From: Josef A (josefnet@gmail.com)
Date: Sat Apr 07 2007 - 13:57:26 ART
All other routers other than the active forwarder will be in the listen
state for that mac address, any of these listeners would start
forwarding packets for the mac address if the active dies or a tracked
interface goes down; the AVG may also be a listener for the mac address if
it's not the active forwarder.
The important thing though is that the command that accomplishes IMMEDIATE
forwarding preemption is:
glbp 1 forwarder preempt delay minimum 0.
thx
On 4/7/07, nhatphuc <nhatphuc@gmail.com> wrote:
>
> Hi Josef,
>
> The secondary AVF may not necessarily be the AVG. If this is the case and
> AVG is configured with glbp 1 forwarder preempt delay minimum 0. So how
> does
> the secondary AVF become active immediately after the 1st down?
>
> Thanks
>
> Phuc
>
> On 4/7/07, Josef A <josefnet@gmail.com> wrote:
> >
> >
> > Dear Phuc,
> >
> > This is my opinion on this:
> >
> > Bear in mind that there can be more than 2 routers in a glbp group, and
> > that the router that is actively forwarding traffic for a particular
> glbp
> > group mac address is the AVF - the Active Virtual Forwarder for that mac
> > address.
> >
> > The AVG is the Active Virtual Gateway - is the router that shares the
> > different glbp mac addresses amongst the AVFs. The AVG itself can also
> be an
> > AVF for a mac address. GLBP allows up to four virtual mac addresses per
> > group.
> >
> > The documentation says that if the AVF fails, one of the secondary
> virtual
> > forwarders in the listen state will assume the responsibilty for the
> > virtual mac address. This secondary AVF may not necessarily be the AVG.
> >
> > The first part of your requirement states that if the interface goes
> down
> > ensure traffic is still forwarded without any delay:
> >
> > Initially we must track the appropriate interface on the Primary
> > Forwarder, and set weighting values. If the interface goes down, the
> weight
> > will be decremented. As soon this occurs, we want the secondary virtual
> > forwarder to preempt the primary and starts forwarding packets for that
> mac
> > address:
> >
> > We will configure on the secondary virtual forwarder:
> >
> > glbp 1 forwarder preempt delay minimum 0
> >
> > The second part of your requirement states that: When the interface
> comes
> > back up, we want to resume the active forwarder role in 60s.
> >
> > We will configure on the Primary forwarder:
> >
> > glbp 1 forwarder preempt delay minimum 60.
> >
> > Note that the command: glbp 1 preempt delay min 0: actually configures
> > preemption for the AVG, but the AVG might not be the router forwarding
> > traffic for the mac address we are using.
> >
> > Just my 2 cents.
> >
> > thx
> >
> >
> >
> >
> > On 4/3/07, nhatphuc <nhatphuc@gmail.com> wrote:
> >
> > > Hi Group,
> > >
> > > I want to configure tracking in GLBP as follow:
> > >
> > > when the interface goes down, ensure traffic is still forwarded
> without
> > > any
> > > delay. So I configure: glbp 1 preempt delay min 0
> > > But when the interface goes up, I want 60 seconds delay before
> resuming
> > > the
> > > active forwarder role (for routing convergence). How do I configure?
> > >
> > > Thanks
> > >
> > > Phuc
> > >
> > >
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