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Policy Map Shape Average Question

Mark Wagnon
Level 1
Level 1

Hello,

I have a question about the shape average command on our 3845 router. Currently we have a 100 Mbps Opteman connection that we are upgrading to Gigaman. We have the policy configured as so:

policy-map Shape100Meg
class class-default
  shape average 100000000
 
I was going to create a new policy for 1000000000 bps like so:

policy-map Shape1000Meg
class class-default
  shape average 1000000000

but I get an error:

sbusd-3845-opteman(config-pmap-c)#shape average 1000000000

                                                         ^

% Invalid input detected at '^' marker.

It seems the value is one digit too long:

sbusd-3845-opteman(config-pmap-c)#shape average ?
  <8000-154400000>  Target Bit Rate (bits per second), the value needs to be multiple of 8000
  percent           % of interface bandwidth for Committed information rate

We're a bit dated on the IOS:

Cisco IOS Software, 3800 Software (C3845-SPSERVICESK9-M), Version 12.4(11)T2, RELEASE SOFTWARE (fc4)

Is this something that can be fixed through an update? Or can I choose not to shape? It's my understanding the connection is capped at 1 gig.

Any and all help is much appreciated!

Mark

2 Accepted Solutions

Accepted Solutions

Rejohn Cuares
Level 4
Level 4

I dont understand why you still need to shape your traffic when your ISP is providing 1G link hand off to your Cisco 3845 ISR's 1G capable interface.

Apply traffic shape when you want to match the ISP's contracted access speed so excess traffic won't be dropped. Example: You had a 100M interface on your router but the ISP's contracted access speed was 10M.

Please rate replies and mark question as "answered" if applicable.

Please rate replies and mark question as "answered" if applicable.

View solution in original post

Patrick Lloyd
Cisco Employee
Cisco Employee

If your interface is a gigabit interface, it won't be able to send over that speed.  You can set the speed or shape to a lower rate than the gigabit, but why would you shape to the maximum that your interface is going to support anyway?

That being said, testing on a 2851, I can confirm that as of 12.4(24)T you can set the maximum shaping speed to 10,000,000,000 bits per second.

View solution in original post

3 Replies 3

Rejohn Cuares
Level 4
Level 4

I dont understand why you still need to shape your traffic when your ISP is providing 1G link hand off to your Cisco 3845 ISR's 1G capable interface.

Apply traffic shape when you want to match the ISP's contracted access speed so excess traffic won't be dropped. Example: You had a 100M interface on your router but the ISP's contracted access speed was 10M.

Please rate replies and mark question as "answered" if applicable.

Please rate replies and mark question as "answered" if applicable.

Patrick Lloyd
Cisco Employee
Cisco Employee

If your interface is a gigabit interface, it won't be able to send over that speed.  You can set the speed or shape to a lower rate than the gigabit, but why would you shape to the maximum that your interface is going to support anyway?

That being said, testing on a 2851, I can confirm that as of 12.4(24)T you can set the maximum shaping speed to 10,000,000,000 bits per second.

Joseph W. Doherty
Hall of Fame
Hall of Fame

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Posting

As the other posters have already noted, there's no need to shape at physical port speed.  Shaping is used when there's a bottleneck further downstream but you're unable to manage congestion there.

Also BTW, a 3845 may have gig ports but the router does not have gig forwarding performance.

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