Network Servers

• Functions
• Hardware Specifications
• Hot-pluggable Redundancy
• RAID
• Types

• Functions
• Selection Criteria
• Specifics
• Novell NetWare
• Windows 95/98
• Windows NT/2000

• Licensing
• Tracking

Network Server Functions

• Central repository for shared resources
• Provide services to other computers on the network
• File storage
• Print services
• Application sharing
• Communication services
• Enforce enterprise-wide rules - provide consistency
• Facilitate communications
• Client/Server
• Distributed data
• Distributed processing
• Fat client - primary processing is done on the client computer
• Thin client - primary processing is done on a terminal server computer which client accesses; client is used as a terminal

• Typically, fastest computer with the most resources on the network
• Hot-pluggable redundancy
• Power supplies
• Disk bays
• Cooling fans
• Multiple processors
• Backup capabilities
• RAID - Redundant Array of Inexpensive Disks
• RAID 0 - data is written (striped) in sequential sectors across 3 or more drives
• No redundancy
• Dramatically increased performance
• RAID 1 - identical data is written (mirrored) onto identical drives
• Redundancy - half of total drive capacity is lost
• RAID 5 - data is striped across several drives; parity data is distributed across the drives
• Parity data allows recovery from the failure of any single drive

• Application server - manages access to centralized applications software
• Database server
• File server - manages access to individual user files
• Print server - manages print queues for output to printers
• Mail server - manages the flow of electronic mail
• Should be secured against Spam! - only mail originating at the site should be transferred to external locations
• IMAP - Internet Message Access Protocol - uses SMTP to transfer data between server and mail application
• Mail remains on server so it can be accessed from multiple locations
• POP - Post Office Protocol - also uses SMTP
• Mail typically removed from server when it is accessed
• News server - provides access to Usenet News groups
• Web server - provides access to Web resources
• Secure server - encrypted transmissions between browser and server via PKI
• Commerce server - provides secured (hopefully!) environment from which commercial transactions may be performed
• Proxy server - a server that sits between a client application and a real server
• Allows sharing a single Internet connection with an entire network
• Barrier between Internet and internal network
• Firewall - blocks various protocols and IP addresses from coming into the network or going out from the network (this function can also be done via a router)
• Terminal server - provides computing power in place of less powerful computers (thin clients) for client/server applications
• Fax server - manages the flow of facsimiles
• Directory services server - keeps track of data spread across multiple servers

Network Operating System Functions

• Network Housekeeping
• Manage Network Files
• Contain Network Control Functions
• Printer Queues
• Security Functions
• File Server Control
• Nondedicated Server - performance of the LAN may suffer
• Dedicated Server - preferred for all but the smallest LAN

• Application Compatibility
• Not all applications work with all network operating systems
• Single-user Software - metering software
• Multi-user Software - file, record, or field locking
• Network Software - built-in license-server software
• Performance
• Processor Support
• Single processor - typical in most smaller LANs (i.e., those under 100 nodes)
• Multiple processors - for larger LANs
• Asymmetric - specific tasks to specific processors
• Symmetric - load shared across all processors
• Network Interface Card Support
• Multiple cards in the server can reduce segment traffic
• Access method - Ethernet or Token Ring
• Network Tuning - allows network to be customized for server type and application type
• Fault Tolerance
• Uninterruptible Power Supply (UPS) - not NOS specific
• Maintains server integrity during power failures
• Allows controlled shutdown of server
• Disk Mirroring - separate identical disks, same disk controller
• Disk Duplexing - separate identical disks, separate controllers
• Server Duplexing - two servers running in parallel; if one fails, the other continues
• Security
• Access Privileges
• File and directory access
• LAN device privileges - firewall routers, printers, etc.
• Audit trails
• Interoperability
• NFS - Network File System
• AFS - distributed file system
• Manageability
• SNMP - Simple Network Management Protocol
• Ease of Use for Users and Administrators
• Graphical user interface (GUI)
• Text-based interface - menu or command line interface
• Client System Support
• DOS/Windows
• Windows NT/2000
• Apple Macintosh
• UNIX-based systems
• Network Operating System Support
• Direct through manufacturer
• Through reseller (dealer)
• Formal training program (e.g., CNE - Novell Certified NetWare Engineer, MCSE - Microsoft Certified Systems Engineer)
• Internetworking Capability
• Global Naming - the network appears as one big entity
• Support for internetworking protocols

