Cisco 3750 switch

I just bought a used 3750 cisco switch and I wanted to know, how do I know if spanning tree is enabled, if not, how do I enable it?  I'm looking online at cisco's site, and there's so many options for spanning tree, that I'm not sure whether to use mst, pvst, or rapid-pvst, etc...

Any ideas.
DanNetwork EngineerAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Shahnawaz AhmedTechnical Services SpecialistCommented:
Dear Afacts,

You can enable this feature by using the spanning-tree portfast interface configuration or the spanning-tree portfast default global configuration command.
0
Shahnawaz AhmedTechnical Services SpecialistCommented:
Commands Examples are below

1. Switch-A> (enable) show version
It will output the version of your switch

2. Switch-A> (enable) show port spantree 2/1
Port      Vlan  Port-State     Cost   Priority  Fast-Start  Group-Method
--------  ----  -------------  -----  --------  ----------  ------------
 2/1      1     forwarding        19        32  disabled

3. Switch-A> (enable) set spantree portfast 2/1 enable

4. Switch-A> (enable) show port spantree 2/1

Port      Vlan  Port-State     Cost   Priority  Fast-Start  Group-Method
--------  ----  -------------  -----  --------  ----------  ------------
 2/1      1     forwarding        19        32  enabled
0
DanNetwork EngineerAuthor Commented:
so do I have to enable spanning tree on each port?

Can't I just enable it on the entire switch?

When I did the show run, here's what it says about spanning tree:

!
spanning-tree mode pvst
spanning-tree extend system-id
!


So I think it's enabled, but not sure if it's using the best option or method.

So how do I know if it's enabled on all ports?
0
Powerful Yet Easy-to-Use Network Monitoring

Identify excessive bandwidth utilization or unexpected application traffic with SolarWinds Bandwidth Analyzer Pack.

Shahnawaz AhmedTechnical Services SpecialistCommented:
Dear Afacts,
i don't  know this into deep however i can help you with some good informative articles on this, which might help.

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/12-2_55_se/commmand/reference/3750cr/cli3.html
0
Shahnawaz AhmedTechnical Services SpecialistCommented:
Some more info i found for you.



Spanning Tree Protocol (STP) is enabled by default on modern switches. It is possible to disable or enable the Spanning Tree Protocol (STP) when required.

To enable Spanning Tree Protocol (STP) on an IOS based switch, use the "spanning-tree vlan vlan_number" command from global configuration mode as shown below.

omnisecu.com.switch01>
omnisecu.com.switch01>enable
omnisecu.com.switch01#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
omnisecu.com.switch01(config)#spanning-tree vlan 1
omnisecu.com.switch01(config)#exit
omnisecu.com.switch01#

To disable Spanning Tree Protocol (STP) on an IOS based switch use "no spanning-tree vlan vlan_number" command from global configuration mode as shown below.

Note: Never disable Spanning Tree Protocol (STP) if there is no valid reason to disable it. Disabling Spanning Tree Protocol (STP) can cause Broadcast Storms and Layer 2 Switching Loops, which can make your network down within a short span of time. Use with extreme care.

omnisecu.com.switch01>enable
omnisecu.com.switch01#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
omnisecu.com.switch01(config)#no spanning-tree vlan 1
omnisecu.com.switch01(config)#exit
omnisecu.com.switch01#
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
DanNetwork EngineerAuthor Commented:
thanks, so it looks like it's already enabled, so I'll just leave it as such.
0
Shahnawaz AhmedTechnical Services SpecialistCommented:
Your welcome. Afacts.

Happy to assist you.
0
Jonathan DunnCommented:
you might want to change the default to rapid spanning tree. Has some quicker convergence features
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Cisco

From novice to tech pro — start learning today.