Project-Based Learning of Telecommunication Networking Gary Rubendall, Sergio Chacon and Mequanint Moges Engineering Technology Department University of Houston Abstract Session 12-8 This paper presents a student project in the telecommunications course that has been developed to provide a solution that is an improvement over a baseline design. The baseline design is the Optical Network Research Laboratory, a telecommunications network used by the College of Technology and the AT&T Technology Laboratory for training and research. The project uses technology standards in place today and planning for future technology being discussed, researched and commercialized. The project is divided in two phases: the equipment familiarization phase or the research phase and the design phase. The first phase mainly involves extensive research as well as visitations in order to understand and learn the operations of the existing baseline network infrastructure of the college and to become familiar with all the required telecommunication hardware and software. The second phase is the project proposal or design phase of a telecommunication system using any combination of T1, T3 or SONET networks that connects five cities with a combined distance of 2766 miles and 800 total users using a ring format OC-3 carrier system that interconnects the branches of a fictitious company. Every city is to have a PBX system and telephones based on PSTN to support the users and calling features. Although the design is based on a fictitious company, the concepts of researching, developing and designing a solution provides the building blocks that are used in the realworld environment. Therefore, the research of the system design recommends different equipment to provide a better solution with performance upgrades at a lower cost for future growth. Introduction The increasing demand of technical expertise associated with the current and future growth of telecommunication infrastructure and the trend to design and implement the equipment calls for the integration of project-based learning in undergraduate curriculum. The College of Technology at the University of Houston incorporates the framework of project-based learning into the undergraduate courses in order to dramatically improve the quality of technology education. The College of Technology at the University of Houston approach to project-based learning in the telecommunications course involves a basic or fundamental overview and
two Hands-On phases as represented in Figure 1: Basic introduction to the networking technologies; Phase 1, a familiarization with the AT&T Lab test bed network equipment; Phase 2, the student project research and design implementation. Research And Design Project Completion Introduction Of Technology Familiarization With Equipment Figure 1. Basic Overview Introduction of Technology; Phase 1, Familiarization with Equipment in the AT&T Lab; Phase 2, Student Research and Design of Project During the first phase, the network administrator of the College of Technology s test bed, a campus-wide network that connects five University of Houston (UH) s laboratories, gives a presentation about the network, its equipment, and how it is used for a variety of applications. Next the students are divided into groups and each group visits the College of Technology s test bed where they have a chance to see the network first hand and to ask questions related to their projects. The College of Technology s test bed (see Figure 2 for the configuration) includes a campus-wide three node OC-3 SONET ring that uses single-mode fiber and FLM150 optical multiplexers, Giga Ethernet Cisco 3700 series switches connecting three locations using multimode fiber, MPLS-enabled Cisco 7200, 2800 series routers. In the second phase, students continue their research by using the internet, re-interviewing the network administrator or contacting experts in the field to obtain the necessary information from equipment specifications, cost, and capabilities to network-specific such as bandwidth and utilization. Once the information has been obtained, the students design the network according to the minimum specifications as stated by the professor.
Figure 2. OC-3 Synchronous Optical Networking (SONET) website: http://www.tech.uh.edu/onrl/sonet.php The required project specifications as shown by the schematic in Figure 3 represent the SONET communication link to connect the five cities. The number of users in each city represents the minimum number for designing the equipment needs for each city. The distance between the cities is a static number which will be used to figure out how many repeaters will be needed to develop the link. Theory of Operation The SONET communication link is used to provide high speed connection to the five cities using the OC-3 format with the capability to be upgraded to higher OC Levels as needed for expansion. The OC-1 level would work, but because of other equipment selections the OC-3 format will be used. The SONET Ring is designed to use Linear APS (Automatic Protection Switching) which has two primary fibers and two backup fibers to allow for automatic switching if a break occurs. The SONET Ring is capable of unidirectional or bidirectional depending on the requirement of the Network Element decision on how to transmit the packet of information to the next SONET Network Element. The Network Element is the combination of software and hardware, the software allows the flexibility to adapt to new standards and the requirements of the users. The hardware maintains the speed and propagation delays to the proper standards for the different OC levels. The Fujitsu FLM150 and the Cisco ONS 15454 provide the same function as the SONET Multiplexer. The FLM150 supports OC-3 and OC-12 speeds and is unidirectional, while the ONS 15454 supports DS-1 through to OC-192 speeds and can be configured either unidirectional or bidirectional. Using the Cisco ONS
15454 instead of the Fujitsu FLM150 gives the design the flexibility to use Linear APS protocols, since the Network Element is incorporated in the product. This provides redundancy or automatic healing as presented in Figure 4 to maintain a 100% connect time. The Cisco 7600/12000 device is connected to the WAN, which is connected to the ONS 15454. This will give each City Site connection to the WAN through the DS3 connector. 420 Miles City A 255 Users City B 272 Users 1820 Miles 120 Miles City C 49 Users 256 Miles City E 125 Users 150 Miles City D 99 Users Figure 3. Project specifications Repeaters will be used to handle the transmission between the City Sites. The Repeaters use Single or Multi-Mode transmission links, where Single Mode or Monomode uses one light as the carrier for the data and has a smaller fiber core and is used for long distances. Multi-Mode fiber is a larger core, but can only be used for short distances because of the light dispersion, called Modal Dispersion. The distance for Single-Mode is 40Km, while 2Km is the maximum distance for Multi-Mode. Therefore, Single Mode will be used to connect the City Sites together. The Repeaters using the Coarse Wave Division Multiplexing (CWDM) techniques can achieve distances of 80Km. The Central Office connects to the SONET ring and the PBX system at each City Site giving the User access to local calling and the other City Sites. The Central Office is provided by the Local Bell provider and the equipment must interface with this provider. The Central Office is providing the backup or secondary Internet service for the Users.
