Spanning Tree Protocol

bcall64

Can someone explain to me in detail how this works? I have read a few different things but it's not clicking for some reason. I understand that it ensures that only one active path exists between two network devices but how?

Forsaken_GA

If you want a good detailed explanation, read this book:

Amazon.com: Cisco LAN Switching (CCIE Professional Development series) (0619472700945): Kennedy Clark, Kevin Hamilton: Books

It's a massive tome, but a fairly easy read, if a bit dated. Well worth the ~$20 you'll pay for it used

hexem

Definitely one of those thing's you need to read about, it's a big topic and would take up an entire forum :P but yes the basic's of it are removing layer 2 loop's in network's with redundant link's, as by default switches flood unknown unicast, broadcast and multicast traffic, without STP this would cause broadcast storm's, MAC database instability (seeing the same mac address off differn't ports, or the same multiple copies of the same unicast frame arriving at a destination.

bcall64

I think I will check out that book when I get a chance. I found a flash video on the Cisco site that explained it in regards to bridges that was very helpful. I will do some more in depth studying but I'm feeling better about it. Thanks for the help.

chrisone

Good job , to be honest with you, asking how such and such works will get mostly replies with books or web pages with sources. If you studied and understood some basics of a concept and then asked how it works , i think we can better help you out. If you told us, that you need help with STP and you get this part but not this part, we can give you better answers. Saying how does STP work will get you short replies with books and web pages because explaining STP or other big networking concepts is hard to do in a brief sentences or two. Not trying to be a jerk or anything i just want to help you out in case you thought the earlier replies were brief, its not that we dont want to help you its just that explaining such things is massive.

blackninja

@chrisone

Network Warrior: What a book, wish I had read this a few years ago!

This should be on the reading list of every newly certified CCNA

I think I'll also take a look at the Wireshark University DVD - a tool I have used since Ethereal but never really made the time to "get to know it".

I wish more people would have a sig list like yours. Thanks.

Bl8ckr0uter

blackninja wrote: »

@chrisone

Network Warrior: What a book, wish I had read this a few years ago!

This should be on the reading list of every newly certified CCNA

I think I'll also take a look at the Wireshark University DVD - a tool I have used since Ethereal but never really made the time to "get to know it".

I wish more people would have a sig list like yours. Thanks.

Making my way through Network Warrior as well.

chrisone

blackninja wrote: »

@chrisone

Network Warrior: What a book, wish I had read this a few years ago!

This should be on the reading list of every newly certified CCNA

I think I'll also take a look at the Wireshark University DVD - a tool I have used since Ethereal but never really made the time to "get to know it".

I wish more people would have a sig list like yours. Thanks.

Thanks, Yep i agree Network Warrior is a great book. To be honest with you i picked up network warrior after i completed my CCNP lol but to be flat out honest with you , the book has information not presented in either CCNA or the CCNP, like the telecom , firewall/security, server load balancing sections of the book. I also look forward to reading the Designing networks part of the book as well. I can never get enough of reading or learning from another network engineers point of view. The book is not like your cisco technical jargin cert books, but everything is presented through another engineers perspective and everything is well written to understand concepts easily.

Its not that i dont like the cisco press books, its just that there is a difference from being a technical jargin straight forward book like the cert books from cisco press and books written from other engineers perspective outside of the cisco "way of writting." Books like Richard Deals cisco ASA configuration and network warrior are somewhat free from the cisco written flow. I dont know how to explain it but there is a different written flow between the two lol

Forsaken_GA

STP, and all of it's modern derivatives are just animals with alot of intricacies. The STP algorithim itself is pretty simple, but ramifications of deploying STP and figuring out how to fix it when it breaks are not subjects that can be covered adequately in a forum post. Hell, STP is a big enough pain in our ass that we finally got fed up and redesigned the network to where we could turn it off almost everywhere in the network.

So yeah, the OP's question basically requires a book sized post to answer, so it's easier just to recommend a book. Now, if he wanted to get into whatever aspect of STP that he doesn't understand, that we can probably do some damage with!

mella060

Are you studying for your CCENT/CCNA ? Maybe have a look at the books by Todd Lammle and Wendell Odom. From memory, Odom does explain it pretty well. It does take time to understand and digest. Take your time with it.

bcall64

To be completely honest I sort of jumped the gun on asking this question. I kept seeing STP everywhere and had been reading through for the ICND1 and wasn't completely getting it. I did some google searches and have a better understanding how it works now.

With that said I want to thank everyone for their help here it did help a lot. I've more motivated than I've ever been for the test on March 8th. There is so much to networking it's a lot of fun and there is endless amounts of things to learn. I'm hoping I pass.

hexem

There's more of it in ICND2, RSTP And PVST And PVRST+ ! hehe it's not that complicated tho, takes abit of getting use to. Keep reading over and over until it's just natural that you could answer any possibilities that may arise, i admit, i still have a few problems with it and my exam is in a few weeks.

GrayhenTor

STP 'clicked' for me when I read through this...
Spanning tree protocol - Wikipedia, the free encyclopedia
Maybe not the best explanation, but it helped me..

phoeneous

bcall64 wrote: »

Can someone explain to me in detail how this works? I have read a few different things but it's not clicking for some reason. I understand that it ensures that only one active path exists between two network devices but how?

bcall64, Imagine two buildings. Those two buildings are connected by two seperate and enclosed walkways so that people can access either building. Only one walkway is open at any given time so people dont walk around in circles or loops. If one walkway gets closed, shutdown, or is inaccessible, the other one opens so traffic can flow from building to building. Thats a simplified analogy to stp.

With switches, you dont want frames being looped around from switch to switch creating broadcast storms. Look at the pic below, when stp has converged, in order for switch A and B to communicate, their traffic must go through switch C. The path directly connecting A and B is blocked to prevent switching loops. If for some reason A > C or B > C is inaccessible then stp opens up that blocked port so that all three switches can communicate.

bcall64

Awesome thanks! I've really learned a lot this week.

chrisone

Awesome bud! its motivates me when i see other motivated. Just remember do not get upset angry or frustrated if you fail. Just redo it and take more time studying. Learn from your weak points that will be displayed on your results. Trust me it will happen , everyone fails at least one time. I fail my CCNA twice then split it up into two exams ICND 1 and ICND 2 , so it litterally took me 4 attempts to get my CCNA. Mainly because the first time i failed right after they came out with the new 2006 CCNA exams, then i had to restudy. Anyways good luck and update us on your results.

phoeneous

bcall64 wrote: »

Awesome thanks! I've really learned a lot this week.

Wait until you get to access-lists and nat

Nevins

Here are some videos that explain STP really well.

YouTube - Broadcast Yourself.

bcall64

Nevins wrote: »

Here are some videos that explain STP really well.

YouTube - Broadcast Yourself.

This helped a lot.