To develop a 16-station Ethernet LAN system (100 Mbps system) which should include a file server, printer and a gateway/bridge to connect to similar other networks. Use real components and systems from industry leaders such as Cisco, IBM, Nortel, 3Com and other companies (go to their respective web sites and obtain information). Also show how your LAN can be interfaces to another similar LAN through appropriate network connection (internet or any other network) using real routers.

Describe in sufficient detail, the function of the components and systems you are using and provide the cost information. Also show how the LAN can be upgraded to 1 Gigabit systems.

2. Ethernet LAN Technologies

2.1. Background

The term Ethernet refers to the family of local area network (LAN) implementations that includes three principal categories.

· Ethernet and IEEE 802.3: - LAN specifications that operate at 10 Mbps over coaxial cable.

· 100-Mbps Ethernet: - A single LAN specification, also known as Fast Ethernet, that operates at 100 Mbps over twisted-pair cable.

· 1000-Mbps Ethernet: - A single LAN specification, also known as Gigabit Ethernet, that operates at 1000 Mbps (1 Gbps) over fiber and twisted-pair cables.

This chapter provides a high-level overview of each technology variant.

Network managers have always turned to Ethernet and its derivatives as effective solutions for a range of campus implementation requirements. Even though Ethernet networks are difficult to scale one cannot overlook the fact that its underlying transmission scheme continues to be one of the principal means of transporting data for contemporary campus applications.

2.2. Ethernet and IEEE 802.3

Ethernet is a baseband LAN specification invented by Xerox Corporation that operated at 10 Mbps using carrier sense multiple access collision detect (CSMA/CD) to run over coaxial cable. Ethernet was designed to serve in networks with sporadic, occasionally heavy traffic requirements, and the IEEE 802.3 specification was developed in 1980 based on the original Ethernet technology.

An Ethernet network runs CSMA/CD over coaxial cable. [1]

Digital Equipment Corporation, Intel Corporation, and Xerox Corporation jointly developed Ethernet Version 2.0, which is compatible with IEEE 802.3. Ethernet and IEEE 802.3 are usually implemented in either an interface card or in circuitry on a primary circuit board. Ethernet cabling conventions specify the use of a transceiver to attach a cable to the physical network medium. The transceiver performs many of the physical-layer functions, including collision detection. The transceiver cable connects end stations to a transceiver.

IEEE 802.3 provides for a variety of cabling options, one of which is a specification referred to as 10Base5. This specification is the closest to Ethernet. The connecting cable is referred to as an attachment unit interface (AUI), and the network attachment device is called a media attachment unit (MAU), instead of a transceiver.

2.2.1. Ethernet and IEEE 802.3 Operation

In Ethernet's broadcast-based environment, all stations see all frames placed on the network. Following any transmission, each station must examine every frame to determine whether that station is a destination. Frames identified as intended for a given station are passed to a higher-layer protocol.

Under the Ethernet CSMA/CD media-access process, any station on a CSMA/CD LAN can access the network at any time. Before sending data, CSMA/CD stations listen for traffic on the network. A station wanting to send data waits until it detects no traffic before it transmits.

As a contention-based environment, Ethernet allows any station on the network to transmit whenever the network is quiet. A collision occurs when two stations listen for traffic, hear none, and then transmit simultaneously. In this situation, both transmissions are damaged, and the stations must retransmit at some later time. Back-off algorithms determine when the colliding stations should retransmit.

2.2.2. Ethernet and IEEE 802.3 Service Differences

Although Ethernet and IEEE 802.3 are quite similar in many respects, certain service differences distinguish the two specifications. Ethernet provides services corresponding to Layers 1 and 2 of the OSI reference model, and IEEE 802.3 specifies the physical layer (Layer 1) and the channel-access portion of the link layer (Layer 2). In addition, IEEE 802.3 does not define a logical link-control protocol but does specify several different physical layers, whereas Ethernet defines only one.

Each IEEE 802.3 physical-layer protocol has a three-part name that summarizes its characteristics. The components specified in the naming convention correspond to LAN speed, signaling method, and physical media type.

IEEE 802.3 components are named according to conventions.

The table given below summarizes the differences between Ethernet and IEEE 802.3, as well as the differences between the various IEEE 802.3 physical-layer specifications.

Comparison of Various IEEE 802.3 Physical-Layer Specifications

Characteristic	Ethernet Value	IEEE 802.3 Values
Characteristic	Ethernet Value	10Base5	10Base2	10BaseT	10BaseFL	100BaseT
Data rate (Mbps)	10	10	10	10	10	100
Signaling method	Baseband	Baseband	Baseband	Baseband	Baseband	Baseband
Maximum segment length (m)	500	500	185	100	2,000	100
Media	50-ohm coax (thick)	50-ohm coax (thick)	50-ohm coax (thin)	Unshielded twisted-pair cable	Fiber-optic	Unshielded twisted-pair cable
Topology	Bus	Bus	Bus	Star	Point-to-point	Bus

2.2.3. Ethernet and IEEE 802.3 Frame Formats

The given figures illustrate the frame fields associated with both Ethernet and IEEE 802.3 frames.

Various frame fields exist for both Ethernet and IEEE 802.3.

The Ethernet and IEEE 802.3 frame fields illustrated in the above figure are as follows.

· Preamble: -The alternating pattern of ones and zeros tells receiving stations that a frame is coming (Ethernet or IEEE 802.3). The Ethernet frame includes an additional byte that is the equivalent of the Start-of-Frame field specified in the IEEE 802.3 frame.

