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Next Generation Networks

VIEWS: 5 PAGES: 14

									Next Generation Networks

  What’s New and What Isn’t

          John C. Bellamy
        Xalted Networks Inc.
           Bellhead v. Nethead
•   Circuit v. Packet
•   Reliability v. Flexibility
•   Line Protection v. Network Protection
•   Hierarchical v. Flat Networking
•   SONET v. Ethernet
•   Conclusions
Integrated Voice Data v. Ethernet
                                       Circa 1985




                             PSTN
                                                               PBX           PSTN


                  IVD
              Switch


                                                    Ethernet

   Twisted Pair                                     Coax

                                                                Mainframe/Server
                        Mainframe/Server

       (Switched Access)                            (Shared Access)
         AT&T v. Ethernet
                       Circa 2001




                                                          PSTN

       PSTN

                                              Ethernet
                                              Switch




                                    Twisted Pair         Router
Coax
              Router

                                       (Switched Access)
(Shared Access)
Next Generation Digital Loop Carrier

                   TDM Digital Transmission

        Remote                                      Local
        Digital                               IDT   Digital
        Terminal                                    Switch
Hierarchical v. Flat Multiplexing
                                                             STS-1
                                                             DS3
                            DS2                                                                     DS2
                                                                 ...
            DS1                   ...          DS1                                DS1                 ...        DS1
       DS0 DS0          DS0             DS0 DS0            DS0             DS0 DS0        DS0               DS0 DS0          DS0


                a) Transport of PDH Multiplexed DS1 Signals in SONET STS-1

                                                             STS-1

            VT1.5
           VT1.5                          VT1.5
                                         VT1.5                                           VT1.5
                                                                                      VT1.5                       VT1.5
                                                                                                               VT1.5

           DS1                           DS1                     ...                    DS1                      DS1
                 ...                           ...                                            ...                      ...
      DS0 DS0          DS0        DS0 DS0            DS0                      DS0 DS0               DS0     DS0 DS0          DS0


                 b) Transport of VT1.5 Mapped DS1 Signals in SONET STS-1




                        H                                              H          H
                Data                        Data                           Data


                 c) Single Layer Multiplexing of Packet Switching
              Complexity on the Edge
                 Leased Circuits                           Circuit Emulation

                 PSTN                               ES/R            ES/R
       PSN                PSN                              IP/ATM
                                                            Core
                  R
                                                              R


                  R                                           R
        PSN              PSN                        ES/R            ES/R



                        Packetization                          Speech Compression
                                            Edge Switch/Router Echo Control
                        Addressing          (ES/R)
Packet Switching Node   Flow Control                           Voice Activity Detection
(PSN)                                       Adaptation         Segmentation
                        Error Control
                        Reassembly                             Clock Recovery
                                                               Reassembly
    Router (R)          Store and Forward        Router (R)     Store and Forward QoS

 Old Generation Data Network                New Generation Voice Network
          Reliability v. Flexibility
•   Tight Configuration Management         •   Auto Discovery
•   Grade of Service Traffic Engineering   •   Best Effort
•   Battery and Generator Power Back Up    •   UPS?
•   Line Powered 2500 Set Telephones       •   Commercial Power CPE
Variable Length v. Fixed Length Addressing
             4 Digit
             Dialing
                                                                 32-bit Addresses
                           End Office                            Processed by
                 EO                                              All Routers
                                                 R
                                   Toll Office                    R
                              TO
  7 Digit
  Dialing
                 EO                     EO       R
                                                                          R

                            10 Digit
                             Dialing


      PSTN Dialing Plan                              IPv4 Addressing
            (Circa 1995)
Fixed Length v. Variable Length Addressing
                                                                Short Addresses (Tags)
              10 Digit                                          Processed by
              Dialing
                                                                Label Switched
                                                                Routers (Switches)
                  EO        End Office
                                                  LSR
                                    Toll Office                       LSR
                               TO
  10 Digit
  Dialing
                  EO                     EO       LSR
                                                                       LSR

                             10 Digit
                              Dialing


       PSTN Dialing Plan                            MPLS Addressing
             (Circa 2001)
             SONET v. Ethernet
         ADM                                               ES



ADM               ADM
                                                 ES                  ES




ADM               ADM                            ES                  ES




         ADM                                               ES    Ethernet Switch
                 Add/Drop Multiplexer

Fast Ring Protection Switching          Slow Network Layer Protection Switching
½ Capacity Dedicated to Protection      All Bandwidth Available with Discretionary Discard
Symmetrical Bandwidth Allocation        Unsymmetric Traffic Flows Supported
Coarse Bandwidth Granularity
No Bandwidth Reuse on Ring (UPSR)
 SONET v. Ethernet Augmentations

       SONET                    Ethernet

• Virtual Concatenation   • Quality of Service
• Generic Framing         • Resilient Packet Rings
  Protocol (GFP)          • Ethernet over SONET
• Hybrid Data Transport
• Discretionary Traffic
            Protocol Overlays
   IP


   ATM          IP                  IP                     IP         IP


SONET/SDH    SONET/SDH              ATM                Frame Relay   Ethernet


                         Physical Transmission Layer
              Conclusions
• Different Portions of the Network will have
  Different Solutions
• SONET will live
• A Nationwide Transparent Optical
  Backbone will not Happen

								
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