From: Duongla (duongla@vnn.vn)
Date: Thu Sep 08 2005 - 11:34:54 GMT-3
Lee,
As far as I know, the normal behaviour of RIP (both ipv4 and ipv6) is: when
a router receives a route with metric of N then it installs the route in the
routing table with metric of N ( no increase). Then the router will
advertise the route out its interfaces with metric of (N+1).
Do you agree ?
Here, the problem is at R2: it increases the metric by one before it
installs the route int routing table. That's why R2 sees Z 2 hops away. In
fact, it is just 1 hop. And from R3 and on if we have a chain of routers,
the metric of route to Z will be 1 hop count greater than its actual metric.
Thanks
Duongla
----- Original Message -----
From: "Lee Donald" <Lee.Donald@t-systems.co.uk>
To: "Duongla" <duongla@vnn.vn>; "Lee Donald" <Lee.Donald@t-systems.co.uk>;
"Cisco certification" <ccielab@groupstudy.com>
Sent: Thursday, September 08, 2005 9:33 PM
Subject: RE: IPv6 RIP metric: strange calculation
> Duongla,
>
> You've said below that R2 receives the route with a metric of 1, then R2
> would add it's own cost onto the route, so R2 now has a cost of 2 for this
> route. R2 would send this route to R3 with a cost of 2, R3 would add it's
> own cost on and then R3 would have this route with a cost of 3.
>
> That is correct as far as I can read it??
>
> Regards
>
> Lee.
>
>
> :)
>
>
>
>
>
> -----Original Message-----
> From: Duongla [mailto:duongla@vnn.vn]
> Sent: 08 September 2005 15:22
> To: Lee Donald; Cisco certification
> Subject: Re: IPv6 RIP metric: strange calculation
>
> Hi Lee
>
> From R3, the metric to destination Z should be 2 hop-counts (R2-R1). The
> problem starts at R2, he he.
> Pls review the scenario if you could help.
>
> Thanks
> Duongla
> ----- Original Message -----
> From: "Lee Donald" <Lee.Donald@t-systems.co.uk>
> To: "Duongla" <duongla@vnn.vn>; "Cisco certification"
> <ccielab@groupstudy.com>
> Sent: Thursday, September 08, 2005 9:15 PM
> Subject: RE: IPv6 RIP metric: strange calculation
>
>
> > What problem?
> >
> > R3 should have a metric of 3 should it not?
> >
> > On your topology R2 has the route with a metric of 2, passes it to R3,
now
> > R3 has the route with a metric of 3, hop count has increased by 1 hop,
> which
> > is correct.
> >
> > Regards
> >
> > Lee.
> >
> >
> >
> > -----Original Message-----
> > From: Duongla [mailto:duongla@vnn.vn]
> > Sent: 08 September 2005 14:54
> > To: Cisco certification
> > Subject: IPv6 RIP metric: strange calculation
> >
> > Hi group,
> >
> > Doing a simple IPv6 RIP lab on 3 routers:
> > f0/0-R1-s0/0------s0/0-R2-s0/1------s0/0-R3-f0/0
> > Suppose R1 f0/0 IPv6 address is Z.
> > I noticed the following:
> > R1 advertises Z with metric of 1: this is normal behaviour
> > R2 receives the route Z with metric of 1. "show ipv6 route" output
shows
> > route Z with metric 2. R2 continues to send route Z metric 2 to R3
without
> > increasing the metric.
> > R3 has a route to Z with metric 3. It also sends the route out int
f0/0
> > with
> > metric 3.
> > All my routers use c2600-is-mz.122-15.T16.bin. Is this the bug of the
IOS
> ?
> >
> > Has anyone got the same problem ?
> >
> > Regards
> > Duongla
> >
> > _______________________________________________________________________
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> >
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