01-12-2009 06:40 PM - edited 03-06-2019 03:24 AM
hi every body!
Let say we have sw1 using extended system, priority 4096. It is currently a root.
Now we introduce the another switch sw2 with command " spanning-tree vlan 2 root primary.
Will the new switch sw2 will set its priority as 4096(current root)-4096=0?
2)According to my book,the command" spanning-tree vlan 2 root diameter 3" will adjust the 1) hello timer 2)forward delay 3)max-age.
But i find the in 802.1d specification that command enters the two vaiable, hello time and diameter in following equations to determine forward delay and max age;
Max-age= 4*hello= 2*diameter-2
forward-delay=[(4*hello)+(3*diameter)]/2
If hello timer is not specified, default helo time=2 sec is assumed.
The question is according to book the command" spanning-tree vlan 2 root diameter 3" sets hello timer, forward delay, max-age.
But according to rfc for 802.1q, it sets only two timers foward delay and max age if given hello time and diameter.
Which one is correct?
thanks a lot!
01-12-2009 07:29 PM
Well I found the answer for first one .
1) sw2 will set its priority to zero.
01-12-2009 11:47 PM
Hello Sarah,
1) 0 when using extended-id because
prioriy in vlan X = base pri + X
2) hello-time can be specified as an optional parameter in spanning-tree root macro.
As observed by Jon in another post the diameter parameter can only be between 2-7:
SW-TO-CRN-P1-C-1(config)#spanning-tree vlan 889 root prim dia ?
>>>> <2-7> Maximum number of bridges between any two end nodes
SW-TO-CRN-P1-C-1(config)#spanning-tree vlan 889 root prim dia 4 ?
hello-time Hello interval for this spanning tree
SW-TO-CRN-P1-C-1(config)#spanning-tree vlan 889 root prim dia 4 hello-time ?
<1-10> Hello interval in seconds
Hope to help
Giuseppe
01-14-2009 10:55 AM
Thanks a lot Giuseppe!
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: