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Explaining TCP/IP (Transport Control Protocol / Internet Protocol) |
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IP Address Conflicts - Internet or IP Address devices won' work |
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Computer
Communications - Protocols
A protocol is a set of instructions, like a language, which enables parties/objects/devices to interact or communicate with each other.
Computers use many types of protocols but most are used in networks.
Networks may be local area network (LAN) - PCs attached to each other by cables; or wide area networks (WANS) where computers are connected by telephone land lines /microwave communications /satellite communications. Another network is the Internet, a worldwide interconnection of computers.
For example a network of computers in an office connected by network cable, is usually called a LAN (local area network). This type of network may use IPX/SPX protocol, or NetBEUI or NDISWAN or TCP/IP. The Internet and Wide Area Networks use TCP/IP.
Many LANs like those with Windows 3.11 (Windows for Workgroups),Windows 95/98/ME operate using NetBEUI as the LAN Manager, whilst Windows NT, 2000 tend to use TCPIP. IPXSPX helps Win95/98 computers to communicate, and would be need for Dialup networking to another PC (Not the Dialup for an Internet server PC – this as mentioned uses TCPIP).
Another protocol is NDISWAN which is used by a computer's dial-up adapter to connect to ISDN devices.
Because most computers can be connected to the Internet, or may be connected to a serving device, we shall look at the protocol for this first: TCP/IP
You may however access the Internet not by a Dialup Adapter and a modem, but on a LAN network which has an ADSL unit and/or Router attached to the network hub or Network Switch. For information on this see adsl.htm.
Explaining
TCP/IP (Transport Control Protocol / Internet Protocol)
Computers send data, not in one lump down one line/frequency but in small packets, with each packet often routed down different lines or routes to the destination.
This stops congestion on one route and with many possible routes if one route is blocked/busy then an alternate route can be found for the packet of data.
Routing of data packets also gives security in that one route does not receive the complete set of packets - the full transmission. Any person attempting to intercept the message or file on one route will probably only get one small packet, the others being transmitted down different lines.
TCP - Controls physical transfers of data packets between computers, e.g: accepting and confirming receipt, sending or re-sending of data packets.
IP - Internet Protocol - The common protocol (or language) for all Internet communication used so that different computer systems (e.g: DOS, Windows, UNIX, LINUX..etc) can all communicate using this one protocol.
Gateways
Allow connection between networks that are not compatible with each other.
For example a network of computers in an office connected by network cable, is usually called a LAN (local area network). This type of network normally uses IPX/SPX protocol (or sometimes TCP/IP - see below). The Internet and Wide Area Networks use TCP/IP.
A Gateway will allow inter-communication between these differing networks (protocols).
DNS - Domain Naming Service.
The normal PC communicating with an ISP (Internet Service Provider) does not use this service. You may even have a website offered by an ISP which is just space on their server. If however, you have a Domain Site (e.g. myname.com) then this a domain site and will use DNS
WINS - Windows Internet Naming Service
Used for programs that require NETBIOS protocol support. Most computers do not use programs which need NETBIOS protocol support on TCPIP.
DHCP - Dynamic Host Configuration Protocol
Automatically obtains necessary Information such as an IP address e.g. from your ISP's (Internet Service Provider) server computer. Your PC connecting to an ISP will not use WINS but get the IP Address via DHCP.
PPP - point-to-point protocol
Used by a Dial-up Router or other routing device. Not used by the standard computer.
TCP/IP Transport
Control Protocol / Internet Protocol
Reminder of what TCP/IP is:
TCP - Controls physical transfers of data packets between computers, e.g: accepting and confirming receipt, sending or re-sending of data packets.
IP - Internet Protocol - The common protocol (or language) for all Internet communication
IP Address &
Subnet Mask
IP address - Assigned by a DHCP Server (See above) or PPP Router computer or other PPP device
Subnet Mask - 255 in a position relates to a number up to 255 available in that same position in the IP Server address.
0 in a position blocks a number from the Server Address in that same position in the IP Address.
thus. IP: 209. 12. 26. 25
Mask: 255. 255.255. 0
The last number (here 25) is blocked from the Server address because it denotes not the address of the server but of a number relating to a specific computer attached to the server.
IP Addresses are not only used for Internet connections, but for WANS (Wide Area Networks) and even devices which serve other computers, such as Printer Servers (large printer devices e.g a Cannon Gp). Computers attached to these devices will not see (be able to communicate with) the server if they do not have an IP address & Mask. E.g:
Server Address: 209.12.26
1st Computer: IP Address 209.12.26.01
Mask 255.255.255.0
2nd Computer: IP Address 209.12.26.02
Mask 255.255.255.0
Etc.
IP Address
Conflicts - Internet or IP Address devices won' work
IP addresses are not confined to your ISP Internet Server, but can be found on a other devices such as a network Print Server printer-copier.
This is probably because one server is polling for attention whilst another is in operation, or because the have conflicting 'gateways'.
Example:
Printer Copier Server: IP Address 240.240.240.0
Conflicting with:
Internet Service Provider. IP Address: obtained automatically.
Resolution:
- Under TCP Network Card, remove the 'gateway'.
- Under the Dial-up Networking connection for the Internet Service Provider (My Computer, Dial-up Networking), change the TCPIP setting from automatic to the actual IP Address (if not known, get this address from your ISP)
Configuring
a Printer Server that uses TCPIP
We have seen at TCP/IP addresses are used for servers whether on the
Internet, or local printer servers.
Normally to connect a network printer to a PC on a network, you would use
"Add Printer, then Network Printer …etc" from the Printers icon in My
Computer. In the case of HP Lazer printers, you don't usually have to load the
software drivers from a CDRom, as this come over the network during the
process. Many other printers however may need software manually adding to the
local PC.
BEFORE you try to connect a network printer however, in the case of a
Printer Server printer, you should NOT carryout the above first.
BEFORE adding the printer you must determine and set the TCP/IP address
for the Network Adapter card in the PC. This means adding the IP address (and
Subnet Mask), the last digit of the IP address being a new number from that of
the printer/server.
This last digit in the IP address, indicates the ID of the device on the
printer/server network - in this case the PC. For details about these settings
see: TCPIP settings and how to change them
see: Changing IP Addresses .
Failure to do this will result in the Printer/Server not being visible on
the network when you go to add it .
Having set the IP address for the PC's network adapter, now when you go
to 'Add a Printer' the Printer Server will appear on the relevant PC on the
network and you may proceed.
To find or adjust the IP address and Mask of
a computer's network device, so that it can communicate with a Serving device
that requires addressing.
Option1.
- Start, Settings, Control Panel, Network
- In the Configuration tab, Components installed list, select the TCI/IP for the network card
e.g: TCP/IP -> <your adapter name>Ethernet Adapter
- Click the Properties button
- Select the IP Address tab
- The 'Specify IP Address' option should already be selected
- If not then you are not currently connecting to any network server that requires the IP address to be given - e.g. The server of your ISP is gained automatically by DHCP
- If there is a serving device on the network that does require an IP address, then contact your network manager or the supplier of the device for the correct address
- Change the IP Address and Mask accordingly.
Option2.
- Run Winipcfg.exe contained in your Windows folder, then view/supply new address.
