From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Fri Nov 10 2006 - 21:51:38 ART
> For the end-to-end part, if I understand you correctly, if two routers
> are connected back to back, the LMI would be end to end. If there is
a
> FR switch in between, then no (because there is no way for R1 to know
if
> R2's connection to FR switch is up or not)
No, it depends on the service provider. If it is one service
provider with true Frame Relay end-to-end on the circuit then LMI will
be end to end. Most implementation are not like that nowadays with
Frame Relay on the edge going into an IP MPLS cloud via AToM for
example, in which case LMI is not end to end. Running FREEK works
around this situation though.
> For the interface up/down part, if my main interface is configured
with
> IP and I want to use backup interface when circuit 20 goes down, I
> should create a new subinterface with something like:
You can't have the same circuit on multiple interfaces. In that
case your best bet it to run GRE with keepalives and put the backup
interface command on the tunnel.
HTH,
Brian McGahan, CCIE #8593 (R&S/SP)
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987 x 705
Outside US: 775-826-4344 x 705
24/7 Support: http://forum.internetworkexpert.com
Live Chat: http://www.internetworkexpert.com/chat/
> -----Original Message-----
> From: Michael Zuo [mailto:mzuo@ixiacom.com]
> Sent: Friday, November 10, 2006 5:52 PM
> To: Brian McGahan; Frank; ccie >> Cisco certification
> Subject: RE: applying backup command to serial interfaces
>
> Thanks Brian :)
>
> For the end-to-end part, if I understand you correctly, if two routers
> are connected back to back, the LMI would be end to end. If there is
a
> FR switch in between, then no (because there is no way for R1 to know
if
> R2's connection to FR switch is up or not)
>
> For the interface up/down part, if my main interface is configured
with
> IP and I want to use backup interface when circuit 20 goes down, I
> should create a new subinterface with something like:
>
> Interface s0/0
> Enc frame-relay
> Ip address ....
> Frame-relay map ip 1.1.1.1 20 broadcast
> Frame-relay map ip 1.1.1.2 30 broadcast
>
> Interface s0/0.1 point
> no ip address
> backup ...
> frame-relay interface-dlci 20
>
> Is this correct?
>
>
>
> -----Original Message-----
> From: Brian McGahan [mailto:bmcgahan@internetworkexpert.com]
> Sent: Friday, November 10, 2006 11:22 AM
> To: Frank; Michael Zuo; ccie >> Cisco certification
> Subject: RE: applying backup command to serial interfaces
>
> It depends if LMI is end-to-end. If LMI is end-to-end then if
> one side goes down or there is a failure somewhere in the cloud the
> other end's circuit status will reflect this.
>
> Whenever you configure the backup interface command you need to
> ask yourself what will cause the line protocol of the interface to go
> down. For Frame Relay the line protocol of the main interface is
based
> on receiving LMI keepalive from the Frame Relay cloud. For Frame
Relay
> subinterfaces it is based on the circuit status. If all the circuits
on
> the subinterface are in Inactive or Deleted status then the line
> protocol will go down.
>
> For PPPoFR you need to put the command on the Serial interface
> not the virtual-template. The reason why is that the
virtual-template's
> line protocol is always down, as the virtual-access is the logical
> instance that is used from the template. However you can't access the
> virtual-access interface directly to configure it so you can't put the
> backup interface command on it.
>
>
> HTH,
>
> Brian McGahan, CCIE #8593 (R&S/SP)
> bmcgahan@internetworkexpert.com
>
> Internetwork Expert, Inc.
> http://www.InternetworkExpert.com
> Toll Free: 877-224-8987 x 705
> Outside US: 775-826-4344 x 705
> 24/7 Support: http://forum.internetworkexpert.com
> Live Chat: http://www.internetworkexpert.com/chat/
>
>
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of
> > Frank
> > Sent: Friday, November 10, 2006 8:50 AM
> > To: Michael Zuo; ccie >> Cisco certification
> > Subject: Re: applying backup command to serial interfaces
> >
> > Michael Zuo schrieb:
> >
> > Actually you have to put keepalives to the PVC to track the circuit
> for
> > the backup
> > command. If one side shuts down, the other side will not recognize
it.
> > You could use a tunnel over the cirtuit also to track the
availability
> > and put the
> > backup command on the tunnel.
> >
> > Frank
> > > Just curious: when using the "backup" command on a frame relay
> > > interface, should it always be applied to a subinterface to able
to
> > > track the VC status, even when the IP is configured on the main
> > > interface or a virtual-template interface (PPPoFR)?
> > >
> > >
> > >
> > >
> > >
> > > Basically, I'd like to find out when backup command is supposed to
> go
> > > the main interface and when a subinterface...
> > >
> > >
> > >
> > >
> > >
> > > Thanks in Advance...
> > >
> > >
>
This archive was generated by hypermail 2.1.4 : Fri Dec 01 2006 - 08:05:46 ART