3onedata IES615-1F-2DI, Руководство пользователя

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User Manual
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(Figure 5.9.2.15)
5. Use a wire to connect Port 1 and 2 of Device 101-105 in turn to make a Single Ring. Use a wire to
connect Port 1 and 2 of Device 118-122 in turn to make a Single Ring. Use a wire to connect Port 4 and
5 of Device 106-118 in turn to make a dual_homing. Then use a wire to connect Port 5 of Device 104 to
Port 3 of Device 105, Port 4 of Device 107 to Port 3 of Device 101. The dual_homing is completed.
5.9.3 Rapid Spanning Tree Protocol (RSTP)
The first spanning tree protocol was invented in 1985 at the Digital Equipment Corporation by Radia
Perlman. In 1990, the IEEE published the first standard for the protocol as 802.1D, based on the
algorithm designed by Perlman. Subsequent versions were published in 1998 and 2004, incorporating
various extensions.
Although the purpose of a standard is to promote interworking of equipment from different vendors,
different implementations of a standard are not guaranteed to work, due for example to differences in
default timer settings. The IEEE encourages vendors to provide a "Protocol Implementation
Conformance Statement", declaring which capabilities and options have been implemented, to help
users determine whether different implementations will interwork correctly.
Also, the original Perlman-inspired Spanning Tree Protocol, called DEC STP, is not a standard and
differs from the IEEE version in message format as well as timer settings. Some bridges implement both
the IEEE and the DEC versions of the Spanning Tree Protocol, but their interworking can create issues
for the network administrator, as illustrated by the problem discussed in an on-line Cisco document.
Rapid Spanning Tree Protocol
In 2001, the IEEE introduced Rapid Spanning Tree Protocol (RSTP) as 802.1w. RSTP provides
significantly faster spanning tree convergence after a topology change, introducing new convergence
behaviors and bridge port roles to do this. RSTP was designed to be backwards-compatible with
standard STP. While STP can take 30 to 50 seconds to respond to a topology change, RSTP is typically
able to respond to changes within 3 × Hello times (default: 3 times 2 seconds) or within a few
milliseconds of a physical link failure. The so-called Hello time is an important and configurable time
interval that is used by RSTP for several purposes; its default value is 2 seconds. Standard IEEE
802.1D-2004 incorporates RSTP and obsoletes the original STP standard Select RSTP function in rapid
ring network interface as follows:
Enter into RSTP interface, figure as 5.9.3.1, the priority of this switch is 32768, port 1 participated in STP
and priority is 128, port 2 participated in STP and priority is 240, other ports did not participated in STP
and connect to the terminal directly.