Classroom Companion: Business

 
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Questions
1. Which organizations are responsible for standardization and allocation of:
(a) Telephone numbers?
(b) E-mail addresses?
(c) Web addresses?
Hint: this information is found by searching the Internet.
2. How can a 4G smartphone communicate with a GSM phone for voice com-
munication despite being designed to incompatible standards?
3. Which protocols are standardized by RFC791, RFC2616, and RFC793?
 
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Answers
1. The standardization bodies responsible for allocation of telephone numbers, 
e-mail addresses, and web addresses are:
(a) ITU has standardized the general formats of international telephone num-
bers and is responsible for allocating unique country codes identifying the 
country. This code consists of the first one, two, or three digits of the inter-
national telephone number. The remaining digits (called the national tele-
phone number) are allocated by national authorities, either a regulatory 
authority or the telephone network operator.
(b) The e-mail address is written as local-name@domain-name (e.g., 
Joe.
[e-mail]
) where domain name is accredited and registered by 
15.6 · Conclusions

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the Internet Corporation for Assignment of Names and Numbers 
(ICANN), and the local name is allocated by the e-mail provider. The allo-
cation principle is standardized by the Internet Engineering Task Force 
(IETF). The domain name identifies the host and is converted to a unique 
IP number for sending the e-mail over the Internet to the e-mail server.
(c) The format of the web address was proposed by Tim Berners-Lee and stan-
dardized by IETF. The format is composed of three parts as follows: 
ptotocol://
7
www. domain- name/index. html
. The protocol is either http or 
https, the domain name is the same as for e-mail addresses (allocated by 
ICANN), and the index is the local address generated automatically by the 
file management system of the host computer. The index identifies the web 
page uniquely within the file system of the host computer.
2. The voice format is translated from the GSM format to the 4G format—and 
vice versa—by interworking units in the network. The same applies to conver-
sations between 4G (or GSM) and fixed telephones, between ordinary tele-
phones and VoIP telephones, between different standards of fixed telephones 
(e.g., between European and North American coding standards), and so on.
3. RFC791, IP version 4; RFC2616, http; and RFC793, TCP.