Single–hop WDM networks with a central Passive
Star Coupler (PSC), as well as single–hop networks with a central
Arrayed–Waveguide Grating (AWG) and a single transceiver at
each node, have been extensively studied as solutions for the
quickly increasing amounts of unicast and multicast traffic in
the metropolitan area. The main bottlenecks of these networks
are the lack of spatial wavelength reuse in the studied PSC based
networks and the single transceiver in the studied AWG based
metro WDM networks. In this paper we develop and evaluate
the FT? ? FR? AWG network, which is based on a central
AWG and has arrays of fixed–tuned transmitters and receivers
at each node. Transceiver arrays are a mature technology, making
the proposed network practical. In addition, the transmitter
arrays allow for high speed signaling over the AWG while
the receiver arrays relieve the receiver bottleneck arising from
multicasting in conjunction with spatial wavelength reuse on the
AWG. Our results from probabilistic analysis and simulation
indicate that the FT? ? FR? AWG network gives particularly
good throughput–delay performance for multicast traffic with
small multicast group sizes or localized destination nodes, as
well as for a mix of unicast and multicast traffic.
Quality of Service (QoS) mechanisms in networks
supporting mobile Internet communications give
rise to new threats: these mechanisms could be abused
by malicious entities launching so-called Denial of Service
(DoS) attacks. If the network can not efficiently check the
credibility of a QoS-request during a handover process,
malicious entities could flood the network with bogus QoSrequests;
if the authentication check is performed by means
of an AAA protocol before the access network commits its
resources to the request, the authentication process may
not only introduce a notable latency to the handover process,
but also generate an extensive traffic which degrades
the signaling capacity in the network when there are a considerable
amount of malicious requests. In order to defend
against these kinds of attacks and meet the low-latency
micro-mobility handover requirement, we 1propose to have
a preliminary authentication check with a cookie-based
mechanism before processing the requests and performing
authentication and authorization. The performance evaluation
shows that the cookie-based mechanism is efficient in
dealing with the identified issues.