RE: Rip Metric

From: Huan Pham (Huan.Pham@peopletelecom.com.au)
Date: Wed Sep 10 2008 - 00:27:34 ART

This is interesting observation. I have never noticed it before.

I now also notice that the metric gets increased by 1 when these two
conditions must meet

- manual interface summarization
- this is summary route for routes that you redistribute from other
protocols (e.g. OSPF, static)

This means, if you do manual summary for RIP routes, then the metric is
equal to the minimum metric amongh more specific routes, and NOT the
minimum metric + 1.

Also, when you enable Auto-Summary, the metric of summary-route for
prefixes redistributed from other protocols does not get increased by 1
automatically.

This could well a bug!

In a real lab, if the task asks for a specific metric, and you can not
make the metric for redistributed routes, and the summary route the same
using interface summary command, then remember that you may meet the
task requirement by leaving the AutoSummary ON - an option that we
normally overlook.

Cheers,

Huan

 

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Zealist Hammad
Sent: Monday, 8 September 2008 6:43 AM
To: CCIE3000
Cc: Mohamed Tandou; ccielab@groupstudy.com
Subject: Re: Rip Metric

 I also thinks that its a correct behaviour .
Also if its written in Question that they need AD of 3 or 4 after
summarization then u will have to take care of that and give metric one
less for it.

regards
Hammad raza

On Sun, Sep 7, 2008 at 5:59 PM, CCIE3000 <ccie3000@googlemail.com>
wrote:

> Hi Tandou,
>
> Good spot, I've never noticed that!
>
> I don't think it's a bug (without doing a search for a bug) I've just
> configured something with my equipment and I get the same result.
>
> It's going to be one of those things to ask the proctor I should
imagine.
>
> FYI, it's the same if you use default-metric command, the summary
> address command adds an extra hop to the metric.
>
> On Sun, Sep 7, 2008 at 12:32 AM, Mohamed Tandou <dtandou@gmail.com>
wrote:
>
> > Hello GS,
> > i need someone expertise on this. i advertised OSPF into RIP V2 with

> > a metric of 3. when i do show ip route on the adjacent router i can
> > see the metric of 3 on the route being redistributed into RIP. When
> > i summarize
> the
> > routes being redistributed i see the metric going from 3 to 4 on
> > the summary route. i don't know if this is a bug. My concern is if
> > they ask
> me
> > to advertise a protocol into rip with a metric of 4 and summarize it
> should
> > i summarize it using metric 3 ? Can someone clear this one out?
> >
> > Thanks
> >
> > Tandou
> >
> >
> > Before summary
> > interface FastEthernet0/0
> > ip address 150.1.11.1 255.255.255.0 duplex auto speed auto router

> > rip version 2 redistribute ospf 11 metric 3 network 150.1.0.0 no

> > auto-summary BB1#sh ip route rip
> > 11.0.0.0/8 is variably subnetted, 14 subnets, 2 masks
> > R 11.11.2.2/32 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.1.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.3.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.4.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.5.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.6.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.12.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.14.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.20.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.25.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.30.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.40.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.60.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > R 11.11.100.0/24 [120/3] via 150.1.11.1, 00:00:02, Ethernet0
> > BB1#
> >
> >
> ======================================================================
> ==============================
> > After summary
> > interface FastEthernet0/0
> > ip address 150.1.11.1 255.255.255.0 ip summary-address rip
> > 11.11.0.0 255.255.0.0 duplex auto speed auto router rip version 2

> > redistribute ospf 11 metric 3 network 150.1.0.0 no auto-summary
> > BB1#sh ip route rip
> > 11.0.0.0/16 is subnetted, 1 subnets
> > R 11.11.0.0 [120/4] via 150.1.11.1, 00:00:05, Ethernet0
> > BB1#
> >
> >
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