From: tom cheung (tkc9789@xxxxxxxxxxx)
Date: Sun Nov 18 2001 - 12:39:07 GMT-3
Yes, that's how I understood it.
>From: "Chua, Parry" <Parry.Chua@compaq.com>
>To: "tom cheung" <tkc9789@hotmail.com>, <hbae@nyc.rr.com>,
><ccielab@groupstudy.com>
>Subject: RE: OSPF Load Balance
>Date: Sun, 18 Nov 2001 17:38:04 +0800
>
>Hi,
>
>I thought that when we show IP route, there could be one or more path to
>reach a particular destination based on the routing protocol type. For
>OSPF, if we know there could be more than one path to reach that
>destination, we can then manuiplate the COST to get a equal cost
>for load balanceing, right ? Other protocolos such as (E)IGRP support
>unequal cost load balancing. As for RIP, I belive we can use offset to
>change the hop count from unequal to
>equal and vice versa, right ?
>
>Regards
>Parry
>-----Original Message-----
>From: tom cheung [mailto:tkc9789@hotmail.com]
>Sent: Sunday, November 18, 2001 10:31 AM
>To: hbae@nyc.rr.com; ccielab@groupstudy.com
>Subject: Re: OSPF Load Balance
>
>
>I'll have to disagree, and someone else please correct me if I'm wrong.
>
>OSPF only understands intra-area, inter-area and external route types.
>OSPF
>route preference is based upon route types and within the same route
>type,
>costs. If there're equal cost routes within the same route type, then
>load
>balance is automatic. Sure you can look at same cost as hop counts. If
>I
>make the cost of two paths to the same destination, say 100, you
>certainly
>can view that as 100 hops. But load balance will happen.
>If there're no equal cost paths to the same destination, fast switch
>will
>not put packets on the higher cost path, period.
>
>Tom
>
> >From: Hansang Bae <hbae@nyc.rr.com>
> >Reply-To: Hansang Bae <hbae@nyc.rr.com>
> >To: ccielab@groupstudy.com
> >Subject: Re: OSPF Load Balance
> >Date: Sat, 17 Nov 2001 20:14:20 -0500
> >
> >>>From: Hansang Bae <hbae@nyc.rr.com>
> >>>I don't think you accomplished what you wanted to do. Setting all
>the
> >>>costs to be the same causes OSPF to act like RIP. That is, the
>metric
> >>>now
> >>>becomes a hop count. So unless you have the same number of hops, it
> >>>won't
> >>>work.
> >>>Even then, route-cache will cause per destination load-balancing.
> >
> >
> >At 10:17 AM 11/17/2001 -0600, tom cheung wrote:
> >>Correct me if I'm wrong. By default, OSPF load balances up to a max
>of 4
> >>equal cost, equal path-type routes. OSPF does not take into
>consideration
> >>of hop counts.
> >
> >
> >
> >All correct. *Except*, that the original poster made all the interface
> >costs to be the same. So basically, the metric acts just like hop
>counts.
> >And while load balancing works across 4 links (w/o using
>maximum-paths),
> >the route-cache (fast processing) makes the router use one link for a
> >particular destination. This isn't unique to OSPF, it's just the way
>fast
> >processing works (w/o using CEF etc.)
> >
> >hsb
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