1-3-3. switch cascading in topology – Microsens MS453522M User Manual
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MICROSENS 8 Port Gigabit Ethernet Switch
User’s Manual
13
2-1-3-3. Switch Cascading in Topology
• Takes the Delay Time into Account
Theoretically, the switch partitions the collision domain for each port in switch cascading
that you may up-link the switches unlimitedly. In practice, the network extension (cascading
levels & overall diameter) must follow the constraint of the IEEE 802.3/802.3u/802.3z and other
802.1 series protocol specifications, in which the limitations are the timing requirement from
physical signals defined by 802.3 series specification of Media Access Control (MAC) and PHY,
and timer from some OSI layer 2 protocols such as 802.1d, 802.1q, LACP and so on.
The fiber, TP cables and devices’ bit-time delay (round trip) are as follows:
1000Base-X TP, Fiber
100Base-TX TP
100Base-FX Fiber
Round trip Delay: 4096
Round trip Delay: 512
Cat. 5 TP Wire:
11.12/m
Cat. 5 TP Wire: 1.12/m Fiber
Cable: 1.0/m
Fiber Cable :
10.10/m
TP to fiber Converter: 56
Bit Time unit : 1ns (1sec./1000 Mega
bit)
Bit Time unit: 0.01
μs (1sec./100 Mega bit)
Table 2-2
Sum up all elements’ bit-time delay and the overall bit-time delay of wires/devices must be
within Round Trip Delay (bit times) in a half-duplex network segment (collision domain). For
full-duplex operation, this will not be applied. You may use the TP-Fiber module to extend the
TP node distance over fiber optic and provide the long haul connection.
• Typical Network Topology in Deployment
A hierarchical network with minimum levels of switch may reduce the timing delay
between server and client station. Basically, with this approach, it will minimize the number of
switches in any one path; will lower the possibility of network loop and will improve network
efficiency. If more than two switches are connected in the same network, select one switch as
Level 1 switch and connect all other switches to it at Level 2. Server/Host is recommended to
connect to the Level 1 switch. This is general if no VLAN or other special requirements are
applied.