· Start-of-Frame (SOF): -The IEEE 802.3 delimiter byte ends with two consecutive 1 bits, which serve to synchronize the frame-reception portions of all stations on the LAN. SOF is explicitly specified in Ethernet.

· Destination and Source Addresses: -The first 3 bytes of the addresses are specified by the IEEE on a vendor-dependent basis. The last 3 bytes are specified by the Ethernet or IEEE 802.3 vendor. The source address is always a unicast (single-node) address. The destination address can be unicast, multicast (group), or broadcast (all nodes).

· Type (Ethernet): -The type specifies the upper-layer protocol to receive the data after Ethernet processing is completed.

· Length (IEEE 802.3): -The length indicates the number of bytes of data that follows this field.

· Data (Ethernet): -After physical-layer and link-layer processing is complete, the data contained in the frame is sent to an upper-layer protocol, which is identified in the Type field. Although Ethernet Version 2 does not specify any padding (in contrast to IEEE 802.3), Ethernet expects at least 46 bytes of data.

· Data (IEEE 802.3): -After physical-layer and link-layer processing is complete, the data is sent to an upper-layer protocol, which must be defined within the data portion of the frame, if at all. If data in the frame is insufficient to fill the frame to its minimum 64-byte size, padding bytes are inserted to ensure at least a 64-byte frame.

· Frame Check Sequence (FCS): -This sequence contains a 4-byte cyclic redundancy check (CRC) value, which is created by the sending device and is recalculated by the receiving device to check for damaged frames.

2.3. 100-Mbps Ethernet

100-Mbps Ethernet is a high-speed LAN technology that offers increased bandwidth to desktop users in the wiring center, as well as to servers and server clusters. The IEEE Higher Speed Ethernet Study Group was formed to assess the feasibility of running Ethernet at speeds of 100 Mbps.

The study group divided into two camps over this access-method disagreement: the Fast Ethernet Alliance and the 100VG-AnyLAN Forum. Each group produced a specification for running Ethernet (and Token Ring for the latter specification) at higher speeds: 100BaseT and 100VG-AnyLAN, respectively.

100BaseT is the IEEE specification for the 100-Mbps Ethernet implementation over unshielded twisted-pair (UTP) and shielded twisted-pair (STP) cabling. The Media Access Control (MAC) layer is compatible with the IEEE 802.3 MAC layer. Grand Junction, now a part of Cisco Systems Workgroup Business Unit (WBU), developed Fast Ethernet, which was standardized by the IEEE in the 802.3u specification.

100VG-AnyLAN is an IEEE specification for 100-Mbps Token Ring and Ethernet implementations over 4-pair UTP. The MAC layer is not compatible with the IEEE 802.3 MAC layer. 100VG-AnyLAN was developed by Hewlett-Packard (HP) to support newer time-sensitive applications, such as multimedia. A version of HP's implementation is standardized in the IEEE 802.12 specification [1].

2.3.1. 100BaseT Overview

100BaseT uses the existing IEEE 802.3 CSMA/CD specification. As a result, 100BaseT retains the IEEE 802.3 frame format, size, and error-detection mechanism. In addition, it supports all applications and networking software currently running on 802.3 networks. 100BaseT supports dual speeds of 10 and 100 Mbps using 100BaseT fast link pulses (FLPs). 100BaseT hubs must detect dual speeds much like Token Ring 4/16 hubs, but adapter cards can support 10 Mbps, 100 Mbps, or both.

802.3 MAC and higher-layer protocols operate over 100BaseT.

2.3.2. 100BaseT Signaling

100BaseT supports two signaling types:

· 100BaseX

· 4T+

Both signaling types are interoperable at the station and hub levels. The media-independent interface (MII), an AUI-like interface, provides interoperability at the station level. The hub provides interoperability at the hub level.

The 100BaseX-signaling scheme has a convergence sub layer that adapts the full-duplex continuous signaling mechanism of the FDDI physical medium dependent (PMD) layer to the half-duplex, start-stop signaling of the Ethernet MAC sublayer. 100BaseTX's use of the existing FDDI specification has allowed quick delivery of products to market. 100BaseX is the signaling scheme used in the 100BaseTX and the 100BaseFX media types.

The 100BaseX convergence sublayer interfaces two signaling schemes.

The 4T+-signaling scheme uses one pair of wires for collision detection and the other three pairs to transmit data. It allows 100BaseT to run over existing Category 3 cabling if all four pairs are installed to the desktop. 4T+ is the signaling scheme used in the 100BaseT4 media type, and it supports half-duplex operation only [1].

4T+ requires four UTP pairs.

2.3.3. 100BaseT Hardware

Components used for a 100BaseT physical connection include the following:

Physical Medium: -This device carries signals between computers and can be one of three 100BaseT media types:

· 100BaseTX

· 100BaseFX

· 100BaseT4

Medium-Dependent Interface (MDI): -The MDI is a mechanical and electrical interface between the transmission medium and the physical-layer device.

Physical-Layer Device (PHY): -The PHY provides either 10-or 100-Mbps operation and can be a set of integrated circuits (or a daughter board) on an Ethernet port, or an external device supplied with an MII cable that plugs into an MII port on a 100BaseT device (similar to a 10-Mbps Ethernet transceiver).

