Data Communications Networking Devices - 4th Ed.pdf

3.5 TOKEN-RING _________________________________________________________________ 331Figure 3.32a) Redundant and b) non-redundant main ring pathsTable 3.13 Intra-MAU cabling distance feet)Type of cableOperating rate Type 1 Type 34 Mbps 330 100016 Mbps 330 250distances can be extended through the use of repeaters; however, their use adds toboth the complexity and the cost of the network.As indicated in Table 3.13, the cabling distance between MAUs depends uponboth the operating rate of the LANÐ4 Mbps or 16 MbpsÐand the type of cableused. Type 1 is a double-shielded pair cable, while Type 3 is non-shielded twistedpairtelephone wire.In examining the entries in Table 3.13, it may appear odd that the maximumintra-MAU cable distance is the same for both 4 and 16 Mbps networks when Type1 cable is used. This situation occurred because, at the time IBM set a 100 meterrecommended limit for a 4 Mbps network, the company took into consideration theneed to reuse the same cabling when customers upgraded to a 16 Mbps operatingrate. When using Type 3 cable, distances are shorter since signal line noise increasesin proportion to the square root of frequency. Thus, upgrading the operating ratefrom 4 to 16 Mbps with Type 3 cable decreases the maximum permissible distance.