Adding a network

Unanswered Question
Feb 13th, 2007


I currently have the following network in a Cat 3560g, I have a spare Cat 3560 and i would like to add a second network Is it possible to do this so the networks can talk to each other without using a router? Can anyone give me any info on this.

Many Thanks

J mac

I have this problem too.
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guruprasadr Tue, 02/13/2007 - 04:02


10 is a Class A Network

192.168 is a Class B Network

2 different class of Network will not work unless & until L3 Functionality is enabled.

You can make 10 as VLAN1 & 192.168 as VLAN2 & then enable L3 functionality(Inter-VLAN Routing) between VLANs.

VLAN 1 router-ip

VLAN 2 router-ip

Hope this Helps for you in Understanding..Rate this reply if Helps !!


Guru Prasad R

johnnymac Tue, 02/13/2007 - 04:04

Hi Thanks,

So is it possible to acheieve this on two switches with out the need for a router?


J mac

johnnymac Tue, 02/13/2007 - 04:40

Thanks for your help, I shall read up. Can i just confirm that I should be going down the Vlan route to achieve my goal or would I be able configure the switch as i would a router, static routes / routing protocols etc and get it to work that way.


J Mac

johnnymac Tue, 02/13/2007 - 06:54


Thanks again. I wonder if I could trouble you again. I have set up my new Vlan (Vlan 2) on both switches. I have assigned switports and also configured a gig port on each to dot1q trunk. I have assigned ip addresses of and for Vlan2 on the switches. a show ip route on both switches confirms they both see network as directly connected. From the switches i can ping hosts in both networks. However I cannot ping a host in the network from a host in the network and vice versa. Any ideas?

Many thanks

J mack.

rickyt888 Tue, 02/13/2007 - 14:00

Make sure to set the host gateway on the PC on vlan 2 to and host PC gateway for vlan 1 to

johnnymac Thu, 02/15/2007 - 03:22


Thanks for your responses. I have assigned the gateways as reccomended which has improved things. I have a host in my network and i can now ping that host from a host on the network. However i can't get a sucessful ping in the opposite diection?

can i just confirm, i have Vlan 2 on my two 3650's and have assigned to Vlan 2 on one switch and to the Vlan 2 on the other switch, is that correct or should they both be

Can anyone suggest some things to try in terms of getting full connectivity between these two networks?

Many thanks

J mack

glen.grant Thu, 02/15/2007 - 03:50

If you have just 2 3560's just have one of them do the routing and run a trunk to the second and then for for each vlan the pc nics gateway would just point to the 3560 layer 3 address for the subnet (vlan) they are attached , sounds like you are trying to put ip addresses on both and making it more confusing .

3560#1 (with routing)-------Trunk ----- 3560#2 (no routing)

For the trunk link between the 3560's.


switchport trunk encapsulation dot1q

switchport trunk native vlan 1

switchport trunk trunk dynamic desirable

switchport trunk allowed vlan 1,2

johnnymac Thu, 02/15/2007 - 04:02

Thanks, so are you saying remove the Vlan 2 ip address from the second switch ?

and by routing? both switches see both networks as directly connected, do i need to be running a routing protocol or static routes?

Many Thanks

J mac.

glen.grant Thu, 02/15/2007 - 04:05

Yes remove it unless you are using that address to management the second 3560 , myself I would just assign one in vlan 1 if you need to telnet to that 2nd switch for management purposes. On the second issue the "no ip routing command" .

johnnymac Thu, 02/15/2007 - 04:14

thanks again, I have done what you suggested and i haven't lost any functionality however i still can't get to that network from the host. I did a tracert and i get 1 hop, so the host can presumably get to the other switch, however it doesn't seem to know how to get any further. Any thoughts?


J mack

glen.grant Thu, 02/15/2007 - 04:18

You may have to post the configs , its easier than speculating what may or may not be there that should be there . Make sure any pc nics in the 10.x.x.x space have their default gateways pointed to the 3560#1 ip address for vlan 1 . did the trunk come up ok ? Show int trunk .

johnnymac Thu, 02/15/2007 - 07:58


Maybe it just a little time to sort itself out but it seems to be working ok now. Thanks alot.

J Mack


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