Media-Independent Interface (MII): -The MII is used with a 100-Mbps external transceiver to connect a 100-Mbps Ethernet device to any of the three media types. The MII has a 40-pin plug and cable that stretches up to 0.5 meters.

100BaseT requires several hardware components.

2.3.4. 100BaseT Operation

100BaseT and 10BaseT use the same IEEE 802.3 MAC access and collision detection methods, and they also have the same frame format and length requirements. The main difference between 100BaseT and 10BaseT (other than the obvious speed differential) is the network diameter. The 100BaseT maximum network diameter is 205 meters, which is approximately 10 times less than 10-Mbps Ethernet.

Reducing the 100BaseT network diameter is necessary because 100BaseT uses the same collision-detection mechanism as 10BaseT. With 10BaseT, distance limitations are defined so that a station knows while transmitting the smallest legal frame size (64 bytes) that a collision has taken place with another sending station that is located at the farthest point of the domain.

To achieve the increased throughput of 100BaseT, the size of the collision domain had to shrink. This is because the propagation speed of the medium has not changed, so a station transmitting 10 times faster must have a maximum distance that is 10 times less. As a result, any station knows within the first 64 bytes whether a collision has occurred with any other station.

2.3.5. 100BaseT FLPs

100BaseT uses pulses, called FLPs, to check the link integrity between the hub and the 100BaseT device. FLPs are backward-compatible with 10BaseT normal-link pulses (NLPs). But FLPs contain more information than NLPs and are used in the autonegotiation process between a hub and a device on a 100BaseT network.

2.3.6. 100BaseT Autonegotiation Option

100BaseT networks support an optional feature, called autonegotiation, that enables a device and a hub to exchange information (using 100BaseT FLPs) about their capabilities, thereby creating an optimal communications environment.

Autonegotiaton supports a number of capabilities, including speed matching for devices that support both 10-and 100-Mbps operation, full-duplex mode of operation for devices that support such communications, and an automatic signaling configuration for 100BaseT4 and 100BaseTX stations.

2.3.7. 100BaseT Media Types

Three 100BaseT media types exist at the physical layer.

100BaseT supports three media types at the OSI physical layer (Layer 1): 100BaseTX, 100BaseFX, and 100BaseT4. The three media types, which all interface with the IEEE 802.3 MAC layer, are shown in Figure 7-9. Table 7-2 compares key characteristics of the three 100BaseT media types.

2.4. 100BaseTX

100BaseTX is based on the American National Standards Institutes (ANSI) Twisted Pair-Physical Medium Dependent (TP-PMD) specification. The ANSI TP-PMD supports UTP and STP cabling. 100BaseTX uses the 100BaseX signaling scheme over 2-pair Category 5 UTP or STP.

Characteristics of 100BaseT Media Types

Characteristics	100BaseTX	100BaseFX	100BaseT4
Cable	Category 5 UTP, or Type 1 and 2 STP	62.5/125 micron multi-mode fiber	Category 3, 4, or 5 UTP
Number of pairs or strands	2 pairs	2 strands	4 pairs
Connector	ISO 8877 (RJ-45) connector	Duplex SCmedia-interface connector (MIC) ST	ISO 8877 (RJ-45) connector
Maximum segment length	100 meters	400 meters	100 meters
Maximum network diameter	200 meters	400 meters	200 meters

The IEEE 802.3u specification for 100BaseTX networks allows a maximum of two repeater (hub) networks and a total network diameter of approximately 200 meters. A link segment, which is defined as a point-to-point connection between two Medium Independent Interface (MII) devices, can be up to 100 meters

2.5. 100BaseFX

The 100BaseTX is limited to a link distance of 100 meters.

100BaseFX is based on the ANSI TP-PMD X3T9.5 specification for FDDI LANs. 100BaseFX uses the 100BaseX-signaling scheme over two-strand multimode fiber-optic (MMF) cable. The IEEE 802.3u specification for 100BaseFX networks allows data terminal equipment (DTE)-to-DTE links of approximately 400 meters, or one repeater network of approximately 300 meters in length.

The 100BaseFX DTE-to-DTE limit is 400 meters.

2.6. 100BaseT4

The 100BaseT4 supports a maximum link distance of 100 meters.

100BaseT4 allows 100BaseT to run over existing Category 3 wiring, provided that all four pairs of cabling are installed to the desktop. 100BaseT4 uses the half-duplex 4T+ signaling scheme. The IEEE 802.3u specification for 100BaseT4 networks allows a maximum of two repeater (hub) networks and a total network diameter of approximately 200 meters. A link segment, which is defined as a point-to-point connection between two MII devices, can be up to 100 meters.

3. Overall Design

We have researched into all aspects of Ethernet LAN design to design a 100 Mbps – 16 station Ethernet LAN system. We would initially discuss the components available to make the LAN. We would also discuss all the available choices we have while designing the LAN [3].

3.1. Components of a Local Area Network

There are five major components in a Local Area Network:

1. Network Infrastructure

· Horizontal Distribution System

· Riser System

· Backbone System

2. Network Hardware

· Hubs/Concentrators

· NIC (network interface cards)

· Routers/Modems

· Switches

· Bridges

3. Network Operating System (NOS)

· Novell

· Windows NT

· UNIX

4. Computers and Related Hardware

· File Servers

· Computers

· Printers/Scanners

· CD ROM Towers/Jukeboxes

5. Application Software

· Administration

· Databases/Spreadsheets/Word Processing

· Educational

· Library

· Other

We would like to mention that here we are just concerned with building a Fast Ethernet Network that has a speed of 100 Mbps, so we would disregard the cost of purchasing the last 3 components i.e. Application software, Network Operating system and Computers & related hardware.

