From: Godswill Oletu (oletu@inbox.lv)
Date: Mon Jul 05 2004 - 12:28:35 GMT-3
I can't agree more Adel, but if I redistribute a prefix say 12.1.1.0/24 from
EIGRP AS100 into EIGRP AS200, however EIGRP AS200 already have the same
prefix 12.1.1.0/24 learnt from another source.
In this case I am not dealing with two ASs any more, I am now left to deal
with AS200, because both routes are now is AS200, prefix 1 with AD = 90 and
the other with AD=170 (depending on their sources).
If I can get the ADs of both prefixes to be same in EIGRP AS200 but retain
different metrics, EIGRP will still pick the best route based on its metric
value.
I should be able to get an unequal load balancing from EIGRP by computing
the appropriate variance value to be used in EIGRP AS200, because when EIGRP
looks into its topological database, it sees two routes to the same prefix
of 12.1.1.0/24.
Godswill Oletu
===========
In the future everything will Work
----- Original Message -----
From: "Adel Abouchaev" <adel@netmasterclass.net>
To: <ccielab@groupstudy.com>
Sent: Monday, July 05, 2004 8:16 AM
Subject: RE: Modifying AD for EIGRP external routes
> It is not stated in Cisco docs, but EIGRP will not load balance between
the
> same prefix learned from multiple processes. It will prefer one AS to
> another, I am not quite sure what is the rule-of-thumb in that case,
either
> AS number or the lowest next hop IP, something like that.
>
> For the prefixes to be load balanced in EIGRP, if for example your metrics
> are 1000 and 3000, then variance shall be set to 4, since the document
says
> "less than", not "less or equal to". Mind that.
>
> The last but not the least, both prefixes shall point to the feasible
> successor to be considered for variance.
>
> Adel Abouchaev
> CCIE# 12037, MCSE, MCSA
> Netmasterclass, LLC
> www.netmasterclass.net
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of MD
> Sent: Monday, July 05, 2004 2:18 AM
> To: ccielab@groupstudy.com; security@groupstudy.com
> Subject: Re: Modifying AD for EIGRP external routes
>
> FYI--Variance command did not help.
>
> Let me explain the problem again. Router has 2 EIGRP processes 318 and
305.
> It is learning route 172.16.15.0 from both the AS with same
> metric(46738176/4622617).
>
> AS318 from Serial 0(NBMA) and AS305 from Serial2(PtoP)
>
> Here is the EIGRP topological database--See the difference in FD of both
> routes but same metric. IOS for some reason is increasing the FD for one
> route when it learns the same route from 2 EIGRP processes. Check
this--when
> I shut down Serial2. see the change in FD. .
>
>
> EIGRP TOPOLOGICAL DATABASE WHEN BOTH S0 and S2 are UP.
>
> IP-EIGRP (AS 318): Topology entry for 172.16.15.0/28
> State is Passive, Query origin flag is 1, 0 Successor(s), FD is
4294967295
> Routing Descriptor Blocks:
> 172.16.123.1 (Serial0), from 172.16.123.1, Send flag is 0x0
> Composite metric is (46738176/46226176), Route is Internal
> Vector metric:
> Minimum bandwidth is 56 Kbit
> Total delay is 40000 microseconds
> Reliability is 255/255
> Load is 1/255
> Minimum MTU is 1500
> Hop count is 1
> IP-EIGRP (AS 305): Topology entry for 172.16.15.0/28
> State is Passive, Query origin flag is 1, 1 Successor(s), FD is 46738176
> Routing Descriptor Blocks:
> 172.16.35.2 (Serial2), from 172.16.35.2, Send flag is 0x0
> Composite metric is (46738176/46226176), Route is Internal
> Vector metric:
> Minimum bandwidth is 56 Kbit
> Total delay is 40000 microseconds
> Reliability is 255/255
> Load is 1/255
> Minimum MTU is 1500
>
> SH IP ROUTE-- shows only one route
>
> D 172.16.15.0/28 [90/46738176] via 172.16.35.2, 00:01:29, Serial2
>
> EIGRP TOPOLOGICAL DATABASE WHEN S2 is SHUT DOWN
>
> h ip eigrp topology 172.16.15.0 255.255.255.240
> IP-EIGRP (AS 318): Topology entry for 172.16.15.0/28
> State is Passive, Query origin flag is 1, 1 Successor(s), FD is 46738176
> Routing Descriptor Blocks:
> 172.16.123.1 (Serial0), from 172.16.123.1, Send flag is 0x0
> Composite metric is (46738176/46226176), Route is Internal
> Vector metric:
> Minimum bandwidth is 56 Kbit
> Total delay is 40000 microseconds
> Reliability is 255/255
> Load is 1/255
> Minimum MTU is 1500
> Hop count is 1
> % IP-EIGRP (AS 305): Route not in topology table
>
> SH IP ROUTE- again shows only one route
>
> D 172.16.15.0/28 [90/46738176] via 172.16.123.1, 00:00:07, Serial0
>
>
> This tells me there is something in the IOS that prevents load balancing
for
> a particular route over 2 different AS( Irrespective of being external or
> internal and despite having same Metric). Please confirm if you also think
> so , unless anybody has actually tried load balancing over 2 AS
???????????
