Inexpensive Cisco switch that can shape?

[johnelliot6]

Hi,

We currently "need" to shape certain services very specifically....we curently do this via routers for CE's (881's etc)

i.e. 10Mb service, we need:

class class-default

shape average 9800000 40000 0

Some of our clients want to run firewalls as CE's that are unable to shape to this degree, so we are wanting to put an inexpensive switch in front of their CE to do the shaping for them(L2 - either per-port or per-vlan)...the ME3400 looks ok, but is quite expensive - Any other suggestions are greatly appreciated.

Cheers

[paolo bevilacqua]

Switches do not really shape. They are generally poor at slowing traffic artificially.

You must use a router for that.

[Joseph W. Doherty]

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Posting

Much depends on your shaping needs.

A 2960-C may support 2960 QoS such as bandwidth limiting the physical port or SRR shaping of its 4 egress queues.

If you need more than 4 shapers, you'll need something better.

[johnelliot6]

Thanks Joseph - Would a 2960C be able to replicate something similar to this:

class class-default

shape average 9800000 40000 0

Then applied to an Interface egress?

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

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In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

It appears it should.  You'll only have class-default?

If you want to mimic 10 Mbps, why not run it through an Ethernet interface running at 10 Mbps?  Shapers don't emulate 10 Mbps as well as the real thing.

[johnelliot6]

Hi Joseph - Yes, only class default, but speed will be variable - i.e. The links(Purchased speed) can be anything from 4Mb -> 100Mb+

The supplier we purchase them from requires us to be very specific with regards to shape speed, burst + interval time - We are able to satisfy these requirements with smaller Cisco routers (i.e. 881's etc)....Maybe we need to look at running a router in bridge mode, and shape the bvi int, if a switch will not allow us to do it "easily"?

Thanks for your reply.

[Joseph W. Doherty]

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

2960 has 4 egress queues, all which could be shaped (I believe).  So if you only need one shaper, such as a branch/spoke, it might do well.  If you needed to shape for multiple branches/spokes, e.g. at a HQ/hub, you'll again want something better.

One issue with low end switch shaping, you're not going to be able to specify Bc or Tc.  If your provider is that exacting (most aren't - in fact trying to find the Bc or Tc they use can be difficult), by shaping just a little slower, you'll probably stay under contract bandwidth allowance.

881 might be a fine, and less (?) expensive choice, as long as you don't exceed its bandwidth processing performance.  (Cisco recommends the 880 series for up to 8 Mbps; a very conservative recommendation.)