ch. fourteen
remote access and long-distance communications
Summary
■ The deregulation of the telecommunications industry allows for separate local
telephone systems and long-distance telephone systems, which increases
competition and reduces overall costs.
■ The Point of Presence (PoP) is the point where the public telephone line ends
and the customer premises telephone line and equipment begin.
■ Since the deregulation of the telecommunications industry, residents and
business owners are responsible for the telephone system on their side of the
Point of Presence (PoP).
■ There are many types of media available for communicating over long-
distances, such as Cable, DSL, ISDN, PSTN, satellite, SONET, and T1. Each is
offered at various speeds and costs.
■ Basic Rate ISDN (BRI-ISDN) consists of two B channels and one D channel
with a total bandwidth of 128 kbps.
■ Primary Rate ISDN (PRI-ISDN) consists of twenty-three B channels and one
D channel with a total data rate of 1.544 Mbps.
■ Broadband ISDN (B-ISDN) is the newest category of ISDN and is designed to
carry multiple frequencies; hence, the term Broadband.
■ Cable Internet service offers data rates as high as 36 Mbps downstream and
10 Mbps upstream. However, 10 Mbps is a theoretical speed.
■ Cable Internet service is defined by the Data Over Cable System Interface
Specification (DOCSIS) standard developed independently of IEEE 802.14.
■ DSL is offered in many varieties, such as ADSL, SDSL, HDSL, and VDSL.
■ The maximum allowable distance between a DSL modem and the Local
Central Office is typically 1,000 feet to 18,000 feet. This distance varies
according to the type of DSL used and any special equipment that might
exist on the telephone line, such as loading coils or a change in the media.
■ DSL bandwidth varies from 1.5 Mbps to 52 Mbps depending on the DSL
variation used and the distance from the Local Central Office.
■ Satellite communications is ideal for remote locations and offers various
speeds based on cost of equipment and service.
■ Consumer satellite service bandwidth is typically 400 kbps to 500 kbps.
■ Commercial satellite service bandwidth is a maximum 1.5 Mbps in the USA
and 2 Mbps in Europe.
■ Satellite communications use microwave technology and must have a clear
line of site between the satellite and the satellite dish.
■ T-carriers are leased lines and range from fractional T1 to T4. The most common
T-carrier lines encountered in networking are fractional T1, T2, and T3.
■ A T1 line consists of 24 channels with 64 kbps of bandwidth available per
channel.
■ T1 offers a maximum bandwidth of 1.544 Mbps, and T3 offers 44.736.
■ Synchronous Optical Network (SONET) offers the highest bandwidth and
the greatest distances.
■ X.25 is an older telephone line technology that is rarely encountered in the
USA but still exists in other parts of the world.
■ Frame Relay is the replacement for X.25 and employs a Permanent Virtual
Circuit (PVC).
■ Frame Relay and X.25 are packet switching technologies.
■ Dial-up networking allows a user to access a network remotely using
telephone lines.
■ Dial-up networking requires a modem and remote access software to be installed
on the client side of a remote connection and on a remote access server.
■ Serial Line Interface Protocol (SLIP) is an older protocol used to support remote
connections over telephone lines. It has been replaced by PPP and PPTP.
■ Point-to-Point Tunneling Protocol (PPTP) encapsulates other protocols inside
the PPTP packet, resulting in a secure connection.
■ Multi-Protocol Label Switching (MPLS) can be used with IPv4- or IPv6-based
networks as well as, ATM, Frame Relay, or most any networking technology
available today.
■ MPLS provides a more efficient method of routing packets than traditional
routing protocols.
■ The main two applications of MPLS are network traffic shaping and support
for VPN.
■ A Virtual Private Network (VPN) is a secure connection over a public
network system based on software, not hardware.
Review Questions
Answer the following questions on a separate sheet of paper. Please do not write in this book.
1. What is the name used for the telephone line running between customer
premises and the Local Central Office?
2. Where is the Point of Presence (PoP) located?
3. What does the acronym ISDN represent?
4. How many channels are there in a BRI-ISDN cable assembly?
5. What is the maximum bandwidth of a BRI-ISDN service?
6. What is the maximum bandwidth for a telephone modem?
7. What is the purpose of the D channel in an ISDN cable assembly?
8. What is the maximum theoretical bandwidth for Cable Internet access?
9. What factors influence the speed of a Cable Internet service connection?
10. What is the difference between a T1 and a fractional T1 line?
11. How many T1 lines make up a T3 line?
12. Which has the highest bandwidth: a T1 connection or a telephone modem
connection?
13. Which has the highest bandwidth: SONET or ISDN?
14. Which has the highest bandwidth: T1 or X.25?
15. What high-speed technology is used for long-distance communications
especially overseas via underwater?
16. Which has a highest bandwidth: ISDN or consumer satellite service?
17. What does the acronym CSU/DSU represent?
18. What type of media is a CSU/DSU associated with?
19. Match the following:
1. ISDN
2. DSL
3. SONET
4. T3
5. Telephone modem
20. What is the main difference between SLIP and PPP?
21. In what situation is the PPPoE protocol used?
22. What is the main difference between PPTP and PPP?
23. What is the difference between a Virtual Private Network (VPN) and a
network that uses a T1 line to connect two branch offices?
24. What does the MPLS represent?
25. What are the two main applications for MPLS?
26. To which layer of the OSI model does MPLS align?
27. Which protocol is used to distribute MPLS label information to all MPLS-
enabled routers?
