Implementing Vlan in a Flat network

[sid916207]

Hi all,

Right now i have 6 2950 switches all in same subnet and connecting different deprtments.we have 2 routers and Pix 506e.Now I m told to create Vlans in a way where we can use some departments using one first ISP-Line and rest on 2nd ISP line.I want to kno that how can i use same Vlan name/group across the switches or do i have to re arrange cables from various departments and then creating vlans.?we have 2600 series router with 2 ILL.Can i use 1 switch in command mode and other switches connected to various departments as a member of 1st switch and VLan on first switch only? please provide me details on this.

Thanks in Advance..

Sid

[thisisshanky]

When you create multiple vlans, you will need a router (or l3 device) to route between vlans. Since your switches are 2950s, they are layer 2 only. You can use the 2600 router for external inter vlan routing.

Vlans can span different switches if you use trunking between the switches. (802.1q or ISL - 2950 support only 802.1q) To facilitate ease of configuration of vlans in the database of each switch, you should utilise VTP. One switch will be the VTP server, while all others are clients. You create vlans in the VTP server and it will propagate the information automatically to all other VTP clients. Still you will need to log into each switch and associate the physical port to the appropriate vlan.

Check out some of these guides on,

VTP - http://www.cisco.com/en/US/products/hw/switches/ps628/products_configuration_guide_chapter09186a00800d84bf.html

Clustering - Helps in managing all switches in a cluster using one IP address

http://www.cisco.com/en/US/products/hw/switches/ps628/products_configuration_guide_chapter09186a00800d84b7.html

Trunking and Vlan configuration -

http://www.cisco.com/en/US/products/hw/switches/ps628/products_configuration_guide_chapter09186a00800d84be.html

External Inter vlan routing with a 2600 router

http://www.cisco.com/en/US/tech/tk389/tk390/technologies_configuration_example09186a00800949fd.shtml

[sid916207]

Hi, Thanks for ur reply it was helpful.Please guide me regarding this more. We have all swtiched behind firewall so do I have to make any changes in firewall configuration too? can you proide me a sample diagram of that?

Thanks in advance!

Sid

[vedran.djakovic]

I have attached part od Case Study with 2950 switches, 2600 router and VLAN-s and sample config files.

In this example you don't need do rearange cables but if you want to have more than one VLAN (one per department for example) you will need to add new subnes.