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FEATURE 1
The Secret of the Numbers Used on IP Networks
The mechanism of communications over an IP network can be seen by examining
five different kinds of numbers
- In an IP network the following five numbers are used to identify
users and message senders: the MAC Address number, the Ethernet Type
number, the IP Address number, the Protocol number, and the Port number.
These numbers are indispensable to communications over an IP network.
What are they used for? Who decides on the numbers?
This article examines
their roles and formats in detail.
Prologue
An IP network requires the five numbers to function properly
Part 1: Overview
The meaning and role of the numbers can be understood by answering
four questions
Part 2: Examination of Each Number
It is important to understand the various features of the numbers,
such as their length, the systems for expressing a number, and ways
to allocate the numbers
Epilogue
Data can be delivered to a destination through a combination of the
five numbers
Boxed Article
In addition to the five numbers, there are other numbers necessary
for an IP network
FEATURE 2
Introductory Course on IP Centrex
Learning about a new IP telephone service for businesses
- In the beginning, the IP phone service was launched for individual
users. Now, the service is spreading among corporate users. Under such
circumstances, a new IP phone service for businesses, called “IP
Centrex,” is attracting the most attention.
This article presents
a broad overview of the service, including features, mechanisms, and
points to be considered at the time of its introduction.
Part 1: What is IP Centrex?
- IP phones and the PBX service can be integrated, leading to a reduction
in communications expenses and the elimination of the labor required
for the operation of the PBX service
Part 2: How does it work?
- IP phones and servers work together, and internal phone functions
are carried out through an extension of SIP
Part 3: What points should be considered at the time when IP Centrex
is introduced?
- It is important to keep subscribed telephone lines available, and
the bandwidth for WAN connection can be ensured through QoS
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