Legacy Netware (3.x)

• clients
  • DOS, Windows, Windows 95, Windows NT (Netware 4.1), Unix, OS/2, Macintosh
  • client software is operating specific
  • example: client software for DOS clients (through version 3.11 of Netware) called NetWare Shell or NETx (NETx.com)
  • x refers to DOS version
  • the NetWare Shell program intercepts commands generated by programs running on the PC and decides if the commands should be handled by the PCs operating system (DOS in this example) or the Netware operating system of the network
• netware server
  • can communicate with clients using various communication protocols such as TCP/IP or IPX/SPX
  • offers clientssuch services and file and print sharing
  • the netware operating system or kernel resides in its own disk partition
  • note that DOS (or UNIX or Windows NT) needed to be first installed in its own partition so that NetWare could later be installed

• NetWare Loadable Modules (NLMs)
  • special programs that interact with the Netware kernel. These special programs are written by other software vendors
  • NLMs fall in three major categories
    • operating system enhancements
      • like virus protection, network interface card drivers, disk drivers
    • application programs
      • these actually run on the server rather than being transferred to the client
    • relational database management systems
      • like application programs, these databases run on the NetWare server
• Bindery Services
  • NetWare 3.12 keeps track of users, user groups, file and directory access rights, print queues, printers and other services in bindery files
  • service and authorization requests (like login and password verification) are verified against the information in the bindary files
  • bindary services are organized around three related concepts
    • objects - users, printers, disk volumes, etc.
      • kept in NET$OBJ.SYS
    • properties - login time restrictions, file and directory access rights, etc.
      • kept in NET$PROP.SYS
    • values - these describe the properties like 8am to 5 pm for login time restriction
      • kept in NET$VAL.SYS
• Communication protocols
  • client and server communication depends on communication rules or standardized communication protocols
  • IPX (internet packet exchange)
    • at network layer of OSI
    • connectionless - fully addressed packets able to find network destination
    • unreliable - no error checking or acknowledgment of error free receipt
    • encapsulates higher level packets
  • SPX (sequenced packet exchange)
    • at transport layer of OSI
    • connection-oriented - virtual circuits established before packets are sent. Then packets are sent sequentially
    • reliable - error checking and acknowledgment
  • RIP (routing information protocol)
    • router-to-router protocol keeps addresses stored in routers up to date
    • a RIP packet can transport multiple routing table entries in one packet
    • a negative of RIP is that every router broadcasts its entire routing table every 60 seconds to all other routers directly attached to it
  • SAP (service advertising protocol)
    • advertises services provided to all other reachable networked servers
    • broadcasts every 60 seconds
    • networked servers store the information in their NetWare bindery for future reference
    • local workstations query their local server which looks in its bindery for the closest service
    • some services are: file server, job server, gateway, print server, TCP/IP gateway
    • information of several servers can be requested or stored on one packet
  • NCP (netware core protocols)
    • provides a standard set of commands or messages used to communicate requests and responses for services between clients and servers
    • extends workstation's operating system capabilities onto the network
    • some of the messages would be: get file size, close a file, delete a file, rename a file, open a file, create a file, get a directory entry