Introduced 1980 - first standard 1983 : IEEE 802.3
Advantages 
  If no-one else using transmitting, unlimited access.

  Technology cheap.

  Layout very flexible (star, bus, tree)

Disadvantage
  Single machine can dominate bandwidth.

  Also as more devices attempt to access, 
    Collisions more likely. 
    The greater the number of devices, the more collisions that occur.

  If machines very far apart, increases chance of not detecting busy until
    collision.

  In worst case scenario, no device can get anything sent because of 
    collisions.

  As number of nodes on network rises
    Successful transmission tends to exhibit normal curve for total throughput.

  Modern systems use switching hubs that limit collisions, but added cost.
    If source/target on same switch, it creates a virtual p to p connection. 
      Packets are not broadcast to other nodes.

    If different sources are not competing for same target, establishes 
     parallel connections. Number of these may be limited.

    If larger tiered local network, isolates communication to source/target
      portion of network.

    Queue/buffer packets to limit collisions if target busy.