|
|
This chapter describes the preinstallation guidelines and sample configurations for FastHub 112F. These guidelines and configurations can help you determine how FastHub 112F fits into your network.
FastHub 112F can be installed in the same locations as your other Ethernet hubs, bridges, routers, and servers. By following these simple guidelines, FastHub 112F will be easy to install and maintain.
The FastHub 112F can be table, shelf, or rack mounted. FastHub 112F will typically be located in a wiring closet or data center, although it can also be located in an office environment. The key requirement is that FastHub 112F be located within certain distances of its attached devices, as discussed in this chapter.
The FastHub 112F LEDs and cable connectors are located on the front panel, so make sure you can see and access the FastHub 112F from the front after mounting.
See the "Technical Specifications" appendix for more information.
The Fast Ethernet ports are compatible with the 100Base-FX specification and can connect to any 100Base-FX device.
There are simple guidelines for cabling the FastHub 112F. The following figures show some common configurations and the guidelines that apply.
In general, the rules are as follows:
Therefore:
Fast Ethernet ports require 62.5/125 or 50/125 micron multimode fiber optic cabling. The cable connecting to the attached server, workstation, or hub can be any length as long as it does not exceed the total maximum cable length allowable between two nodes, as described above. The server or workstation must have a 100Base-FX-compatible adapter installed.
For example, the FastHub 112F can be used to interconnect up to twelve 100Base-FX devices. Because this is a one-repeater configuration, the maximum cable length between any two attached devices is 305 meters.
Figure 2-1 The FastHub 112F Interconnecting 12 100Base-FX devices
You can build 100Base-FX power workgroups of up to 22 nodes using 2 daisy-chained FastHub 112Fs as shown in Figure 2-2. The workgroup can consist of both workstations and servers, which in each case require a 100Base-FX adapter.
Only two FastHub 112Fs can be daisy-chained in this manner, and the total length of the cable from node to node through the repeaters must not exceed 210 meters, as discussed previously.
This "210-meter rule" can be applied to any configuration including two FastHub 112Fs, or a FastHub 112F and a repeated port on a Cisco Catalyst 2800 workgroup switch. If the length of cable between the two FastHub 112Fs is 10 meters, then each workstation or server can be connected to its FastHub 112F by a cable no more than 100 meters long.
If the length of cable between the two repeaters is 50 meters, then each workstation or server can be connected to its FastHub 112F by a cable no more than 80 meters long. (50 + 80 + 80 = 210 meters.)
Or, one cable could be 60 meters long and the other cable 100 meters long, because 50 + 60 +100 = 210 meters.
You can use two FastHub 112Fs to aggregate up to 22 Cisco Catalyst 2800 workgroup switches as shown in Figure 2-3. All interswitch traffic would use the 100Base-FX local backbone provided by the FastHub 112Fs. This configuration supports up to 550 private Ethernet nodes and 22 switched Fast Ethernet servers, each connected to a Catalyst 2800.
Only two FastHub 112Fs can be connected in this manner, and the 210-meter rule discussed above applies to any two Catalyst 2800s connected through the repeaters. The cable from each server or workstation on either the Catalyst 2800 10-Mbps ports or switched Fast Ethernet port to its Catalyst 2800 can be up to 100 meters long using Unshielded Twisted Pair (UTP) cabling, outside the application of the 210-meter rule. Using fiber optic cabling, the distance from each server or workstation on a Catalyst 2800 switched Fast Ethernet port to its Catalyst 2800 can be up to 400 meters (standard) or up to 2 kilometers using full-duplex mode.
Figure 2-3 High-Density Catalyst 2800 Aggregation
For example, in this configuration the maximum cable distance between Server 1 and Server 22 could be tabulated as follows:
Two FastHub 112Fs can be used to provide up to 375 private Ethernet users with high-speed access to 100Base-FX equipped, high performance servers as shown in Figure 2-4. Only two FastHub 112Fs can be connected in this manner and the 210-meter rule applies.
Server farms can also be connected to either Catalyst 2800 or 10Base-T hub users utilizing a FastHub 112F and routing software in the servers, as shown in Figure 2-5. In this configuration, the 305-meter rule applies.
In both these server farm examples, the cable from each server or workstation on the Catalyst 2800 ports and the 10Base-T hub ports is outside the 210- or 305-meter rules.
|
Copyright 1988-1996 © Cisco Systems Inc.