1 報告人：張克章教授應用密碼學與資安應用 dept. information management chang gung...

1報告人：張克章教授

應用密碼學與資安應用

Dept. Information ManagementChang Gung University

Applied cryptography & Information security

ModemModemADSLADSLISDNISDN

4G4G

103/1/2





CONTENTSCONTENTS

1. Modem (Modulation & De-Modulation)1. Modem (Modulation & De-Modulation)2. ADSL (symmetric digital subscriber line) 2. ADSL (symmetric digital subscriber line)

3. ISDN(Integrated services digital 3. ISDN(Integrated services digital network)network)4. 4G4. 4G





1. Modem1. Modem Cable modem [1 ] services are not only carriers

that deliver broadband services to household. Cable television operators, besides bringing Cable television operators, besides bringing

television into homes, also offer high-speed television into homes, also offer high-speed Internet access, as shown in Figure 6-22.Internet access, as shown in Figure 6-22.

The coaxial cable coming the home plugs into a The coaxial cable coming the home plugs into a device called a cable modem.device called a cable modem.

The cable modem has a coaxial cable port plus The cable modem has a coaxial cable port plus either an RJ-45 port or a USB port to connect PC either an RJ-45 port or a USB port to connect PC or access router.or access router.

[1] Cable modem,





Cable modem speed is shared by all users in a neighborhood, so rated speed is not very descriptive.

In practice, cable modem today normally provides real downstream throughput of about 5Mbps.

In general, individual cable modem throughput depends heavily on how many users in the neighborhood are shared the aggregate capacity at any time.





2. ADSL (symmetric digital subscriber line) 2. ADSL (symmetric digital subscriber line) ADSLADSL

ADSL [2] was originally designed to enable ADSL [2] was originally designed to enable telephone companies to deliver digitized signals to telephone companies to deliver digitized signals to subscribers at about 1.5 Mbps over existing twisted subscribers at about 1.5 Mbps over existing twisted pair copper telephone wire-wire connection.pair copper telephone wire-wire connection.

ADSL circuits have the high-speed downstream ADSL circuits have the high-speed downstream channel, the medium-speed upstream channel, and a channel, the medium-speed upstream channel, and a standard telephone channel. standard telephone channel.

[2] S. H. Rowe & M. L. Schuh, Computer Networking, Pearson Prentice [2] S. H. Rowe & M. L. Schuh, Computer Networking, Pearson Prentice Hall, 2005. Hall, 2005.





Figure 9.5 An ADSL circuit is divided into several Figure 9.5 An ADSL circuit is divided into several channels, and uses a much wider frequency range than a channels, and uses a much wider frequency range than a standard telephone circuit. standard telephone circuit.





Another offering is symmetric digital subscriber Another offering is symmetric digital subscriber line (SDSL).line (SDSL).

SDSL provides equal speed channels in both SDSL provides equal speed channels in both directions and many not include a telephone directions and many not include a telephone channel.channel.

SDSL is capable of speed of 2.3 Mbps in each SDSL is capable of speed of 2.3 Mbps in each direction, and is targeted at business customers.direction, and is targeted at business customers.

It technically is easier for the network service It technically is easier for the network service provider to implement SDSL than ADSL, provider to implement SDSL than ADSL, because simpler, less expensive equipment is because simpler, less expensive equipment is required at both head end and customer end of required at both head end and customer end of circuit.circuit.





The newest development is very-high-rate digital The newest development is very-high-rate digital subscriber line (VDSL).subscriber line (VDSL).

VDSL transmits data at top speeds of 51 to 55 VDSL transmits data at top speeds of 51 to 55 Mbps over short twisted pair telephone lines of Mbps over short twisted pair telephone lines of up to 1,000 feet and a lower speed of 13 Mbps at up to 1,000 feet and a lower speed of 13 Mbps at 4,000 feet.4,000 feet.

Early versions of this technology are asymmetric, Early versions of this technology are asymmetric, like ADSL, and have an upstream channel of 1.6 like ADSL, and have an upstream channel of 1.6 to 2.3 Mbps.to 2.3 Mbps.

Very-high-rate digital subscriber line (VDSL)Very-high-rate digital subscriber line (VDSL)





Cable TV (CATV) Circuits Cable TV (CATV) Circuits

CATV was primarily designed to carry signals one CATV was primarily designed to carry signals one way-from the cable company’s site, called the head way-from the cable company’s site, called the head end, to the home.end, to the home.

