vlans questions

Unanswered Question
Dec 22nd, 2009
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I am moving all my users off of vlan 1, currently I have 323 users on vlan 1 and I have performance issues that I can't see on my switches.


I have some design questions.


  1. How many users per vlan?
  2. Can I have multiple vlans for one subnet?
  3. With no layer 3 if I have multiple subnets, each with a seperate vlan, will they be able to talk to each other.
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Reza Sharifi Tue, 12/22/2009 - 16:22
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markmarek wrote:


I am moving all my users off of vlan 1, currently I have 323 users on vlan 1 and I have performance issues that I can't see on my switches.


I have some design questions.


  1. How many users per vlan?
  2. Can I have multiple vlans for one subnet?
  3. With no layer 3 if I have multiple subnets, each with a seperate vlan, will they be able to talk to each other.


Hi Mark,


How many users per vlan?

Usually 254 hosts which is equivalent to /24 per subnet/vlan.  This is a common practice.


Can I have multiple vlans for one subnet?

You can have multiple subnets per vlan, but it is not a common practice and I would do just one subnet for one vlan.(a lot cleaner and easy to keep track of  and manage)


With no layer 3 if I have multiple subnets, each with a seperate vlan, will they be able to talk to each other

You will need a router so different subnets can talk to one another.  Now, if funding is an issue you can have a switch do the routing by that, I mean if you have an extra  switch with layer-3 licence, it will do the job for you.


HTH

Reza

markmarek Tue, 12/22/2009 - 17:12
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Can you post a sample configuration for a router and 3 vlans on the switch?


vlan HR 10.1.0.0/24

vlan Users 10.2.0.0/24

vlan Servers 10.3.0.0/24

Jon Marshall Tue, 12/22/2009 - 17:30
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markmarek wrote:


Can you post a sample configuration for a router and 3 vlans on the switch?


vlan HR 10.1.0.0/24

vlan Users 10.2.0.0/24

vlan Servers 10.3.0.0/24

Mark


Do you mean "routing-on-a-stick" ie. where the switch is L2 only and you have subinterfaces on the router to route between the vlans or the config for a L3 switch ?


Jon

markmarek Tue, 12/22/2009 - 18:25
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I am curious how to configure it for both router on a stick or with a layer 3 switch. I know you have to use one or the other but I am curious how the configurations look.

Jon Marshall Wed, 12/23/2009 - 02:53
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This is just a test post - please ignore

lusandi Sat, 01/16/2010 - 14:05
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Hello,

If you have a layer 2 switch, as you told, the best way will be routing on a stick, the problem will be that the link is going to be a bottle neck on you design because it will be handling all the traffic of all the VLANS.

Whit a layer 3 switch, you will have the CEF, enable, and routing whit wire speed, that will increase your network speed.

in the second case, the every subnet just need to point their default gateway to the switch itself who will be handling all the routing.

If you have any other questions please let me know.

Thanks,

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