From: Joel Amao (femmy79@hotmail.com)
Date: Wed Feb 06 2008 - 13:56:25 ARST
You are correct..just looked at this again. In newer code the default admin
distance will always win. In older ios (less than 12.2(16)), we would have
installed both routes (static and ospf).
Joel Amao
CCIE#18128
Date: Wed, 6 Feb 2008 10:35:46 -0500From: cc13lab@gmail.comTo:
femmy79@hotmail.com; ccielab@groupstudy.comSubject: Re: Route preference
Metric is not used in this calculation, admin distance is. The defualt admin
distance is used when there is a tie. Route preference:
1. longest match
2. admin distance
3. if equal default AD, then use metric to determine best route.
4. if equal metric, loadbalance equal cost paths.
The metric is not used until like routes are found in a single protocol.
Metrics are not distinguishable between different protocols so to use metric
between them would be useless (metric of 20 in ospf and eigrp have 2
completely different meanings). HTH
larry
On 2/6/08, Joel Amao <femmy79@hotmail.com> wrote:
Same AD but different metric ...Thats why. In your output below:static
-0ospf-2 Joel AmaoCCIE#18128 > From: joe@affirmedsystems.com> To:
cc13lab@gmail.com> CC: ccielab@groupstudy.com> Subject: RE: Route preference>
Date: Tue, 5 Feb 2008 12:00:46 -0500> > >So, if a router is learning
192.168.1.0/24 through ospf and there is a> static route for 192.168.1.0/24
with AD of 110. Thank you in advance.> > > > Read this part. both routes have
an AD of 110.> > > > So here goes,> > > > I lab'd it up.> > > > rack1r1#sh ip
route ospf> > 1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks> > O
1.1.13.0/24 [110/2] via 172.16.11.11, 00:00:02, FastEthernet0/0> > (towards
sw1)> > > > But, when I put the static route with ad 110,> > > > ip route
1.1.13.0 255.255.255.0 172.16.11.11 110> > > > it uses the static route
instead of ospf> > > > rack1r1#sh ip route 1.1.13.1> > Routing entry for
1.1.13.0/24> > Known via "static", distance 110, metric 0> > Routing
Descriptor Blocks:> > * 172.16.11.11> > Route metric is 0, traffic share count
is 1> > > > > > rack1r1#sh ip route ospf> > > > > > (nothing)> > > > LOL, I
guess even with same AD you can't use two TYPES of routes to load> balance.> >
> > -Joe> > > > > > _____ > > From: Larry [mailto:cc13lab@gmail.com] > Sent:
Tuesday, February 05, 2008 11:30 AM> To: Joseph Brunner> Cc:
ccielab@groupstudy.com> Subject: Re: Route preference> > > > That should be a
1 not a 0...> > > > default ad = 0> > > > On 2/5/08, Larry <cc13lab@gmail.com>
wrote: > > Only the static route would be put into the table as its default ad
= 0:> > > > r1#show ip route 150.1.3.3 <http://150.1.3.3/> > Routing entry for
150.1.3.3/32> Known via "ospf 1", distance 110, metric 65, type intra area>
Last update from 150.1.13.3 <http://150.1.13.3/> on Serial1/1, 00:00:26> ago>
Routing Descriptor Blocks:> 150.1.13.3 <http://150.1.13.3/> , from 150.1.3.3
<http://150.1.3.3/> ,> 00:00:26 ago, via Serial1/1> Route metric is 65,
traffic share count is 1> * 150.1.12.2 <http://150.1.12.2/> , from 150.1.2.2
<http://150.1.2.2/> ,> 00:00:26 ago, via Serial1/0.1> Route metric is 65,
traffic share count is 1> > r1#conf t> Enter configuration commands, one per
line. End with CNTL/Z.> r1(config)# ip route 150.1.3.3 <http://150.1.3.3/>
255.255.255.255> <http://255.255.255.255/> 150.1.13.3 <http://150.1.13.3/> 110
> r1(config)#^Z> r1#show ip route 150.1.3.3 <http://150.1.3.3/> > Routing
entry for 150.1.3.3/32> Known via "static", distance 110, metric 0> Routing
Descriptor Blocks:> * 150.1.13.3 <http://150.1.13.3/> > Route metric is 0,
traffic share count is 1> > -larry > > > > On 2/5/08, Joseph Brunner
<joe@affirmedsystems.com> wrote: > > Both would be in the routing table. But
there will no load balancing unless> cef is disabled (no ip cef). With cef the
OLDEST or first learned route is> USED only... so if you want true load
balancing using the routing table,> disable cef.> > josCEF> > -----Original
Message-----> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
Behalf Of> Robert CCIE> Sent: Monday, February 04, 2008 8:07 PM> To:
ccielab@groupstudy.com> Subject: Route preference> > Hello Everyone,> I was
just wondering how a router behaves in these situations. If a> router learns a
route through a routing protocol but there is a static> route with the same
admin distance configured. Which route would be> installed in the routing
table? Or would both be installed? Also, I'm> guessing metrics only matter for
that routing protocols process as far> as calculation since a static route has
a metric of 0.> > So, if a router is learning 192.168.1.0/24 through ospf and
there is a> static route for 192.168.1.0/24 with AD of 110. Thank you in
advance.> > -Robert> >
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