Jimmy wrote: > > First of all, thank for the wonderful response. > > So from what you all have said. If the user is for normal > purpose like > running some application on servers and access the Internet. > Will a 100Mbps > be sufficient for 300 users.
We don't have enough info about the applications or the placement of servers in the topology to give you very valuable suggestions. But, we may be able to make a few generalizations. If I get out on a limb with these generalizations, hopefully somebody will come out after me and correct my mistakes. :-) 100 Mbps is probably sufficient for 300 users using typical desktop applications and browsing typical Web sites. As someone else said, actually 10 Mbps is proably sufficient also. If you are using switches, remember that EACH switch port has 100 (or 10) Mbps, so you may have more bandwidth than you realize. The bottleneck may the switch itself. You will want to research the backplane speed of any switches you are considering. Another bottleneck will be links between switches which aggregate many traffic flows. Also, links to servers often get congested and should have more bandwidth than links to end users. As many people have mentioned, you are on the edge as far as how many devices you have in one switched network. All those devices are in the same broadcast domain. They will all hear and process each other's broadcast traffic. Some protocols and applications, including Windows networking, send a lot of broadcasts. This is especially a problem on slow, older PCs. Cisco recommends you minimize the size of a broadcast domain to a few hundred devices. The exact number depends on the protocols. I think most people limit it even more than Cisco says to, actually. A router does not forward broadcasts. Adding a router or two to the design will solve the broadcast problem. VLANs also limit the size of broadcast domains and could be a good solution. > As for the users, they will be > splitted into > several group of around 15-20 each.Or a 10Mbps switch will be > more than > sufficient for it. > > Can i calculate the BW for each user in this manner: > 100M / 300 (no of user) > Assuming full usage. Which bandwidth? The bandwidth on shared links? What traffic flows through those links? See, we can't give you specific info without more info on the topology you have planned. > > Let say i have around 3 storey of about 300 users each, 300 users on each floor? OK, so you do need some routers or routing switches in there. Or at least some VLANs to contain the spread of broadcasts. > The > backbone switch > should be 10x the BW of each floor rite? In general, you don't need to provision enough bandwidth for every device to be using all of its theoretical capacity all at the same time. That would be too expensive, for one thing. Also network traffic is bursty and the capacity isn't used all the time. And we need to know where the traffic is flowing. Some traffic may be peer-to-peer and not cross the backbones. Some will go to the servers. Some will go to the Internet, etc. There are no easy answers. I think that has become my new motto. _______________________________ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com > > Cheers, > Jimmy > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=54169&t=54023 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
