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Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
Pricing Network Services
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Pricing Network Services

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Transcript

  • 1. Network Services
  • 2. Network Services A classification of network services
  • 3. Contents  Transport and value-added services  Layering  The Internet Value Chain  Business Models Telecommunication Services - 3
  • 4. What are networks Telecommunications network (Logical) circuit services ΑΤΜ access Frame Relay SDH ISDN Packet routing services Ethernet Data transport service between Internet (IP) applications Pipe for bits = optical fiber satellite channel wireless channel Telecommunication Services - 4
  • 5. Connection and connectionless services  Connection-oriented services have the semantics of a directed virtual pipe (or perhaps a tree) R bps, delay T, error rate r  Connectionless services have the semantics of a datagram service (perhaps to multiple destinations) A B Deliver message of size M to A,B with delay T and ber = r Telecommunication Services -5
  • 6. Multiplexing 1 Fixed TDM (circuit-switching) 2 1 Statistical TDM (packet-switching) 2 Telecommunication Services - 6
  • 7. Layering in multiplexing SDH connection IP flow light path ΑΤΜ VP Application creates flow between Α - Β. What technology will the network choose to support the flow? Light path: 2.5 Gbps SDH: 155-2.5Gbps (PDH:34Mbps) pipes of constant size ATM: 0-2.5Gbps IP: 0-... Fills what it finds! (does not define pipe) Telecommunication Services - 7
  • 8. A hierarchy of transport services TCP/IP, UDP/IP shared BW (no QOS) ATM, guaranteed BW, FR Fine - medium granularity SONET, guaranteed BW shared+ guaranteed BW SDH medium – coarse granularity Ethernet Fiber with DWDM Protocol transparency x/IP: short – long lived bursty connections, edges control connection setup, no BW guarantees, statistical multiplexing ATM, FR: long lived connections, network controls connection setup, fixed BW Ethernet: two modes: shared BW (for short lived bursty connections)+ guaranteed BW (for long lived fixed rate connections) Fiber using DWDM: long lived connections (for now), protocol transparency Telecommunication Services - 8
  • 9. Network Services The Internet value chain
  • 10. The Internet Value Chain  Infrastructure Services Layer: simple services that are bought from the other layers  Bit-pipe level connectivity, equipment, call-center services, billing  Internet Services Layer:  End-to-End Connectivity Services: IP connectivity services (unicast, multicast, streaming,…), connection with applications (data centers) and with users – data center, IP backbone, access, end-user IP network, distribution  Content Providing Services: content services: applications, telecommunication services to the end-user, e-commerce – Application Service Provider (ASP), Content Provider (CP), Electronic Marketplace Provider (EMP), Communication Service Provider, Internet Retailer  End-User Layer Telecommunication Services - 10
  • 11. The Internet Value Chain (cont.) Backbone ISP user Applications and content Access (ASP) Bit pipes Server farm Telecommunication Services - 11
  • 12. The Internet Value Chain (cont.) Infrastructure Layer Network Component Service Provider (Dark fiber,  , SONET Ethernet, Satellite,…) Billing Financial Service Provider Service Provider Internet Service Layer Information Provider Connectivity Provider End-User Telecommunication Services - 12
  • 13. ISP Reference Business Model Internet Service Provider Connectivity Provider Information Provider Data Center Application Service Provider Content Provider Backbone Provider Internet Retailer Internet Retailer Access Provider Communication Service Provider End-User Network Provider Market Place Provider End-User Telecommunication Services - 13
  • 14. Business Model: typical ISP Business Relationship Generic Stakeholder End user - ISP Communication Service provider Backbone Provider Backbone Provider Access Internet Provider Retailer Telecommunication Services - 14
  • 15. Value Chain Example End User Information Provider Access and Backbone Provider Money flow Data Center Provider Physical Line Connection Telecommunication Services - 15
