3Com 100 TX - Manual (Page 33)

Classification of Repeaters 3-9
Classification of
Repeaters The IEEE 802.3 standard defines two classes of repeaters for 100BASE-T
Fast Ethernet networks, as detailed below.
Class I Repeaters A Class I repeater is a hub with internal delay such that only one repeater can
exist between any two DTE (data terminal equipment) devices within a single
collision domain when two maximum-length cable segments are used.
The LinkBuilder FMS 100-TX Hub (product number 3C250-TX/1) is a Class I
device only.
Internal delay is the time delay between the sensing of the first data bit
received and the sensing of the first bit transmitted on a 100 Mbps CSMA/CD
network. Propagation time delays also affect repeater classification. Class I
repeater delays are longer than Class II repeater delays.
A Class I network topology consists of one hub (or hub stack) in a single collision
domain existing between any two end stations. The stack of LinkBuilder FMS
100-TX Hubs in this configuration can contain up to eight hubs.
Figure 3-8 shows a single collision domain containing one Class I hub stack
between two end stations, with the distance between end stations being
200 meters. If one of the hub-to-node segments is implemented with fiber
cabling (by using the 100BASE-FX transceiver interface module), the total
span can be 260.8 meters. That is, up to 100 meters can consist of UTP
cabling, with up to 160.8 meters of fiber cabling.
Figure 3-8 Class I Hub
® LinkBuilder REPEATER 1x 1x 1x 1x 1x 1x 1x 100BT STATUS 1x 1x 1x 1x 1x
1 2 3 4 5 6 7 8 9 10 11 12 13
ACTIVITY UNIT LINE PARTITION CLS2 3C12345 CLS1 PWR FAN FAIL OVERTEMP COLLISION
® LinkBuilder REPEATER 1x 1x 1x 1x 1x 1x 1x 100BT STATUS 1x 1x 1x 1x 1x
1 2 3 4 5 6 7 8 9 10 11 12 13
ACTIVITY UNIT
LINE PARTITION CLS2 3C12345
CLS1 PWR FAN FAIL OVERTEMP COLLISION
® LinkBuilder REPEATER 1x 1x 1x 1x 1x 1x 1x 100BT STATUS 1x 1x 1x 1x 1x
1 2 3 4 5 6 7 8 9 10 11 12 13
ACTIVITY UNIT LINE PARTITION CLS2 3C12345 CLS1 PWR FAN FAIL OVERTEMP COLLISION
® LinkBuilder REPEATER 1x 1x 1x 1x 1x 1x 1x 100BT STATUS 1x 1x 1x 1x 1x
1 2 3 4 5 6 7 8 9 10 11 12 13
ACTIVITY UNIT LINE PARTITION CLS2 3C12345 CLS1 PWR FAN FAIL OVERTEMP COLLISION
® LinkBuilder REPEATER 1x 1x 1x 1x 1x 1x 1x 100BT STATUS 1x 1x 1x 1x 1x
1 2 3 4 5 6 7 8 9 10 11 12 13
ACTIVITY UNIT
LINE PARTITION CLS2 3C12345
CLS1 PWR FAN FAIL OVERTEMP COLLISION
® LinkBuilder REPEATER 1x 1x 1x 1x 1x 1x 1x 100BT STATUS 1x 1x 1x 1x 1x
1 2 3 4 5 6 7 8 9 10 11 12 13
ACTIVITY UNIT
LINE PARTITION CLS2 3C12345
CLS1 PWR FAN FAIL OVERTEMP COLLISION
® LinkBuilder REPEATER 1x 1x 1x 1x 1x 1x 1x 100BT STATUS 1x 1x 1x 1x 1x
1 2 3 4 5 6 7 8 9 10 11 12 13
ACTIVITY UNIT
LINE PARTITION CLS2 3C12345
CLS1 PWR FAN FAIL OVERTEMP COLLISION
® LinkBuilder REPEATER 1x 1x 1x 1x 1x 1x 1x 100BT STATUS 1x 1x 1x 1x 1x
1 2 3 4 5 6 7 8 9 10 11 12 13
ACTIVITY UNIT
LINE PARTITION CLS2 3C12345
CLS1 PWR FAN FAIL OVERTEMP COLLISION
Class I configuration
200 meters: maximum UTP distance
(260.8 meters: mixed UTP and fiber cable)
100 meters maximum
(160.8 meters: fiber cable) 100 meters maximum