Primary BREAK! Primary Backup City Site A City Site B City Site E Primary Backup Backup Backup City Site C City Site D Primary Figure 4. APS protocol The PBX system provides the analog phone service to the users at each City Site. The PBX is connected by T1 lines and the number is determined by the number of users at each City Site. The T1 lines are connected to PBX by Angel Trunk cards. By using the PBX system, the users will have enhanced features not supported by Channel Bank equipment. The features include: Call Waiting, Forwarding, Hold, Music on Hold, Transfer, Conferencing and Message if Busy, Message if Not Available. The PBX system also will provide the secondary Internet connection if the primary connection fails. The secondary Internet is connected to a Bridge to provide switchover if the Primary connection fails. The Bridge is then connected to a single stage Firewall device, providing minimal security at each City Site. A more robust Firewall should be implemented to provide better security for the site. The Firewall is connected to Routers and Switches to provide the Internet connection to Users. By using Routers and Switches, the users can be separated into workgroups to provide hierarchical organization and dedicated servers to each group. Design and Schematic The configuration as shown in Figure 5 is repeated at each City Site. The SONET Ring is notated by the red dash lines and the User Infrastructure is notated by the green dash lines. The solid red line inside the SONET ring is the Primary connection and the solid blue line is the Secondary connection in case primary connection failure. The Central Office is connected between the SONET Ring and the User Infrastructure to give the users access to standard telephone infrastructure. Although, Voice over IP (VoIP) could be used, this is not part of the specifications. The Definity PBX system has been around since the mid 1970s and was the standard selected to be used to handle the telephones at each city site. There were several internet sites that sold the Definity PBX systems, the
system selected came equipped with digital Angel cards, and it was decided to provide backup Internet service through the bridge equipment. Although the internet speed would be greatly reduced, the users would have limited access until the primary service was restored. Primary Internet service is provided by the Cisco ONS 15454 system and the Cisco 7600 connection to the WAN. This provides Internet service to the workstations at the site. Layout of a City Site To City (C-1) Radiance R4000 Secondary (2 Fibers) Radiance R4000 T1/L TP/n Telephone User #1 Primary (2 Fibers) Central Office Definity PBX WAN Bridge Cisco 7600/12000 Cisco ONS 15454 Firewall Telephone User #n Primary (2 Fibers) Secondary (2 Fibers) Router and/or Switches To City (C+1) Radiance R4000 Radiance R4000 Workstation User #1 Workstation User #n SONET Ring City T1/L TP/n A 11 255 B 12 272 C 3 49 D 5 99 E 5 125 User Infrastructure Figure 5. City Site configuration for each city The design selection for the SONET Ring will be OC-3 to use the newer hardware and protection solutions. There are a total of 800 users using the standard 64Kb/sec bandwidth for voice which needs 51.2Mb/sec (800 x 64Kb/sec), or OC-1. Since the design is three times the actual requirement, there is plenty of headroom to allow the use of video conferencing or subletting the unused bandwidth to other companies.
