1-8
8237 Hub Installation and Planning Guide
Why Segment 8237s within a Stack?
Three major uses of segmentation are to improve performance, to troubleshoot, and
to isolate groups of users. This section details those uses. "Segmenting 8237s
within a Stack" explains how segmenting is controlled.
Improving Performance
In an unsegmented stack, all of the 8237s remain in the factory-default
segmentation status and are assigned to Backplane 1. This configuration
represents a single collision domain. All devices attached anywhere in such a stack
see all of the Ethernet frames generated anywhere in the stack; thus, they share a
single 10-Mbps bandwidth.
As network traffic increases, excessive collisions can cause network performance to
slow. You can improve performance by segmenting one or more 8237s in the stack
to another backplane or by isolating them from any backplane. Each backplane or
isolated 8237 is a separate collision domain, thus providing multiple 10-Mbps
bandwidths.
To enable segmented 8237s to communicate with the rest of the stack, interconnect
them using a FEM or a bridge, router, or switch. See "Linking Segmented 8237s"
for more detail.
Troubleshooting
Segmentation can help you isolate areas of your network that are experiencing
problems. You can segment 8237s one at a time while monitoring stack
performance. This technique can help you localize a problem area to the devices
attached to a specific 8237.
Isolating User Groups
You might have users in your network who have no need for connectivity outside
their department or workgroup. By placing their workstations on a separate
backplane, you can limit their network access and isolate their bandwidth demands
from the remainder of the network while retaining management of the 8237s.
Segmenting 8237s within a Stack
You can use a VT100 terminal emulator or an SNMP management application to
connect an 8237 to any of the three backplanes, or to isolate it from the stack.
When this is done, the 8237 is said to have been
segmented
. Even though one or
more hubs have been logically removed from the Ethernet bus, the management
bus permits the management information, described in "Inter-8237 Communications
in Managed Stacks" on page 1-6, to be passed.
Linking Segmented 8237s
When you segment an 8237, you cause it to be either connected to another
backplane or to be isolated completely from the rest of the stack. Devices
connected to 8237s in any backplane are able to communicate with all other devices
connected to any 8237 in that backplane. Each backplane is a separate collision
domain, as are any 8237s that have been isolated.
One easily implemented method of interconnecting multiple backplanes is by means
of the 10BASE-T/100BASE-TX FEM. You can connect a 10BASE-T/100BASE-TX
FEM in one 8237 to a port in an 8237 that is in a different backplane.
Summary of Contents for 8237
Page 1: ......
Page 2: ......
Page 7: ...vi 8237 Hub Installation and Planning Guide...
Page 15: ...xiv 8237 Hub Installation and Planning Guide...
Page 41: ...2 8 8237 Hub Installation and Planning Guide...
Page 91: ...3 50 8237 Hub Installation and Planning Guide...
Page 109: ...4 18 8237 Hub Installation and Planning Guide Figure 4 20 8237 Field Replaceable Parts...
Page 113: ...4 22 8237 Hub Installation and Planning Guide...
Page 117: ...A 4 8237 Hub Installation and Planning Guide...
Page 147: ...B 30 8237 Hub Installation and Planning Guide...
Page 166: ...Part Number 85H8847 Printed in Taiwan 85H8847 GA27 4186 00...