Spanning-tree detected flag

Hi All,

   When I was going through the "show spanning-tree active detail " command
,I noticed about the detected flag as pasted below (output truncated)

  VLAN0001 is executing the ieee compatible Spanning Tree protocol
  Bridge Identifier has priority 24576, sysid 1, address 0015.2b2c.f680
  Configured hello time 2, max age 20, forward delay 15
  We are the root of the spanning tree
  Topology change flag not set, *detected flag not set*
**
I was trying to understand,whether the detected flag is a seperate flag in
801.2d BPDU frame format or it just the switch sets for his purpose to
understand that the TC notification has received from another switch with TC
flag set.

The way in which I understand the spanning-tree flags are

1) Its 1 byte in length
2) Only 2 bits are used for the flag
3) If the lower order bit is set (00000001),then its TC flag is set or if
the high order bit is set (10000000),then it is TCA flag set.

For some reason I couldn't understand the detected flag,Kindly help me to
understand the same.I am sure missing some basic.

Thanks for the help

Regards
Anantha Subramanian Natarajan

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Received on Wed Sep 02 2009 - 10:58:17 ART