When using multiple vlans in a network, a good rule of thumb is to limit a vlan size to no more than 254 hosts per vlan. Since you have less then that, you should not be seeing severe issues with broadcast. I would look at some of the traffic to make sure is all legit. Also, it would be good for you to start segmenting your network with layer3 boundaries. Since you are have 3550s and 3560s to work with, this is what I would do:
Use the 3560 as my core switch
Each user segment on a different switch should be in a different vlan
On the 3560, create an SVI for each vlan
Tag the appropriate ports for each vlan and allow for proper inter-vlan routing.
when you say 3350 switches, I assume you mean the 3550's ? Both the 3550 and the 3560 switches have the interface command 'storm-control broadcast level' available. When you e.g. set the level to 20 (percent), broadcast traffic exceeding that threshold will be dropped until it falls back under that level. Check this link for details:
in addition to Sean's post, just be aware that segmenting your network (actually introducing Layer 3 SVI's) might negatively affect the performance of your network, since all traffic between the segments now has to be routed instead of switched. I would also try and find out first what causes the excessive broadcasts (it could simply be a broken NIC in one of the PC's), since even with segmenting your network, the clients in the same network segment would probably still have the same problem.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...