From: Mark Lewis (markl11@xxxxxxxxxxx)
Date: Wed Aug 02 2000 - 14:06:57 GMT-3
Hi all,
Even if only one pvc is configured on an interface, there is still the
possiblity that line protocol will stay up. The reason for this is that a
pvc's status is indicated in one of three ways: 1.active - indicates that
end-to-end the circuit is good (ie. router to LOCAL fr switch,across telco
net., and from far end fr switch to far end router; 2.inactive -indicates
that there is a problem between the FAR end fr switch and FAR end router (or
possibly in telco cloud); 3.deleted - indicates that there is a problem from
LOCAL router to LOCAL fr switch.
Now, HSRP only tracks (with standby track command) carrier detect and
keepalives on the line (VC) to LOCAL fr switch. The upshot of this is that
HSRP will only detect loss of keepalives if there is a problem between LOCAL
router & LOCAL fr switch. Or to put it another way, if the status of the PVC
is deleted.
Use of dynamic routing prot. is of course the solution to this little
problem.
Hope this is useful!
Mark
CCSI/CCNP
>From: mark salmon <masalmon@cisco.com>
>Reply-To: mark salmon <masalmon@cisco.com>
>To: Johnny Dedon <jdedon@cohesive.com>, Ccielab <ccielab@groupstudy.com>
>Subject: Re: HSRP tracking of Frame ciruits
>Date: Wed, 02 Aug 2000 11:08:13 -0700
>
>I came in late so forgive me if I state something others have said. If
>there are more than one pVCs on the interface, you are correct, however
>if there is only one pvc and the remote end goes down, then I believe
>the local end will show aa line protocol down.
>
>In addition, even if the local interface line protocol stays up, if you
>are using dynamic routing protocols, the far end reachability over the
>local interface will cease, with availability now over the other router,
>it will become the active router.
>
>Johnny Dedon wrote:
> >
> > Guys,
> > If the far end frame circuit is down, the local router's circuit still
>shows
> > as up up. The local router will accept routes for the destination and
>since
> > HSRP is enabled, ICMP redirects is disabled for the peer, and you end up
> > with a black hole.
> > Johnny
> > ----- Original Message -----
> > From: "Brian Hescock" <bhescock@cisco.com>
> > To: "Jason T. Rohm" <jtrohm@athenet.net>
> > Cc: "Ccielab" <ccielab@groupstudy.com>; "Johnny Dedon"
><jdedon@cohesive.com>
> > Sent: Wednesday, August 02, 2000 7:10 AM
> > Subject: RE: HSRP tracking of Frame ciruits
> >
> > > Jason,
> > > Yes but with one significant difference, RTRA would still be the
>active
> > > router so all packets would be sent there first then it would forward
>the
> > > packets to RTRB. We would end up routing the packets twice instead of
> > > only once if RTRB was the active router. Another disadvantage is you
>end
> > > up having the switch between the two routers handling twice as much
>data.
> > >
> > > Brian
> > >
> > > On Tue, 1 Aug 2000, Jason T. Rohm wrote:
> > >
> > > > I am trying to understand the questions but... wouldn't simple
>routing
> > force
> > > > the data through the other PVC?
> > > >
> > > > IE:
> > > >
> > > > PVC1 = RTRA to RTRC
> > > > PVC2 = RTRB to RTRC
> > > >
> > > > If the PVC1 goes down, RTRA's new route to RTRC will through RTRB
>any
> > ways,
> > > > if the local default gateway is set to RTRA, it will just issue an
>ICMP
> > > > redirect to move the data to RTRB.
> > > >
> > > > Maybe I am wrong...
> > > >
> > > > -Jason T. Rohm
> > > > jtrohm@athenet.net
> > > >
> > > > -----Original Message-----
> > > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf
>Of
> > > > Johnny Dedon
> > > > Sent: Tuesday, August 01, 2000 5:27 PM
> > > > To: ccielab@groupstudy.com
> > > > Subject: HSRP tracking of Frame ciruits
> > > >
> > > > Can anyone tell me how to track the status of a serial frame relay
> > > > connection with hsrp setup on the lan connections. I want to
>failover
> > my
> > > > LAN connection if the far end of my primary router's frame
>connection is
> > > > down.
> > > >
> > > > RTRC
> > > > X |
> > > > ------------------------------
> > > > Frame Relay
> > > > ------------------------------
> > > > | |
> > > > RTRA - hsrp - RTRB
> > > > | |
> > > > -------Ethernet-----------------
> > > >
> > > > Router A is primary and link at RTRC fails
> > > >
> > > >
> > > > Johnny
> > > >
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