Re: Redistribution Problem

  Kambiz,

Do you mean using two static routes one along each path?

On 29/08/2010 12:54 AM, Kambiz Agahian wrote:
> Vince,
>
> Let's put it this way; from the local router's point of view is there
> any way to make those routes look like 2 suggestions from the "same"
> routing protocol?
>
>
>
> HTH
>
> Kambiz Agahian
>
> CCIE Instructor/Consultant
> M.Eng Telecom, CCIE# 25341, CCSI# 33326, MCSE, MCSA
>
> On Sat, Aug 28, 2010 at 12:55 AM, Vince Librandi
> <vlibrandi_at_internode.on.net <mailto:vlibrandi_at_internode.on.net>> wrote:
>
>
>
> I was always under the impression that it was first in would stay
> in (until withdrawn) when it came two routing processes with the
> same AD. But at least this way it gives you a predicatable
> behaviour you can work with.
>
> If the man with the expensive tie really wanted it 3 ways you
> could solve it would be:
>
> Split the network to be load balanced in half. Then on R5 set the
> AD for one 1/2 down in one AS and the other down in the other. Not
> true load balancing and it wouldn't work with /32.
>
> 2x GRE tunnels. One via R3-R5 and the other via R4-R5 then extend
> out the OSPF domain to R5. Then tweak the metrics to get the
> network to load balance on R5.
>
> MPLS TE. set up 2 paths one via R5 - R3 - R2 - R1 and the other R5
> - R4 - R1
>
> Are there any others that I have missed (or an easier one)?
>
>
> Question for the group, when you have 2 OSPF routing processes
> with the same prefix is it the lowest process ID that gets chosen?
> Just wondering if this is common across the protocols now.
>
> Vince
>
>
>
>
> On 28/08/2010 8:28 AM, Kambiz Agahian wrote:
>
> Hemanth,
>
> Now the million dollar question is how to enable load
> balancing in scenarios
> like this ? :) ... we can think of several ways.
>
> PS. Just to make sure everyone's clear on the last point and
> everybody's on
> the same page, in this case since we're learning the routes
> from two
> different AS's (AS - Autonomous System - just think about
> it...."autonomous" what does it mean?) both ways of route
> selection (prior
> to 12.2 and beyond that) make perfect sense. And the LB option
> is not such a
> great idea.
>
> In a normal situation however you probably don't want to load
> balance across
> two different networks (i.e. different management, routing
> policies, fees,
> SLA's etc.).
>
> Older versions of IOS (12.2 and again some switches) take the
> path that they
> hear about first. On the other hand, more recent versions of
> IOS choose the
> path with the lowest AS number.* Just a sort of tie breaker*.
>
> But what if your boss the guy with that expensive tie and belt
> keeps saying
> "load balancing"?! I always believe when something obvious
> (even in IOS 15)
> is not there probably it should not be! but how would you save
> your team?
>
>
>
> Kambiz Agahian
> CCIE Instructor/Consultant
> M.Eng Telecom, CCIE# 25341, CCSI# 33326, MCSE, MCSA
>
>
> On Fri, Aug 27, 2010 at 10:42 AM, Kambiz
> Agahian<aussiecert_at_gmail.com <mailto:aussiecert_at_gmail.com>>wrote:
>
> Yeah as the otehr user posted the link and I asked before,
> you will see
> either the route picked based on timestamp OR based on AS
> numbers. With the
> IOS version you're using (12.4T) the one with the lower AS
> number takes
> precedence. But again, this is still the case with old
> versions of IOS and I
> believe still some switches.
>
>
> HTH
>
>
> Kambiz Agahian
> CCIE Instructor/Consultant
> M.Eng Telecom, CCIE# 25341, CCSI# 33326, MCSE, MCSA
>
>
> On Fri, Aug 27, 2010 at 9:49 AM, HEMANTH
> RAJ<hemanthrj_at_gmail.com <mailto:hemanthrj_at_gmail.com>> wrote:
>
> No wat i have done first with AS 100 and then AS 200.
> It goes thorugh AS
> 100
> And then created another interface with another in AS
> 50 ,then afterwards
> it is goin via AS 50
> tats the confusing point!!!
>
>
> On Fri, Aug 27, 2010 at 10:17 PM, Kambiz
> Agahian<aussiecert_at_gmail.com
> <mailto:aussiecert_at_gmail.com>>wrote:
>
> The one with a lower number or the one to be seen
> first?
>
> Kambiz Agahian
> CCIE Instructor/Consultant
> M.Eng Telecom, CCIE# 25341, CCSI# 33326, MCSE, MCSA
>
> On Fri, Aug 27, 2010 at 9:43 AM, HEMANTH
> RAJ<hemanthrj_at_gmail.com
> <mailto:hemanthrj_at_gmail.com>>wrote:
>
> yes Vince u r right it chooses the one with a
> lower Autonomous system
> .Experts pls guide me for this question.
>
>
>
> On Fri, Aug 27, 2010 at 11:35 AM, Vince Librandi<
> vlibrandi_at_internode.on.net
> <mailto:vlibrandi_at_internode.on.net>
>
> wrote:
> Woops forgot to add the answer to your
> question.
>
> The router will only choose use the routes