3.2. Cabling

Common types of computer cable include:

· UTP

· STP

· Coaxial

· Fiber Optics

The most popular computer cable currently being installed is UTP, specifically Cat-5. Since we are going to use horizontal distribution where all the cabling is going to be within one building, and from the patch panel at the cross connect to the wall outlet (I/O). (Horizontal does not mean the cable runs are horizontal, as most runs do have a vertical aspect to them. It means that the cable runs are confined to that particular building, typically on the same level.)

Cat-5 UTP Cable

UTP cable has eight solid conductors of 24 AWG copper individually sheathed and twisted into four pair of two conductors each. Each pair is also individually twisted. The number of twist per inch varies per manufacturer. The amount of twisting increases substantially with each increase in Category. For example, the amount of twists per inch is much greater in Cat-5 than in Cat-3 [2].

Cat-5 UTP Pair Colors

The four pairs inside the UTP cable are color coded. They are twisted separately and are:

Pair 1 White Blue / Blue (WB/B)

Pair 2 White Orange / Orange (WO/O)

Pair 3 White Green / Green (WG/G)

Pair 4 White Brown / Brown (WBr/Br)

Length of cable

The actual, physical length of Cat-5 cable from the I/O to the patch panel is not to exceed 295 feet. This is the total length of the cable run, including slack.

Allowed length of the cable [2]

Patch Cords

Use only Cat-5 rated patch cords. According to ANSI specifications, the recommended patch cords maximum lengths are:

At the cross connect -- 6 meters (19.5 feet)

At the I/O -- 3 meters (10 feet)

Cable Slack

Additional Cat-5 cable at each end of the horizontal cabling system is recommended. A suggestion is two to ten feet at the Patch Panel end and one to ten feet at the I/O end. Be flexible when determining the amount of slack; consider possible additions, moves, or changes, which may be made in the future.

Advantages of Cat-5 UTP Cable:

· It is compatible with most LAN systems

· It is widely used, thus parts and cables are readily available

· The cost for installation (both labor and material) is low compared with other cabling systems

Disadvantages of UTP Cable:

· It is subject to EMI

· More cable is required than is used in coaxial networks

Rules to follow to avoid EMI (Very Important)

· Stay five inches away from lighting ballast including fluorescent fixtures (watch the ballast in the fixture). Cross them perpendicularly.

· Stay four feet away from electric motors and transformers.

· Stay one foot away from electric power distribution conduits.

· Cross-electrical conduits in a perpendicular pattern.

Supports

Cat-5 cable needs to be supported every 4-½ feet when it is installed without conduit. A system of split rings is what is commonly used.

Splices

Under no circumstances are any cables in the Cat-5 system to be spliced, tapped, or bridged. All cable runs are home runs from the I/O to the patch panel. The one exception is the transition point to change to an under carpet cable.

Bend Radius

The bend radius of Cat-5 cable can vary per manufacturer but a safe rule is that no bends should be less than four times the diameter of the cable.

Pulling Tension

Cat-5 cable can only be pulled with 25 pounds (lb) of pull. This is to prevent the stretching of the copper conductors.

Avoid Cable Stress

When installing Cat-5 cable do not tighten plastic wraps around cable bundles to a point where it will pinch the exterior sheathing of the cables.

Using Conduit

· When installing a UTP system in conduit, consider the following:

· Do not place UTP cable into any conduit shared with electrical wires unless there is a physical separation

· UTP cable can be included in conduit along with low voltage wires including phone, CATV, and security

· The conduit should never have more cabling within it than half the inside diameter of the conduit

Exterior Cat-5 and Electrical Protection

Exterior Cat-5 cable (not PVC or Plenum) is designed to be placed in an underground conduit that may be exposed to water or subject to freezing. PVC or Plenum cable should never be run outside of a building, including overhead or underground runs. If exterior Cat-5 cable is used between buildings it must have electrical protection on each end as the cable enters each building for lightning protection. This includes cable installed under a walkway connecting two buildings.

Bonding and Grounding

This is normally not required on a horizontal cabling system using UTP and having no exterior cable attached to the rack or backbone cable. If an exterior backbone cable is terminated at the rack and the cable contains any metal, the cable needs to be grounded. A good rule of thumb is to always ground freestanding racks to the main electrical ground [2].

3.3. Backbone cables

Backbone cables are the cables that connect cross connects together. With in the same building or between buildings. The cables are designed in a star topology.

The following options can be used for backbone cables:

· UTP Cat-5 -- with a maximum distance of ninety meters (295 feet) between cross connects (CAT-5 is not recommended by ANSI as a backbone cable).

· UTP proposed Level-6 -- with a maximum distance of ninety meters (295 feet) between cross connects ( is not recommended by ANSI as a backbone cable).

· STP -- with a maximum distance of ninety meters (295 feet) between the MCC and ICC.

· Multi mode fiber optics -- with a maximum distance of 2000 meters (6560 feet) between buildings and 1500 meters (4920 feet) between the MCC and ICC.

· Single mode fiber optics -- with a maximum distance of 3000 meters (9840 feet) between buildings and 2500 meters (8200 feet) between the MCC and ICC.

· The numbers of cables used between each cross connect for backbones vary but the rule we used is for copper cables a minimum of 3. When designing or installing a fiber backbone a minimum of 6 strands between cross connects within a building and 12 strands between buildings is the guidelines I recommend.