Using a CATV system for data transmission Using a CATV system for data transmission requires a modem to be installed on the cable at the requires a modem to be installed on the cable at the user’s home or office. user’s home or office.

The service has proven to be quite reliable from the The service has proven to be quite reliable from the user’s perspective, and it provides an additional user’s perspective, and it provides an additional source of revenue for CATV companies.source of revenue for CATV companies.

They are many usages for businesses and customers They are many usages for businesses and customers at home. at home.





Satellite Circuits Satellite Circuits Direct broadcast satellites (DBS), sometimes Direct broadcast satellites (DBS), sometimes known as digital sate service (DSS), is also a known as digital sate service (DSS), is also a competitor to cable television and DSL for high competitor to cable television and DSL for high speed communications circuits. speed communications circuits. DSS service is most frequently used to provide DSS service is most frequently used to provide high-speed access to the Internet. high-speed access to the Internet. DSS is a receive-only service, meaning that the DSS is a receive-only service, meaning that the customer must also use a telephone lone and modem customer must also use a telephone lone and modem to send data to the Internet.to send data to the Internet.





The information you requested is sent 22,300 miles The information you requested is sent 22,300 miles up to the satellite, and back down 22,300 more up to the satellite, and back down 22,300 more miles to your DSS dish.miles to your DSS dish.

There is a noticeable delay in response, which is There is a noticeable delay in response, which is okay for file downloads but is probably not okay for file downloads but is probably not acceptable to most people if they are trying to chat acceptable to most people if they are trying to chat interactively with another person.interactively with another person.

While the download speeds from the satellite are in While the download speeds from the satellite are in the range of 350 Kbps, the overall service is much the range of 350 Kbps, the overall service is much slower.slower.

As usual the suitability of this technology depends As usual the suitability of this technology depends on the application for which it will be used.on the application for which it will be used.





9-5 CIRCUIT ACQUISITION AND OWNERSHIP9-5 CIRCUIT ACQUISITION AND OWNERSHIP

Private CircuitsPrivate Circuits Private Circuits are those installed and maintained by a Private Circuits are those installed and maintained by a

common carrier. common carrier.

Leased CircuitsLeased Circuits They are owned by a common carrier, but leased from They are owned by a common carrier, but leased from

them by another organization for full-time used. them by another organization for full-time used.

9-6 CIRCUIT SWITCHING 9-6 CIRCUIT SWITCHING Some of the nodes have user stations connected to Some of the nodes have user stations connected to them, represented by the small dark circles in the cities them, represented by the small dark circles in the cities in Figure 9-6. in Figure 9-6.





Figure 9-6 Circuit switch networks build temporary connection Figure 9-6 Circuit switch networks build temporary connection between devices that wish to communicatebetween devices that wish to communicate





Another offering is symmetric digital Another offering is symmetric digital subscriber line (SDSL).subscriber line (SDSL).

SDSL provides equal speed channels in SDSL provides equal speed channels in both directions and many not include a both directions and many not include a telephone channel.telephone channel.

Communications by circuit switching Communications by circuit switching means that there is a dedicated means that there is a dedicated communication line between the two communication line between the two stations.stations.

This is the way the STN works.This is the way the STN works.





Call setup timeCall setup timeThe connection between telephone A and telephone The connection between telephone A and telephone B in Figure 9-6. B in Figure 9-6. 9-7 PACKET SWITCHING 9-7 PACKET SWITCHING Packet switching technology is illustrated in Figure Packet switching technology is illustrated in Figure 9-7 9-7 The process of segmenting messages into packets is The process of segmenting messages into packets is called packetizing called packetizing Packetizing is performed by hardware or software Packetizing is performed by hardware or software called the called the PADPAD, which stands for packet , which stands for packet assembly/disassembly.assembly/disassembly.





Connection Connection TypesTypes A switched virtual circuit (SVC) between the A switched virtual circuit (SVC) between the

sending and destination nodes. sending and destination nodes. If two packet nodes communicate frequently, a If two packet nodes communicate frequently, a

permanent virtual circuit (PVC)permanent virtual circuit (PVC) A third type of connection called datagram A third type of connection called datagram

service, is available in PDNs.service, is available in PDNs. 9-8 MULTIPLEXING9-8 MULTIPLEXING Figure 9-8 FDM channels have full time use of a Figure 9-8 FDM channels have full time use of a

limited range of frequencies, TDM channels can limited range of frequencies, TDM channels can use the full range of frequencies, but only during use the full range of frequencies, but only during predetermined time slots.predetermined time slots.