Equipment/Products The equipment list for the two configurations that are considered is shown in Figure 6. The Metrobility Radiance R4000 product and the Angel Analog card for the Definity PBX system have two configurations that are used to determine the most effective setup to achieve the goals of the design. Parts List Description Qty Cisco ONS 15454 - Optical Switch per each city site 5 a. Used in the SONET Ring to provide the optical connection between the City Sites (2 x) Metrobility Radiance R4000 CWDM (Distance 80Km / ~50mi) for optical transmission 54 between City Sites a. Distance between stations from 2Km to 80Km, depending on Single or Multi-Mode transmission and/or carrier signals (2 x) Metrobility Radiance R4000 (Distance 20Km / ~12mi) for optical transmission between 229 City Sites a. Distance between stations from 2Km to 20Km, depending on Single or Multi-Mode transmission and/or carrier signals Cisco 7600 / 12000 Router 5 a. Provide WAN support for the Users at each City Site Definity PBX (w/ Digital Ports) per each city site 5 a. Phone System to handle the analog phones Angel Analog Card (24 Port) for PBX 37 a. Interface cards for analog phones, 24 ports Angel Analog Card (16 Port) for PBX 52 a. Interface cards for analog phones, 16 ports Angel Trunk Card (2 Port T1/E1) for PBX - CO Trunk to Central Office 20 a. Interface card to connect to the Central Office in each City Site Telephones to work with Definity PBX System 800 a. Phone Handsets using single line with digital display Bridge (Drop - Pass) 5 Firewall Configuration (1 Level) 5 Cisco Router 5 a. Provide LAN support for the Users at each City Site Cisco Switch 50 1. Provide LAN support and organizational hierarchy Figure 6. Parts List for both design considerations Cost The costs are based on the design specifications as stated in Figure 7, which include the distances from city to city and the number of users in each city. The number of T1 lines is calculated by dividing the number of users by 24 and then rounding up to the next whole number.
City Distance Users T1 From To (miles) Lines A B 420 255 11 B C 1820 272 12 C D 256 49 3 D E 150 99 5 E A 120 125 6 Figure 7. Design Specification using Ring Network Each City site will have a common set of equipment that will not vary, thus maintaining a standard setup and maintenance contracts. Figure 8 lists the common equipment and costs. Common Equipment @ Each City Site SONET Ring Equipment Cost (ea) Set Qty Sub Total Cisco ONS 15454 $84,000.00 1 $84,000.00 WAN Connection Cisco 7600 / 1200 $35,000.00 1 $35,000.00 PBX System Definity PBX (w/ Digital Ports) $7,000.00 1 $7,000.00 LAN Bridge (Drop - Pass) $1,000.00 1 $1,000.00 Firewall Configuration (1 Level) $3,000.00 1 $3,000.00 Router $2,200.00 1 $2,200.00 Figure 8. Common Equipment List Next, each City Site will have a list of equipment created for the number of users at the site. Along with it, how the SONET Ring Radiance 4000 would be configured by using the standard optical transmission or the CWDM transmission standard. The Radiance R4000 repeaters using standard optical transmission would have a maximum distance of 20Km or 12 miles. The Radiance R4000 chassis will allow plug in modules that use the CWDM technology that will increase the distance to a maximum of 80Km or 50 miles. This unit is more expensive, but less units will be needed and therefore reducing the number of failure points and maintenance. The Definity PBX can have different Angel Analog Cards; they can be a 16 Port or a 24 Port. Again, the more ports on a card, less cards in the Definity chassis. An example of the equipment list for a City Site A is shown in Figure 9.
Equipment Variables: City A to B SONET Ring Equipment Cost (ea) Set Qty Sub Total (2 x) Metrobility Radiance R4000 $2,800.00 CWDM (Distance 80Km / ~50mi) 2 8 $44,800.00 (2 x) Metrobility Radiance R4000 $1,000.00 (Distance 20Km / ~12mi) 2 35 $70,000.00 PBX System Angel Analog Card (24 Port) $750.00 11 $8,250.00 Angel Analog Card (16 Port) $125.00 16 $2,000.00 Angel Trunk Card (2 Port T1/E1) $2,440.00 6 $14,640.00 Phones $100.00 255 $25,500.00 LAN Switch - Setup with 5 groups $1,800.00 15 $27,000.00 Figure 9. Equipment List example for a City Site (City Site A represented) Finally, by considering the two options for the SONET Ring and the two options for the Definity PBX system a calculated cost can be estimated. The estimation is based on using one SONET Ring configuration for the complete network and one model of the Angel Analog card for entire City Sites. The total distance of the SONET Ring is 2766 miles in which a minimum and maximum cost is calculated. The minimum cost uses the SONET Ring with the newer technology of the CWDM and the 16 Port Angel Analog Cards in the PBX totaling ~$ 1.2 Million. The maximum cost uses the standard optical transmission in the SONET Ring with the 24 Port Angel Analog Cards in PBX which totals ~$ 1.4 Million. Figure 10 shows the cost breakdown for the two cost structures. The delta cost is ~ $200 K, by using the minimum cost structure, the cost savings and the newer SONET Ring technology is the better choice. TOTAL COST Total Miles 2766 SONET: CWDM Repeater, WAN $897,400.00 SONET: Std Repeater, WAN $1,053,000.00 PBX: 24 Port Analog, Trunk, Phones $191,550.00 PBX: 16 Port Analog, Trunk, Phones $170,300.00 LAN: $121,000.00 Minimum Cost: SONET (CWDM), PBX (16 Port), LAN:: $1,188,700.00 Maximum Cost: SONET (Std), PBX (24 Port), LAN:: $1,365,550.00 Difference: (Max - Min):: $176,850.00 Figure 10. Total Cost Structure
