. The level of management available in any segmentation situation is the differentiation between products.
Ethernet Design Example As an example, we can examine a network design that is being planned for a group of Computer-Aided Design (CAD) engineers in a large architectural firm. These CAD designers want to replace their existing shared Ethernet LAN with a network that provides greater throughput between their end stations.
Ethernet The Network Designer is looking for one or more per-port Ethernet switches that can be used to make network connections to the stations in the CAD department. The Network Designer examines the selection field of Ethernet switches, shown in Table 6-2. All of these devices meet the initial criteria; they are manageable Ethernet switches with similar expansion capabilities.
Ethernet The Network Designer selects the ESX-1320 and calculates that two ESX-1320 switches, each containing one BRIM module for an FDDI connection, will meet the needs of the CAD department. The Network Designer would then go on to select the correct BRIMs and any necessary PIMs for these switches. Referring to the BRIM chart, the Network Designer finds that the BRIM-F6 is the BRIM that is needed. This FDDI BRIM requires two FDDI Port Interface Modules, or FPIMs.
Ethernet Permutations It is also possible to use an Ethernet switch to connect a series of individual workgroups, rather than workstations or other devices. In these situations, the Ethernet switch acts as a device collapsed backbone for the network. The design process is exactly the same as that used to connect multiple workstations over an Ethernet switch, but the connections are made to workgroups rather than individual stations.
Chapter 7 Fast Ethernet This chapter examines the decisions and selections that must be made when designing a Fast Ethernet workgroup solution. Should a Fast Ethernet workgroup solution be selected, the Network Designer has a specific series of issues to resolve and decisions to make before selecting a Fast Ethernet device that meets the requirements of the network. This chapter identifies and discusses these issues and provides a series of examples for different Fast Ethernet network approaches.
Fast Ethernet Table 7-1. Shared Fast Ethernet Workgroup Devices Type Max Management Media Port Count PIMs/BRIMs SEH100TX-22 stackable NONEa UTP 22 1 EPIM SEHI100TX-22 stack base SNMP UTP 22 2 EPIMs Product a. These products can be managed through the addition of an intelligent stackable device to their stack. The columns in the table provide the same information that Table 6-1 provides regarding Ethernet devices.
Fast Ethernet Fast Ethernet Workgroup Design The network design process for Fast Ethernet workgroups is nearly identical to that used for standard Ethernet workgroups. The Network Designer must first break the network up into workgroups, if desired, determine how the stations in each workgroup will relate to one another, and then begin the process of selecting hardware. The types of hardware considered will be dependent upon the type of network installation that the workgroup is being designed for.
Fast Ethernet Port Count The first device in the stack, whether an intelligent SEHI100TX-22 or non-intelligent SEH100TX-22, will provide connections for up to 22 Fast Ethernet stations. For every additional 22 Fast Ethernet stations or fraction thereof, the Network Designer must add one SEH100TX-22 to the stack. The maximum number of ports that can be supported in this fashion is 110.
Fast Ethernet The current network consists of 43 stations, including the shared servers and order entry system. The department currently operates on two standalone 24-port Ethernet repeaters that are connected to one another with a single jumper cable. All stations in the network are connected to these standalone repeaters with Category 5 UTP cable. All of the distances and network radii have been calculated to be within the acceptable limits for a Fast Ethernet network using a Class I repeater.
Fast Ethernet This expansion can continue until the stack contains five devices, the maximum number allowable with the stackable hub design. At this limitation, the stack will be capable of supporting up to 110 Fast Ethernet users. The network, as designed, will look like the depiction shown in Figure 7-2. Order Entry Servers (2) (future) TX SEH100TX-22 TX Stations (40) SEHI100TX-22 2094n22 Figure 7-2.
Fast Ethernet Abstracting the Design Process As the Fast Ethernet switch selection field, shown in Table 7-2, contains only one device, the amount of decision-making remaining in the design process after the decision to use the Fast Ethernet technology is minimal. Due to the fact that the FN100-TX series is available with either eight or 16 switch interfaces and front panel ports that use either UTP or multimode fiber optic media, there are a few design issues left where decisions have to be made.
