2.1.c Implement and troubleshoot VLAN

2.1.c [iii] Normal, extended VLAN, voice VLAN

STP

In order to facilitate a loop free topology a root switch is elected as a reference point for the entire tree. This is accomplished by establishing a BID (bridge id) for every switch in the diameter. A bridge ID is an 8 byte construct composed of 2 bytes of priority, and 6 bytes MAC address. Further, the priority is segmented into 4 bits priority and 12 bits extended system id, where the extended system id is the VLAN ID.

 

VLAN0010

Spanning tree enabled protocol rstp

Root ID Priority 32778

Address 0009.b73f.ce80

Cost 12

Port 64 (Port-channel2)

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

 

Bridge ID Priority 32778 (priority 32768 sys-id-ext 10)

 

32768 16384 8192 4096 2048 1024 512 256 128 64 32 16 8 4 2 1

 

here is the binary math with the example vlan 10

 

1000 0000 0000 1010

 

32768 + 8 + 2