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Outlines Received due 13 March. 24 %. Homework. Review for Midterm on 1 March 2000 Research Paper Readings [11] “ATM Systems: What’s Next?” [12] “Long Distance LAN Interconnectivity”. MID-TERM. 1 Hour 15 minute Test Practice LAN/MAN problems on the Web Work 4 of 5 pages
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Homework • Review for Midterm on 1 March 2000 • Research Paper • Readings[11] “ATM Systems: What’s Next?”[12] “Long Distance LAN Interconnectivity”
MID-TERM • 1 Hour 15 minute Test • Practice LAN/MAN problems on the Web • Work 4 of 5 pages • Know the last midterm, 7 Layer Model • Memory Dump in the space provided • Calculators are NOT allowed...Set up numerical problem for full credit
IP over Frame Relay • 7 Application • 6 Presentation • 5 Session TCP • 4 Transport TCP • 3 NetworkIP • 2 Data Link Frame Relay • 1 Physical
Internet Service Provider Backbone Trunks Leased Line Router If you look closely at the Router Trunks, you may find they are...
Frame Relay is an ISP favorite Trunks FRPVC Leased Line ISP Router FR Switch ... Frame Relay Virtual Circuits.
Frame Relay as a Corporate Backbone... • More Secure than the Internet • Can move a lot of data rapidly (if you pay for proper CIR and burst rate) • Is marginal for moving time sensitive traffic • Generally Cheaper for data than Leased Lines Fewer access lines required Backbone has higher Carrying Capacity
ATM • OSI Layer 2 Protocol • Uses Cell Switching5 bytes overhead, 48 bytes traffic • Capable of hauling all types of traffic (voice, data, & video) • Works at any speed, any distance • Uses Virtual Circuits
Consider ATM if... • Your network is moving mixed traffic • You need sheer SPEED • You get a good deal $$$$
Connection Relationships • Virtual Channel: Individual Service Component. Smallest switchable unit. • Virtual Path: Group of Virtual Channels with same endpoints & QoS requirements • Backbone ATM switches: Switch VP’s • Edge ATM switches: Switch VC’s and VP’s
Selected ATM Parameters • PCR: Peak Cell RateMaximum submission rate • SCR: Sustainable Cell RateAverage sustainable submission rate • MCR: Minimum Cell RateGuaranteed minimum delivery rate • CDV: Cell Delay VariabtionVariability in cell inter-arrival times
ATM Classes of Service • Constant Bit Rate (CBR)Circuit Switched Emulation • Fixed rate voice or video (compressed or uncompressed) • Leased Lines • Key Parameters: PCR & CDV (small)
ATM Classes of Service • Variable Bit Rate - Real Time (VBR-RT)Interactive variable rate compressed voice or video • Telephony • Videoconferencing • Key Parameters: PCR, SCR, CDV (larger)
ATM Classes of Service • Variable Bit Rate - Non Real Time (VBR-NRT)Non-interactive variable rate compressed voice or video • Broadcast Radio • Broadcast TV • Could, and has been, used instead of ABR VC’s • Key Parameters: PCR, SCR
ATM Classes of Service • Available Bit Rate (ABR)Data traffic needing some guarantees • Interactive data traffic • Frame Relay or ISP Trunks • Key Parameters: PCR & MCRFeedback Loop: Available bandwidth adjusts to network conditions.MCR < Available Bandwidth < PCR
ATM Classes of Service • Unspecified Bit Rate (UBR)Data traffic flying standby • EMail • Fax • Key Parameter: PCR
ATM Backbone Trunks Leased Line ATM Switch ATM ‘Cloud’ Trunks use StatMux & Cell Switching CBR trunk traffic may use TDM & Cell Switching
ATM Call Admission Control • Procedure for setting up SVC’s & PVC’s • End user requests call set-upProvides destination, CoS, parameters • Switches determine if resourses are availableSufficient Buffer Space?Sufficient unreserved trunk bandwidth? • Call is rejected if insufficient resources
ATM • Hookups:WAN see Frame RelayMAN see OSU BackboneLAN see Switched Ethernet • Performance:Depends on the Class of Service
ATM Performance UBR Probability of dropped cells ABR* VBR-nrt* & VBR-rt* CBR 0% 100% Trunk Offered Load *Provided we are following traffic contract
ATM Performance Delays of delivered cells UBR ABR* VBR-nrt* & VBR-rt* CBR 0% 100% Trunk Offered Load *Provided we are following traffic contract
Switched Network Carrying Capacities Carrying Capacity Packet Switch StatMux Cell Switch StatMux Circuit Switch TDM 0% Data 100% Data 100% TST 0% TST Offered Load
ATM Status • is flunking at the desktop • Mixed Traffic? No • Speed Advantage? No • $$$ savings? No • PC protocols can’t handle QoS • is succeeding on Carrier Backbones • Mixed Traffic? Yes • Speed Advantage? No (at the moment) • $$$ savings? Competitive
U.S. ATM WAN Revenues Source: Data Communications About 3-4 years behind Frame $0.72B ‘99 $0.38B ‘98 $0.00B ‘93 $.16B ‘97 $0.03B ‘95 $0.01B ‘94 $0.06B ‘96
ATM Backbone Carrying Mixed Traffic.Trunks are more effectively utilized. Private ATM ‘Edge’ Switch Carrier Frame Relay Switch Trunks Leased Line Carrier Backbone ATM Switch ISP Router Carrier Voice Switch
Frame Relay Backbone Trunks Leased Line FR Switch A close look at the FR Trunks may reveal that...
Frame Relay over ATM Carrier Frame Relay Switch Trunks ATM PVC Leased Line Carrier Backbone ATM Switch ISP Router ...they are actually ATM Virtual Circuits.
Frame Relay over ATM • 7 Application • 6 Presentation • 5 Session TCP • 4 Transport TCP • 3 NetworkIP • 2 Data Link Frame Relay/ATM • 1 Physical