Installation Guidelines - Siemens SIMATIC NET Operating Instructions Manual

3.3

Installation guidelines

Note the information on the topic of redundancy in the configuration manuals of the
connected devices.
You will find the configuration manuals of the SCALANCE X switches on the Internet pages
of Siemens Industry Online Support
(http://support.automation.siemens.com/WW/llisapi.dll?func=cslib.csinfo2&aktprim=99&lang=
en).
Operating the SCALANCE XC100-4OBR in an (R)STP network
Bypassing an (R)STP bridge
If you want to bypass an (R)STP bridge with a SCALANCE XC100-4OBR using the TAP
function, connect the (R)STP bridge to the (R)STP network only via the two ports of the
bypass relay.
Note
If you connect the (R)STP bridge with the (R)STP network via other ports, the TAP function
causes a network loop in bypass mode and communication in the network fails.
Bypassing the root bridge
If the root bridge of an (R)STP network is bypassed by a bypass relay, an alternative root
bridge is selected. By turning the root bridge on and off, the (R)STP network is recalculated.
If an (R)STP bridge is bypassed, the (R)STP section is longer and attenuation increases.
This changes the path costs.
Operating the SCALANCE XC100-4OBR in a redundant ring structure
Bypassing the redundancy manager
Within an MRP or HRP ring, a permanently configured redundancy manager must not be
bypassed using a bypass relay.
Note
If the redundancy manager is bypassed, this causes a network loop and the communication
fails.
Bypassing ring nodes
If the ring nodes are operated in the redundancy modes "MRP Auto Manager" or "Automatic
Redundancy Detection", any ring nodes can be connected and disconnected by the bypass
relay.
If the current redundancy manager is bypassed, another ring node takes over control of the
redundancy. If the redundancy manager changes, the logical communications connections
are reconfigured.
SCALANCE XC100-4OBR
Operating Instructions, 10/2013, C79000-G8976-C297-02
Description of the device
3.3 Installation guidelines
17