Local Area Networking Notes
This article describes local area networking protocols and APIs, including NetBEUI, NETBios, TCP, IP, IPX, SPX, ARP, RARP, RIP, SNMP, DLC, IPX/SPX, NDIS, ODI, AND TDI.
Part 10: Local Area Networking Protocols and APIs
Summary of Networking Protocols
Network Classes and IP Addresses
A=Assigned by NIC
Networking Addresses For Exercises
A network segment is a physical division, set off by switches/routers. All it means is it's a broadcast area, i.e. broadcasts will go to an entire network segment.
A subnet is a logical organization method for IP networking (also IPX, I believe). You can have multiple subnets running on a single hub even.
Example: In Newport, all the PCs are on 155.42.140.x and all the Macs are on 155.42.139.x. Doesn't matter that a Mac and a PC can sit next to each other and be plugged into the exact same hub. The router in the closet knows that these two subnets are local, and handles the interchange between the two.
A subnet mask is a number that defines what part of an IP address refers to the network (subnet), and which part refers to the host (node).
Assigning IP Addresses
IP addresses can be manually assigned to machines using the Networking Applet in Win9x and NT.
When addresses are assigned manually, they are called static IP addresses.
On larger networks, the 254 addresses available to a class C license are inadequate to provide an IP to every seat, so hosts which are not actually connected to the Internet use private network IP addresses.
The standard private network addresses (which are not passed along by routers) are standard ranges of addresses which any network can assign to hosts which are not being connected to the Internet.
Reasons for using private network addresses on our networks:
Private Network Addresses
Dynamically assigned IP addresses (DHCP)
Dynamically assigned IP addresses offer two advantages over static addresses:
A server running the Dynamic Host Configuration Protocol (DHCP) dynamically assigns IP addresses to clients.
DHCP does NOT relate host names to IP addresses. This is the job of DNS and WINS
Setting up DHCP on NT Server
Settings needed on the workstation
How does it work? See Minasi, p.933.
Four steps in client getting an IP Address from a DHCP server:
Service Pack 4 makes at least 6 improvements to the DCHP service.
The DCHP database should be backed up so that if the DCHP machine buys the farm another one can be put up and running.
Domain Names and WINS (Windows Internet Naming Service)
Because IP addresses are not the easiest things to remember, and, indeed, because they may always be changing, we associate a word-like naming system with the actual IP addresses needed by the network protocols to create communications between computers and networks.
WINS (Windows Internet Naming Service)
WINS is only recognized by MS software, so it works for resolution inside your network/intranet (Minasi, p. 939), but, contrary to its name, it does not work for addresses outside your network/intranet - on the Internet, for example. For that you need DNS.
WINS provides name resolution for NetBIOS names in a routed environment, while DNS's job is provide name resolution for WinSock names in a routed environment. (Minasi p.939).
See Minasi pp.938-955 for full discussion of WINS.
Diagram of TCP/IP Protocol Suite
See Andrews, p.944).
Sockets relate to the OSI Application Layer.
(See Diagram of TCP/IP Protocol Suite, Andrews p.944).
Sockets are connections made between programs on one computer and those on another computer. They have three parts to them:
UDP is a connectionless protocol, it is used to broadcast messages when no response is required. Example of an application for UDP is mapping network drives. Error correction is not done by UDP, it must be provided by the application using it.
Error correction maps to the OSI Transport Layer)
(See Diagram of TCP/IP Protocol Suite, Andrews p.944).
IP is a routing protocol, TCP is a connection protocol, which means that it is there to provide end-to-end integrity.
TCP uses AKS's and NAK's to ensure that all packets are delivered and delivered in an undamaged state. It uses the IP's header checksum to determine if a packet is a good one.
Address Resolution relates to the OSI Network Layer)
(See Diagram of TCP/IP Protocol Suite,
DLC (Data Link Control)
Often used by Token-Ring networks to make their PC workstations talk to mainframe gateways, many (but not all) of which require DLC.
Also used to communicate with network printers. Eg. Use DLC to control a laser printer attached directly to the network with a JetDirect print server (network interface) card.
Supported by NT.
IPX/SPX (Internetwork Packet Exchange/Sequenced Packet Exchange)
"The most popular local area network type in the world is Novell Netware". (Minasi, p.81)
Supported by NT beginning with NT 4.(as part of the NetWare Compatible Services.
Like TCP/IP, IPX is routable and enjoys widespread support, but TCP/IP provides Internet connectivity.
Multiple transport stacks
Loading more than one protocol at a time permits connecting with diverse servers (Novell/MS), mainframe gateways, and routers (internet mail).
Example: the NT Network Stack:
Network Binding Interfaces
Bindings interface the NIC software driver with a network transport protocol.
This way one driver can be written to the interface's standard and can then communicate with any higher-level transport protocol.
Network APIs(Minasi, p.84)
Application Programming Interface. Primitive commands which are used by programmers to access (network) operating system services. Examples:
Bruce Miller, 2002, 2017
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