Specifications

11
STAR TOPOLOGY
Advantages: greater network size—up to 200 meters (656
feet); high reliability; readily expandable; uses standard
Ethernet patch cables
Disadvantages: higher cost
Add nodes—i.e., RAVE units—to the previous net layout
and you have the classic star topology. This name comes
from the hub being at the center and the nodes radiating out from it like the points of a star. It doesn’t matter
if the nodes are actually right next to one another while the hub is in another room—it’s still a star topology.
You can connect as many RAVE units as there are ports on the hub.
DISTRIBUTED STAR TOPOLOGY
Advantages: greater network size (see text); high reliabil-
ity; readily expandable; uses standard Ethernet patch cables
Disadvantages: higher cost than smaller topologies
What do you do when you have more RAVE units than
available hub ports? Add more hubs, of course. Most Fast
Ethernet hubs now are stackable, either through an uplink
port that lets you connect an additional hub to one already
in the network, or through a backplane connection. The
resulting network topology is called a distributed star,
because it is made up of interconnected multiple stars.
The example shown here uses three hubs, so the maximum
size of this particular CobraNet network would be 400
meters (1312 feet), allowing two 100-meter cable runs
among the three hubs, plus 100-meter cable runs from the
two outer hubs to their RAVE units.
You can expand the distances even further by daisy-chaining
more hubs and cable segments. There are technical and
practical limits to this strategy; see the section on network
limitations for further information.
Maximum span for
this system (e.g.,
furthest node-to-hub
+ hub-to-hub + hub-
to-hub +
hub-to-node): 400
meters (1312 feet)