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VLAN Basics - need some clarification

lmsaeb123
Level 1
Level 1

Hi. I am hoping to get some feedback from some networking gurus.

I have a small LAN - about 300 nodes. I am at the point where I think I need to consider implementing VLANS. I understand the concept of VLANs. Where I am getting 'hung up' is in regards to my servers. On my LAN I have about 5 servers and all the PCs on the Lan need to communicate with these servers.

So, when creating my VLANS, do I have to setup the ports my servers connect to for all the VLANS I create with hosts that need to communicate with my servers or do I create a separate VLAN for my servers and allow all my PCS to communicate with that VLAN.

I understand that if I implement VLANS, the broadcast traffic will be limited to that VLAN. However, I am getting confused on how this works when the devices on one VLAN needs to communicate with devices on other VLANS.

Thanks so much.

6 Replies 6

Collin Clark
VIP Alumni
VIP Alumni

Creating a VLAN for servers is a good logical place. You can create two VLANs, one for servers and one for the PC's. The two VLANs will communicate through your layer 3 device (router or L3 switch). That router/switch is the gateway for both VLANs. Since the router/switch has both networks directly connected it knows how to route between the two VLANs.

Hope that makes sense

lmsaeb123
Level 1
Level 1

Thank you colin - that makes sense. Do most of the managed switches today have routing capabilites in them.

At the low end, most switches are layer 2 only(2xxx), all the current 3xxx switches and higher have L3 capability.

Hth,

Bobby

Sent from Cisco Technical Support iPhone App

Eugene Lau
Cisco Employee
Cisco Employee

Hi Ashley,

Inline with the other replies, this might help you understand how it works when doing interVLAN routing on multi-layer switches (L3 capability).

InterVLAN routing

http://www.cisco.com/en/US/tech/tk389/tk815/technologies_configuration_example09186a008019e74e.shtml

Depending on your budget and future requirements, you may also do a router on a stick topology:

http://www.cisco.com/en/US/tech/tk389/tk815/technologies_configuration_example09186a00800949fd.shtml

Muti-layer switches have the performance advantage as packets are switched in hardware.

Router would be used if you required specific features such as NAT etc.

Hope this helps clearing things up.

Eugene.

sansarav720e
Level 1
Level 1

Hi ,

     3560-24 ports can solve your queries , You can connect your server directly to 3560 switch and user access on switch connected to this  layer 3 switch .

server lan : 192.168.2.0/28

end user lan : 192.168.0.0/23 to accomdate (300 users )

HTH Regards Santhosh Saravanan

hi ashley

all the above replies will help you.

layer 3 devices (3750, 3550, 3560 etc, router) will help you. keep your servers in different vlan and users in other vlan and then perform interVLAN routing using layer devices.

Regars

Narendra Banduni