From: Ronnie Angello (ronnie.angello@gmail.com)
Date: Fri May 02 2008 - 15:43:54 ART
Sorry, I must have missed the original post because the one that I
responded to didn't mention variance at all.
Setting a variance value enables EIGRP to install multiple loop-free
routes with unequal cost in a local routing table. A route learned
through EIGRP must meet two criteria to be installed in the local
routing table:
The route must be loop- free. This condition is satisfied when the
reported distance is less than the total distance or when the route is
a feasible successor.
The metric of the route must be lower than the metric of the best
route (the successor) multiplied by the variance configured on the
router.
Thus, if the variance is set to 1, only routes with the same metric as
the successor are installed in the local routing table. If the
variance is set to 2, any EIGRP-learned route with a metric less than
2 times the successor metric will be installed in the local routing
table.
On Fri, May 2, 2008 at 1:40 PM, Matt Bentley <mattdbentley@gmail.com> wrote:
> Thanks everyone for getting back to me. I thought that "show ip route"
> would show all paths advertised in EIGRP as long as the variance between the
> two metrics did not exceed the ratio established with the "variance"
> command. Correct?
>
>
> On Fri, May 2, 2008 at 1:08 PM, Ronnie Angello <ronnie.angello@gmail.com>
> wrote:
> > They are not "equal cost" paths so only the path with the lowest
> > metric is installed in the routing table. You should see both paths
> > if you do a 's ip eigrp top <network> <mask>.' You can also achieve
> > unequal cost load balancing if you use the eigrp 'variance' command.
> >
> >
> >
> >
> > On Fri, May 2, 2008 at 12:51 PM, Matt Bentley <mattdbentley@gmail.com>
> wrote:
> > > Hi GS:
> > >
> > > Maybe I'm missing something. I have two routers connected to each other
> > > with both a serial and ethernet connection. A route is redistributed
> into
> > > EIGRP on one router. Shouldn't I see it when I do a "show ip route
> x.x.x.x"
> > > as being advertised over both links? It is preferring the ethernet
> > > interface, but if I shut the ethernet interface, than I see it
> advertised
> > > over the serial link - so I don' think it is a FD/AD issue. Any help
> would
> > > be greatly appreciated.
> > >
> > > With Ethernet Link On
> > > Routing entry for 222.22.2.0/24
> > > Known via "eigrp 1024", distance 170, metric 284160, type external
> > > Redistributing via eigrp 1024
> > > Last update from 174.1.45.5 on Ethernet0/1, 00:06:16 ago
> > > Routing Descriptor Blocks:
> > > * 174.1.45.5, from 174.1.45.5, 00:06:16 ago, via Ethernet0/1
> > > Route metric is 284160, traffic share count is 1
> > > Total delay is 1100 microseconds, minimum bandwidth is 10000 Kbit
> > > Reliability 255/255, minimum MTU 1500 bytes
> > > Loading 1/255, Hops 1
> > >
> > > With Ethernet Link Shut
> > >
> > > Rack1R4(config-if)#do sh ip route 222.22.2.0
> > > Routing entry for 222.22.2.0/24
> > > Known via "eigrp 1024", distance 170, metric 2684416, type external
> > > Redistributing via eigrp 1024
> > > Last update from 174.1.145.1 on Serial1/0, 00:00:21 ago
> > > Routing Descriptor Blocks:
> > > * 174.1.145.1, from 174.1.145.1, 00:00:21 ago, via Serial1/0
> > > Route metric is 2684416, traffic share count is 1
> > > Total delay is 40100 microseconds, minimum bandwidth is 1544 Kbit
> > > Reliability 255/255, minimum MTU 1500 bytes
> > > Loading 1/255, Hops 2
> > >
> > >
> >
> >
> >
> > > Pass the CCIE in six weeks, Guaranteed!
> > > http://www.certscience.com/CCIE
> > > _______________________________________________________________________
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> > >
> > >
> > >
> > >
> >
> >
> >
> > --
> > Ronald Angello
> > CCIE #17846
> >
>
>
-- Ronald Angello CCIE #17846
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