RSTP expertise/suggestions required

[shahid_raza74]

I am new in Cisco...RSTP is a global function and it can't run on specific port, right or wrong...? So it means when I run "spanning-tree mode rapid-pvst" command then it enables RSTP on all 24 ports but will it also enable RSTP on Gigabit/uplink ports?

Secondly, can any one tell me the command to disable RSTP on any port?

Here, I want to discuss my Network topology on which I will run RSTP...I have Six 2955T-12 Industrial Grade Switches. Two of them are Core Switches (using Two switches to provide redundancy in case of one Switch failure) and Four Switches are Access Switches for LAN1 and LAN2 (Again for LAN1 we using two switches for redundancy and same for LAN2). We will connect all Switches to each other with their Uplink Gigabit ports.

One more important thing is that both LAN's Computers (i.e. LAN1 and LAN2) have Dual LAN cards so that they will be connected with their both access Two Switches with Two LAN cards (we using Two LAN cards in Computers b/c of redundancy) e command to disable RSTP on any port

Now can anyone tell me configuration of RSTP ...?

Also I want to know that how we can run/enable RSTP on ONLY Uplink Gigabit ports?

Lastly, can I create Two or three VLANs in Catalyst 2955T-12 Switches but all VLANs should be Up?

Regards,

Shahid

[vladrac-ccna]

Hello Shahid,

partial answer for your questions:

You can create up to 250 vlans on your CAT 2955T-12, but I believe you are actually asking about SVI (interface vlans) am I correct?

Layer 2-only switches only allows for 1 active interface vlan where you can assign 1 IP.

Why do you need to enable RSTP only on the uplinks? if its for compatibility issues. You should check the following link, as RSTP can work together with other STP modes with no problems:

Spanning-Tree Interoperability and Backward Compatibility

http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12225see/scg/swstp.htm#wp1150840

Hope this help a bit, if it does remember to rate this post.

thanks, Vlad

[shahid_raza74]

Thanks for the reply.

But I still unanswered...

Let me tell you what I understood RSTP is :RSTP can't run on specific port (b/c its a global function/command of switch) but it can be stop/prevent any specific port to run RSTP, right, my questoin is How I can stop any specific port to run RSTP? (need that command)."

As you asked why I want to run RSTP on only uplink ports...answer is as I wrote in my topology desig that 2 core switch (no need to run RSTP on uplink Ports) but other 4 switches are access switches connected to my end workstations AS WELL AS 2 CORE SWITCHES(so thats why i want to run rstp on the ports connected to core switch and want to stop rstp on that ports connected to my workstation.)...

waiting..

Shahid

[jolmo]

Hi Shahid

I think the best way to do so is configuring "spanning-tree portfast" on every port connected to a workstation.

An interface with PortFast mode enabled is moved directly to the spanning-tree forwarding state when linkup occurs without waiting for the standard forward-time delay.

HTH