Fast Ethernet The Network Designer begins the design process by examining the available Fast Ethernet switch products. As the only devices available offering per-port Fast Ethernet switching are the four types of FN100 standalone switch, the selection field is very narrow, consisting of the products shown in the table below.
Fast Ethernet Stations (14) Facility Hub FN100-16TX 2094n23 Figure 7-3. Fast Ethernet High-End Department Solution Fast Ethernet as a Backbone Due to the high throughput provided by Fast Ethernet, it is conceivable that the technology could be used as a backbone solution to interconnect a series of workgroups. The Fast Ethernet switch will act as a device collapsed backbone for the network.
Fast Ethernet StockPhoto Archive1 Archive2 2094n24 Figure 7-4. Initial Network Design Each departmental stack consists of one MicroMMAC-24E and one or more SEH-24 stackable hubs. In the initial configuration, the MicroMMAC-24Es have been configured with EPIM-A modules, which provide AUI ports for connection to a standard Ethernet AUI cable. These AUI cables are then connected to thick coaxial cable transceivers that are connected to the coaxial cable backbone.
Fast Ethernet The Network Designer examines the four types of FN100 Fast Ethernet switch, looking to see which models support front panel multimode fiber optic connections. The FN100-8FX and FN100-16FX both provide multimode fiber optic connections for 100BASE-FX network media, and thus both meet the requirements of this site. The Network Designer then examines the port count supported by each device, and finds that both devices will fill the required network link count of six.
Fast Ethernet Once the backbone switch has been selected, changes need to be made to the workgroups that will connect to the switch itself. As they stand, the current workgroups cannot connect to the Fast Ethernet backbone network. In order to support Fast Ethernet connections to the FN100-16FX, the MicroMMACs will require a BRIM. The Network Designer examines the available BRIMs that can be placed in the MicroMMAC-24Es.
Chapter 8 Token Ring This chapter examines the decisions and selections that must be made when designing a Token Ring workgroup solution. The process of designing a Token Ring workgroup or a series of interconnected workgroups is somewhat different from the processes involved in designing an Ethernet or Fast Ethernet workgroup.
Token Ring The available devices and the main distinctions between them are summarized in Table 8-1. Table 8-1.
Token Ring Token Ring Workgroup Design Once a Network Designer understands the fundamentals of Token Ring design, as described in the Cabletron Systems Networking Guide - MMAC-FNB Solutions, the design of a Token Ring workgroup using standalone and stackable products is quite simple.
Token Ring Media It is assumed by this document that the selection of a networking media for the facility has already been completed before the hardware is examined. The media decision in the hardware selection stage of network design is one of ensuring that the selected device or devices will support the cabling media that is either planned or in place. In some cases, a small number of station connections will have to be made using a less common media such as fiber optic cable.
Token Ring This extension of the ring can be used to allow the Token Ring network to connect widely-separated groups of stations in a single ring, or can be used to support greater numbers of users than a single Token Ring stack can accommodate. A Token Ring stack of maximum size will provide for the connection of 120 stations, well below the 250 station maximum of the IEEE 802.5 standard for some cabling types.
Token Ring Type Max Management Media Port Count PIMs/BRIMs STHI-22/24 stack base SNMP UTP 12/24 2 TPIMs STHI-42/44 stack base SNMP STP 12/24 2 TPIMs Product When examining the Media characteristics of the devices remaining in the selection field, the Network Designer immediately eliminates the STHI-42/44 from consideration. The network being designed will use UTP cabling, which is not directly supported by the STHI-42/44.
Token Ring Looking back at the initial selection field, the Network Designer locates the non-intelligent stackable devices and examines them for compliance with the needs of the network. The STH-22/24 non-intelligent stackable hub supports UTP cabling, and provides either 12 or 24 ports of station connectivity. The addition of an STH-24 to the STHI-24 already in the design would supply 48 ports of Token Ring station connectivity and four RI/RO ports for future links if required.
Token Ring 8-8 Token Ring Workgroup Design
Appendix A Charts and Tables This appendix provides a central location for a series of tables that contain useful network design information. Workgroup Design Tables Ethernet Table A-1.
