LOYTEC L-IP, Руководства пользователя, Страница: 149 / 173

L-IP User Manual 149 LOYTEC
Version 6.1 LOYTEC electronics GmbH
LINX-151
192.168.44.10
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Upstream Switch 1
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Upstream Switch 2
1 2 3 4
LINX-151
192.168.44.11
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LINX-151
192.168.44.12
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Figure 144: Ring Ethernet topology
11.4.2 Upstream Options
In case of redundant switches, there are two possible upstream topologies:
Single upstream connection : Switch1 (or Switch2, but not both) is connected to the
upstream network while Switch2 only provides a redundant path to the Loytec devices. The
redundant path is created by a direct Ethernet cable between Switch1 and Switch2 which
needs to be plugged into a lower-numbered port than the L-IP devices are connected to. If
this is not possible, the STP port priority for the cross-connection cable needs to be set to a
low value. The RSTP domain should be restricted to Switch1 and Switch2. This can be
done by enabling a BPDU filter on the port on Upstream Switch 1. This will block all RSTP
packets to enter the upstream network. A sample setup for this topology is shown in Figure
145.
LINX-151
192.168.44.10
1 2
Upstream Switch 1
1 2 3 4
LINX-151
192.168.44.11
1 2
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Direct Ethernet cable between Switch1 and Switch2
LINX-151
192.168.44.12
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Figure 145: Single upstream connection.
Redundant upstream connection : Switch1 and Switch2 are both connected to the
upstream network, either to two ports on the same switch or to two redundant upstream
switches. In this case, RSTP is needed to ensure a loop-free topology between the upstream
switches, Switch1 and Switch2, so the RSTP domain includes the upstream network and the
chained L-IP devices. The configuration of Switch1 and Switch2 need to ensure that they
are not selected as the root bridge. If possible device communication should be bound to a
separate VLAN and MSTP (Multiple Spanning Tree Protocol) should be employed to
isolate the spanning tree operations. This topology is shown in Figure 143.
11.4.3 Preconditions
For the fully redundant and ring topology, the following preconditions have to be met: