Configuring switch on 3448

[elk]

I'm not a routing expert by any means and I may be looking at this wrong.  I currently have a 3440 at the edge of my network.  LAN interface is 107.0.255.113/255.255.255.240.  At the moment a hub is connected to that LAN interface and it has three devices connected to it.  The main device uses 107.0.255.114 through 107.0.255.124.  A second device uses 107.0.255.125 and a third device uses 107.0.255.126.  The hub is old and needs to be replaced.  So I had this idea to get a 3448 and connect the main device directly to the LAN interface.  The other two devices would be connected via the switch ports.  But I don't quite understand how to handle the routing.  Would appreciate it if someone could explain this or at least point me to documentation that explains it.  I haven't found anything yet.  Thanks.

[Anonymous · Accepted solution]

@elk Thanks for asking this question on the community forums! The 3448 has 8 switchports built in so you can certainly get rid of that hub. Switch > Hub because each port is it's own collision domain meaning those 3 devices can Tx and Rx full duplex simultaneously at line rate.

As far as configuring the 3448, you can create a VLAN (or use the default VLAN 1) and assign your current LAN IP address to the interface...

Router#conf t

Router(config)#int vlan 100

Router(config-intf-vlan 100)#ip add 192.168.1.113 255.255.255.240

Router(config-intf-vlan 100)#no shut

Router(config-intf-vlan 100)#

2012.04.05 18:19:40 INTERFACE_STATUS.vlan 100 changed state to administratively up

2012.04.05 18:19:41 INTERFACE_STATUS.vlan 100 changed state to up

Next assign the # of required switchports to that VLAN (by default all switchport interfaces are in VLAN 1) Here I created ports 0/1 through 0/4 to be part of this VLAN

Router(config-intf-vlan 100)#int range switchport 0/1-4

Router(config-swx 0/1-4)#switchport access vlan 100

Router(config-swx 0/1-4)#

Next plug in your devices to the ports associated with your "LAN VLAN"

Lastly if those devices need routed to the WAN, create a default route to your WAN interface...

Router(config)#ip route 0.0.0.0 0.0.0.0 ?

atm                    - ATM

demand                 - Demand routing

frame-relay            - Frame Relay

hdlc                   - HDLC

loopback               - Loopback

null                   - Null (drop packet)

ppp                    - PPP

tunnel                 - Tunnel

A.B.C.D                - Forwarding router's address

[elk]

That makes sense.  I knew I was looking at this wrong.  I may not be able to try this until tomorrow, but I will report back and rate the reply as soon as I finish this.  Thanks!

[elk]

I had a chance to test it.  Works great!  Thanks!

[Anonymous]

Great! Feel free to reply to this post if there's anything else you have in mind for your 3448. We'll be glad to advise.

Best Regards,

Andy