From: Larry Metzger (larrymetzger@sbcglobal.net)
Date: Tue Aug 10 2004 - 12:41:58 GMT-3
I thought of another place to use portfast with trunking. I know they
are not popular, but awhile back they came out with NICs for servers
that provided trunking capabilities. If a server were connected to the
switch with a trunk you would want portfast enabled. Just a thought.
Larry
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
tycampbell@comcast.net
Sent: Tuesday, August 10, 2004 6:54 AM
To: asadovnikov; 'ccie2be'; 'Group Study'
Subject: RE: spanning-tree portfast trunk
Thanks!!!
> Say you have a switch (3550) acting as L2 only with 5 VLANs and a
router
> (7200) connected to the switch over single gigabit interface to
provide
> inter-vlan routing (but does not do bridging), all 5 VLANs are trunked
on
> the port between router and switch. This is exactly when you would
use
> spantree portfast on the trunk on the switch side.
>
> Best regards,
> Alexei
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> ccie2be
> Sent: Tuesday, August 10, 2004 9:22 AM
> To: tycampbell@comcast.net; Group Study
> Subject: Re: spanning-tree portfast trunk
>
>
> Ty,
>
> I saw that also but thought that the only time it made sense to use
portfast
> on a trunk port was if the port were connected to a IP Phone.
>
> So, I'm trying to find out more about this trunk option to the
portfast
> command and I'd like to see examples where this option should be used
or
> shouldn't be used.
>
> I think the trunk option was really put in there by an evil cisco
programmer
> just to make ccie candidates go nuts.
> ----- Original Message -----
> From: tycampbell@comcast.net
> To: ccie2be ; Group Study
> Sent: Tuesday, August 10, 2004 9:11 AM
> Subject: Re: spanning-tree portfast trunk
>
>
> Tim,
>
> I haven't tried it with the trunk option on the portfast, I don't
believe
> it is needed.
>
> I am leaning this way because when you configure the voice vlan on
the
> interface, the interface is put into the portfast state automatically,
> without the "trunk" keyword. I think I could use a little more resaech
into
> this myself.
>
> Could it be that when trunking, the portfast command is only
applied, or
> used by the voice vlan, and not the access vlan or native vlan ?
>
> What I found on the DOC CD is very interesting
>
> "To enable Port Fast on trunk ports, you must use the spanning-tree
> portfast trunk interface configuration command. The spanning-tree
portfast
> command will not work on trunk ports."
>
> I cannot find any reference to spanning-tree portfast under
configuring
> voice vlan guide for 3550, however I do have a reference to portfast
in the
> IPExpert student guide written by Scott Morris
>
> :-)
>
> -------------- Original message --------------
>
> > Thanks Ty,
> >
> > Actually, I was asking about the trunk option in the
spanning-tree
> portfast
> > [trunk] command.
> >
> > In your 2 examples, the trunk option doesn't appear after the
> spanning-tree
> > portfast command. Why not? Is that because the port is trunking
in any
> > case? If so, then why bother to ever include "trunk" in the
portfast
> > command?
> >
> > If the trunk option (of portfast command) isn't needed when an
IP
> Phone is
> > attached to a port, when is it needed?
> >
> > Are there any situations where NOT having the trunk option
configured
> will
> > cause problems? Or, conversely, are there situations where you
MUST
> have
> > the trunk option or you'll have problems.
> >
> > Actually, I can't think of any reason why the portfast ! command
has a
> "trunk"
> > option. It seems to be completely pointless and only serves to
> distract
> > ccie candidates from more important topics.
> >
> > What do you think?
> >
> > Tim
> > ----- Original Message -----
> > From:
> > To: "ccie2be" ; "Group Study"
> > Sent: Tuesday, August 10, 2004 8:14 AM
> > Subject: Re: spanning-tree portfast trunk
> >
> >
> > > Tim,
> > >
> > > When doing voice vlan, portfast is automatically configured
wether
> in
> > trunk mode or not.
> > >
> > > here are 2 examples
> > >
> > > no trunking specified
> > > int f0/1
> > > switchport trunk encapsulation dot1q
> > > switchport voice vlan 105
> > > switchport access vlan 106
> > > spanning-tree portfast
> > >
> > > trunking specified
> > > ! int f0/2
> > > switchport trunk encapsulation dot1q
> > & gt; switchport voice vlan 105
> > > switchport mode trunk
> > > switchport trunk native vlan 106
> > > spanning-tree portfast
> > >
> > > on the 2nd example, since you are trunking, you should use
> "switchport
> > trunk native vlan" in place of "switchport access vlan". The
> spanning-tree
> > portfast is automatically configured when you configure the
voice vlan
> (I
> > believe)
> > >
> > > I hope that is what you were looking for :-)
> > >
> > > Ty
> > >
> > >
> > > > Hi guys,
> > > >
> > > > Is the only time the "trunk" option can be used correctly on
above
> > command is
> > > > when port is connected to an IP Phone?
> > > >
> > > > Also, if an IP Phone is connected to a port, and span
portfast is
> > configured
> > > > without the trunk option, will that cause a problem or
generate an
> er! ror
> > > > message?
> > > >
> > > > Thanks, Tim
> > > >
> > > >
>
This archive was generated by hypermail 2.1.4 : Fri Sep 03 2004 - 07:02:36 GMT-3