Technical information

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Topologies (continued)
Technical information
Ethernet network
Infrastructure
Different network topologies (continued)
Daisy chain topology (continued)
Limitations of the daisy chain:
Limitations of the daisy chain topology in terms of operational integrity of the network
and performance metrics are as follows:
b Dual port Ethernet devices only support 10 Mbps and/or 100 Mbps operational
speeds and must use one or the other.
b The network will operate only as fast as the slowest device that is connected to the
network.
b In order to improve network trafc latency, the number of devices in a single scan
chain is limited to 32 devices. This means that the time for a round trip of a packet
through the daisy chain is likely to be less than 5 milliseconds.
The maximum latency of a packet passing through any device in a scan chain is no
more than 10 µs.
Ring topology
In a ring topology, all devices or network infrastructure components are connected in
a loop. Through this type of topology, a type of network redundancy is achieved.
Ring topologies also help improve the availability of the network and its
communication to devices.
Ethernet ring
Ethernet rings are usually the backbones of applications in which high availability is
required. If ring topology is required then switches that support this feature should be
ordered.
Deploying ring topologies using ConneXium
ConneXium offers switches that allow the deployment of single and coupled
self-healing rings (see page 2/11 for more information).
Daisy chain loop
A daisy chain loop consists of several daisy chain devices that are placed in a ring
topology.
When an Ethernet network forms a loop, all the devices in that loop must use the
same protocol (RSTP, MRP, or HIPER-Ring).
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