Cabletron Systems SEHI100TX manual Network Cable Lengths

Chapter 3: Installation Requirements and Specifications

3.2NETWORK CABLE LENGTHS

This section details the maximum network cable lengths specified by the IEEE 802.3u standard for a Class I repeater. As stated previously, the physical size of the network is limited primarily by propagation delay. The round trip delay cannot exceed 512 bit times or 5.12 ∝s.

NOTE

A stack of five SEH hubs or four SEH hubs and one SEHI hub is equivalent to one repeater.

A 100BASE-T network might use all UTP links, all fiber links or a combination of both. Table 3-1 details the maximum link lengths for each type and combination of cable when used with a Class I repeater.

Figure 3-1 shows a simplified example of a network with one Class I repeater. Link segments A and B represent the longest links in the network. In this case, if both segment A and segment B are UTP, each segment may be up to 100 meters long for a maximum network length of 200 meters. If segment A is UTP and segment B is fiber, the maximum length of the network is 263 meters (with a maximum UTP segment length of 100 meters). If both segments A and B are fiber, the maximum length is 274 meters.

The maximum length of an individual UTP segment may be no

!more than 100 meters.

C AUT IO N

Table 3-1 Maximum Class I Network Cable Length

Number of	UTP	UTP & Fiber	Fiber
Repeaters
1	200 m	263 m	274 m

3-4 SEHI100TX User’s Guide