3.4. Hubs

Hubs will be located in all cross connects. While this is not a part of the Horizontal Distribution System, the following information is important to note:

Hubs can be purchased in either individual or stackable forms.

Individual Hubs -- when connected together, look as though they are two separate units. These hubs are less expensive to purchase.

Three possible choices to connect basic Ethernet hubs

· Crossover cable (Port to Port between hubs)

· Uplink port (port in hub to uplink port in hub)

· MID/MIDX Button (when button is pushed one port becomes a uplink port)

Note: Uplink port means that pins 1&2 receive and 3&6 transmit. The pins are crossed internally so a straight patch cord will work.

Stackable Hubs: -

When connected together, look like one single, larger unit. When stackable hubs are connected together, they are in the same room and usually on the same rack. The manufacturer of the hubs will have a special cable, which will connect the hubs together. When designing the networking hardware in a school, it is recommend that all cross connects which require more than one hubs be stackable if possible.

Managed Hubs: –

These hubs have a software module in them and can be managed from a workstation or remotely. By managed you can see if the hubs is working, if all the ports are working and check the traffic [2].

Switches: –

Allows the separation of LAN’s by segmenting out to smaller LAN’s to reduce the traffic per LAN and increase performance.

3.5. Topology

The basic types of computer cable topologies are:

· Daisy Chain

· Bus

· Ring

· Star

ANSI EIA/TIA 568-A only recognizes the star topology. In the star topology, all cables from the cross connect to the I/O are separate cable runs. The cross connect is the central point where the I/O cables terminate [2].

If all cabling running within the building from the I/O to the cross connect is less than 295 feet and there is no structure in the building which should be avoided, then use the basic star design. If the building is so large that some cable runs will exceed 295 feet or for economical reasons, additional cross connects can be added.

4. Proposed Solution

Looking at all the requirements that have to achieve, we have 2 options to develop a 100 Mbps Ethernet LAN.

Fast Ethernet LAN
10/100 Switched Ethernet
100VG any LAN

For all practical purposes we would discuss the differences, the advantages and the disadvantages of both the above systems. Also it is observed that the 10/100 switched Ethernet is used only if an existing 10 Mbps LAN is to be upgraded to provide a speed of 100 Mbps to only some workstations. Using the 10/100 switched Ethernet is obviously the cheaper option of the 2 available choices. The 100VG any LAN has entirely different setup than the Fast Ethernet LAN and hence we would go ahead and discuss only Fast Ethernet [4].

4.1. Proposed Design

We came across various design issues that had to be addresses while designing a Fast Ethernet LAN supporting 16 stations with a running speed of 100 Mbps. The most CISCO design manual for Fast Ethernet Design gave the most viable option for building such a network. We would initially discuss all the following :-

Cabling to incorporate Fast Ethernet LAN,
Topology that supports the Fast Ethernet LAN
Choice of Hubs/Switches or bridges, which we may have to use for connecting the Fast Ethernet LAN. We will also discuss how we can use switches to develop the 10/100 Switched Ethernet LAN.

4.2. Cabling

Fast Ethernet follows the EIA/TIA Commercial Building Telecommunications Wiring Standard. This standard defines the types of cable used, the maximum cable distances, and the way buildings should be wired [3].

Fast Ethernet can run over the same variety of media as 10BaseT, including UTP, shielded twisted-pair (STP), and fiber. The Fast Ethernet specification defines separate physical sub layers for each media type: -

· 100BaseT4 for four pairs of voice- or data-grade Category 3, 4, and 5 UTP wiring

· 100BaseTX for two pairs of data-grade Category 5 UTP and STP wiring

· 100BaseFX for two strands of 62.5/125-micron multimode fiber

In most cases, organizations can upgrade to 100BaseT technology without replacing existing wiring. However, for installations with Category 3 UTP wiring in all or part of their locations, four pairs must be available to implement Fast Ethernet

100 BaseT operates at 100Mbps. It uses RJ45 connectors on Category 5 UTP cable. Category 5 patch cables are required in fast Ethernet networking. Maximum cable length is 100 meters. Maximum number of devices is 1,024.

100 Base FX uses two strands of multimode fiber (62.5 µm fiber optic core and 125 µm outer cladding). The physical level is that of FDDI MMF-PMD (Fiber Distributed Digital Interface Multimode Fiber - Physical Medium Dependent). The maximum attenuation allowed per link is 11 dB. The total power loss through the fiber (including its associated connectors) must not be greater than 11 db as measured by a fiber optic power meter. The 100 Base FX scheme uses one fiber for transmission and the other fiber for collision detection and receive.

4.3. Topology

The Topology that we used is from the CISCO design manual for design of Fast Ethernets using a Star topology [3]. Given below a diagram showing how a Fast Ethernet Network may be connected using routers/switches, repeaters and cables. Again we have the option to use 100BaseFX (Fiber optic cables) to obtain faster network speeds.

Fast Ethernet Topology Guidelines [3]

While the 100BaseTX and 100Base T4 specifications maintain the same 100-meter limit from the wiring closet to the desktop as 10BaseT, 100BaseFX can exceed the 100-meter limit because it uses fiber instead of UTP. However, 100BaseFX is used primarily between wiring closets and campus buildings to better leverage its support for longer cables. Figure 2 shows a typical wiring topology for a single building.

