GE Multilin F650, Руководство пользователя

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GEK-113000AE F650 Digital Bay Controller B-9
APPENDIX B B.2 RSTP (IEEE 802.1D-2004) AND DAISY CHAIN
B
B.2.3 USE IN MESHED NETWORKS
One great strength of RSTP is its support for all kinds of meshed topologies. The resulting flexibility regarding the
installation is a clear advantage over the stringent restrictions that are imposed by ring protocols such as MRP and ring
installations. However, this flexibility harbors one great disadvantage, namely the reconfiguration time, which for an
interconnected network will depend – among other things – on the complexity of the network topology and the location in
the network at which the failure occurred. Since RSTP is a decentralized protocol, it may also provoke highly unpredictable
race conditions in the establishment of new communications paths, particularly when choosing a new root bridge. This
gives rise to network reconfiguration times that can be estimated only very roughly, and this does restrict the use of RSTP,
particularly in meshed networks. In the case of meshed networks with very little complexity (such as ring networks with two
or three additional loops or subrings), a detailed analysis can make it possible to determine upper limits, but these will
always need to be worked out individually. Unlike with the protocols MRP, HSR and PRP, it is not possible to make a
general statement.