  • 16. Examples of ISP Business Models Service AOL Mindspring/Ear Covad Exodus Akamai thlink Access X X X X Backbone X Data Center X X Application X Content X Retailer X X Communication X X Telecommunication Services - 16
  • 17. ISPs market segmentation AOL Mindspring Covad Exodus Akamai /Earthlink Customer Residential Residential Business Business Business End-Users End-Users Customers Customers End-Users Addressed Backbone Broadband Broadband Reliable Fast Content Needs of Connectivity and Access and Information and Streaming Customers and Content Narrowband VPN Delivery Media and Hosting Delivery Owned Content Hosting Access and Backbone and Data Centers Services Backbone Data Centers Bundled in Access and Access, Data --- Broadband --- Services Backbone Center, and Access Backbone Telecommunication Services - 17
  • 18. AOL Business Model Internet AOL Backbone Retailer Internet Provider Retailer Content Provider Content Communication Provider Service Access Provider Provider Stakeholder End User Business Relationship Telecommunication Services - 18
  • 19. Network Services Service contracts
  • 20. Contents  Service contracts  Best-effort and guaranteed services  Policing Telecommunication Services - 20
  • 21. Service contracts  Services = packet/cell transport service (1->1, 1->M)  Traffic contract = connection’s (or flow’s) performance + traffic profile user must conform to  Unicast: usually sender initiates service establishment  Multicast: might be receiver initiated, more flavours Network Service Interface Service contract Telecommunication Services - 21
  • 22. Guaranteed and best-effort services  Guaranteed services (contracts):  network provides some form of performance guarantees in terms of loss, delay, and delay jitter  users request some amount of resources  subject to admission control  Best-effort services (contracts):  no specific performance guarantees  performance deteriorates during overload periods  no specific bandwidth request  intended for applications that can adapt sending rate – elastic applications Telecommunication Services - 22
  • 23. Guaranteed services  Performance guarantees  Quality of Service (QoS): loss, delay, and delay jitter  statistical (e.g., loss < 10-7) or deterministic (delay < 30 ms)  Required mechanisms:  Connection Admission Control (CAC)  Policing  User-network traffic contract: connection’s QoS and traffic description: Network promises to support the specified QoS, provided the user’s traffic is within his traffic contract Telecommunication Services - 23
  • 24. Best-effort services  No specific performance guarantees, but can provide some form of fair treatment to different connections  Feedback mechanisms inform source of congestion  Explicit (binary, rate), implicit (packet loss)  Mechanisms in routers/switches to share bandwidth, enforce fairness, etc.  Example of source behaviour  increase (additive) when there is no congestion  decrease (multiplicative) when there is congestion  Examples:  ABR: rate-based flow control (EFCI, Explicit Rate)  Internet: TCP flow control Telecommunication Services - 24
  • 25. Policing: leaky buckets r = leak rate (cells/s) , b = bucket size (cells) Real cell arriving r cells/s Virtual cell b cells Arriving cell = conforming : there is space in token bucket = non-conforming : no space for complete cell Case of variable size cells (packets): measure r in bytes/s Telecommunication Services - 25
  • 26. The Leaky Bucket 100 same connections .1  t copier Properties: • the central buffer never overflows 10 • maximum delay = .1s .1 In time t the source can transfer maximum .1  t volume of liquid 1/s 100/s Telecommunication Services - 26
  • 27. Wide Area Networking
  • 28. What is interconnection  Technologies: circuit switched, packet switched  Circuit switched: leased lines, ISDN (based on PSTN)  Packet switched: ATM, Frame Relay, IP VPNs  Dark fiber, light paths LAN 1 LAN 2 Router A Router B WAN service Telecommunication Services - 28
  • 29. Service contracts  The network service is described by a contract (Service Level Agreement, SLA)  The contract includes  the responsibilities of the network – maximum delay, losses, jitter, …  the responsibilities of the client – maximum rate, burstiness, ... SLA Telecommunication Services - 29
  • 30. Multiplexing 1 Fixed TDM (circuit-switching) 2 1 Statistical TDM (packet-switching) 2 Telecommunication Services - 30
  • 31. The economics of multiplexing  multiplexing is driven by economics  Different technologies suited for different customer traffic needs Telecommunication Services - 31
