How Routers/Switches Work & Bandwidth Optimization

[xlb4udie]

Does my Router or Switch automaticaly optimize the internet connection between all the computers that are currently connected or do I have to do configure that on my own?

Scenario: I have a 2610 Router which is connected to my DSL Modem. The Router is connected to a 2912-XL Switch and I have multiple computers connected to the Switch. My DSL provides roughly 1.0 Mb/s download speed.

Q1: What happens when I, simultaneosly start downloading the same file (100 MB), from the same website, at 4 different computers?

Does the available download speed, 1Mb/s, split up evenly between all 4 computers (25% - 25% - 25% -25%) or do some computers have priority over others.

Q2: What happens if I start downloading the same file at a second computer 1 minute after I already started downloading it at computer one? Does the Router/Switch split the available bandwidth then, or does the first computer have priority?

If anyone knows what I am talking about, please advise. Do i configure the Switch or the Router? Do I need a special IOS?

[Kevin Dorrell]

In the scenarios you describe, you don't have any control over how the 1 Mbps bandwidth is split between the PCs, That is determined by the algorithm used by your ISP, the Internet, and the remote server. In general, you can manage the priorities of traffic that you transmit, but not the priorities of traffic you receive.

OK, in theory it might be possible to rate-limit received traffic by holding up acknowldgements, or maybe with sophisticated Qos techniques, but it would be difficult to achieve, and certainly not by default.

Kevin Dorrell

Luxembourg

[jason.aarons]

In general nothing needs to be done to the router/switch, except maybe hardcode the speed/duplex to match everywhere.

There are a lot of variable that may be unknown, ie does the website provide host content switches, are they load balancing to different servers, how many connections does each server have, are the servers loadbalanced in the same data center, same isp, same bgp path, etc.

I wouldn't expect the 4 computers to all start/finish the download at the same time, etc.

You can enable "ip accounting" on the 2610 router and "show ip accounting" to see packets counts, etc.

That 2912 is fairly old..end-of-sale/end-of-life status.