Time Division Multiplexing (TDM).Time Division Multiplexing (TDM). TDM is a technique that divides a circuit’s TDM is a technique that divides a circuit’s

capacity into time slots. Each time slot is used by capacity into time slots. Each time slot is used by a different data signal. a different data signal.

Figure 9-8 illustrates this concept. Figure 9-8 illustrates this concept. This process is shown in Figure 9-9 This process is shown in Figure 9-9 Although four terminals are shown in Figure 9-9 Although four terminals are shown in Figure 9-9

more than four could be multiplexedmore than four could be multiplexed Figure 9-9 Time Division Multiplexing (TDM)Figure 9-9 Time Division Multiplexing (TDM)





Statistical Time Division Multiplexing (STDM)Statistical Time Division Multiplexing (STDM) STDM transmits the terminal’s along with each STDM transmits the terminal’s along with each

character or message of data illustrated in character or message of data illustrated in Figure9-10Figure9-10

Figure 9-10 STDM tries to avoid having empty Figure 9-10 STDM tries to avoid having empty slots in a frame, thereby improving the line use.slots in a frame, thereby improving the line use.

Concentration Concentration Concentrators combine several low speed circuits Concentrators combine several low speed circuits

into one higher speed circuit.into one higher speed circuit. Six 9,600 bps circuits might be concentrated onto Six 9,600 bps circuits might be concentrated onto

one circuit that has a 56 kbps capacity shown in one circuit that has a 56 kbps capacity shown in Figure 9-11.Figure 9-11.





ISDN [3] is less of a network and more a set of ISDN [3] is less of a network and more a set of standards than the name implied.standards than the name implied.

ISDN standards were developed by ITU-T as a ISDN standards were developed by ITU-T as a version for the direction that the world’s public version for the direction that the world’s public communications system should taken.communications system should taken.

They believed that ISDN would eventually replace They believed that ISDN would eventually replace leased and switched circuits as we knew them.leased and switched circuits as we knew them.

ISDN can best be visualized as digital channels of ISDN can best be visualized as digital channels of two types shown in Figure 13-12.two types shown in Figure 13-12.

3. ISDN (Integrated Services Digital Network)3. ISDN (Integrated Services Digital Network)

[3] S. H. Rowe & M. L. Schuh, Computer Networking, Pearson Prentice [3] S. H. Rowe & M. L. Schuh, Computer Networking, Pearson Prentice Hall, 2005. Hall, 2005.





Figure 13-12 ISDN basic and primary access arrangement Figure 13-12 ISDN basic and primary access arrangement





The basic rate interface (BRI)The basic rate interface (BRI) One typeOne type ““B” (bearer) channel, carry up to 64 Kbps of B” (bearer) channel, carry up to 64 Kbps of

digital data.digital data. Other type, “D” (delta) channel, carries 16 Kbps Other type, “D” (delta) channel, carries 16 Kbps

od data and is used for signaling.od data and is used for signaling. BRI, also known as 2B + D, provides two 64-Kbps BRI, also known as 2B + D, provides two 64-Kbps

B channels and one 16-Kbps D channel.B channels and one 16-Kbps D channel. Two B channels can be combined to yield a single Two B channels can be combined to yield a single

channel operating at 128 Kbps. channel operating at 128 Kbps. BRI is made available in home and offices on BRI is made available in home and offices on

standard twisted pair wiring.standard twisted pair wiring.





For Primary rate interface (PRI), or 23B +DFor Primary rate interface (PRI), or 23B +D Primary rate access provide 23 64-Kbps B Primary rate access provide 23 64-Kbps B

channels for carrying data and 1 64-Kbps D channels for carrying data and 1 64-Kbps D channel for signaling.channel for signaling.

The total carrying capacity of a T-1 circuit as 23B The total carrying capacity of a T-1 circuit as 23B + D used in USA, Canada or Japan.+ D used in USA, Canada or Japan.

In Europe, primary access is defined as 30B + D, In Europe, primary access is defined as 30B + D, as Europe E-1 circuit.as Europe E-1 circuit.

中華電信公司中華電信公司提供提供 T-1T-1 或或 E-1E-1給各給各公司公司 The large bandwidth provided by ISDN circuit can The large bandwidth provided by ISDN circuit can

be used for digitized voice and data. be used for digitized voice and data.





