Maximum MAC addresses

[Haden]

We have quite big eithernet network (~60 users) based on cheap
10/100 switches (Gembird, Target, Surecom and such), which have 2K for MAC addresses.

I can't find real information about when this buffer will be maxed out (I gues ~300 MAC addresses should fill it) and what exactly will happen then (maybe switches will begin to work as simple hubs?)

Should we begin to worry? We're going to expand a bit, and frankly I'm afraid some problems may accur.

Thanks in advance.

 

[ScottMac]

It's usually not a concern. Most of the MAC addreses "age out" after a while if they're inactive (usually within minutes).

If you did manage to max out the table, then the usual process is to age out either the oldest entry or the least-used entry, depending on whose switch it is. I've heard that some switches will go to flood when they max out, but I've never actually heard of any that have .... it'd be pretty rare.

IMHO, it should be the somewhere near the bottom of the list of things to worry about.

FWIW

Scott

 

[spidey07]

Normally mac address tables are listed by number of addresses and not by size.

2048 is a common size for number of mac addresses supported. Are you sure your switches aren't measured this way?

60 nodes is actually very small, I can't imagine a switch not supporting hundreds of nodes. If you're expanding the network then now would be the ideal time to get two 48 port switches and hook them up with gigabit ethernet. If you see much more growth (greather than 96 ports) then a chassis based switch would be the way to go.

 

[Haden]

I hope they use any throw away mechanism.
We can't buy many port switches because network is very scattered (for 60 people we have ~5Km of FTP cable and tons of these 5/8 port swithes).

I'm not sure what they mean by "MAC address table 2K", 2000 macs or 2KB.

BTW is it worth using CAT6 cable to get 1gbit at 100m distance? Or we should go for fibre?