Brain Twister xD

llllvllll

Ok whoever finds out the Root Bridge & Port mode gets a Cookie

71937_4521242397369_1693843995_n.jpg

Find more posts tagged with

SAVE $250 on Your CISCO Boot Camp — Use Code "EXAM26"

Exclusively for TechExams members for Infosec Boot Camps starting before April 30, 2026

View CISCO Boot Camps

Comments

atorven

SW1 is the root bridge due to priority, so all its ports are designated, on SW2 f0/0 will be the root port and f0/1 will be blocking. I know that that hub in the middle is half duplex but what does it have to do with STP, what I’m I missing?

llllvllll

well you r wrong mate. When SW1 sends BPDU packet , hub will broadcast it to all of it interface, So think again which port will be DP ,RP & blocked.

P.S :- No Cookie for you :P

llllvllll

ok f0/0 on sw1 will be DP , f0/0 on sw2 will be RP and all the other ports will be blocked

xXErebuS

llllvllll wrote: »

well you r wrong mate. When SW1 sends BPDU packet , hub will broadcast it to all of it interface, So think again which port will be DP ,RP & blocked.

P.S :- No Cookie for you :P

ima say sw1 fa0/0 DP / sw1 fa0/1 BP , SW2 fa0/0 root , SW2 fa0/1 ALT PORT/backup/blocked depending on version

dmcneil330

llllvllll wrote: »

well you r wrong mate. When SW1 sends BPDU packet , hub will broadcast it to all of it interface, So think again which port will be DP ,RP & blocked.

P.S :- No Cookie for you :P

So does this mean that Fa0/1 on SW1 will be blocked? even though for STP the root bridge doesn't block any of its ports? Wish I had a hub to lab this up with.

dmcneil330

Labbed it up this weekend:

SW1 fa0/0 - Desg - FWD
SW1 fa0/1 - Back - BLK

SW2 fa0/0 - Root - FWD
SW2 fa0/1 - Altn - BLK

Spanning-tree on shared medium is interesting. If the ports power on in weird ways root ports can be put into the inconsistent state depending on when BPDUs get looped to and fro.

Good brain teaser!

llllvllll

Thank You