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Port Roles: STP=root, designated,
Port State:
| STP | 802.1d-1998 | |
|---|---|---|
| disable | no STP or RSTP enable | |
| Blocking State | drop data frame don't send BPDU Only listen BPDU | |
| Listening State | Drop data frame send cfg BPDU ( Mcst: 01:80:C2/00:00:00 + link local scope ) + Bridge ID or BID: priority + Mac@ Default BID= 32K | 1- use for election of Root bridge / broadcast network Lowest BID win 2- select the designated bridge / segment Lowest BID win |
1- set the port priority: default 1G= 20K and 10G= 2K 2- send in the BPDU "root path cost" locally calculate the root path cost, 3- update the BPDU | 1- Set the Port Roles: lowest root path cost win | |
| Learning State | send and learn BPDU | |
| 15sec | Forwarding Delay Timer | to avoid transient loop |
| forwardingForwarding State | send and receive Data frame | |
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