What do I have to consider when switching access layer from 10/100 to gigabit ethernet?

Unanswered Question
Apr 21st, 2010

Hi all,

we plan to switch our switchport configuration template for the access layer (office pcs, printers, etc.) from only allowing 10/100 autonegotiation connections to allowing also gigabit ethernet connections. Switches and also cabling infrastructure support ge, servers are also connected with ge.

In addition to uplink oversubscription, which important facts / experiences do we have to consider when changing to ge (like e.g. client driver problems, server overload, ...)?

Best Regards,

Thorsten

I have this problem too.
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Jon Marshall Wed, 04/21/2010 - 02:58

thorsten.steffen wrote:

Hi all,

we plan to switch our switchport configuration template for the access layer (office pcs, printers, etc.) from only allowing 10/100 autonegotiation connections to allowing also gigabit ethernet connections. Switches and also cabling infrastructure support ge, servers are also connected with ge.

In addition to uplink oversubscription, which important facts / experiences do we have to consider when changing to ge (like e.g. client driver problems, server overload, ...)?

Best Regards,

Thorsten

Thorsten

It really is about oversubscription. If your devices can actually generate more than 100Mbps of traffic once they have been switched over to Gbps then you need to make sure your switch uplinks can handle the extra load. Obviously as you say the servers may also experience issues but as these are Cisco forums we'll concentrate on the network

If your network is a best-effort network ie. no QOS prioritising voice or multimedia then you may be alright but you could start to see many more interface drops on the switch uplinks if they are getting overloaded. Do you have the fibres spare so you could increase your uplinks if needed ?

Also be aware of the knock-on effects within your network. So if the clients can now generate more traffic and your switch infrastructure can cope with the additional traffic what about WAN traffic ie. you have a user who is now gigabit connected and they decide to download a movie trailer to their desktop. The additional traffic will hit a bottleneck at either your WAN or internet link and if you are not prioritising traffic then this could seriously impact other users. The movie download was simply an example, it could just as easily be something downloaded internally.

I'm not trying to put you off doing this but you do need to have a good uderstanding of how much additional traffic this could put onto your network, where the likely bottlenecks will be and how this would affect critical business traffic.

Jon

thorsten.steffen Fri, 04/23/2010 - 02:11

That's exactly what we are thinking about at the moment, uplink and wan overloads, where uplink capacity is used average at 10% at the moment with some peaks.

Thanks for your input.

Thorsten

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