Fluke NetDAQ 2645A - Manual (Page 274)

2640A/2645A NetDAQ
Users Manual
I-12
Currently, the WINSOCK DLL that operates with LAN Workplace must be
downloaded from the Novell forum on CompuServe or you must request a copy
from Novell. TCP/IP protocol packages with included WINSOCK DLLs can be
purchased from a variety of sources including Microsoft, Banyan, FTP, SunSoft,
and IBM.
The Transmission Control Protocol/Internet Protocol (TCP/IP) has evolved as a
networking protocol that supports communication among diverse computers and
devices (at U.C. Berkeley there once was a TCP/IP-connected Coke machine). The
TCP/IP protocol can be used to communicate between programs running on many
different computer systems, running under many different operating systems, and
even running on several different physical network types (Ethernet being only one
of the many types supported).
The TCP/IP protocol stack is isolated from the underlying network hardware by a
device driver. Applications use TCP/IP resources via one of the several
Application Programming Interfaces (API) that are commonly supported by
network software vendors. The API used by the NetDAQ software is WINSOCK
(discussed below). There are also API’s for file transfer (FTP) and file sharing
(NFS and others).
You rarely need to know the details of the TCP/IP protocol. In summary, TCP/IP
enables two computer systems to establish a connection that allows data to be
exchanged. Data to be transmitted is broken up into manageable chunks (packets)
by the TCP portion of TCP/IP. TCP also reconstructs the data at the receiving end
by merging the chunks back together in the correct order. TCP also assures error-
free communication by use of a checksum within each packet. Finally, TCP uses
the Port ID to specify the specific application within each system that is sending
and receiving the data.
The IP portion of the TCP/IP protocol simply addresses, sends, and receives
packets. It uses the IP address, the Subnet Mask, and the Default Gateway
information. The IP address is described in “IP Addresses and Segmented
Networks” in this appendix.
The subnet mask is used to separate the network ID from the host ID in an IP
address. For example: if the IP address of a NetDAQ address was 198.178.246.10,
and a class C network ID was active, the subnet mask would be 255.255.255.0.
When this mask is applied to the address, the network ID is extracted as
198.178.246 and the host ID as 10.
The default gateway information is only used when your network contains more
than one subnet, or is connected directly to the Internet. When the network ID of
the source and destination address of a packet are different (hosts on different
network segments), the packet is forwarded to the default gateway for delivery.
The default gateway has knowledge of the network IDs of the other network
segments, so it forwards the packet to other gateways on the network until the
packet is delivered to the gateway attached to the destination segment with the