Conclusion The total distance of 2766 miles to connect the 5 City Sites using a SONET Ring is based on the cost of the two scenarios presented in this report; the minimum cost scenario actually includes newer technology for the SONET ring. By using the Radiance Repeaters with CWDM, fewer repeaters are needed to complete the link between City Sites. This in turn, would reduce the number repeater locations, fiber connections and potential failures that would be considered in the MTBF calculations. Although the cost of the CWDM Repeater is more than the standard Repeater, the cost can be justified by fewer devices and maintenance cost. The Cisco ONS 15454 was chosen for two reasons: 1) The Networked Element is included in the hardware and software of this device which allows for better management of the link; 2) Very limited information could be found for the Fujitsu FLM150 or the Network Element that is needed for the SONET implementation. The ONS 15454 appears to have better strategy to maintain connections between other ONS 15454 on the SONET Ring in the event of a link failure. The PBX system is the same system for all the City Sites except for the number of Analog cards needed to support the users. Because of the dramatic cost difference between the 16 Port and 24 Post Analog card, the 16 Port card will be used, even though it requires more cards in the cabinet. The City Site A and B may require a second PBX system at each site because of the number of users. There will be an additional $14K added to the final cost of both the Minimum and Maximum configuration. By maintaining the same system at all City Sites, maintenance and updating will be easier. In addition, each City Site will have Internet access through the SONET Ring by using the ONS 15454 connected to Cisco 7600/12000. Each City Site internet users are divided up into five groups; Accounting, Sales, Administration, Executive, and Designers. The Router provides the separated workgroups, while the Switches connect the users to the Router. The Internet connection is maintained through a Bridge connection, the primary access comes directly from the ONS 15454. The backup connection is provided by the PBX system to the Bridge at a reduced access speed. The cost savings is around $200K for using the Minimum Cost implementation and includes the newer fiber CWDM technology. The cost for the Maximum Cost implementation would be more, if in the future, upgrading to the CWDM Repeaters would mean scrapping some of the Repeaters. The chassis for the Repeaters will handle the CWDM Cards. The problem that arises is the splicing of the fiber cable where the previous repeater was and now new failure points have been added to the link. It should be noted that the cost savings is directly related to the SONET Ring and the number of repeaters needed. The PBX systems cost is minimal, since the cost difference between the analog port cards is insignificant.
References 1. Maximizing fiber Capacity, METRObility Qptical Systems, Copyright 2004 revised March 2005 2. URL: http://www.metrobility.com/products/pdf/cwdm.pdf, Managed Coarse Wave Division Multiplexing, METRObility Optical Systems, Copyright 2003 Revised July 2005 3. URL: http://www.sheltronics.com/docs/cwdm_whitepaper.pdf, CWDM - The Wave of the Future, METRObility Optical Systems, Copyright 2004 4. URL: http://www.metrobility.com/news/index.asp?display=detail&id=118, In The News, Metrobility Introduces Enhanced Ethernet over CWDM for Metro Access and Campus Networks, September 22, 2003 5. Solutions Overview - Cisco Optical Metro Ethernet Solutions, Cisco Systems, Copyright 1992-2006 6. URL: http://www.skullbox.net/sonet.php, SONET Networks, Author: Erik Rodriguez, Last Updated 10/18/04 7. URL: http://www.avaya.com/, AVAYA Website searched the Support and Products for information on the Definity PBX system GARY L. RUBENDALL Gary L. Rubendall graduated in December of 2007 with a Bachelor of Science Computer Engineering Technology from the University of Houston. He has 29 years of work experience during the time he pursued his Bachelor Degree at the University of Houston in 1981.Suspended his studies in 1985 and then returned to the University of Houston in 2006 to complete his degree, taking courses in Networking and Programming. SERGIO CHACON Sergio Chacon manages the University of Houston s AT&T Technology Laboratory and the College of Technology s test bed as well as junior and senior level laboratories in the Department of Engineering Technology of the University of Houston s College of Technology. His main research interests are converged networks, voice over IP, and network security. MEQUANINT MOGES Dr. Moges joined the faculty at the University of Houston, College of Technology in august 2005, where he is presently an instructional assistant professor at the Department of Engineering Technology. Dr. Moges has taught various courses at various levels such as ones basic circuits, embedded systems, sensor networks, data communications, computer networks and telecommunications. He is also actively involved in curriculum development and revision.