As Europe E-1 circuit is used PRI.As Europe E-1 circuit is used PRI. With sic access the home, a person could be With sic access the home, a person could be

having a telephone conversation and having a telephone conversation and simultaneously transiting data at 64 Kbps from a simultaneously transiting data at 64 Kbps from a PC.PC.

A business that has a primary ISDN access group A business that has a primary ISDN access group could subdivide the bandwidth in any necessary to could subdivide the bandwidth in any necessary to meet the needs of its application sets.meet the needs of its application sets.

Half of the capacity, or 772 Kbps, might used for Half of the capacity, or 772 Kbps, might used for television transmission while the other 772 Kbps is television transmission while the other 772 Kbps is divided to support 24 voice conversations at 16 divided to support 24 voice conversations at 16 Kbps and 64 Kbps data channels Kbps and 64 Kbps data channels





The other ISDN access available is the Primary Rate The other ISDN access available is the Primary Rate Interface (PRI), which is carried over an E1 (2048 kbit/s) in Interface (PRI), which is carried over an E1 (2048 kbit/s) in most parts of the world.most parts of the world.

An E1 is 30 'B' channels of 64 kbit/s, one 'D' channel of 64 An E1 is 30 'B' channels of 64 kbit/s, one 'D' channel of 64 kbit/s and a timing and alarm channel of 64 kbit/s.kbit/s and a timing and alarm channel of 64 kbit/s.

In North America PRI service is delivered on one or more In North America PRI service is delivered on one or more T1 carriers (often referred to as 23B+D) of 1544 kbit/s (24 T1 carriers (often referred to as 23B+D) of 1544 kbit/s (24 channels).channels).

PRI uses out of band signaling which provides the 23 B PRI uses out of band signaling which provides the 23 B channels with clear 64 kb for voice and data and one 64 kb channels with clear 64 kb for voice and data and one 64 kb 'D' channel for signaling and messaging.'D' channel for signaling and messaging.

The bearer channel (B) is a standard 64 kbit/s voice The bearer channel (B) is a standard 64 kbit/s voice channel of 8 bits sampled at 8 kHz with G.711 encoding. channel of 8 bits sampled at 8 kHz with G.711 encoding. B-Channels can also be used to carry data, since they are B-Channels can also be used to carry data, since they are nothing more than digital channels.nothing more than digital channels.





4. 4G4. 4G

In telecommunication systems, 4G [3] is the In telecommunication systems, 4G [3] is the fourth fourth generationgeneration of mobile phone mobile communication of mobile phone mobile communication technology standards.technology standards.

It is a successor to the third generation (3G) It is a successor to the third generation (3G) standards, a different style of GSM continues.standards, a different style of GSM continues.

A 4G system provides mobile ultra-broadband A 4G system provides mobile ultra-broadband Internet access, for example to laptops with USB Internet access, for example to laptops with USB wireless modems, to smartphones, and to other wireless modems, to smartphones, and to other mobile devices. mobile devices.

[3] [3] Wikipedia,Wikipedia, 4G, http://en.wikipedia.org/wiki/4G.4G, http://en.wikipedia.org/wiki/4G.





Two 4G candidate systems are commercially Two 4G candidate systems are commercially deployed: the Mobile WiMAX standard, first used in deployed: the Mobile WiMAX standard, first used in South Korea in 2006, but South Korea in 2006, but IntelIntel denied to continue 3 denied to continue 3 years before.years before.

The first-release Long Term Evolution (LTE) The first-release Long Term Evolution (LTE) standard are used in Oslo, Norway and Stockholm, standard are used in Oslo, Norway and Stockholm, Sweden since 2009.Sweden since 2009.

It has however been debated if these first-release It has however been debated if these first-release versions should be considered to be 4G or not, as versions should be considered to be 4G or not, as discussed in the technical definition. discussed in the technical definition.





Conceivable applications include amended mobile Conceivable applications include amended mobile web access, IP telephony, gaming services, high-web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, 3D definition mobile TV, video conferencing, 3D television, and cloud computing. television, and cloud computing.





In the United States, Sprint (previously Clearwire) In the United States, Sprint (previously Clearwire) has deployed Mobile WiMAX networks since 2008, has deployed Mobile WiMAX networks since 2008, and MetroPCS was the first operator to offer LTE and MetroPCS was the first operator to offer LTE service in 2010service in 2010..

