Media Specifications
The specifications for Thicknet (10Base5) are as follows:
0.4 inch, 50 ohm coax cable.
Maximum segment length is 500 m.
Maximum number of attachments per segment is 100.
Maximum AUI cable length is 50 m.
Minimum separation between attachments (MAU) is 2.5 m.
Cable ends terminate with 50 ohm terminators.
MAU attach workstations.
Maximum network length is 5 segments and 2500 m.
Maximum number of stations on the network is 1024.
The media specifications for 10Base2 are as follows:
0.2 inch, RG58-U, 50 ohm coax cable.
Maximum segment length is 185 m.
Maximum number of attachments per segment is 30.
Minimum separation per segment is 0.5 m.
T-connectors attach workstations.
The 10BaseT specifications are as follows:
24 AWG UTP .4/.6 mm cable.
Maximum segment length is 100 m.
1 device per cable.
The media specifications for 100Base-TX are as follows:
Transmission over Cat 5 UTP or Cat 1 STP wire.
RJ-45 connector (same as in 10BaseT).
Punchdown blocks in the wiring closet must be Category 5 certified.
4B5B coding.
Table 4-14 IBM and IEEE 802.5 Token Ring Specification Similarities
|
Specification |
IBM Token Ring |
IEEE 802.5 |
|
Data Rate |
4 or 16 Mbps |
4 or 16 Mbps |
|
4 Mbps only, on UTP |
|
|
|
Stations per segment |
260 (on STP) |
|
|
72 (on UTP) |
250 (on STP) |
|
|
72 (on UTP) |
|
|
|
Physical Topology |
Star |
Not specified |
|
Media |
Twisted pair |
Not specified |
|
Signaling |
Baseband |
Baseband |
|
Access Method |
Token passing |
Token passing |
|
Encoding |
Differential Manchester |
Differential Manchester |
Table 4-15 Token Ring Characteristics
|
Token Ring Function |
Description |
|
Active Monitor (AM) |
Acts as the centralized source of timing information for other ring stations and performs a variety of ring-maintenance functions. |
|
Beaconing |
A beacon frame is sent by a station that does not receive any more frames from its upstream neighbor. |
|
Early Token Release (ETR) |
A token is released immediately after the sending station transmits its frame. |