Table of Contents
Advertisement
Ethernet
Wiring
Bus line
Parameter
Attenuation [dB/100 m]
NEXT [dB/100 m]
ACR [dB/100 m]
Return Loss [db/100 m]
Characteristic impedance [ Ω ]
Category
Class
Cable length restrictions
For the maximum possible cable lengths within an Ethernet network various factors have to be taken into
account. So, for twisted pair cables (for transmission rates of 10 Mbit/s and 100 Mbit/s) the maximum
length of a segment which is the maximum distance between two network components is restricted to
100 m due to the electric properties of the cable.
Furthermore the length restriction for one collision domain has to be observed. A collision domain is the
area within a network which can be affected by a possibly occurring collision (i.e. the area the collision
can propagate over). This, however, only applies if the components operate in half duplex mode since
the CSMA/CD access method is only used in this mode. If the components operate in full duplex mode,
no collisions can occur.
Reliable operation of the collision detection method is important which means that it has to be able to
detect possible collisions even for the smallest possible frame size of 64 bytes (512 bits). But this is only
guaranteed if the first bit of the frame arrives at the most distant subscriber within the collision domain
before the last bit has left the transmitting station. Furthermore the collision must be able to propagate to
both directions within the same time. Therefore, the maximum distance between two ends must not be
longer than the distance corresponding to the half signal propagation time of 512 bits. Thus, the resulting
maximum possible length of the collision domain is 2000 m for a transmission rate of 10 Mbit/s and 200
m for 100 Mbit/s. In addition, the bit delay times caused by the passed network components have also to
be considered.
____________________________________________________________________________________________________________
V2
AC500 Hardware
100Base-TX [100 MHz]
23.2
24
4
10
100
5
D or higher
1-50
System data
AC500 / Issued: 05.2007
Advertisement
Table of Contents
