shape average effect for the entire pipe??

[jacob6000]

Okay, so I used Josephs's example from a previous post.  I'm combining snippets from two of his posts actually. My question is:

If I have 75mb down and 5mb up, how does the "shape average 42500000" command below affect the download speeds? Won't the router attempt to behave like the connection is only 5mb, period?  Or does that only kick in during times of congestion?

I have to think that once traffic starts being policed, drops and retransmissions  will occur because the router is attempting to mimic a 5mb pipe. (??)

BTW, have  read several articles on the "shape average" command. I couldn't find a clear answer on this.

policy-map VoIP
class real-time
priority percent 33
class HiPriority
bandwidth remaining 81 percent
fair-queue
class LoPriority
bandwidth remaining 1 percent
fair-queue
class class-default
bandwidth remaining 9 percent
fair-queue

policy-map QOS
class class-default
shape average 42500000 --> 75mb down but 5mb up
service-policy VoIP

interface gi0/1
bandwidth 76800
service-policy output QOS

[Joseph W. Doherty · Accepted solution]

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Posting

A shaper isn't supported on an "in" policy.  Assuming you've applied the policy on the interface connected to the 75/5 link, it would only affect your 5 Mbps up.

[jacob6000]

It is applied on the out. And Thank you.

I will say from my performance testing in the past, with and without the QoS policy, there is a small decrease in throughput overall. 

Thanks,