1. Building Corporate Data Networks – A Case Study
Delivered at
Institution of Engineers, Sri Lanka - Saparagamuwa Provincial Center
31st March 2005

2. Objectives At the end of this case study you will be able to
Transfer a business communication requirements into a data network requirement
Describe the primary components that constitutes a data network
Identify the basic elements of LAN, WAN and Security sub systems
Prescribe a high level network structure for a generic corporate data network

3. Acme Corporation
Acme Corporation is a multinational organization who has two of their manufacturing plants in Sri Lanka. They produce automobile tires for export and local market. The main factory and head office is located at Kelaniya and another factory at BOI zone, Katunayake. They have a warehouse at Peliyagoda and a raw material store at Thalawakale. Acme Corp need to build a data network to deploy their new ERP (Enterprise Resource Planning) application. The Katunayake factory and Peliyagoda warehouse are to be connected online to the head office and the raw material store is to be connected for batch processing via a dial up facility. In addition they need to have Internet connectivity, a local web site and service for their staff. Staff from corporate head quarters (abroad) and telecommuters in Sri Lanka need to gain access to Acme Corp network for various activities. Data and network security are concerns of the network administrator.

4. Acme Corporation (Cont’d)
Raw Material Stores
(Thalawakale)
Branch Factory
(BOI Zone - Katunayake)
Warehouse
(Peliyagoda)
Internet
Head Office / Main Factory
(Kelaniya)
Telecommuters
Mobile Users

5. Network Elements
User and server local connectivity at head office, branch, warehouse and store
Network switches and devices
Cabling infrastructure (copper/fiber)
Wide area interconnectivity
Routers
Links from a network service provider
Internet connectivity
Router
Internet connection from as Internet Service Provider (ISP)
Security
Firewall
Virtual Private Network (VPN) device
Telecommuting
Remote access server
Modems
Telephone lines
Wireless connectivity at head office
Wireless access point
Network address planning

6. Branch LAN Branch, Warehouse & Stores LAN Devices
Branch Factory
10/100 Base-TX
Warehouse
10/100 Base-TX
Stores
10/100 Base-TX
Branch, Warehouse & Stores LAN Devices
10/100 Base-TX Autosense Ethernet Switch nos.
Copper (UTP) Cable plant at all 03 locations

7. Head Office LAN Floor 3 ERP Server and other shared Resources
Wireless
Access Point
Mobile Users
ERP Server and other
shared Resources
Network Printer
Floor 3
10/100 Base-TX
Optical Fibre
Uplinks
100 Base-FX
Floor 2
10/100 Base-TX
Floor 1

8. Head Office LAN (cont’d)
Head Office LAN Components
10/100 Base-TX Autosense Ethernet Switch – 03 nos.
Optical fiber transceivers – 4 nos.
Wireless Access Point – 1 no.
Copper (UTP) / Fiber Cable plant

9. Wide Area Network Branch Factory Router Head Office Ethernet Modem
DSU/CSU
Modem
Leased Line
Ethernet
Router
Ethernet
DSU/CSU
Router
Warehouse
Ethernet
Modem
Router
PSTN
Modem
Ethernet
Stores

10. Wide Area Network (cont’d)
WAN Components
Routers – 4 nos.
DSU/CSUs – 4 nos.
(Digital Service Units/Channel Service Units)
Modems (synchronous) – 5 nos.
Leased Lines – 2 nos.
Head Office ↔ Branch Factory
Head Office ↔ Warehouse
PSTN Links (Telephone lines) – 5 nos.
Head Office – 2 nos.
Branch Factory – 1 no.
Warehouse – 1 no.
Stores - 1 no.

11. WAN Connectivity Options
Leased Links / Clear Channel Circuits
Dead copper loops
Active copper loops
Microwave point-to-point links
Microwave point-to-multi point access system
PDH/SDH* transmission networks
Satellite links
Dark fiber loop
Free space optics (laser)
Public Switched Data Networks
Frame Relay
ATM
Public IP Backbone
Multi Protocol Label Switching (MPLS) IP backbone
VPN over Internet
Packet over SONET/SDH
* PDH – Pleisiochronous Digital Hierarchy
SDH – Synchronous Digital Hierarchy

12. WAN Data rates Link speeds DS0 - 64 kbps 128 / 256 / 512 / 1024 kbps
E1 – 2 Mbps
E3 – 34 Mbps
OC-3c / STM-1 – 155 Mbps
OC-12 / STM-4 – 622 Mbps
OC-48 / STM-16 – Gbps
Gigabit Ethernet – 1,000 Mbps
10 Gigabit Ethernet Gbps
Fiber Channel – 2 Gbps
Uses OSI Layer 2 Framing Protocols

13. Dial-up Services Dial Backup Dial on Demand Bandwidth on Demand
to recover from failed links
Dial on Demand
to provide on demand access and disconnect while idling
Bandwidth on Demand
to provide increased bandwidth during congestion
Options
PSTN – Public Switched Telephone Network
ISDN – Integrated Service Digital Network

14. Internet Connectivity
Unprotected Network
De-militarized Zone
Secure Network
Web Server and
Mail Server
Internet
VPN Gateway
ISP
ERP Server and other
shared Resources
DSU/CSU
Firewall
Router
Downlinks to
2nd and 1st Floors
To Router
10/100 Base-TX

15. Firewall Security Policy
Web Server and
Mail Server
Internet
VPN Gateway
ISP
Web, Mail server
connections
Outgoing
Mail
Incoming Web, Mail
VPN connections
ERP Server and other
shared Resources
DSU/CSU
Router
Firewall
Downlinks to
2nd and 1st Floors
To Router
Corporate users’ Internet Access
No access

16. Secure Access to ERP Server
IPSec ‘Tunnel’ for secure communication
Client at Headquarters
Encrypted
Authenticated
Authorized
Accounted
…. access only.
Internet
Web Server and
Mail Server
ISP
VPN Gateway
ERP Server and other
shared Resources
DSU/CSU
Router
Firewall
To Router
Downlinks to
2nd and 1st Floors

17. Internet and Security Internet connetivity Security Router – 1 no.
DSU/CSU – 1 no.
ISP connection – 1 no.
Security
Firewall – 1 no.
VPN Gateway device – 1 no.

18. Remote Access Service RAS Components Remote Access Server – 1 no.
PSTN
Ethernet (DMZ)
Remote Access Server
Modem Pool
Home User
Notebook
Computer
RAS Components
Remote Access Server – 1 no.
Modems (Asynchronous) – 4 nos.
PSTN (telephone) lines – 4 nos.

19. Complete Head Office Network
Leased Line
DSU/CSU
Modem
Router
PSTN
Internet
Router
Firewall
ISP
DSU/CSU
Remote
Access
Server
Modem Pool
Web Server and
Mail Server
ERP Server and other
shared Resources
VPN Gateway
Wireless
Access Point
Mobile Users

20. Bill of Material Head Office Branch Warehouse Store Total
Ethernet Switch 3 1 6
Optical Transceivers 4
Router 2 5
DSU/CSU
Modem (Sync.)
Remote Access Server
Modem (Async.)
Firewall
VPN Gateway
Wireless AP  1 1 
Cable Plant ü

21. Summary Business requirement Network requirement Local area network
Wide area network
Internet connectivity
Firewall and VPN

22. Thank you