Just as with 10-Mbps Ethernet, different wiring types can be connected through a repeater. The 100BaseT standard defines two classes of repeaters: Class I and Class II.

At most, a collision domain can include one Class I or two Class II repeaters. Fast Ethernet is implemented in a star topology, but even with repeaters, the network diameter is proportionately smaller than 10-Mbps Ethernet, given Fast Ethernet's tenfold increase in packet speed. For example, using two Class II repeaters, the maximum distance using copper wire is 100 meters to the Class II repeater, 5 meters between Class II repeaters, and 100 meters to the desktop.

4.3.1. Topology designed for our network

Based on our analysis and design done in the OPNET Modeler and Simulator, we have achieved the following results. The diagram below shows the topology and the design we have used to connect our network.

4.4. Routers/Switches

We have the choice of using Routers or Switches to act as a central entity, which connects all the workstations and the file servers and the printers. Since we still have to connect our Fast Ethernet LAN network to other LAN networks or to the Internet, it would be a better if we use a router.

Following the guidelines laid down by the Cisco manual, we have designed the network in the following way. We decided to use the 3Com 24 Port 10/100 Switch. Initially we were tempted to use Cisco 3500 series routers, but decided against it. Since a Cisco router has to be used in conjunction with a Fast-10/100 switch or a 16 port Cisco hub to allow connectivity to LANs of lower speeds (10 Mbps). Using just a 3Com 24 port 10/100 Switch instead of the router and the hub solved the problem and cost much less.

Another class of Network Designers feels that a Network security would be in jeopardy if a Router in not used to filter out unwanted traffic. Although it would be practical to just use a 10/100 Fast Ethernet Switch for connecting a network of 16 workstations, but it would be wise to use a Router in addition to a switch so that all the traffic coming from all the other networks are filtered out before they reach the switch. This way we can also provide much needed security firewall to the network so that malicious users are not allowed to hack through the system. This will increase the system cost but provide a safe and secure network so the user can decide on the Router as an option. The Router, which we have decided to be used be optionally is the CISCO 2500 series router.

Connected to the 3Com switch are the 16 workstations, 1 file server and 1 print server. One of the ports is also connected to the local Internet connection. Any other LAN network running at 10 mbps or higher can be linked with this switch. The features of the 3Com 24 ports 10/100 fast Ethernet switch Is given below.

4.4.1. Specifications & Features of CISCO 2650 Series Router

· Main Processor: 80 MHz RISC (Cisco 265x); 50 MHz RISC (Cisco 262x); 40 MHz RISC (Cisco 261x)

· Flash Memory: 8 to 16MB (Cisco 261x and Cisco 262x); 8 to 32MB (Cisco 265x only)

· System Memory (DRAM): 32 to 64MB (Cisco 261x and Cisco 262x); 32 to 128MB (Cisco 265x only, uses SDRAM)

· WAN Interface Card Slots: 2

· Network Module Slot: 1

· AIM Slot: 1

· Console/Aux Speed: 115.2 Kbps (maximum)

· Internet/intranet access with Firewall security

· Multiservice voice/data integration

· Analog and digital dial access services

· Virtual Private Network (VPN) access

· Inter-VLAN routing

· Routing with Bandwidth Management

4.4.2. Specifications & Features of 3Com 10/100BT Switch

· Total ports: 24 auto sensing 10/100 Ethernet

· Media interfaces: 10/100BASE-TX/RJ-45

· Ethernet switching features: Store-and-forward; full-/half-duplex auto-negotiation; 802.3x flow control

· Works "right out of the box" with no configuration and no management software needed.

· LED indicators makes it easy to spot faults and check the status of individual ports.

· Automatic sensing of link speed, duplex mode, and cable type optimizes connectivity.

· MDI/MDIX pushbutton simplifies installation and configuration without crossover cables.

· 802.3x congestion control helps reduce packet loss and improve performance.

4.5. Miscellaneous Accessories

4.5.1. Ethernet Cards [4]

We have used the Farallon Fast Ethernet 10/100 PCI Cards. Each of these cards cost 45.00 $ approximately. Each of these cards will be attached in the workstations and the print, file server. These PCI cards will give the connectivity to the workstations and the servers to the 10/100 3Com Switch. These cards have the ability to perform at 10/100 Mbps. Other features of the card are listed below.

4.5.1.1. Specifications

	Fast EtherTX 10/100 PCI Plus
Part Number	PN996L
System interface	PCI slot
Protocol compatibility	CSMA/CD 802.3 Ethernet
Drivers supported	Open FirmWare, Open Transport & NDIS, ODI Ethernet
Media Interface	RJ-45
N-Way auto-negotiation support	100% compliant
Full Duplex	Yes
Bus addressing	32 bit
Peak bus performance	132 MBps
Bus mastering	Yes
Diagnostic LEDs	10Mb mode, 100Mb mode, Link, Activity
Dimensions	4.68" x 3.19" (11.9 cm x 8.1 cm)
Weight	4.2 oz (119 gm)
Power requirements	5V @ 500mA, 12V@ 160mA
100Base-T cable	2-pair Category 5

4.5.2. Repeaters and Hubs

We always have a option of using Repeaters and Hubs. Repeaters are used to connect if the cabling distance increases over 100 meters and we would be using the Fasthub 400 10/100 TX Switched Repeater. Optionally we may have to use an additional hub to connect workstations in a particular floor. We decided to use the repeater FastHub 400 10/100TX Switched Module # WS-X401 in case the distance between any connection increases above 100 meters. This is optional. In case we have 2 or 3 workstations separated on a floor, we can connect them using a 8 port 100Mbps Fast Ethernet Hub Encore Model: 708TX , which is again optional. We have taken into consideration such rare occurrences so that we don’t have any loopholes in our network design

4.5.3. Servers and Workstations

We would be using a Dell “Power Edge” General Purpose Servers for the File Server and it would also act as the Print server. Since there are only 16 workstations we would assume that there are not going to be many print jobs, so that File server can handle the print jobs as well. We would be using the Dell Precision Workstations since they were the cheapest options available. The Specifications of the Servers and workstations are given below.

