Think of it like this. Each switch is supposed to block redundant ports leading to the root bridge. Say Switch1 and Switch2 are interlinked, and also have downlink connections to the root bridge, like this:
Switch1 ------ Switch2 | | | | Core1 ---------- Core2 Say Core1 is the root bridge. Assuming equal cost links (All Gigabit ports) and no tweaking, what link would be blocked? It should be the inter-link port between Switch1 and Switch2 on Switch1's side. Now, this is not exactly how it works, but if it helps you can think of it like, since Switch1 blocked its port going to Switch2, Switch2 can't "See" the root bridge on that port, so it keeps it open. Like I said, that's not exactly how it works, but if it helps you understand what port gets blocked then so be it. I'd suggest reading the IEEE docs though. They are a little hard to follow, because of the similar terms it uses (too many "Designated" for my taste), but it is the definitive text on the topic. Fred Reimer - CCNA Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA 30338 Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 NOTICE; This email contains confidential or proprietary information which may be legally privileged. It is intended only for the named recipient(s). If an addressing or transmission error has misdirected the email, please notify the author by replying to this message. If you are not the named recipient, you are not authorized to use, disclose, distribute, copy, print or rely on this email, and should immediately delete it from your computer. -----Original Message----- From: Curious [mailto:[EMAIL PROTECTED] Sent: Tuesday, September 02, 2003 12:02 PM To: [EMAIL PROTECTED] Subject: RE: Amazing Spanning Tree [7:74594] Hello friends, I want to thank every answer to this post. I knew that a port with spanning tree in blockin state has not any relation with being "down", I was surprised with some answers. What surprised me, is that one port were in forwarding state and the port in front be in blocking state. For me, there is no sense in having one port in forwarding state when the port in front is in blocking state, why not both in blocking state?? I know that RFC's stablish the rules but I want to understand the sense. Thanks again!! **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 Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74674&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
