reducing both speed and bandwidth

[malesefxx]

hi all,
I have question about managing bandwidth and speed for a small business company.
My ISP is providing me 20Mb of internet and I would like to split in 2 parts as 15mb and 5 mb.
I  have catalyst 2950  which is not allowing me bandwidth per port  configuration so I plugged wrt54 router with dd-wrt flashed one of the  line which coming out from the switch
I found way to reduce bandwidth with dd-wrt QOS settings, but I guess I managed to reduce bandwidth not speed
Since 5mb user's speedtest. net results was still 20mbps.
I  was able to control speed and bandwidth control with traffic shaping in  firewall(pfsense),,, but for this case  I am not allowed to use any  firewall.
So how can I  split my bandwidth and speed to 5 mbps or 15 mbps?
As hardware I thought to run 10Base-T cable but it just makes it 10 and 10, I guess.
any device that makes it I can buy or any ideas more than welcome???
I really appreciate all help
Thanks so much

[Scott Bradley]

Hi

You want to split the internet feed into 2 parts 5 and 15 mb.  How is this split going to be determined? By user or ip subnet?  By port?  Let me know the topology of the network on the inside to make more recommendations.

[malesefxx]

hi,

my network topology roughly shown on image.
I hope, image make sense.Thank you so much