IWAN Spoke with DSL asymmetric transport bandwidth.. Interface bandwidth best practice?

[Matthew Needs]

Hi Everyone,

I have an IWAN customer with multiple spokes and two types of transport (MPLS + WWW). The spoke sites have various combinations of leased line symmetrical bandwidth and asymmetrical DSL/4G (E.g. 1Mbps up, 10Mbps down). My question is around best practice when setting interface bandwidth on DMVPN tunnel interfaces. Here's a snippet from the IWAN design guide FYI..

The physical interface bandwidth setting should be set to match the bandwidth of the respective transport, which should correspond to the actual interface speed or, if you are using a subrate service, use the policed rate from the carrier

So my question is this :-  Where asymmetrical DSL based services are present should I set the spoke DMVPN Tunnel bandwidth to the upstream (As I have at the moment) or the downstream?.. Obviously the downstream is higher but if I use that value I would imagine I could run the risk flooding the upstream when IWAN load sharing is enabled? I have tried setting the following but IWAN only seems to pay attention to the upstream 1000kbps. Does this mean im not able to make use of all the available downstream DSL bandwidth? 

interface TunnelXX

description DSL Interface
bandwidth 1000
bandwidth receive 6000

I cant find any documentation around this so if anyone could help point me in the right direction I would really appreciate it?

Thanks a lot

Matt  

[vamikhai · Accepted solution]

Hello.

On a spoke, under the tunnel, you specify upstream bandwidth - this hints PFR on how much it may put to the interface. On the Hub with per-tunnel QoS you shape to spoke's downstream rate (minus 10%).

[Matthew Needs]

Thanks for the reply! Very hepful.. Can I ask another IWAN related question please? Is it possible to configure an MC/BR spoke specific policy? I do realise that IWAN is designed around the central MC's policy. But I was just interested if there was any way to override the Hub MC's policy at a specific spoke if required. And if so, could it cause issues?

Thanks 

[vamikhai]

Hello.

It's not possible to specify spoke-specifi policy.

It's possible (starting from iWAN 2.2.1) to specify inter-dc policy per transit site.

Best regards,

[Joseph W. Doherty]

Why "minus 10%"?