Click to download Ethernet Basics manual - Grant Industrial Controls

Ethernet 33
A switch that support LLDP can carry out topology detection via other participants that also
support LLDP.
Advantages:
• Improved detection of network errors
• Tool for replacing modules
• Better network configuration and network management
LDDP information is used within engineering tools to visualise a network topology in a graphic
manner.
2.9.2 IEEE 802.1x
IEEE 802.1x is a security standard for authentication on each individual port of a switch.
Authentication occurs even before the user is given access to the network. The recognition
of an authorised user therefore occurs at Layer 2 of the OSI model. This can all be done,
regardless of the hardware used, both wirelessly and with wires.
IEEE 802.1x uses a protocol to exchange information with a device/user that sends a request
for access to a port. The messages contain a user name and a password. The switch does not
perform the identification itself but forwards the request to a RADIUS authentication server
on the network. The server processes the request and gives feedback to the switch, which
then opens the port for the user.
There are three important players in the operation of the protocol:
• The user, the client, is known in the protocol as the supplicant.
• The access device, the switch or the access point is the authenticator.
• The controlling device, the RADIUS infrastructure, is an authentication server.
Figure 2.25: Three important players in the operation of the protocol
The authentication for 802.1X is performed with a flexible authentication mechanism called
the Extensible Authentication Protocol (EAP), under which various forms of authentication are
possible. This makes it possible to demand another form of authentication depending on the
type of user: both strong and weak authentication. It is for instance possible to make a user
name and a password compulsory for students and for staff to use a certificate. This aspect
is dealt with in more detail on the section concerning security.