So 2010, Intel discards theSo 2010, Intel discards the laboratory room in laboratory room in Taiwan, since Intel watches the development of Taiwan, since Intel watches the development of LTE.LTE.

Technical understanding for 4G, the system does not Technical understanding for 4G, the system does not support traditional circuit-switched telephony support traditional circuit-switched telephony service.service.

The spread spectrum radio technology used in 3G The spread spectrum radio technology used in 3G systems, is abandoned in all 4G candidate systems.systems, is abandoned in all 4G candidate systems.





OFDMA multi-carrier transmission and other OFDMA multi-carrier transmission and other frequency-domain equalization (FDE) schemes, making frequency-domain equalization (FDE) schemes, making it possible to transfer very high bit rates despite it possible to transfer very high bit rates despite extensive multi-path radio propagation (echoes).extensive multi-path radio propagation (echoes).

The peak bit rate is further improved by smart antenna The peak bit rate is further improved by smart antenna arrays for multiple-input multiple-output (MIMO) arrays for multiple-input multiple-output (MIMO) communications.communications.

““Generation" is to name successive evolutions of radio Generation" is to name successive evolutions of radio networks in general is arbitrary.networks in general is arbitrary.

There are several interpretations, and no official There are several interpretations, and no official definition has been made despite the consensus behind definition has been made despite the consensus behind ITU-R's labels. ITU-R's labels.





From ITU-R's point of view, 4G is equivalent to From ITU-R's point of view, 4G is equivalent to International Mobile Telecommunications Advanced International Mobile Telecommunications Advanced (IMT-Advanced) specification, setting peak speed (IMT-Advanced) specification, setting peak speed requirements for 4G service at 100 megabits requirements for 4G service at 100 megabits (100(100 每每秒秒 100100兆比特兆比特 )) for high mobility communication.for high mobility communication.

For such as the trains, stationary users and cars, IMT-For such as the trains, stationary users and cars, IMT-Advanced which has specific performance Advanced which has specific performance requirements as explained.requirements as explained.

LTE Advanced standardized by the 3GPP, their LTE Advanced standardized by the 3GPP, their bandwidth is very large.bandwidth is very large.

The pre-4G LTE technology is often branded "4G-The pre-4G LTE technology is often branded "4G-LTE", but the first LTE release does not fully comply LTE", but the first LTE release does not fully comply with the IMT-Advanced requirements.with the IMT-Advanced requirements.





Difference [5] expressed that there have some points Difference [5] expressed that there have some points for 3G and 4G, this description can shown below:for 3G and 4G, this description can shown below:

3G is currently the world’s best connection method 3G is currently the world’s best connection method when it comes to mobile phones, and especially when it comes to mobile phones, and especially mobile Internet.mobile Internet.

4G means 4th generation. This is a set of standard 4G means 4th generation. This is a set of standard that is being developed as a future successor of 3G in that is being developed as a future successor of 3G in the very near future.the very near future.

The biggest difference between the two is in the The biggest difference between the two is in the existence of compliant technologies.existence of compliant technologies.

[5] Differencebetween.net, http://www.differencebetween.net/technology/difference-between-3g-and-4g/





A bunch of technologies that fall under 3G, including WCDMA, EV-DO, and HSPA among others.

Enhanced Voice-Data Optimized or Enhanced Voice-Data Only (Ev-DO, EV, EVDO, etc.) is a telecommunications standard for the wireless transmission of data through radio signals, typically for broadband Internet access.

LTE, WiMax and UMB are actually compliant to the specifications set forth by the 4G standard.

These technologies are often referred to as Pre-4G or 3.9G.

Current 3G speeds are topped out at 14Mbps downlink and 5.8Mbps uplink.





Current 3G speeds are topped out at 14Mbps downlink and 5.8Mbps uplink.

To be able to qualify as a 4G technology, speeds of up to 100Mbps must be reached for a moving user and 1Gbps for a stationary user.

So far, these speeds are only reachable with wired LANs.

Summary: 1. 3G stands for 3rd generation while 4G stands for 4th generation.2. 3G technologies are in widespread use while 4G compliant

technologies are still in the horizon.3. 4G speeds are much faster compared to 3G.4. 3G is a mix of circuit and packet switching network while 4G is

only a packet switching network.





Do you have any idea on Modem?

What is the difference between ADSL and ISDN?

What will it be as 4G is developing?

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