Page 844 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

Broadcast technology supports communications to all possible
recipients.

Multicast technology supports communications to multiple specific

recipients.

Unicast technology supports only a single communication to a
specific recipient.

LAN Media Access

There are at least five LAN media access technologies that are used to
avoid or prevent transmission collisions. These technologies define
how multiple systems all within the same collision domain are to

communicate. Some of these technologies actively prevent collisions,
while others respond to collisions.

Carrier-Sense Multiple Access (CSMA) This is the LAN media
access technology that performs communications using the following
steps:

1. The host listens to the LAN media to determine whether it is in use.

2. If the LAN media is not being used, the host transmits its
communication.

3. The host waits for an acknowledgment.

4. If no acknowledgment is received after a time-out period, the host
starts over at step 1.

CSMA does not directly address collisions. If a collision occurs, the
communication would not have been successful, and thus an
acknowledgment would not be received. This causes the sending
system to retransmit the data and perform the CSMA process again.

Carrier-Sense Multiple Access with Collision Avoidance

(CSMA/CA) This is the LAN media access technology that performs
communications using the following steps:

1. The host has two connections to the LAN media: inbound and
outbound. The host listens on the inbound connection to
determine whether the LAN media is in use.