Charts and Tables Table A-2. Ethernet Workgroup Switches Max Management Media Port Count Switch Interfaces PIMs/BRIMs NBR-220 SNMP – 0 2 2 EPIMs NBR-420 SNMP – 0 4 4 EPIMs NBR-620 SNMP – 0 6 4 EPIMs 2 BRIMs FN10 SNMP UTP 12/24 12/24 0 ESX-1320 RMON UTP 12 13 1 BRIM ESX-1380 RMON Multimode Fiber Optics 12 13 1 BRIM Name Fast Ethernet Table A-3.
Charts and Tables Table A-4. Fast Ethernet Workgroup Switches Max Management Media Port Count Switch Interfaces PIMs/BRIMs FN100-8TX SNMP UTP 8 8 0 FN100-16TX SNMP UTP 16 16 0 FN100-8FX SNMP Multimode Fiber Optics 8 8 0 FN100-16FX SNMP Multimode Fiber Optics 16 16 0 Name Token Ring Table A-5.
Charts and Tables PIMs and BRIMs Table A-6.
Charts and Tables Table A-6.
Charts and Tables Table A-7. BRIM Reference Table Technology Connector Type Ethernet EPIM Fast Ethernet EPIM BRIM-F6 FDDI FPIM (2) BRIM-A6 ATM APIM BRIM-A6DP ATM APIM (2) BRIM-W6 WAN WPIM BRIM BRIM-E6 BRIM-E100 Table A-8.
Charts and Tables Networking Standards and Limitations Ethernet Distance Limitations Table A-9. Ethernet Standard Distance Limitations Media Max Distance Thick Coax 500 m Thin Coax 185 m Standard AUI 50 m Office AUI 16.5 m UTP 100 m Fiber Optics (Multimode) 1000 m Fiber Optics (Single Mode) 1000 m General Rules Table A-10.
Charts and Tables Fast Ethernet Distance Limitations Table A-11. Fast Ethernet (100BASE-TX/FX) Distance Limitations Media Max Distance UTP 100 m Fiber Optics (Multimode) 412 m Network Radii Table A-12.
Charts and Tables Token Ring Distance Limitations Table A-13.
Charts and Tables Ring-In/Ring-Out Limitations Table A-14. Ring-In/Ring-Out Distances Max Distance (4 Mbps) Max Distance (16 Mbps) 770 m 346 m Category 3/4 200 m 100 m Category 5 250 m 120 m Fiber Optics (Multimode) 2000 m 2000 m Fiber Optics (Single Mode) 2000 m 2000 m Media Shielded Twisted Pair Unshielded Twisted Pair General Rules Table A-15.
Charts and Tables FDDI FDDI Distance Limitations Table A-16. FDDI Distance Limitations Media PMD Standard Max Link Distance Fiber Optics (Multimode) MMF-PMD 2 km Fiber Optics (Single Mode) SMF-PMD 60 km Unshielded Twisted Paira TP-PMD 100 m Shielded Twisted Pairb 100 m a. Category 5 UTP cabling only b. IBM Type 1 STP cabling only General Rules Table A-17.
Charts and Tables A-12 Networking Standards and Limitations
Glossary This glossary provides brief descriptions of some of the recurrent terms in the main text, as well as related terms used in discussions of the relevant networking discussions. These descriptions are not intended to be comprehensive discussions of the subject matter. For further clarification of these terms, you may wish to refer to the treatments of these terms in the main text.
Attenuation to Client-Server Attenuation Loss of signal power (measured in decibels) due to transmission through a cable. Attenuation is dependent on the type, manufacture and installation quality of cabling, and is expressed in units of loss per length, most often dB/m. AUI Attachment Unit Interface. A cabling type used in Ethernet networks, designed to connect network stations and devices to transceivers.
Coaxial to Decryption Coaxial An Ethernet media type which consists of a core of electrically conductive material surrounded by several layers of insulation and shielding. Concentrator A network device which allows multiple network ports in one location to share one physical interface to the network. Congestion An estimation or measure of the utilization of a network, typically expressed as a percentage of theoretical maximum utilization of the network.
Dedicated to Fault-Tolerance Dedicated Assigned to one purpose or function. Device (network) Any discrete electronic item connected to a network which either transmits and receives information through it, facilitates that transmission and reception, or monitors the operation of the network directly. DLM Distributed LAN Monitor.
