Hubs
Switches
Media
Converters
UL 1604
Industrial
Ethernet U
|
Cascading EIM Hubs Using Twisted-Pair
Cabling
| In shared Ethernet networks, repeating hubs and associated
cabling all reside in a common collision domain. Expanding the network
beyond the maximum allowable collision
domain results in unstable operation. When expanding 10 Mbps twisted-pair
networks, a maximum of four repeating hubs can be cascaded. Each
|
 |
twisted-pair segment cannot exceed
100 m. No crossover cables are required since the EIM has an internal
crossover port 4X. When port 4X is being used, port 4 must remain
unused. In this example, the maximum network diameter is 500 m consisting
of five 100 m twisted-pair segments and four repeating hubs.
|
|
|
Cascading EI Hubs With One Fiber
Optic Segment
 |
The restriction that all repeating
hubs and associated cabling must reside within the
collision domain limits the deployment of fiber optics. However,
it is possible to create a network of four repeating hubs and a
mix of twisted-pair and fiber optic cabling. The end hubs incorporate
twisted-pair
cabling, on |
| all ports, while the two inner hubs share a single
fiber optic segment which can be up to 2 km in length. All other
twisted-pair segments are limited to 100 m in length. The EI Series
does not have any internal crossover ports, so crossover cables
are required for hub-to-hub connections. With fiber optics, it is
just a matter of reversing one pair of connections. At 10 Mbps,
ST fiber optic connectors are used. In this example, the maximum
network diameter is 2400 m consisting of four 100 m twisted-pair
segments, one 2 km fiber optic segment and four repeating
hubs. |
|
|
Cascading Hubs with Two Fiber
Optic Segments
| A two-port fiber optic model is available in the EI
series, which allows for the cascading of three repeating
hubs using two fiber optic segments. In order not
to violate the collision domain restriction, the two fiber optic
segments cannot exceed an accumulative length of 2 km. The number
of cascaded hubs |
 |
| in this configuration should not exceed the three
that are shown. A one-port fiber optic repeating
hub can be used at the two ends of the network to
reduce cost. |
|
|
Cascading EISM Switches Using
Twisted-Pair Cabling
 |
Switching
hubs terminate one end of the collision domain; thereby,
simplifying expansion rules. Switches can be cascaded theoretically
without limit, as long as each twisted-pair segment is limited to
100 m. In the above example, no crossover cables are used since
the EISM has an internal crossover port 5X. When port 5X is being
used, port 5 cannot be used. |
|
|
Cascading EISC Switches Using
Twisted-Pair Cabling
| The EISC16 has an internal crossover port 16X which is used to
connect to another switch or hub using straight-through cables.
If port 16X is used, port 16 cannot be used on the same switch.
All twisted-pair segment lengths are limited to 100 m. The EISC
has an EIA-232 console port wired as a DTE.
In order to connect to either a Windows-based desktop or laptop
PC for configuration purposes, a null modem cable not exceeding
50 ft. in length must be used. |
 |
|
|
Cascading EISC Switches Using
Fiber Optic Segments
 |
There are two fiber optic ports on the EISC12
allowing for the cascading of more than two switches using fiber
optic cabling. Notice that the crossover function is accomplished
over the fiber segment by reversing the connections on one side.
The fiber optic ports all operate at 100 Mbps and, therefore, should
be configured for full-duplex
in order to achieve the maximum segment length of 2 km with multimode
fiber and 15 km with single-mode fiber. Connectors for multimode
can be either ST
or SC.
For single-mode, only SC
connectors are available. |
|
|
Trunking EISCs Creates a High-Speed
Backbone
By dedicating four ports to a trunk,
a high-speed backbone between two EISCs can be created. During configuration,
ports are assigned to a trunk in groups of four. Data between switches
is carried over four segments instead of one; thereby, increasing
throughput. Like all other twisted-pair segments, length is limited
to 100 m and the trunk segments must be crossover cables. More than
one trunk can be created for additional cascading at the cost of
reduced ports for device connections.
|
 |
|
|
Port Virtual Local Area Networks
(VLANs)
 |
The EISC is capable of creating either 14 or 15 separate
Port VLANs.
Port VLANs
allow one physical network to be segmented down to multiple independent
"virtual" networks in order to reduce unnecessary traffic,
limit broadcast domains and improve security. Each Port VLAN
can be expanded using one or more standard hubs or switches and
still function independently from the others. The only common connection
is through either ports 15 and 16 on EISC. These ports are members
of all Port VLAN
and could serve as server connections. |
|
|
EIMC Media Converters in Transparent
Mode
| In transparent mode, two EIMCs are connected back-to-back
using a fiber optic cable and their DIP switches are set to transparent
mode. All other connections are made to copper ports. Hub C can
be either a repeating
hub or a switching
hub. Assume either the hub or the switch is not capable
of auto-negotiating.
Then the hub and station A will default to 10 Mbps and half-duplex
operation. In this case an EIMC-10T/F could be used
although an EIMC-100T/F would work equally well. However, if both
station A |
 |
and hub C can auto-negotiate,
then the two will do so as if they were directly connected. The
fiber optic connection is transparent to the operation. In this
situation, the data rate, duplex and flow
control will be auto-negotiated. If 100 Mbps operation
is expected, either the EIMC-100T/FT or EIMC-100T/FC should be
used depending upon the type of connectors needed. An EIMC-10T/F
cannot communicate with an EIMC-100T/F since the fiber optic operating
wavelengths differ. |
|
|
EIMC Media Converters in Half-
or Full-Duplex Mode
 |
Since two fiber optic ports cannot auto-negotiate,
it is necessary to set the data rate and flow rate manually. This
situation will occur when an EIMC must mate to a fiber optic port
on either a hub or switch. Determine the settings of the fiber optic
port on the hub or switch. If it is 100 Mbps, use either the EIMC-100T/FT
or EIMC-100T/FC if the port is complying to the 100BASE-FX
(1300 nm) standard. However, it is possible that the port supports |
| the new 100BASE-SX
(850 NM) standard in which case the EIMC-10T/F must be used in order
to properly match the fiber optic operating wavelength. If the data
rate is 10 Mbps, then use the EIMC-10T/FT since the port must be
complying to the 10BASE-FL
(850 NM) standard. Set the duplex mode on the EIMC via the DIP switches
to match the duplex operation of the fiber optic port. This is important.
With repeating hubs, only half-duplex
is possible. To achieve the maximum fiber distance of 2 km at 100
Mbps, the link must be set for full-duplex
assuming 100BASE-FX
operation. Only the EIMC-100T/FT and EIMC-100T/FC are capable of
achieving this distance at this data rate. At 100 Mbps, the EIMC-10T/F
is only capable of 300 m; however, at 10 Mbps this same device can
span 2 km. |
|
