Curious wrote in message
news:[EMAIL PROTECTED]
Hello,
I know that is a bad idea to configure a port with portfast when this
port
connect with other switch (loops can be created), but the question is:
could
I put a port connected to a router in portfast mode? A router is a layer 3
device
Hello,
I know that is a bad idea to configure a port with portfast when this port
connect with other switch (loops can be created), but the question is: could
I put a port connected to a router in portfast mode? A router is a layer 3
device not a layer 2, so I think this is not a risk, am I right
Curious 6/24/03 10:25:25 AM
Hello,
I know that is a bad idea to configure a port with portfast when this
port
connect with other switch (loops can be created), but the question is:
could
I put a port connected to a router in portfast mode? A router is a layer 3
device not a layer 2, so I think
Sticking a router in a port fast port is probably okay, since there
should be no
Bpdu's generated by the router. Most Cisco switches don't allow the
trunk function
And the stp-portfast function on at the same time...you do not want the
portfast
Function enabled on trunks...
Larry Letterman
In the below website it says not to have portfast on if you connect
switches, hubs, or routers. I understand that point but what if a user
connected a mini-hub (Ex. Linksys EtherFast 8-Port 10/100 Desktop Hub)
or unmanaged mini-switch (Ex. Farallon NetLINE 10/100 switch) so that he
could
yes, but only if he then connects another link to another hub / switch and
causes a bridging loop.
-Original Message-
From: John Chang [mailto:[EMAIL PROTECTED]]
Sent: 01 March 2001 15:08
To: [EMAIL PROTECTED]
Subject: Portfast
In the below website it says not to have portfast
. Then the
users go home, switch off their kit and go to the pub.
Next day. The mini hub is switched back on - because portfast is enabled
the ports go whoosh straight into forwarding mode - result - spanning tree
goes oh my!! and recalculates.
Outcome -- You and every other support
John,
It should not cause any problems provided that the device in question is not
using any kind of dual uplinks. Basically, all portfast does is allow that
port to skip through a majority of the Spanning Tree protocol checking
process. Obviously this is okay for end stations and servers
/disconnecting stations to the hub doesn't bother the switch's
spanning tree, the switch port is still sniffing the hub's heartbeat and
stays in the forwarding state.
/felis
John Chang wrote:
In the below website it says not to have portfast on if you connect
switches, hubs, or routers. I understand
We use it on all of our L2 and L3 Cat6509's... greatest thing since
sliced bread. We were having a SEVERE problem with Win98 clients not being
able to log on because of timing issues (AutoIPconfiguration feature of
Win98 ) that portfast could correct. Before BPDU GUARD it was a manual
:[EMAIL PROTECTED]]On Behalf Of
Chuck Church
Sent: Thursday, March 01, 2001 4:22 PM
To: 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail)
Subject: RE: Portfast
If this bdpu guard works as it supposed to, I'll definitely use it. Windows
2000 machines seem to need portfast for DHCP, and almost all
has a shorter timeout for the DCHP lease request? Anyway, I've been using
portfast on almost all workstation ports for the past few months.
Thanks,
Chuck Church
CCNP, CCDP, MCNE, MCSE
Sr. Network Engineer
Magnacom Technologies
140 N. Rt. 303
Valley Cottage, NY 10989
845-267-4000 x218
a shorter timeout for the DCHP lease request? Anyway, I've been using
portfast on almost all workstation ports for the past few months.
Thanks,
Chuck Church
CCNP, CCDP, MCNE, MCSE
Sr. Network Engineer
Magnacom Technologies
140 N. Rt. 303
Valley Cottage, NY 10989
845-267-4000 x218
You have to enable it on an interface-by-interface basis and make sure the
links only connect to workstations not to other network equipment.
Duck
- Original Message -
From: ed smith [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Wednesday, September 06, 2000 6:32 AM
Subject: Portfast
You can and should have links connected to other switches/hubs/routers that
are portfast enabled.
However you should leave portfast disabled when there is resiliency between
2 network devices which would cause a spanning tree loop.
-Paul
-Original Message-
From: Donald B Johnson Jr
I'm swapping out a 2900XL with a 2924C XL to give us Fiber capability. Since
we have customers on the current switch I want to keep down time to a
minimum. One suggestion has been to, on the new switch put it into portfast
mode.
Has anyone done this before? Are there any problems you
NT and 2000 will have major latency when connecting
directly to a switch without portfast. There is a
article on www.cisco.com about this problem. The
problem is not cisco related it will happen on any
switch. http://www.cisco.com/warp/public/473/12.html
I'm swapping out a 2900XL
Portfast is implemented on a per port basis. It is used (a) when
spanning-tree is used on the switch and (b) on ports that have directly
connected PCs. Without portfast spanning-tree can take up to 40 seconds to
go to forwarding mode. This can be a major "O bleep!" for PCs trying t
only use portfast on workstations or servers. it will prevent another
switch or hub from participating in the spanning tree. I don't think I
would enable portfast just to save users 20 seconds or so of startup one
time while you swap switches.
Unless you are in a 24x7 shop there must be some
Title: RE: Portfast ???
Set portfast on any ports connecting to workstations..this will greatly improve the negotiation time when the station is coming up. Just do not set port fast on ports connecting to hubs or switches as it does not check for loops via spanning tree
Patrick
Patrick,
I will check for loops, however the use of portfast is to put the port
into the forwarding stage of the STP upon connectivity. The alogorithm
will still run in the background, however you do run the risk of a loop
until the port discovers this. If a loop is indeed introduced the port
is configured
correctly.
- Original Message -
From: ed smith [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Wednesday, September 06, 2000 6:32 AM
Subject: Portfast ???
I'm swapping out a 2900XL with a 2924C XL to give us Fiber capability.
Since
we have customers on the current switch I want
ree enable and portfast enable on ports that
clients/workstations are connected to. Should I also have "set spantree
portfast bpdu-guard enable" also and what does that do. The reason I ask is
because some clients are reporting that their ip address does not renew via
dhcp automaticall
I have one port on a Catalyst 6500 connected to a router with fast ethernet.
I also have spantree enable on the switches. Currently I have the spantree
portfast feature disabled on that port on the Catalyst 6500 that connects to
the router. Should that be enable or disable and why
Portfast simply allows the port to begin forwarding immedtiatly as opposed
to going through the blocking, litening, learning, forwarding states that a
spanning tree port goes through. It can safely be disabled if you do not
have redundant paths.
-Original Message-
From: Chen, Scott
Chen,
You don't want to enable portfast on ANY port that hooks up to a multiport
device. Switch, router, hub, even a multi-homed server. Only enable it on a
device that has a SINGLE connection to the network. Even at that it would
be a good idea to set up the portfast guard stuff unless you can
Switch ports that connect to routers or other switches should have portfast
disabled.
Only enable portfast on switch ports that you are certain connect directly
to workstations.
NT workstations are prone to needing portfast enabled to make connections to
the PDC at boot-up.
Portfast places
Would this help a problem I have with a dhcp client timing out? DHCP works
fine but between the switch and my laptops pcmia card it takes to long for
the link to come up. By the time it does DHCP times out.
On Fri, 14 Jul 2000, you wrote:
Portfast simply allows the port to begin forwarding
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