Dell® PowerEdge™ General Purpose Servers [5]

PowerEdge 300SC:	PowerEdge 300SC, Intel Pentium III 800 M 3800SC - [220-6245]
2nd Processor:	Terminator Card,No 2nd Processor 1P - [311-0655]
Memory:	64MB SDRAM,(1X64MB) 64M1D - [311-1464]
Keyboard:	Standard Windows Keyboard S - [310-4100]
Monitor:	No Monitor Option N - [320-0058]
1st Hard Drive:	10GB,IDE,1",7.2K RPM Hard Drive 10GB - [340-2990]
Floppy Drive:	3.5", 1.44MB Floppy Drive FD - [340-1919]
Operating System:	MS Windows 2000 Configuration with NO Factory Installed Operating System NOOS/W2 - [420-5100]
Mouse:	LOGITEC SYSTEM MOUSE,GRAY LDN - [310-3776]
CD ROM/DVD ROM:	48X IDE CD-ROM CD48X - [313-2600]
Documentation/Disks:	Electronic Documentation Only EDOCS - [310-1989]
Hard Drive Configuration:	Drives Connected to Onboard IDE Controller MIDE - [340-2994]
Installation:	No Installation NOINSTL - [900-9997]

Dell® Precision™ Workstation 220 [5]
Dell Precision Workstation 220 Desktop:	Pentium® III 866MHz Processor 2D866 - [220-5510]
2nd Processor (must match speed selection above):	No Second Processor PRNO - [311-8754]
Memory:	128MB PC700 RDRAM® (1 RIMM™) 128N351 - [311-5500]
Keyboard:	Quietkey® 104-key Keyboard W - [310-6521]
Monitor:	17" Dell (16.0" vis) M781P Monitor M781P - [320-0250]
Graphics Card:	nVIDIATNT2 PRO,16MB,4x AGP TNT2PRO - [320-2590]
1st Hard Drive:	20GB ATA-66/100 IDE (7200 rpm) 20I72 - [340-7468]
Floppy Drive:	3.5" 1.44MB Floppy Drive 3 - [340-9121]
Operating System:	Microsoft® Windows® 2000 Professional (Service Pack 1) W2K2 - [420-5200]
Mouse:	Logitech® First Mouse™ (2 button w/scroll) WS - [310-1271]
CD ROM and Read-Write Drives:	20/48X IDE CD-ROM Drive CD48 - [313-4976]

4.6. Cost Analysis

We have done an approximate cost analysis of the network we are trying to build. Initially we would like to assume a few things. We have not included the cost of each of the 16 workstations. Since we assumed that the 16 workstations are already present, but we have included the cost of adding a Fast Ethernet PCI card to each of the 16 workstations.

Also we have not taken into consideration the cost of the 2 servers (File server & print server). Yet we have again included the cost of the PCI Ethernet card for these 2 servers.

Please note that the cost of an average workstation and a server will be given below in another table.

Item	Nos.	Cost
PN996L-TX Fast EtherTX-10/100 PCI Plus Card	16 – For 16 Workstaions, 2 – For File, Print servers Total = 18 PCI Cards	@ 45.00 $ 18 * 45 = 810 $
Cisco 2650 router	1 (Optional)	1700 $
3Com SuperStack 3 Baseline 10/100 Switch 24-Port	1	845 $
FastHub 400 10/100TX Switched Module # WS-X401	1 – 3 (Optional Repeaters)	@ 268.65 $ 3 * 268.65 = 806.00 $
8 port 100Mbps Fast Ethernet Hub Encore Model: 708TX	1 – (Optional hub)	47 $
Miscellaneous cables · Cat5 UTP Cables [6] · Multimode Fiber Cables Plenum Ceramic, with pulling-eye. [6]	Approximately 8 to 10 – 100 feet UTP cables Approximately 30 Feet to act as a backbone for the network	@ 21 $ 10 * 21 = 210 $ @ 120 $/Feet 30 * 120 = 360 $
Cost of Workstations and File Servers along with Printers
Dell® PowerEdge™ General Purpose Servers	1 Pentium® III Processor, 800 MHz	1,194.32 $
Dell® Precision™ Workstation 220	16 Pentium® III Processor, 866-1GH MHz	@ 1,485.99 $ 16 * 1,485.99 $ = 23776.00 $
Hewlett Packard Laser Jet 4100 TN	1	1560 $
GRAND TOTAL	31,308.32 $ (Considering all optional items)

5. Migration from a Fast Ethernet network to a Gigabit Ethernet running at 1000 Mbps

5.1. Gigabit Ethernet Migration

The initial applications for Gigabit Ethernet will be for campuses or buildings requiring greater bandwidth between routers, switches, hubs and repeaters, and servers. In its early phase, Gigabit Ethernet is not expected to be deployed to the desktop but for all academic and research purposes we will take a look into that possibility [7].