> for a prefix from one
>
> routing
>
> protocol because that way it can guarantee
> at least for that AS it has
>
> a
>
> loop free path for the prefix (of course
> redistribution can negate
>
> that).
>
> But if the router where to install one
> route from one AS and another
>
> from a
>
> second AS it wouldn't be able to be sure
> that the path doesn't loop
> somewhere as the two AS's don't share
> routing information.
>
> So it looks like the router chooses the
> lowest AS number when the
>
> prefix
>
> length and AD are the same for a prefix.
>
>
> On 27/08/2010 3:05 PM, Vince Librandi wrote:
>
> Hi Hemanth,
>
> I just lab'ed up your set up and got
> the same affect. Looks like when
>
> you
>
> have two EIGRP process and the metric
> is the same and the AD on the
>
> route is
>
> the same the router chooses the
> process with the lowest AS number.
>
> Just to
>
> prove it I configured another EIGRP
> process (AS 50) on the R5-R4 link
>
> and
>
> the router choose that path instead.
>
> R5(config-router)#do sh ip ei top
> IP-EIGRP Topology Table for
> AS(100)/ID(10.1.45.5)
>
> Codes: P - Passive, A - Active, U -
> Update, Q - Query, R - Reply,
> r - reply Status, s - sia Status
>
> P 1.1.1.1/32 <http://1.1.1.1/32>, 0
> successors, FD is Inaccessible
> via 10.1.35.3
> (3097600/2585600), Serial0/1
>
> IP-EIGRP Topology Table for
> AS(200)/ID(1.1.1.2)
>
> Codes: P - Passive, A - Active, U -
> Update, Q - Query, R - Reply,
> r - reply Status, s - sia Status
>
> P 1.1.1.1/32 <http://1.1.1.1/32>, 0
> successors, FD is Inaccessible
> via 10.1.45.4
> (3097600/2585600), Serial0/0
>
> IP-EIGRP Topology Table for
> AS(50)/ID(10.1.45.5)
>
> Codes: P - Passive, A - Active, U -
> Update, Q - Query, R - Reply,
> r - reply Status, s - sia Status
>
> P 1.1.1.1/32 <http://1.1.1.1/32>, 1
> successors, FD is 3097600
> via 10.1.45.4
> (3097600/2585600), Serial0/0
>
>
>
> but if both links are in the same AS
> then I get the load balancing
>
> R5(config-router)#do sh ip ei top
> IP-EIGRP Topology Table for
> AS(100)/ID(10.1.45.5)
>
> Codes: P - Passive, A - Active, U -
> Update, Q - Query, R - Reply,
> r - reply Status, s - sia Status
>
> P 1.1.1.1/32 <http://1.1.1.1/32>, 2
> successors, FD is 3097600
> via 10.1.35.3
> (3097600/2585600), Serial0/1
> via 10.1.45.4
> (3097600/2585600), Serial0/0
>
> Looks like this is the way the routing
> table chooses between routes
>
> handed
>
> to it from different processes.
>
> Must see if OSPF does the same thing.
>
> Regards
>
> Vince
>
>
> On 27/08/2010 1:21 PM, HEMANTH RAJ wrote:
>
> s0/1 s0/0
> R2-------------------R3\s 0/2
> | | \
> |s0/0 s0/3 | \
> | |
> \ R1-loo 0
> 1.1.1.1/24 <http://1.1.1.1/24>
> | |
> \ s 0/0 R1-loo 1
> 11.11.11.11/24 <http://11.11.11.11/24>
> | |
> \
> | |
> / R5 R2-loo o
>
> 2.2.2.2
>
> /24
> | |
> / R2-loo 1
> 22.22.22.22/24 <http://22.22.22.22/24>
> | |
> / s 0/1
> | | /
> | s0/0 | /
> | s0/3 | /s0/2
> R1-------------------R4
> s0/1 s0/0
>
>
>
>
>
> I'm running ospf area 0 on
> R1,R2,R3 s 0/0,R4 s0/0
>
> R3 s0/3 ospf area 20
> R4 s0/3 ospf area 20
>
> R3 s0/2 eigrp AS 100
> R5 s0/0 eigrp AS 100
>
> R4 s0/2 eigrp AS 200
> R5 s0/1 eigrp AS 200
>
>
> I have done mutual redistribution
> on R3 between OSPF and EIGRP 100
>
> I have done mutual redistribution
> on R4 between OSPF and EIGRP 200
>
> Every route can ping every other route
>
> But when i check on R5 routing
> table I'm learning R1's loopback0 via
>
> R3
>
> But as per the logic it should
> load balance between R3 and R4 but it
>
> is
>
> choosing only R3
> and when i check on R5 topology
> table it shows the route via R4 is
> inaccessible
>
> I have reidstributed from opsf to
> eigrp with same metric on both R3
>
> and
>
> R4
>
> R3
> router eigrp 100
> redis ospf 1 met 1 1 1 1 1
>
> R4
> router eigrp 200
> redis ospf 1 met 1 1 1 1 1
>
> But still R5 is choosing path via
> R3 and not loadbalancing between
>
> R3 and
>
> R4
>
> Can anyone help me out of this
> issue???
>
>
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>
>
>
>
>
>
>
>
>
> --
> Problems arise Bcoz we talk,prblms r not solve
> bcoz we dont talk So gud
> r
> bad talk to ur affectionate one's freely
>
> Urs Friendly,
> HP HEMANTH RAJ
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
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>
>
>
>
>
>
>
>
> --
> Problems arise Bcoz we talk,prblms r not solve bcoz we
> dont talk So gud r
> bad talk to ur affectionate one's freely
>
> Urs Friendly,
> HP HEMANTH RAJ
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
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Received on Sun Aug 29 2010 - 19:22:05 ART