Cisco 3550 Switches

Hey,

i have 3 new cisco 3550 24port switches. i rebuilding a test lab that will not be connected to the internet. the current network has 6 different networks, 3 networks in 2 different suites which are connected. each network has only a couple of clients or servers. most of the equipment (routers, hubs)i have belong to other depts. except for my new switches. since they are layer 3 switches or switches with routing capabilites can i set up the same type of network with just switches, using a vlan or some other setup, or must i still purchase a router or routers. i not sure the exact capabilities of these 3350 switches. i also plan to put network loading software (Chariot by NetIQ) and Sniffer products (by NAI) in the network. :

Haha first off, i noted that you posted this question to
www.techimo.com/forum/t82017.html

Yep i think your hardware is VLAN capable, check on this.. try typing 'vlan database' or 'show vlan brief'. Make sure your IOS version is up to date.. or you may only be able to use the VLAN id 1.

Be aware that inter VLAN routing, requires a router.. though I don't know whether you can use the layer 3 capabilities of the switch to route the VLANs

For all about layer 3 switching, go to Cisco
www.cisco.com/warp/public/cc/so/neso/lnso/cpso/l3c85_wp.htm

cheers,


btw, I really think we need to get working on a 'switching demystified' section covering VLANs and different layer switching... come to think of it i recall Chris saying something about working on a section like that. Will notify you if it comes up.

Yes, you still have to have a router to go between VLANs. Remember, each VLAN is just a subnet.

The problem with this setup would be the problem of interfaces. What if you have 100 VLANS - you would need 100 interfaces. This would be a little expensive. You can handle this problem by configuring a "router on a stick" (one-armed routing) - using the same interface for all your subnets - as long as the bandwidth can handle the traffic.

You would then need to set up your ACLs to handle the access or all people in each VLAN would be able to get to all other VLANs that are trunked.

Hey Thanks for the info, it seems according to that white paper, layer 3 switches maintain there own routing tables adn use packet switching forwording each packet to the appropriate interface/port.
I think i will try, to designate specfic ports to specific vlans and then connect the switches via one of the ports im not using. since each switch also broadcast its routing table.. do you know if using switches will interfere with using a sniffer, or traffic generator software i mentioned thanks again..

j29net

Actually, if your switch supports it you can route if the switch supports RSMs (Route Switch Modules) for 5000 series switches or RSFC (Route Switch Feature Card) on a 6000 series switch. I don't know if the 3000 series switch as a comparable module. You are in essance adding a router to your switch.

Yes, a switch will interfere with your sniffer unless you have port mirroring. The other way to solve this problem, is to add a hub to one of the ports and put your sniffer and systems you want to analyse on the hub. Realize that this will put you back into the same collision domain.