User`s guide

Glossary
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E5810B User’s Guide 131
ICMP
Internet Control Message Protocol (ICMP) is an extension to
the Internet Protocol (IP) defined by RFC 792. ICMP
supports packets containing error, control, and informational
messages. The ping command, for example, uses ICMP to test
an Internet connection.
RPC
Remote Procedure Call (RPC) is a type of protocol that
allows a program on one computer to execute a program on
a server computer. Using RPC, a system developer does not
need to develop specific procedures for the server. The client
program sends a message to the server with the appropriate
arguments and the server returns a message containing the
results of the program executed.
P
Proxy server
Proxy server is a server that sits between a client
application, such as a Web browser and a real server. It
intercepts all requests to the real server to see if it can
fulfill the requests itself. If not, it will forward the request
to the real server. Proxy servers have two main purposes:
Improve performance
Proxy servers can dramatically improve performance for
groups of users, since a proxy server saves the results of all
requests for a certain amount of time. Consider the case
where both user X and user Y access the Web through a
proxy server. First user X requests a certain Web page,
which we will call Page 1. Sometime later, user Y requests
the same page.