On ethernet systems,  "internet" packet placed in a frame which has :
    wikipedia topic : Ethernet Frame  

    Preamble - used to identify start of individual frames. 
      7 octets of 10101010.

    Frame start - 1 octet 10101011.
 
    Destination MAC @ - Media access code. 6 octet.
    Source Mac @ - 6 octet.

    Optional 4 octet sequence number if implemented on Virtual lan.

    Counter or Packet protocol flag. 2 octet.
      42-1500 : Valid payload 42 - 1500 octets. Early version of ethernet.

      1501-1535 : unrecognzied.

      Count > 1535, protocol flag. Size stored elsewhere.
        Specifies packet type, IPv4, IPv6, Novell IPX, Jumbo frame, etc.
        * wikipedia topic ethertype

    Payload (Packet) which include virtual address info. 
      (transport and internet layer).

    CRC - error checking info. CRC checks cannot correct, only check.
      Hardware/data link not responsible for timely delivery.

    Frames are transmitted between nodes (machines) on local network
    or between orignating node and gateway node which acts as an entry/exit
      point between local network and other networks.

    Normal ethernet frames range from 84-1542 octets.

    Gigiabit ethernet supports a Jumbo frame of up to 9000 octets, but is
      only useful if all interfaces on network using them.


  Packet contains payload which is commonly an IP packet but can be 
    alternative network/transport layer protocols.

  *
Tools to view local network and tcp/ip info.

  Windows ipconfig
   

  Linux/Unix /sbin/ifconfig

  eth0    Link encap:Ethernet  HWaddr 00:13:f7:d1:b0:76
          inet addr:131.156.145.2  Bcast:131.156.145.255  Mask:255.255.255.0
          inet6 addr: fe80::213:f7ff:fed1:b076/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:60575908 errors:0 dropped:0 overruns:0 frame:0
          TX packets:60900148 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:5781444556 (5.3 GiB)  TX bytes:58901387369 (54.8 GiB)
          Interrupt:19 Base address:0x2c00

  dig - shows DNS info

  ip addr