dear friend, what u r seeing is absolutly normal you will never see both ends of the link will never go blocking. The way spanning tree works is one end will be blocking and other forwarding. Remember the purpose of the STP is to have a single path to Root bridge. Blocking on one side o the link serves the purpose.
Sandeep --- Curious wrote: > Hello friends, I have an spanning tree question for > you! > > I have a lot of switches connected between them, but > I have seen > something that I can not explain very well. Two of > these switches are > connected using two cables: > > Switch1 Switch2 > Port 29 ------------- Port 29 > Port 30 ------------- Port 30 > > I expected to see one port in blocking state > (spanning-tree) and the other > in forwarding state, but suprisingly I have seen > that port 30 is in blocking > state > in Switch1 but it is in forwarding state in Switch > 2. Let's see these > outputs: > > > > Switch1#sh spanning-tree interface FastEthernet 0/29 > Interface Fa0/29 (port 35) in Spanning tree 1 is > FORWARDING > Port path cost 19, Port priority 128 > Designated root has priority 32768, address > 0002.fd3c.18b5 > Designated bridge has priority 32768, address > 0005.5e0c.57b6 > Designated port is 35, path cost 23 > Timers: message age 0, forward delay 0, hold 0 > Switch1#sh spanning-tree interface FastEthernet 0/30 > Interface Fa0/30 (port 36) in Spanning tree 1 is > FORWARDING > Port path cost 19, Port priority 128 > Designated root has priority 32768, address > 0002.fd3c.18b5 > Designated bridge has priority 32768, address > 0005.5e0c.57b6 > Designated port is 36, path cost 23 > Timers: message age 0, forward delay 0, hold 0 > BPDU: sent 264503, received 2 > > > > Switch2#sh spanning-tree interface FAstEthernet 0/29 > Interface Fa0/29 (port 35) in Spanning tree 1 is > FORWARDING > Port path cost 19, Port priority 128 > Designated root has priority 32768, address > 0002.fd3c.18b5 > Designated bridge has priority 32768, address > 0005.5e0c.57b6 > Designated port is 35, path cost 23 > Timers: message age 4, forward delay 0, hold 0 > BPDU: sent 2, received 264561 > Switch2#sh spanning-tree interface FAstEthernet 0/30 > Interface Fa0/30 (port 36) in Spanning tree 1 is > BLOCKING > Port path cost 19, Port priority 128 > Designated root has priority 32768, address > 0002.fd3c.18b5 > Designated bridge has priority 32768, address > 0005.5e0c.57b6 > Designated port is 36, path cost 23 > Timers: message age 3, forward delay 0, hold 0 > BPDU: sent 2, received 264573 > > > Why a port is in blocking state and the other is in > forwarding??? I > expected to > see both ports in blocking, but one forwarding and > the other blocking > doesn't make > sense!!! > > Thanks a lot! > **Please support GroupStudy by purchasing from the > GroupStudy Store: > http://shop.groupstudy.com > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74629&t=74594 -------------------------------------------------- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
