Notes On Chapter Nineteen -- Networking Technologies Past and Present

• 19.0 Study Guide
  
  
  • Be able to discuss these technologies (much of this is review from previous chapters)
    • T-series circuits
    • OC circuits
    • DSL & cable modems
    • WiFi and WiMax
    • ARPA net
    • X.25
    • ATM
    • MPLS
    • VoIP
  
  
• 19.1 Introduction
  
  
  • Quick summary of technologies that have had a lasting impact
    • because the technology is still being used, or
    • because they contributed ideas that are still important.
  
  
• 19.2 Connection and Access Technologies
  
  
  • 19.2.1 Synchronous Optical Networks or Digital Hierarchy (SONET/SDH)
    • "permits a physical ring to be constructed with the purpose of providing redundancy"
    
    
  • 19.2.2 Optical Carrier (OC)
    • Signaling used on optical fiber
    • Data rates of 10-40 Mbps
    
    
  • 19.2.3 Digital Subscriber Line (DSL and Cable Modems
    • Principle current technology for broadband to homes and small businesses.
    • DSL offers 1 to 6 Mbps
    • Cable modem offers up to 53 Mbps to be shared by a group
    • Fiber to the curb or home is expected to eventually replace DSL and cable modem.
    
    
  • 19.2.4 WiMAX and WiFi
    • Wi-Fi is a set of LAN technologies widely adapted to implement small inexpensive LANs. Data rates have increased impressively over a relatively short period of development.
    • WiMAX is a wireless broadband technology that can provide the infrastructure for a MAN.
    • WiMAX is in use providing access to subscribers, and also in backhaul applications, e.g. between cell towers and a service provider's central network facility.
    • There are two versions of WiMAX - one for fixed stations and one for 'mobile endpoints'.
    
    
  • 19.2.5 Very Small Aperture Satellite
    • Provides Internet service to homes and small businesses.
    • High data rates
    • Long Delays
    
    
  • 19.2.6 Power Line Communications (PLC)
    • Uses high frequency to send data through power lines.
    • Much research has been done, but not much deployment.
  
  
• 19.3 LAN Technologies
  
  
  • 19.3.1 IBM Token Rings
    • IBM created this token-passing ring LAN technology.
    • Originally 4 Mbps and later 16 Mbps
    • Widely accepted in the corporate sector for many years
    
    
  • 19.3.2 Fiber and Copper Distributed Data Interconnect (FDDI and CDDI)
    • In the late 1980's and early 90's, this was the answer to slow 10 Mbps Ethernets and 16 Mbps IBM Token Rings.
    • FDDI offered 100 Mbps data rates and a redundant counter-rotating ring technology
    • There was some reluctance to adopt it because of the expense and expertise required to deal with fiber.
    • CDDI (copper implementation) was introduced to help lower cost and complexity.
    • FDDI and CDDI eventually became obsolete because customers preferred Ethernet.
    
    
  • 19.3.3 Ethernet
    • Ethernet is now extremely dominant as a network technology.
    • However Ethernet evolved and changed drastically compared to its original form.
  
  
• 19.4 WAN Technologies
  
  
  • 19.4.1 ARPANET
    • A project of the US Defense Department Advanced Research Projects Agency (DARPA).
    • One of the first packet-switched WANs
    • Originally connected researchers in academia and the military
    • Precursor to the Internet
    • Researchers developing the design of the TCP/IP Internet did much of their cooperation by using ARPANET.
    • Later ARPA converted ARPANET to TCP/IP
    • ARPANET thus became the first Internet backbone
    
    
  • 19.4.2 X.25
    • Early standard for WAN technology developed by what is now the International Telecommunications Union (ITU).
    • Popular with public carriers in its time
    • Was more popular in Europe than the US
    • Had a traditional WAN design: leased lines connected by packet switches having directly-connected computers.
    • Connection oriented
    • Invented before the era of PC's.
    • Often used to connect remote terminals
    • CSU Stanislaus' first connection to the Internet was over an X.25 link that provided a path to the Chancellor's Office.
    
    
  • 19.4.3 Frame Relay
    • Invented by long-distance voice carriers
    • Inventors envisioned it to bridge LAN segments at LAN data rates of 4-100 Mbps.
    • Connection oriented
    • Expensive
    • Lower-bandwidth versions (56Kbps - 1.5 Mbps) were somewhat cheaper.
    • Popular until lower cost alternatives came along
    
    
  • 19.4.4 Switched Multi-megabit Data Service (SMDS)
    • Invented by long-distance voice carriers
    • Based on an IEEE standard
    • High Speed
    • Small packet headers
    • Connectionless
    • Didn't catch on - partly because telephone companies were more comfortable with connection-oriented technologies.
    
    
  • 19.4.5 Asynchronous Transfer Mode (ATM)
    • Designed to "do it all" - WAN, LAN, voice, video, data
    • Promised superior scalability, partly through the use of "label switching" technology that would get packets through switches faster than conventional forwarding methods.
    • Features included quality of service guarantees (e.g. bandwidth minimums and delay maximums)
    • It enjoyed limited success for quite a few years
    • It was pretty much gone by 2015.
    
    
  • 19.4.6 MultiProtocol Label Switching (MPLS)
    • A follow-on from ATM technology
    • Label switching used at the center of the Internet
    • Provides a way to allow packets to follow a specific path (a service for which some users will pay extra).
    • MPLS-aware routers form a "tunnel" that is not visible to Internet forwarding software.
    
    
  • 19.4.7 Integrated Services Digital Network (ISDN)
    • An early service created by phone companies to perform better than dial-up modem service.
    • Now ISDN is mostly supplanted by DSL, cable modem and 3G cellular services, which have higher data rates.
    
    
  • 19.4.8 Voice and Video over IP (VoIP): SIP and H.323
    • Popular technologies - one can purchase routers that give priority to VoIP traffic.
    • The IETF Session Initiation Protocol (SIP) and ITU H.323 are two standards for implementing VoIP and integrating it with telephone company networks.
    
    
  • 19.4.9 Software Defined Networking (SDN) and OpenFlow
    • The idea: separate network management software from the networking devices being managed
    • For example OpenFlow software on a PC running Linux managing the forwarding configuration on an Ethernet switch.
    • Provides owners with network management software that works with arbitrary vendor's equipment