Need MPLS Guru

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May 11th, 2006
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We are thinking of building an enterpise MPLS backbone consisting of about 30 7206 Vxr routers. This deployement would have basic MPLS L3 capabilities, Vrf -Multicast aware, and support customer QOS.

My question is what code should we be running. Should we be running 12.0 code or 12.4 code based on the features. I see some providers are running 12.0(22)s code. Is there any advantage of running 12.4 if yes what version?

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Overall Rating: 5 (2 ratings)
mheusinger Thu, 05/11/2006 - 14:21
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Hello Parwal,

I would recommend to use the IOS feature navigator and compare the two latest images for the hardware you are interested in.

Select: Compare Images

This will give you a list of features unique to both of the IOS images (f.e. 12.0(32)S and 12.4). Based on the features needed this might already help you to decide, which IOS is right for your environment.

Besides that I would also recommend to get a Test environment (f.e. CPOC) and check for unresolved bugs and other obstacles.

Last thing: Check prices ...

Well given the volume of your project I would let the Cisco account manager do some of the work... ;-)

Hope this helps! Please rate all posts.

Regards, Martin

NAVIN PARWAL Thu, 05/11/2006 - 17:49
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Why are MPLS providers running 12.0(33)s code, I know atleast 2 big providers who are running 12.0 code and not 12.4. Lets say i am looking for basic features like L3 MPLS VPN, Multicast VPN, QOS which are available on both 12.0(33)s and 12.4 code, which one should i go for?


pkhatri Thu, 05/11/2006 - 19:15
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The one major reason a provider would run the 'S' train code is that a lot of service provider features first appear in the 'S' train. While the same feature may eventually appear in a mainline release, a lot of these providers would in fact be the ones that requested some of these features. As a result, they will move to the first stable IOS release that supports the feature.

There is no problem with using 12.4 code if it has all the features you require.

Pls do remember to rate posts.


mheusinger Thu, 05/11/2006 - 22:58
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Hello Parwal,

Paresh is off course right. In addition I would say, that the advantage of using, what the big SPs are using is: it is more likely that bugs related to the features you are interested in will be discovered and fixed quickly.

Another thought: leaving out IOS components, which you are not really interested in (X.25, DLSW, etc.) will provide a - hopefully - more stable IOS.

But as Paresh already stated: both IOS trains will provide the basic MPLS and QoS features you mentioned. So the decision for one or the other IOS train can be based on the other mentioned properties and requirements.

Hope this helps! Please rate all posts.

Regards, Martin

mario_spendier Thu, 05/11/2006 - 23:17
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Depends on what you need in your network! We, for example, need DLSW between customer connections. For putting DLSW process into a VRF we need to have 12.4!



NAVIN PARWAL Fri, 05/12/2006 - 04:33
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Could someone recommend any specific version of 12.4 which is most stable than others if we just want MPLS L3 VPN, Multicast VPN, QOS ? should i go with the T train or general deployment?

mheusinger Fri, 05/12/2006 - 05:32
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Well, ... in principle GD (General Deployment) would be advisable. But realistically no one will guarantee a bug free IOS doing all the things you would like it to do. So in the end it requires testing.

Be aware, that your list of requested features is most likely incomplete.

The other thing is: which new features are required?

What about SNMP? AAA? SSH? IGP to be used? BGP RR? Convergence time tuning? High availability features? Security? NetFlow? Future EoMPLS, AToM, ...

You probably understand that no one can give you a definite answer about the IOS unless the list of features would be complete.

Regards, Martin

rseiler Mon, 05/22/2006 - 11:07
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I'm not sure why anyone would be suggesting 12.4 ios for an mpls backbone. Cisco has been very clear that the 'stable' or 'service provider' code is ONLY 12.0S or 12.2S. Since 12.2S is the later of the two that is what I would recommend. If you are not familiar with the Safer Harbor project within Cisco for recommended and tested versions (including MPLS), then talk to your Cisco account manager or SE.

Harold Ritter Mon, 05/22/2006 - 13:45
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It is false to state that 12.2S is a later version of 12.0S. These two trains run in paralel and usually inherit more or less the same features.

Hope this helps,


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