Configuring MSTP
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CIST port if the CIST root port (IST root bridge root port), it is the main port of all MSTI; if the
CIST Port Role replace the main port of the CIST port, it is the replacement of all MSTI port.
The same port for different MSTI, the port state may be different (such as port v in MSTI1 for
forwarding state, and in MSTI2 for discarding state).
In addition, the bridge priority and port priority and port path cost settings for different MSTI
unrelated (such as MSTI1 and MSTI2 can configure their parameter values, respectively).
23.3.5 Active Topology
According running MSTP switch receives a BPDU perform calculations and comparison,
and ultimately allows the network to reach steady state as follows:
(1) CIST Root :A switch was selected as the CIST root the entire network
;
(2) Each switch will determine the LAN segment and to the CIST root of the path with
minimum cost, to ensure the integrity of the connection and prevent loops;
(3) Within each region will elect a switch as the CIST regional root (CIST Regional Root),
the CIST root switch has reached the minimum cost path;
(4) Each MSTI will be an independent choice of a switch as the MSTI regional root;
(5) Each switch within the region and will determine the LAN segment where the MSTI root
to reach the path of least cost;
(6) CIST Root Port provided through the CIST regional root (if not the CIST regional root
switch) to reach the CIST root (if not the CIST root switch) with minimum cost path;
(7) Alternate and Backup ports in the switch, port or LAN connection fails or is removed to
provide;
(8) MSTI root port (Root Port) providing reach the MSTI regional root of the minimum cost
path (if the switch is not MSTI regional root bridge);
(9) A main port (Master Port) to provide regional and regional CIST root bridge outside the
connections. Within the region, CIST regional root bridge of the CIST root port as the area of
all MSTI master ports.
23.3.6 A topology Change
MSTP and RSTP topology change in a similar spread.
In MSTP, only one is considered a topology change occurs, that is, when a port changes
from an inactive port to port activities that occur when the topology changes, the role of the
port is replaced by the port or backup port to switch to the root port, specify the port or the
main port.
In addition, MSTP and RSTP are also supported as a "proposal / consent" mechanism and