Chapter 11 Enterprise Networks Internet Enterprise Network Architecture

Chapter 11 Enterprise Networks & Internet • Enterprise Network Architecture • Internet • Enterprise Network & Internet

Enterprise Network Architecture • Overview • Logical Design • Physical Design

Overview • Virtual corporation • Virtual private network or enterprise network – Virtual LAN • Technology – LAN switches – ATM switches – Backbone routers – SONET

Overview • Application – Collaborative computing application software – Intelligent-based software • Data: distributed database

Virtual LANs Logical Design • Use LAN switch with software • Types – Layer 2 virtual LAN (switch) – Layer 3 virtual LANs (routing switches) • Pro – Lower cost of constantly changing and moving workstations • Limitations – – Broadcasting and multicasting to its members Hard to manage (switching) No filtering for security No standard and interoperability

Virtual LANs Logical Design • Transmission alternatives – Signaling message (broadcasting address) – Frame tagging (address tag) – Time division multiplexing (bandwidth) • IEEE 802. 10: encryption, authentication, segmentation, reassembly • Bandwidth Hierarchy – Distributed backbones: bridge – Collapsed backbones: router with numerous internetworking modules and enormous bandwidth capacity

Physical Design: ATM LAN emulation • ATM address resolution – LAN emulation client (LEC) software • ATM-to-LAN conversion devices • convert Ethernet, token ring or FDDI into fixed length ATM cells • Unicast (point-to-point) transmission – LAN emulation server (LES) software • LES configuration services • LES broadcast and unknown services (BUS) • LES emulation services (address resolution protocol)

Physical Design: ATM LAN emulation • Pros – support multiple network layer protocols between virtual LANs • Cons – Flat network topoloty – Broadcast storms – No filtering for security

Protocols over ATM Network • Classical IP over ATM – Logical IP subnet or LIS: within subnet – Needs ATM address resolution protocol (ATMARP) • Multiprotocol over ATM (MPOA) – Edge devices – Route server • IP switching – Long file use layer 2 – Short message uses layer 3

Internet Survey • • • 72% enhance company image 22% financially rewarding 40% financial rewards after 12 -24 months Less 6% using credit card transaction 11 million Internet users 200 million television viewers

Business Objectives: Internet • • Customer service Marketing opportunity Competitive pressure Financially profitable

Internet Services/Resources • World Wide Web • Information servers – FTP servers – Gopher servers – WAIS servers – USENET servers • Global e-mail

World Wide Web • Web browsers • Web site • Graphical or multimedia

Information Servers • Telnet: TCP/IP • FTP servers: file transfer protocol • Gopher – Search engines – Text • WAIS (wide aarea information services) • USENET servers: Network new transport protocol (NNTP)

Global E-Mail • List server • Electronic magazines (E-zines

Internet Pro & Con • Pro – – – Access Bandwidth Front-end tools Server tools Information • Con – – – Security Bandwidth search Ownership Regulation

Internet Connectivity • Internet access providers (IAP) or Internet connectivity providers (ICP) • Internet presence provider (IPP) • Network access device – Modem – CSU/DSU – Router

WWW Connectivity Alternatives • Web browser – Mosaic – Internet Explorer – Netscape • Web terminology – Hypertext transport protocol (HTTP) – Hypertext markup language (HTML) – Uniform resource locator (URL)

Web Browser Selection Criteria • • Vertical integration: e-mail Ease of setup and use Performance Horizontal integration: network attached resources

Internet E-Mail Gateways • Translator • Simple mail transport protocol (SMTP) – No foreign character – Limited file size – No executable file • Multiple Internet mail extension (MIME)

Internet Gateway vs. Internet. Enable Clients • Internet gateway – Pros: single location, easy management – Cons: bottleneck • Internet-enabled clients – Pro: not bottleneck – Cons: configuration, software, LAN protocol

Internet/Web Server Analysis • Link to Internet • IP address (IAP or Inter. NIC) • Server hardware – CPU: 120 MHz Pentium – Storage: RAID – Bus: PCI – Memory: 128 MB – Network interface card: 100 -Mbps Ethernet – High-end UNIX workstation

Internet/Web Server Analysis • Server software – Web page & input form (common gateway interface CGI) – Gateway: file transfer – Security – Management: monitoring & reporting

Assignment • Review chapters 9 -11 • Read chapter 12