FDDI 100Mbps
STS−3c/STM−1 155Mbps
TAXI 4B/5B 100Mbps
LightStream 1010
The LS1010, shown in Figure 9.2, is the most recent addition to the LightStream series of ATM switches used
for multiservice applications. The switch has a five−slot, modular chassis with two fault−tolerant,
load−sharing power supplies. The switch contains a central slot that is dedicated to a single, field−replaceable
switch processor module. The switch processor module supports 5Gbps of shared memory that is fully
non−blocking. Non−blocking means the switch fabric can process and switch just as much or more data than
all the ports on the switch combined can possibly bring in. This is possible because the switch uses a feature
card and a high−performance reduced instruction set computer (RISC) processor that provides the speed and
routing intelligence for the architecture.
Figure 9.2: The LS1010 switch.
The RISC processor provides traffic management mechanisms that allow for bursty data traffic and QoS for
such data as voice, video, multimedia, and other applications that require guaranteed bandwidth. The LS1010
can buffer up to 65,536 cells in its on−board shared buffers; this buffering minimizes the possibility of cell
loss. Policies and scheduling with user−definable thresholds permit flexible support of multiple service
classes.
The LS1010 family’s architecture is flexible. The switch architecture is scalable and can support WAN
interfaces with speeds ranging from a T1 to an OC−12. The LS1010 supports many traffic classes, such as
those listed in Table 9.2.
Table 9.2: Traffic classes supported on the LightStream 1010.
Traffic Class Designation
Constant bit rate (CBR) Used for telephony, legacy, and site−to−site
videoconferencing applications.
Real−time variable Used for time−delay or jitter−sensitive applications
such as those used for videoconferencing at the
desktop level.
Variable bit rate (VBR) Comes in two forms: real time (VBR−RT) and non
real time (VBR−NRT). These forms are used in
high−delay, high−jitter−tolerant, and high−bandwidth
applications, including many video broadcasts.
Available bit rate (ABR) + minimum cell rate (MCR) Used in the WAN. This class provides best−effort
delivery with congestion feedback notification.
Optionally, you can define a minimum bandwidth
requirement.
Unspecified bit rate (UBR) Used by many legacy data applications. This class
provides best−effort delivery.
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