Dynamic equal bandwidth QoS

[john kennedy]

I am new to the QoS field but I have been studying and understand the core concepts quite a bit. What I am trying to do is dynamically allocate bandwidth to users on a subnet for each IP address.

For instance, I have an internet facing 881 router with a 2960 plugged into the backside for office users and the external interface is limited to 20Mbps. Depending on the number of users connected at a given time, I would like to assign equal bandwidth for each of them. Is there a way I can create a dynamic ACL that I can feed into a policy-map that will be able to achieve this? Or is best effort delievery my best option? I don't want to match protocols, I just want to ensure that every host gets an equal piece of the pie.

[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

Normally, FQ per flow provides basic bandwidth fairness, but if you wanted to do it per users, if you didn't have too many, you could define a CBWFQ class per user.  If your router has a later IOS that support HQF CBWFQ, you could FQ each user class too.

e.g.

class-map match-all User1

match access-group User1

class-map match-all UserN

match access-group UserN

policy-map Sample

class User1

bandwidth 8

fair-queue

class UserN

bandwidth 8

fair-queue

interface ethernet4

service-policy output Sample

[john kennedy]

That's the plan B direction i'm going to go in. The office has about 20 users at absolute max, and lots of telecommuting goes on. What I don't want to happen is for there to be only 5 people in the office that are using a small portion of the bandwidth with the rest going to waste.

[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

The way CBWFQ actually works, with what I've posted, it sets bandwidth weights which determine bandwidth ratio guarantees between classes.  As each class, as I configured, has the same bandwidth setting, users would have a guarantee of equal bandwidth regardless of the number of users.  Unused bandwidth is also shared equally.  What I've posted doesn't preclude usage of all available bandwidth by less than the maximum number of users.

At any one time, users might be using different amounts of bandwidth, but what I've posted guarantees equal sharing if they all want more bandwidth than what's available.

One user could use 100%.  Two users are each entitled/guaranteed 50%, but if one doesn't want to use all its whole bandwidth guarantee, the other can have any used bandwidth.  Etc., for N active users.