There are at least four general upgrade scenarios.

· Upgrading switch to server links to obtain high-speed access to application and file servers

· Upgrading switch-to-switch connections to obtain 1,000 Mbps pipes between 100/1000 switches

· Upgrading a switched Fast Ethernet backbone by aggregating Fast Ethernet switches with a Gigabit Ethernet switch or repeater

· Upgrading a shared FDDI backbone by connecting FDDI concentrators/hubs or Ethernet-to-FDDI routers with Gigabit Ethernet switches

In all the scenarios, at the desktop, the NOS, applications, and NIC drivers would all remain the same. The MIS manager can also leverage not only his or her existing multimode fiber but also the current investment in network management applications and tools.

Upgrading Switch to Server Links

The simplest upgrade scenario involves upgrading a Fast Ethernet switch to a Gigabit Ethernet switch to obtain high-speed 1,000 Mbps interconnection to a server farm of high-performance super servers with Gigabit Ethernet NICs installed.

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Upgrading Switch-to-Switch Links

Another very straightforward upgrade scenario involves upgrading 100 Mbps links between Fast Ethernet switches or repeaters to 1,000 Mbps links between 100/1000 Switches. Such high bandwidth switch-to-switch links would enable the 100/1000 switches to support a greater number of both switched and shared fast Ethernet segments [7].

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Upgrading a Switched Fast Ethernet Backbone

A Fast Ethernet backbone switch that aggregates multiple 10/100 switches would be upgraded to a Gigabit Ethernet switch supporting multiple 100/1000 switches and other devices such as routers and hubs with Gigabit Ethernet interfaces and uplinks. Gigabit repeaters could also be installed as needed. Once the backbone is upgraded to a Gigabit Ethernet Switch, high-performance server farms can be connected directly to the backbone with Gigabit Ethernet adapter cards increasing throughput to the severs for users with high-bandwidth applications. Also, the network can now support a greater number of segments, more bandwidth per segment, and hence greater number of nodes per segment.

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Upgrading a Shared FDDI Backbone

An FDDI campus or building backbone would be upgraded by replacing the FDDI concentrator or hub, or Ethernet-to-FDDI router with a Gigabit Ethernet switch or repeater. (As an intermediate step, some customers might migrate to an FDDI switch before installing a Gigabit Ethernet Switch.) The only upgrade required would be the installation of new Gigabit Ethernet interfaces in the routers or switches or repeaters. All the investment in fiber optic cable is retained and the aggregated bandwidth is increased at least tenfold for each segment [7].

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6. Evaluation and analysis of results

We designed our network and simulated the same in OPNET Network Modeler. We designed the topology with general systems already predefined in OPNET. Using similar workstations and servers, and the 3Com 10/100 Fast Ethernet switch we observed and simulated the network with pseudo load of print jobs and file jobs. Below are the results of the simulation, which shows the no of jobs on the Y-axis and the time on the X-axis. The results were quite satisfactory confirming that the design of the network was done in a correct manner so that load balancing is achieved.

Results of the Print server

We tried 3 applications on the servers. The first application is the file request application and the second application is the print application. Both were performed in a satisfactory manner. We also tried the FTP application on the server and the graphs prove that the server managed the load properly and services each and every node properly.

Results of the File request application

Results of the FTP application on the File server

7. Conclusion

We have successfully designed a 16 workstation Ethernet LAN running at 100 Mbps. For this we had to use a Fast Ethernet Design approach. Doing research on all the various Ethernet technologies have given us a good insight on the options we have in designing and implementing a Ethernet LAN system. Getting a Ethernet LAN network to run at 100 Mbps naturally increases the cost of building the network. When we consider the cost of all the components including the 16 workstations, a server, printer, and cables, etc. we get a total cost of 31,302.32 $. The cost of building just the network with the cables, the 3COM 10/100 Fast Ethernet switch along with the router, Ethernet cards and the optional hubs would cost us 4778 $. This just goes on to prove that the bare cost of setting up an optimal working Ethernet LAN running at 100 Mbps is just under 5000/- $.

We also looked into the aspect of possible upgrading the Fast Ethernet network to a Gigabit Ethernet Network running at 1000 Mbps. Upgrading it would require change in lots of the networking hardware. We have given a typical scenario in which this upgrade can be done.

8. References (Citation)

[1] CISCO Systems Inc., Cisco’s Ethernet White Paper, http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/ethernet.htm, 2001.

[2] Edwin Chaplin et Al, LAN Design Engineering, http://www.su-inc.com/lde/index.htm, August 24^th 2000.

[3] CISCO Systems Inc., Technology Brief: Fast Ethernet 100 Mbps Solutions, http://www.cisco.com/warp/public/cc/so/neso/lnso/lnmnso/feth_tc.htm, July 3^rd 2000.

[4] Farallon Inc, Frequently Asked Questions, http://www.farallon.com/support/fastcards/fenfaq.html, 2000.

[5] DELL Computer Corporation, www.dell.com, 2001.

[6] Price Watch inc., www.pricewatch.com, 2001.

[7] Gigabit Ethernet Alliance, Gigabit Ethernet Migration, http://www.gigabit-ethernet.org/technology/overview/migration, November 2000.

PLEASE NOTE: - This document is also available on the net @ http://www.fiu.edu/~vdsouz01/project2.html

Florida, Miami

Data Communication Engineering

- Dr Subbarao Wunnava

Project No. 2