Chapter 3: Networking and Internetworking
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- switching schemes:

        - broadcast;
        - circuit switching;
        - packet switching;
        - frame relay:

- frame relay brings some of the advantages of circuit switching to
  packet switching.  ATM networks are the result.  They switch small
  packets and frames as a whole are not stored at nodes but pass
  through them as short streams of bits.  As a result, ATM can support
  delays in the order of tens of microseconds;

- circuit-switched networks: X.25, frame-relay networks (e.g. ATM);

- IPv6:

        - no payload checksum;
        - no fragmentation can occur once a packet has been sent (?);
                - path MTU?
        - next header handles:
                - information for routers;
                - route definition;
                - fragmentation handling;
                - authentication and encryption;
        - anycast;
        
- ATM:
        - can be implemented in native mode (over optical fiber,
          copper, etc) or over a network of high-speed synchronous
          digital links, such as SONET;

        - composed of three layers: adaptation layer, ATM layer, and
          physical layer;

        - the adaptation layer (AAL) is an end-to-end layer
          implemented only at the sending and receiving hosts.  It is 
          intended to support existing higher-level protocols such 
          as TCP/IP and X.25 over ATM;

        - the ATM layer provides a connection-oriented service that
          transmits cells.  A virtual channel (VC) is a logical 
          unidirectional association between two endpoints.  A virtual
          path (VP) is a bundle of virtual channels that are
          associated with a physical path between two switching nodes;
          VCs are allocated dynamically when connections are set up;

        - cell: 5 bytes of header and 48 bytes of data;