1 / 38

Contemporary and Emerging Telecommunications Technologies

Contemporary and Emerging Telecommunications Technologies. BAD 64046 29 January 2003. The Telecommunications Revolution. Development of telecommunications services have lagged development of the end devices

MartaAdara
Download Presentation

Contemporary and Emerging Telecommunications Technologies

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Contemporary and Emerging Telecommunications Technologies BAD 64046 29 January 2003

  2. The Telecommunications Revolution • Development of telecommunications services have lagged development of the end devices • Improvements in connectivity are imperative because data has exceeded voice volume (end of 1990s) • Volume of traffic on the Internet doubles every 100 days

  3. The Analog Network Must Go • Has been the staple technology for over 100 years • Huge investment in slow, analog, switched voice circuits • Present use of the analog network for data is a jury-rig • MODEMS are a gross way to adapt to the POTS voice network

  4. Problems with the POTS Network • Analog only • Limited (without tricks) to 33.6 Kbps • Oriented toward connections that persist for a period of minutes • Inefficient for burst traffic patterns • All of the network intelligence is centralized at the switches • The local loop bottleneck

  5. Incremental Workarounds to POTS • DSL -- uses existing Cu twisted pair, but sophisticated end electronics, to net much higher rates • Voice and data on cable TV coax network • Wireless local loop technologies

  6. Evolution of Billing Methods • Historically by minute or call count • Unmetered flat rate • Long distance: time and distance • These old methods did not reflect accurate cost accounting • New techniques will include: • Bandwidth based • Traffic based • Timed usage • Flat rate

  7. Telecommunications Service Offerings - Overview (1) • ATM (Asynchronous Transfer Mode) • Connection oriented, packet switching • 155Mbps - 2.5 Gbps • CLASS (Custom Area Local Signaling Services) • Enhanced POTS services • Caller ID, call waiting, call forwarding, conference calling

  8. Telecommunications Service Offerings - Overview (2) • Frame Relay • Packet switched for city and wide area networking • 56/64 Kbps, T1 (1.544Mbps), T3 (44.736Mbps), E1 (2.048Mbps), E3 (34.368Mbps) • Personal Communication Services • Digital mobile wireless comm systems • Use the PCS spectrum allocation

  9. Telecommunications Service Offerings - Overview (3) • POTS (Plain Old Telephone Service) • SMDS (Switched Megabit Data Service) • Connectionless, provided by LECs to interconnect metropolitan LANs • VoIP (Voice Over IP) • Digital voice on packet switched networks using the Internet Protocol

  10. Bandwidth Definitions (1) • Broadband • Allows rates of 1.544 Mbps or higher • Circuits are usually multiplexed • Narrowband • 64 Kbps or less • Wideband • 64 Kbps < wideband < 1.5 Mbps

  11. Bandwidth Definitions (2) • Downstream • Transmission away from the core network • Upstream • Transmission toward the core network

  12. Network Terminology (1) • CO (Central Office) • The location at which all the circuits in the local loop are switched • Circuit Switched Network • Dedicated connection established from end to end for the duration of their ”call” • Connection-Oriented network • Pre-established connection is required • All data follows the same path • All data is received in same order as transmitted • (ATM, for example)

  13. Network Terminology (2) • Digital Subscriber Line (DSL) • Uses traditional POTS Cu pairs • Voice over the data is sometimes supported • Local Loop • From the exchange switch (brick building) to your phone • Cu twisted pair

  14. Network Terminology (3) • Packet Switched Network • Decomposes the bit stream into addressed packets • Packets transmitted independently • Bit stream is reassembled at the receiving end, into the proper order • Utilize bandwidth very efficiently

  15. Network Terminology (4) • PSTN (Public Switched Telephone Network) • The existing worldwide circuit-switched telephone network • Underlying technology is switching to digital, but the architecture is unchanged • Router • Store and forward device • Connects multiple packet-switched networks running the same protocol

  16. Network Terminology (5) • Switch • In packet-switched network: forwards packets to network segments based on hardware addresses of network interfaces • In circuit-switched network: establishes a network path between source and destination for the duration of call • In PSTN: the central office switch which contains all of the intelligence for the whole network

  17. Network Terminology (6) • SONET (Synchronous Optical Network) • An interface standard • For fibre optic internetworking of transmission schemes from various vendors • Base rate for optical line is OC-1, 51.84 Mbps • OC-3 supports 155.52 Mbps

  18. Network Terminology (7) • T-carrier System • Aggregates the bandwidth of voice circuits that have been converted for digital • Bandwidth is multiples of 64Kbps • T1, for example consists of 23 64Kbps channels); T3 has 672 channels • Virtual Circuit • Predefined path from node to node • Supported by a connection-oriented packet-switched network • Packets received in order sent

  19. Telecom Industry Players (1) • CLEC (Competitive Local Exchange Carrier) • Compete against the incumbents • Sometimes have their own local loop infrastructure • ILEC (Incumbent Local Exchange Carrier) • Still service the majority of local users in the U.S.