FDDI to Impedance FDDI Fiber Distributed Data Interface. A high-speed networking technology. FDDI requires that stations only transmit data when they have been given permission by the operation of the network, and dictates that stations will receive information at pre-determined intervals. See also Token. Fiber Optics Network media made of thin filaments of glass surrounded by a plastic cladding. Fiber optics transmit and receive information in the form of pulses of light. See multimode and single mode.
Interface to MAC Address Interface A connection to a network. Unlike a port, an interface is not necessarily an available physical connector accessible through the front panel of a device. Interfaces may be used as backplane connections, or may be found only in the internal operation of a module (All ports are interfaces, but not all interfaces are ports). Internet A world-wide network which provides access through a vast chain of private and public LANs.
MAU to Network Radius MAU Multistation Access Unit. Mbps Megabits Per Second. Mbps indicates the number of groups of 1000 bits of data that are being transmitted through an operating network. Mbps can be roughly assessed as a measure of the operational “speed” of the network. Media Physical cabling or other method of interconnection through which network signals are transmitted and received. MIC Connector 1: Token Ring genderless connector.
Node to Protocol Node Any single end station on a network capable of receiving, processing, and transmitting packets. NVRAM Non-Volatile Random Access Memory. Memory which is protected from elimination during shutdown and between periods of activity, frequently through the use of batteries. Octet A numerical value made up of eight binary places (bits). Octets can represent decimal numbers from zero (0000 0000) to 255 (1111 1111). OSI Model Open Standards Interconnect.
PVC to Server PVC Polyvinyl Chloride. A material commonly used in the fabrication of cable insulation. This term is used to describe a non-plenum rated insulating material. See also Plenum. PVC releases toxic smoke when burned. Redundant Extra or contingent. A redundant system is one that is held in reserve until an occurrence such as a failure of the primary system causes it to be required. Relay An electrical switch which opens and closes in response to the application of voltage or current.
SIMM to Switch SIMM Single In-line Memory Module. A collection of Random Access Memory (RAM) microprocessors which are placed on a single, replaceable printed circuit board. These SIMMs may be added to some devices to expand the capacity of certain types of memory. Single Attached Connected to an FDDI network through a single cable which does not provide for auto-wrap functions. Single Mode A type of fiber optics in which light travels in one predefined mode, or wavelength.
TCP to UTP TCP Transmission Control Protocol. Terminal A device for displaying information and relaying communications. Terminals do not perform any processing of data, but instead access processing-capable systems and allow users to control that system. Throughput The rate at which discrete quantities of information (typically measured in Mbps) are received by or transmitted through a specific device.
UTP to UTP Glossary-12
Index Numerics E 100BASE-FX 2-3 100BASE-TX 2-3 EPIM 4-3 Ethernet 2-2, 6-1 cable lengths 2-2 high-end department 6-19 home office 6-5 remote office 6-16 shared devices 6-2 signal path 2-3 small office 6-11 station count 2-3 switched devices 6-4 Expansion (of networks) 5-15 A Active circuitry 2-6 APIM 4-5 Assistance 1-3 B Backbones collapsed 5-19 definition 5-17 device 5-20 distributed 5-18 Fast Ethernet 7-9 selection 5-21 Bandwidth 2-2 Bridge 3-2 BRIM 3-7, 4-8, 4-8 to 4-10 C Chapter summaries 1-2 Coll
Index H S Help 1-3 High-end department 6-19, 7-6 Home office 6-5 HubSTACK Interconnect Cables 3-5 Segmentation 5-2 Small office 6-11, 7-3, 8-3 Stackable 3-4 interconnect cable 3-5 internetworking 3-7 management 3-6 Standalone 3-1 management 3-3 I Installation planning 5-11 Interconnect cables 3-5 internetworking 4-8 Introduction 1-1 N Network growth 5-15 layout 5-10 planning 5-10 Network map 5-14 Network radius 2-4 Networking Services 1-3 P PIM 4-1 ATM 4-5 decoding 4-2 Ethernet 4-3 Fast Ethernet 4-3
