Help with upgrade from 1605 to 831, please.

[cventicinque]

Hello,

I have purchased an 831 to replace my old 1605r. However, the 1605 has 2 ethernet interfaces and the 831 has one ethernet interface for the WAN connection and an integrated switch for the LAN and I am not sure how to configure this device. On my 1605, e0 is assigned an ip address via dhcp by my isp and e1 was given a static private address from me for my hosts on my lan to use as the default gateway. e1 is connected to my 2900 switch. So, my question is, with no e1 interface to point my hosts to on the 831, what will their new default gateway address be?

I am guessing I create a vlan and assign it an ip address then give one of the switch ports access to that vlan and that vlan is now my default gateway address?

Or, can I go into one of the 831 switch ports and enter "no switchport" and assign it an ip address directly, as if it were a normal ethernet port on a router?

Thanks in advance for the help :)

[ohassairi]

why create VLAN in 2900? use default VLAN in the router and give it the IP of gateway. then make simple cascade between 2900 switch and one port from the 4 ports of teh router.

[cventicinque]

I know there is a default vlan in the switch, but I did not know there was a default vlan in the router. The default vlan in the switch has the ip address that I use to telnet to it.

So, I use the default vlan and give it the ip address of the default gateway and then just cable up a port on the switch to a switch port on the router.

Is there any aditional config necessary to establish the connection between the switch and the router that I might be missing... trunking perhaps?

If I am gonna change the vlan address, how do I telnet to my different devices since that vlan will exist on both devices? I used to telnet to the default gateway address to get to the router and the default vlan address to get to the switch. Now what do I do?

Thanks alot!

[ohassairi]

if your router contains 4 ports switch, so that switch should have in most cases a default VLAN.

if you will assign the Gateway IP to an external layer 2 switch, your will not be able to connect to internet. why? let's imagine you make a ping to an external DNS. your computer will send the paquet to the gateway, that is the external L2 switch. ok the paquet will arrive to the switch, but this one has no routing capabilities to route the paquet to the internet. a L2 switch can just switch based on MAC addresses. so the paquet will be dropped.

the best idea, is to check if the 4 ports switch (that is in your router) contains a default VLAN. if yes, then give that VLAN the Gateway IP. when the paquet will arrive to the gateway, the router will use the default route to send it via its ASDL connection.

[cventicinque]

Thank you very much for your help. The 831 should arrive in the next few days. I will configure it per your suggestion and let you know how it goes. I appreciate your help.!

[cventicinque]

Ok, I got the new router. It did not have a default vlan and the ios would not let me create one. Im out of ideas right now. Any further help is appreciated.

[ohassairi]

well the 4 ethernet ports seem to be layer 3 and not layer 2.

so just connect ethernet 0 to your external switch, and give it the gateway IP address.

you can find here basic config for 831 router.

http://www.cisco.com/en/US/products/hw/routers/ps380/products_configuration_guide_chapter09186a0080118d1a.html

[cventicinque]

I attempted to assign one of the switch ports an ip address last night but ios said you can not assign an ip address to an L2 interface.

IOS reports that this router has 3 ethernet interfaces and 4 fastethernet interfaces yet, there are physically only 5 (6 if you count the console port) rj-45 ports on the back of this router.

I wish I had just gotten a 1721 with an enet wic instead :(

I also read that document last night and it does not explain how to establish a LAN ethernet connection. It explains that I should use CRWS to setup my LAN but, this router does not seem to have CRWS installed.

Thanks again for your help.

[cventicinque]

Ok, its up. It seems that any of the FE switch ports with bring up E0 interface. It did not work last night because I did not do a "no shut" on the FE port I was using. Once I realized my mistake, it worked perfectly. No vlans needed on the router.

Thank you very much for helping me along with this issue.

[ohassairi]

happy to hear it's working :-)