■ The deregulation of the telecommunications industry allows for separate local
telephone systems and long-distance telephone systems, which increases
competition and reduces overall costs.
■ The Point of Presence (PoP) is the point where the public telephone line ends
and the customer premises telephone line and equipment begin.
■ Since the deregulation of the telecommunications industry, residents and
business owners are responsible for the telephone system on their side of the
Point of Presence (PoP).
■ There are many types of media available for communicating over long-
distances, such as Cable, DSL, ISDN, PSTN, satellite, SONET, and T1. Each is
offered at various speeds and costs.
■ Basic Rate ISDN (BRI-ISDN) consists of two B channels and one D channel
with a total bandwidth of 128 kbps.
■ Primary Rate ISDN (PRI-ISDN) consists of twenty-three B channels and one
D channel with a total data rate of 1.544 Mbps.
■ Broadband ISDN (B-ISDN) is the newest category of ISDN and is designed to
carry multiple frequencies; hence, the term Broadband.
■ Cable Internet service offers data rates as high as 36 Mbps downstream and
10 Mbps upstream. However, 10 Mbps is a theoretical speed.
■ Cable Internet service is defined by the Data Over Cable System Interface
Specification (DOCSIS) standard developed independently of IEEE 802.14.
■ DSL is offered in many varieties, such as ADSL, SDSL, HDSL, and VDSL.
■ The maximum allowable distance between a DSL modem and the Local
Central Office is typically 1,000 feet to 18,000 feet. This distance varies
according to the type of DSL used and any special equipment that might
exist on the telephone line, such as loading coils or a change in the media.
■ DSL bandwidth varies from 1.5 Mbps to 52 Mbps depending on the DSL
variation used and the distance from the Local Central Office.
■ Satellite communications is ideal for remote locations and offers various
speeds based on cost of equipment and service.
■ Consumer satellite service bandwidth is typically 400 kbps to 500 kbps.
■ Commercial satellite service bandwidth is a maximum 1.5 Mbps in the USA
and 2 Mbps in Europe.
■ Satellite communications use microwave technology and must have a clear
line of site between the satellite and the satellite dish.
■ T-carriers are leased lines and range from fractional T1 to T4. The most common
T-carrier lines encountered in networking are fractional T1, T2, and T3.
■ A T1 line consists of 24 channels with 64 kbps of bandwidth available per
channel.
■ T1 offers a maximum bandwidth of 1.544 Mbps, and T3 offers 44.736.
■ Synchronous Optical Network (SONET) offers the highest bandwidth and
the greatest distances.
■ X.25 is an older telephone line technology that is rarely encountered in the
USA but still exists in other parts of the world.
■ Frame Relay is the replacement for X.25 and employs a Permanent Virtual
Circuit (PVC).
■ Frame Relay and X.25 are packet switching technologies.
■ Dial-up networking allows a user to access a network remotely using
telephone lines.
■ Dial-up networking requires a modem and remote access software to be installed
on the client side of a remote connection and on a remote access server.
■ Serial Line Interface Protocol (SLIP) is an older protocol used to support remote
connections over telephone lines. It has been replaced by PPP and PPTP.
■ Point-to-Point Tunneling Protocol (PPTP) encapsulates other protocols inside
the PPTP packet, resulting in a secure connection.
■ Multi-Protocol Label Switching (MPLS) can be used with IPv4- or IPv6-based
networks as well as, ATM, Frame Relay, or most any networking technology
available today.
■ MPLS provides a more efficient method of routing packets than traditional
routing protocols.
■ The main two applications of MPLS are network traffic shaping and support
for VPN.
■ A Virtual Private Network (VPN) is a secure connection over a public
network system based on software, not hardware.
Review Questions
Answer the following questions on a separate sheet of paper. Please do not write in this book.
1. What is the name used for the telephone line running between customer
premises and the Local Central Office?
2. Where is the Point of Presence (PoP) located?
3. What does the acronym ISDN represent?
4. How many channels are there in a BRI-ISDN cable assembly?
5. What is the maximum bandwidth of a BRI-ISDN service?
6. What is the maximum bandwidth for a telephone modem?
7. What is the purpose of the D channel in an ISDN cable assembly?
8. What is the maximum theoretical bandwidth for Cable Internet access?
9. What factors influence the speed of a Cable Internet service connection?
10. What is the difference between a T1 and a fractional T1 line?
11. How many T1 lines make up a T3 line?
12. Which has the highest bandwidth: a T1 connection or a telephone modem
connection?
13. Which has the highest bandwidth: SONET or ISDN?
14. Which has the highest bandwidth: T1 or X.25?
15. What high-speed technology is used for long-distance communications
especially overseas via underwater?
16. Which has a highest bandwidth: ISDN or consumer satellite service?
17. What does the acronym CSU/DSU represent?
18. What type of media is a CSU/DSU associated with?
19. Match the following:
1. ISDN
2. DSL
3. SONET
4. T3
5. Telephone modem
20. What is the main difference between SLIP and PPP?
21. In what situation is the PPPoE protocol used?
22. What is the main difference between PPTP and PPP?
23. What is the difference between a Virtual Private Network (VPN) and a
network that uses a T1 line to connect two branch offices?
24. What does the MPLS represent?
25. What are the two main applications for MPLS?
26. To which layer of the OSI model does MPLS align?
27. Which protocol is used to distribute MPLS label information to all MPLS-
enabled routers?