Typically, the attack
is carried out by consuming a significant share of the available bandwidth and network
resources in the targeted system, overloading any existing pieces of hardware with
strenuous and in many cases infinite tasks, resulting in denial of service for legitimate
subscribers and/or deterioration in QoS, from a user??™s point of view. A standard DoS attack
can be perpetrated in a number of ways, comprising three major types of security
breaches:
?– Consumption of computational resources, such as bandwidth, disk space, or CPU
time.
?– Disruption of system sensitive configuration information, such as routing information,
LLIDs, MAC addresses, and VLAN tags.
?– Disruption of network connectivity at the physical level, for example, by flooding
the upstream channel with a strong laser signal, thereby preventing useful transmissions
from any legitimate subscriber.
The simplest type of DoS attack that can be perpetrated in PONs, and more specifically
in EPONs, is a simple network connectivity disruption, which, in this particular case, is
limited to turning on a strong laser signal source transmitting in the upstream channel
at the proper wavelength, coherent with the selected upstream transmission window.
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