Introduction to Information Networks COMT 625 Hans Kruse

COMT Hans Kruse2 What is a network? Nodes End (User) Nodes Interior (Network) Nodes Links

COMT Hans Kruse3 Nodes  End Nodes l Contain the User Equipment CPE - Customer Premise Equipment Demarcation - Interface to the Network  Interior Nodes l Switching, Routing, and Cross-Connects l Signaling, Routing, User Databases l Collection of Billing Information

COMT Hans Kruse4 Some Terminology  Central Office or “CO” l Local Switching Center with direct connection to subscribers  Class 5 Office - same as Central Office  Class 4 Office l Interior switching office in the local network  POP - Point of Presence l Switching office operated by long distance carriers

COMT Hans Kruse5 Network Demand LAN to LAN Connection Voice Conversation Network Traffic: Volume of Traffic Traffic Bursts Quality of Service

COMT Hans Kruse6 User View  Quality l Sound quality for voice conversations l Video quality For video conference applications For Entertainment  Performance l Throughput, Response Time l Internal timing in the information stream

COMT Hans Kruse7 Network View  Capacity l Network planning based on estimated number of subscribers and estimated demand l Physical deployment of network facilities  Performance l Utilization of network transmission capacity l Utilization of network control facilities and billing systems

COMT Hans Kruse8 Segmentation by Location Access Lines Interoffice “Trunks”

COMT Hans Kruse9 Access Lines  Connection between the subscriber and the network  Residential and Small Business l Copper Pairs l CATV network; coaxial cable or fiber  Larger Business l Enhanced copper pairs l Fiber rings

COMT Hans Kruse10 Trunks  Connect Interior Nodes l Within one carrier l From one carrier to the next  Large-Scale Sharing of Subscriber Traffic l High capacity fiber l Microwave l Satellites

COMT Hans Kruse11 Segmentation by Provider Ameritech Time Warner GTE Cellular One MCI Worldcom AT&T

COMT Hans Kruse12 Local Access - The US Version  ILEC - Incumbent Local Exchange Carrier l Created by the 1984 breakup of AT&T l Ameritech, Bell Atlantic, Bell South, etc.  CLEC - Competitive Local Exchange Carrier l Created by the 1996 Telecommunications Act l Cable Companies l Long Distance Carriers l Possibly Electric Utilities and Wireless Carriers

COMT Hans Kruse13 Other Local Services  Resellers l No owned network facilities l Use economy of scale to re-sell and re-bill services aimed at large users, to small businesses and residential communities  ISP - Internet Service Provider l Specialized reseller

COMT Hans Kruse14 Long Distance  Defined as traffic exiting the “LATA” l Local Access and Transport Area l Artificial boundaries drawn in the ‘84 decree  The “Big Three” l AT&T, MCI/Worldcom, Sprint  Others l Qwest, regional carriers

COMT Hans Kruse15 Wireless  Cellular l 2 Providers per market area l Mostly analog service, converting to digital  PCS l Up to 6 license blocks per market area l Digital service l At least two incompatible standards deployed

COMT Hans Kruse16 International  National Carriers l Public or Government Owned l Privatized, or Private Competition Introduced  Cross-Border l Bilateral Billing Agreements l Specialized Operators Undersea cable Satellites

COMT Hans Kruse17 Segmentation by Service Provided Circuit Switched Voice/Data Connection Datagram Packet Network

COMT Hans Kruse18 Distinctions  Circuit Switching l Traditionally used for voice l Fixed, Predictable capacity l Precise timing l Non-shared No Competition No easy way to share capacity  Datagram Packet l Example: IP l Capacity is shared among all users l Facility utilization is very efficient l Service guarantees and timing constraints are difficult to obtain.

COMT Hans Kruse19 Access to Datagram Networks  Small End Nodes l Have little chance to share traffic l Use essentially circuit switched access l Access is a performance and cost bottleneck  Large End Users l Can implement circuit sharing (multiplexing) on their own premises

COMT Hans Kruse20 Voice over Datagrams (IP)  Performance l Better use of facilities l Very difficult to do with good quality  Price l Currently Internet access bypasses voice access charges; FCC is considering rule changes  Features l Combined networks offer enhanced signaling