  20. Telecom Industry Players (2) • LATA (Local Access and Transport Area) • Area around a major city where RBOCs are allowed to conduct business • Modified SMSAs • IXC (Interexchange Carrier) • AT&T, MCI WorldCom, Sprint • Carry traffic between telephone central exchanges

  21. Telecom Industry Players (3) • IntraLATA • RBOCs restricted to selling only IntraLATA service unless they open their local service markets to competition • Only Bell Atlantic, now Verizon, has done so

  22. Telecom Industry Players (4) • Long Distance Service • Generally, service across LATAs • Sometimes toll service within a large LATA • PTT (Post, Telegraph, and Telephone Administration) • Government agency responsible for providing postal and telecom services • Usually a monopoly • Privatized in most countries • See http://www.uts.an for example

  23. Telecom Industry Players (6) • RBOC (Regional Bell Operating Company) • 1982 consent decree broke up AT&T • Seven parent companies formed for the then 22 existing Bell Operating Companies • Ours is SBC, formerly Ameritech

  24. Data Communications Services (1) • Private Line Services • End to end non-switched persistent connection • Only appropriate when cheaper than a switched circuit • T1 is most common • Fractional T1 is possible • Pricing usually fixed monthly; distance sensitive but not usage sensitive

  25. Data Communications Services (2) • ISDN (Integrated Services Digital Network) • Circuit switched narrowband or wideband service • Provides a digital local loop to the CO • Prices for residential service vary widely in U.S. ($30 to $200/month) • Usually two 64Kbps “B” channels and one 16Kbps “D” channel • The B channels can be multiplexed for faster throughput • Widely used for POS and credit card verification because of the persistent connection

  26. Data Communications Services (3) • Frame Relay • Preferred by corporate data network users since mid 1990s • Packet switching system that builds variable length frames that are then relayed from node to node • Advantage is that it can handle many various protocols because of variable length frames • Handles delay sensitive data well, but not as well as ATM

  27. More About Frame Relay • Typical connection speeds of 56Kbps up to 1.5Mbps for LAN to LAN connections • Up to 45Mbps is possible • CIR - Committed Information Rate can be exceeded in small bursts • Frame relay can be transported over SONET • Uses a combination of Permanent Virtual Circuits and Switched Virtual Circuits

  28. Still More... • Frame Relay is standard in the U.S. for enterprise networks • Greatly reduces the need for in-house network engineers • Most of the network intelligence is at the vendor • Popularity is growing internationally because of the flexibility of the variable frame sizes

  29. Frame Relay VPN Features • Data Services • Wide range of connectivity speeds supported • Integration of Voice Over Data • Service Separation • Facilitates coexistence of voice and data services • Integrated Billing

  30. Frame Relay Standards • Developed by the Frame Relay Forum • Standards dictate how software will be used to combine low speed frame relay links into one faster link

  31. Data Communications Services (4) • ATM • Developed in mid-1980s • Intended to be a carrier backbone technology • Uses fixed length packets called “cells” • Low latency supports synchronous demands • Can be implemented across backbones, WANs, LANs

  32. ATM Details • Uses 53 byte cells • Can be switched by hardware very fast • Cell overhead is approximately 10% • Carrier ATM services are as fast as 622Mbps • MCI WorldCom, Sprint, AT&T, BT, France Telecom all have implemented high speed ATM backbones

  33. ATM Advantages • Traffic integration • Isochronous traffic integrates easily with non delay-sensitive traffic • Supports very high bandwidths • Virtual networking capabilities ease network administration • Not widely used yet, as it is overkill except for high end applications such as CAD/CAM and videoconferencing

  34. Service Level Agreements • Contract between vendor and customer • Defines measurement methods • Provides for penalties • Requires: • Baselining • Scope definition • Definition of measurement parameters • Mean Time to Install • Mean Time to Repair

  35. ATM and LANs • ATM can be used to interconnect LANs • Ethernet and Token Ring packets are encapsulated in ATM packets • Standard is LANE 2.0 (“LAN Emulation”)

  36. Data Communications Services (5) • POS (Packet Over SONET) • SONET uses time division multiplexing to transport data over fiber optics at very high speeds (~40Gbps) • POS allows packet data to be sent over a SONET link without the need for the intervening ATM switching layer • POS is 99.5% efficient versus only 88.4% for ATM

  37. Data Communications Services (6) • SMDS (Switched Megabit Data Service) • Connectionless service • Every packet is sent independently of all others • No established virtual circuit is required • As fast as 45Mbps • Primarily used as a niche technique in companies that need multicasting capabilities

  38. Data Communications Services (7) • Internet Based Virtual Private Networks • Used to make “tunnels” over private networks • The service provider’s network and intervening protocols are transparent to the VPN users • A key technology to support Virtual Corporations • Better SLAs are needed

More Related