>
>
>
> thanks,
> MD
>
>
>
> Godswill Oletu <oletu@inbox.lv> wrote:
> Set the AD of both routes to be the same. Check your EIGRP topological
> database to make sure that both routes are in the topological database,
> though it is only the best route that will be selected from the
topological
> database and installed in the routing table.
>
> Note the metric values of both routes in the EIGRP topological database eg
> if:
> route 1 metric= 12313
> route 2 metric= 35262
> route 2 metric/route 1 metric = 2.86 = 3
>
> To setup unqual load balance across both route 1 and route 2:
> Under the EIGRP process, set variance = 3
>
> This will make EIGRP to install both routes into the routing table and
load
> balance across both routes. A simple traceroute command will confirm the
> load balance.
>
> Godswill Oletu
> ===========
> 8,x$:0`0:$x,88,x$:0 In the future everything will Work :$x,88,x$:0`0:$x,8
>
>
>
> ----- Original Message -----
> From: "MD"
> To: ;
> Sent: Sunday, July 04, 2004 10:36 PM
> Subject: RE: Modifying AD for EIGRP external routes
>
>
> > I tried using "distance eigrp 90 91 " command and it does maka the
> external AD to 91 but here is another problem now.
> >
> > My objective was to test load balance 2 routes learned by internal EIGRP
> and external EIGRP by making the AD and metric same for both routes. After
> using the above command , I was able to make metric and AD same but now I
> see that router is not doing load balancing between 2 routes which have
same
> metric and AD but instead prefer the internal Eigrp route.
> >
> > As a workaround , I even tried getting the external route as internal
> route via different AS No. but then again the same problem. Router would
not
> do load balancing even though the metrics and AD are same because it is
> learning routes from 2 different AS's.
> >
> > So my question is- Can you achieve load balancing for a particular route
> learned from 2 different AS's and make the router shows both routes in the
> routing table.
> >
> >
> >
> > thanks,
> > MD
> >
> >
> > Matt Hill wrote:
> > Can you try running EIGRP in different ASes, with different ADs and
> > doing redistribution?
> >
> > Matt
> >
> > --
> > Matt Hill
> > Network Engineering
> > Alcatel Australia Pty Ltd
> > 180-188 Burnley St
> > Richmond, Vic
> > 3121
> >
> > v: +61 3 8687 5739
> > f: +61 3 8414 3115
> > e: matt.hill@aapt.com.au
> > u: http://www.alcatel.com.au
> > m: ask and you may receive
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > ccievision@yahoo.com
> > Sent: Monday, 5 July 2004 4:17 AM
> > To: ccielab@groupstudy.com; security@groupstudy.com
> > Subject: Re: Modifying AD for EIGRP external routes
> >
> > Thanks everyone for your input.
> >
> > I will try changing the AD for all EIGRP routes and then modify AD again
> > at downstream routers to see if I can achieve my objective.
> >
> > Any other suggestions would also be appreciated.
> >
> > thanks,
> > MD
> > Richard Gallagher wrote:
> > It is possible to change the distance for external routes, but you
> > cannot
> > change it for specific prefixes:
> >
> > http://www.cisco.com/en/US/products/sw/iosswrel/ps5207/products_command_
> > reference_chapter09186a00801a807f.html#wp1075239
> >
> > router(config-router)#distance eigrp 90 ?
> > <1-255> Distance for external routes
> >
> > router(config-router)#distance eigrp 90 171 ?
> >
> >
> > HTH, Rich
> >
> > ----- Original Message -----
> > From: "MD"
> > To: ;
> > Sent: Sunday, July 04, 2004 10:56 AM
> > Subject: Modifying AD for EIGRP external routes
> >
> >
> > > Has anybody tested reducing the AD of external EIGRP routes from 170
> > to
> > some other value (say 91).
> > >
> > > I have tried the distance command under EIGRP but it changes the
> > distance
> > only for internal eigrp routes and not external eigrp routes.
> > >
> > > Here is the relevant configs...
> > >
> > >
> > > router eigrp 318
> > > redistribute eigrp 300 route-map 300to318
> > > offset-list 99 in 20 Serial0
> > > network 172.16.123.0 0.0.0.31
> > > neighbor 172.16.123.1 Serial0
> > > neighbor 172.16.123.4 Serial0
> > > distance 91 172.16.123.1 0.0.0.0 98
> > > distance 91 172.16.123.4 0.0.0.0 97
> > > no auto-summary
> > > !
> > >
> > > access-list 97 permit 10.2.4.0 0.0.3.255
> > > access-list 98 permit 172.16.15.0 0.0.0.15
> > >
> > >
> > > SH IP ROUTE
> > >
> > > D EX 172.16.15.0/28 [170/46738176] via 172.16.123.1, 00:00:07, Serial0
> > > D 10.2.4.0/22 [91/46251776] via 172.16.123.4, 00:25:30, Serial0
> > >
> > >
> > > FYI-- 172.16.123.1 is sending external EIGRP routes and 172.16.123.4
> > is
> > sending internal EIGRP routes and I am trying to make both these routee
> > to
> > show up with AD 91 in the routing table.
> > >
> > >
> > > thanks,
> > >
> > > MD
> > >
> > >
> > >
> > >
> > >
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