  • 32. A simple model Post offices Α, Β, C,... C Α D Β 1s Container service Container for K packets A K packets/s B < K/3 p/s Interconnection service K/3 p/s New interconnection Smart management of container space: service overbooking Telecommunication Services - 32
  • 33. Multiplexing technologies 622 Mbps 35 Mbps IP packets ATM IP router SONET 54Kbps Light paths Optical fiber Telecommunication Services - 33
  • 34. ATM και SDH SDH ATM ATM switch switch ATM network router virtual path Telecommunication Services - 34
  • 35. The hierarchy of multiplexing services TCP/IP, UDP/IP shared BW (no QOS) ATM, guaranteed BW, FR Fine - medium granularity SONET, guaranteed BW shared+ guaranteed BW SDH medium – coarse granularity Ethernet Fiber with DWDM Protocol transparency x/IP: short – long lived bursty connections, edges control connection setup, no BW guarantees, statistical multiplexing ATM, FR: long lived connections, network controls connection setup, fixed BW Ethernet: two modes: shared BW (for short lived bursty connections)+ guaranteed BW (for long lived fixed rate connections) Fiber using DWDM: long lived connections (for now), protocol transparency Telecommunication Services - 35
  • 36. Circuit-switched WAN services  Dark fiber and light paths  Leased lines  ISDN TDM Telecommunication Services - 36
  • 37. Dark fiber and light paths  With dark fiber, the customer leases the fiber itself and buys the necessary equipment to actually activate the fiber  The customer pays for the physical media, not for bandwidth  As the customer adds equipment that can either pulse more bits per second or extract more wavelengths out of the underlying fiber, the bandwidth essentially becomes cheaper and cheaper  Light paths: customer buys an optical network service: end-to-end transport of light of a particular colour, with transparency w.r.t. to network technology Telecommunication Services - 37
  • 38. Leased lines  Point-to-point, multipoint, managed, fractional services, offered by PSTN infrastructure, PDH (E1,E3,T1,T3, FE1,..), SDH (OC3..) Single-purpose leased-line networks Telecommunication Services - 38
  • 39. ISDN  One of the ideas behind narrowband ISDN (N-ISDN) was to give customers one access into the network, from which they could then engage in circuit- switched, leased-line, or packet-switched options  Although all these options were available before ISDN, each one generally required its own special access line and device, which meant extra costs and administrative responsibilities because of the large number of options  The goal of ISDN was to provide one plug into the network, from which you could then go out over multiple alternatives. Telecommunication Services - 39
  • 40. Packet-switched WAN services  Based on virtual-circuits (provide QoS)  ATM  Frame Relay  MPLS  Based on packet switching  Ethernet  IP (Internet) connectivity Telecommunication Services - 40
  • 41. Virtual Circuits a,1: d,1 a,1: b,1 1 c,1: d,2 a,2: c,1 1 a S1 S3 b b d1 a c 1 c 2 S2 1 d 1 2 a e 1 2 1b d 1 a,1: e,1 and c,1 ATM cell c1 1 a,2: b,1 VC data d,1: e,2 Telecommunication Services - 41
  • 42. ATM: cell switching Input Port VPI/VCI Output Port VPI/VCI 1 25 2 34 1 30 1 49 Internal Routing Table ATM switch Cell 25 30 30 25 25 49 output Payload Header input port1 (VPI/VCI) port 1 34 input output port 2 port 2 Telecommunication Services - 42
  • 43. Multi Protocol Label Switching (MPLS)  IP is a connectionless protocol, it cannot guarantee that network resources will be available  MPLS allows to define network connections (like VCs) with QoS for specific IP packet flows which bypass intermediate routers  Provide differential treatment for the above IP flows  MPLS offers the advantages of circuit-switching technology—including bandwidth reservation and minimized delay variations, which are very important for voice and video  It enables service providers to create VPNs that have the flexibility of IP and the QoS of ATM Telecommunication Services - 43
  • 44. MPLS architecture Telecommunication Services - 44
  • 45. Virtual networks R1 R3 R1 Leased line network R3 R2 R4 R2 R4 Logical network Using leased lines R1 ATM network R1 R3 R3 R R IP network R R R2 R4 R2 R4 Using ATM Using IP VPN Telecommunication Services - 45

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