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vdadlaney
Beginner

CE Qos Considerations when migrating from P2P to MPLS

Hi All,

I am looking to Migrate from P2P Circuits to a Dual Carrier MPLS Service however the traffic pattern for the most part will still be hub and spoke even though the MPLS Network provides any-to-any. At the 2 x Hub Sites the subscribed BW will be a lot higher than the remote sites eg. 500Mb at the Hubs and anywhere between 10 or 20Mb at the Remote sites. Hence potentially if the traffic is originating from the Hub site to a remote site I could send 500Mb into the SP network however this will be dropped at the Remote PE because the circuit into the remote site is a lot smaller. I am planning on configuring  traffic shaping as I am using ethernet for the local access and there is a mismatch between the Capability on the Interface and subscribed Bandwidth however do I need to create a policy for each remote site and police the rate going outbound based on the remote subnet so that I don't send more than the Remote interface is capable of receiving? Not sure if I am overthinking this because most of the guides and papers that I have read don't seem to indicate or speak about this mismatch between the Hub and Remote Site. Appreciate the help. Thx

Regards,

Vikram

6 REPLIES 6
Mahesh Gohil
Rising star

Hello Vikram,

Idea is good but it will become more complex and troubleshooting part will be more difficult. I think better you leave

your hub site with 500mb pipe with shaping because you have taken mpls from provider and i am sure he will have shaping

at outer towards your spoke sites. And I am sure they will put policer as per subscribed bandwidth at ingress of every site (hub/spoke)

You can ask provider for their plan for qos config and accordingly you can decide your part.

Hope this helps

Regards

Mahesh

Hi Mahesh,

Thanks for responding. My concern with letting the SP take care of this is that there could be dropped traffic because my Main site has the potential to oversubscribe the remote site and am not sure how the SP will be able to limit this because if I send upto 500Mb out of my hub site they are supposed to honor this without dropping. This traffic should go through the SP network until it reaches the remote site PE which is where I believe it will be dropped. I mean even if they are shaping at the remote PE towards the remote CE it will still be harmful so that is the reason why I am thinking of controlling how much traffic I send from my Hub site towards the spoke site to avoid drops etc. I don't see a lot written about this so am wondering if this is something that I need to be concerned about and if so is there any documentation that speaks about this because everyone should be facing this same issue. Thx

Regards,

Vikram

Hello Vikram

Let us focus on results of two method

1- Configuring shaping at hub for 500mb and assume provider has configured shaping towards spoe site

    result: Some of traffic will be shaped at egress of PE towards spoke

2- Configuring police at hub for every spoke based on destination address

    result: All the excess traffic will be dropped at HUB ce.

So it depends upon how you want to manage traffic . If you have application which is drop sensitive you can go for first approach where there is possibility

of shaping at egress of PE. But it your traffic is delay sensitive (and drop is ok) you can go for second approach.

Hope this helps

Regards

Mahesh

Hi Mahesh,

Thx for responding.

mahesh.gohil wrote:

1- Configuring shaping at hub for 500mb and assume provider has configured shaping towards spoe site

    result: Some of traffic will be shaped at egress of PE towards spoke

In the above will traffic be dropped at the egress PE towards the spoke?


2- Configuring police at hub for every spoke based on destination address

    result: All the excess traffic will be dropped at HUB ce.

Won't shaping be a better alternative in this case instead of policing the traffic. I would think that if I shape it to the speed of the Remote PE-CE link than I would get better performance as opposed to policing it and dropping the traffic.

Thx for your help.

Regards,

Vikram

Hello Vikram,

In the above will traffic be dropped at the egress PE towards the spoke?

depends: If provider has policed it will be dropped and it is shaped if it do not exceed the configured level of shaping

In the above will traffic be dropped at the egress PE towards the spoke?

Depends on type of traffic the link is carrying and what is important for your network: delay or drop ?

Regards

Mahesh

Hi Vikram,

Shaping per remote site doesn't scale. You might just let SP handle the congestion. For typical hub-spoke network, DMVPN has per tunnel qos address the similar issue.

Regards,

Lei Tian