Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements
Webcast-Catalyst9k
New Member

STP question...

Hi,

I have a simple setup that consists of Router A (model 1800) and 2 switches (model 2950).

Port 1 of switch A is connected on port 2 of Router A and Port 1 of switch B is connected on port 3

of Router A.  Also, port 49 of switch A is connected on port 49 of switch B.

I want to add a third switch but unfortunately I don't have the finance for a high end switch.  I'm thinking

of adding a low end switch (ex: linksys).  One link to switch A and another link to switch B for redundancy purpose.

I know the low end switch is not STP enabled, but can this type of setup create any loop issues ??

Thanks

1 ACCEPTED SOLUTION

Accepted Solutions
Purple

Re: STP question...

    You would have an inherent loop in your setup when you connect A to B switch and then hang the dumb switch between them .  As long as spanning tree is running on the 2950 it should take care of the loop and block one of the uplinks from the dumb switch I believe .Been a little while maybe someone can chime in whether the 2950's will talk spanning tree thru that dumb switch ,  brain cramp on this side .  :-)  Make sure you do not have portfast turned on for the ports going to that dumb switch . In that setup though if someone connects say 2 ports together  by accident on the dumb switch it will likely take down that portion of the network  with no spanning tree protection on that dumb switch.

3 REPLIES
Purple

Re: STP question...

    You would have an inherent loop in your setup when you connect A to B switch and then hang the dumb switch between them .  As long as spanning tree is running on the 2950 it should take care of the loop and block one of the uplinks from the dumb switch I believe .Been a little while maybe someone can chime in whether the 2950's will talk spanning tree thru that dumb switch ,  brain cramp on this side .  :-)  Make sure you do not have portfast turned on for the ports going to that dumb switch . In that setup though if someone connects say 2 ports together  by accident on the dumb switch it will likely take down that portion of the network  with no spanning tree protection on that dumb switch.

New Member

Re: STP question...

Hi Glen,

Thanks for your quick reply,

I should be good to go.  I'll make sure I have portfast disabled on switch A & B (uplink ports only).

Tony

Re: STP question...

Tony,

Check the LinkSys switch you are getting as some of them you can enable STP.

Glen, 5+ on the helpful information.

Mike

363
Views
5
Helpful
3
Replies
CreatePlease to create content