The portfast command does not turn STP off. The following is from CCO: Cisco added a feature named "portfast" or "fast-start," which means the STP for this port will assume that the port is not part of a loop and will immediately move to the forwarding state, without going through the blocking, listening, or learning states. This command does not turn STP off. It just makes STP skip a few (unnecessary in this circumstance) steps in the beginning on the selected port.
Note: The portfast feature should never be used on switch ports that connect to other switches, hubs, or routers. These connections may cause physical loops and it is very important that spanning tree go through the full initialization procedure in these situations. A spanning tree loop can bring your network down. If portfast is turned on for a port that is part of a physical loop, it can cause a window of time where packets could possibly be continuously forwarded (and even multiply) in such a way that the network cannot recover. ----- Original Message ----- From: "Elijah Savage" To: Sent: Wednesday, March 06, 2002 10:56 AM Subject: RE: Cat 2950-24 [7:37374] > From my knowledge if you use this command (spanning-tree portfast) on a > switch port it actually disable spanning tree for that port you should > only do this if pc's are connected. So if you enable portfast you > disable spanning tree for that port, if you disable portfast you enable > spanning tree for that port. > > What this does with it enabled and a pc connected to it, it will keep > the port from going through all the spanning tree phases you know like > learning, listening, blocking etc it will take the switch 60 seconds to > figure all this out before it starts passing traffic to that port. If > portfast is enabled then it does not go through those phases and will > only take approximately 3 seconds before traffic is passing according to > Cisco. Someone please correct me if I am wrong here or missed something. > Hope that helps > > www.digitalrage.org latest in Technical News and HowTo's > www.digitalrage.org/phpBB Discussion Forums > > > -----Original Message----- > From: Cebuano [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, March 06, 2002 7:21 AM > To: [EMAIL PROTECTED] > Subject: Re: Cat 2950-24 [7:37374] > > You don't disable STP on the port to the PC because > STP is only run between Layer2 devices. > I believe you are referring to PortFast. > > Elmer > > ----- Original Message ----- > From: "Brian" > To: > Sent: Wednesday, March 06, 2002 2:34 AM > Subject: Re: Cat 2950-24 [7:37374] > > > > If you connect a computer to a switch port, it takes spanning tree a > bit > to > > allow traffic to pass. If this is an individual host being connected, > you > > could try disabling spanning tree on the port.. > > > > Bri > > > > ----- Original Message ----- > > From: "Ismail Al-Shelh" > > To: > > Sent: Tuesday, March 05, 2002 10:44 PM > > Subject: Cat 2950-24 [7:37374] > > > > > > > Dear all > > > We have Pc with 3Com 3c90x-Tx 10/100 Network Card. This PC is > installed > > > with Dos 6.22 Operating System. We used to connect this to our 3com > > > Switch1100 with the dos driver provided by 3Com. The sequence of > loading > > > the 3com driver to connect to 3com Switch1100 is as follows: > > > LSL.COM > > > 3C90X.EXE > > > IPXODI.COM > > > NETX.EXE > > > F: > > > LOGIN > > > This is in a batch file and when we run the batch file it will > connect > > > immediately. > > > The problem I am facing while connect to CISCO CATALYST 2950-24 port > is > > that > > > If I am > > > running the same batch file it will not connect. > > > I have to load the LSL.COM first and port on switch to which this > computer > > > is connected will be in Green color. But When > > > I will load 3c90x.exe immediately the port on the switch color > becomes > > > amber. > > > I have to wait for 1 to 1.5 minutes for the port color to become > green > > > and after that if load IPXODI.COM and NETX.EXE then it will connect. > > > I can see this because I am sitting in front of the Cisco Switch. > In > > actual > > > the end user will run the batch file sitting somewhere in his room > and > he > > > will get a message "Novell Netware Server not > > > Found". > > > Why this delay in connecting to Novell Netware through Cisco Switch. > The > > > same > > > delay is not happening while we are connecting to 3Com Switch. > > > We need you help and guidance to sort out this problem. > > > Ismail Al-shelh > > > > > > [GroupStudy.com removed an attachment of type application/ms-tnef] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=37431&t=37374 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