Novell NetWare 3.12

• Dedicated Server - allows network resources to be shared
• files
• applications
• printers
• other peripherals
• NLMs (NetWare Loadable Modules) - allow new services to be added to the server
• TCP/IP Transport Protocols
• Tools for managing TCP/IP
• APIs (Application Programming Interfaces)
• NetWare 3.12 networks can be connected across a TCP/IP internetwork
• IPX (Internetwork Packet Exchange) packets can be tunneled through the Internet Protocol (IP)
• Up to 250 nodes (logical users or simultaneous users)
• Multiple Client Types
• DOS/Windows
• Macintosh
• UNIX-based systems
• VLMs (Virtual Loadable Modules) - client VLMs allow each client to be customized
• ODI (Open Data Interface) - allows third parties to write NetWare drivers for their network interface cards

• Enterprise-wide Network Operating System
• NDS (Novell Directory Services)
• Distributed database of users and resources on the network
• Multiserver network viewed as a single integrated system
• Symmetric Multiprocessing - load shared
• IP/IPX Gateway
• Licensing Services

• "Pure" IP environment
• NDS eDirectory - enhanced Novell Directory Services
• Allows secure Directory-enabled applications between networks (e.g., customers and supplier)
• Tracks demographic information
• Security
• Novell International Cryptographic Infrastructure
• SSL - Secure Sockets Layer
• RSA Public Key Infrastructure (PKI) - public key/private key encryption
• SAS - Secure Authentication Services
• X.509v3 Certificates - PKI for secure/signed email
• Smart cards
• Includes server software
• Web server
• News server
• FTP server
• Multimedia server
• Web search server

• Peer-to-Peer Network - each desktop computer can function as both a workstation (client) and a server
• Local resources can be made available to all computers on the network
• hard disks
• CD-ROMs
• printers
• Can be connected to other networks
• Microsoft Windows NT
• Novell NetWare
• Password Protection
• System Level
• Drive Level
• File Level

• Dedicated Server - Pentium…, RISC-Based Processors
• Part of Microsoft BackOffice
• Microsoft SQL Server - high-end client-server database
• Microsoft SNA Server
• Microsoft Systems Management Server
• Microsoft Mail Server
• Client-Server Applications - claims to support thousands
• Multiple Client Types
• Windows 95/98
• Windows NT Workstation
• Macintosh
• UNIX-based systems
• Unlimited Nodes - just add Client Access Licenses
• Built-in TCP/IP Support
• Works in Conjunction with Most Other Networks

• Symmetric Multiprocessor Support - up to 4 processors (8 w/ adv.)
• Native TCP/IP
• Native ATM and Gigabit Ethernet support
• Cluster service - redundant server support
• Encrypting File System
• Terminal Services
• Active Directory
• Scalability
• Internet standards
• Full LDAP (Lightweight Directory Access Protocol) support
• DNS-based name space
• Security
• Kerberos
• X.509 Certificates
• SSL
• IPSec - IP Security (protocols being developed by IETF)
• Smart cards
• Application Services
• Win32 APIs
• Component Applications Services - Component Object Model (COM)
• Load balancing
• Includes Web tools
• Internet Information Services (IIS) - integrated Web services - including multi-site hosting
• Active Server Pages (ASP) - Web-server scripting
• Windows Media Services - digital media across the Internet
• Web Telephony Engine
• Certificate Server - for PKI functionality

• LAN-unaware applications - the only additional functionality provided to the application by the LAN are additional disk drives upon which to place data
• Word processing
• Spreadsheets, etc.
• LAN-aware applications - obtain additional functionality from the LAN, but would operate in a stand-alone mode
• Database programs
• LAN-dependent applications - applications don't do much of anything without a network connection
• Mail programs
• Groupware
• Licensing
• Per-user license
• Per-seat license
• Network license
• Site license
• Tracking
• Manual
• Metering software