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New Member

Different subnets to VLAN 1

Hi

I have two networks as below

Network 1 = ATM network(Marconi switches) with only vlan 1 created on all switches including Backbone and access being allocated subnet 140.140.x.x/16, which is flats network.

Network 2 = 2 core 6500, 3 distrbution 4507 and other 3750 as access. Vlans would be defined on access switches and ospf would be runing in whole cisco network and PTP links would be created between access/distribution/core.

Now these two ATM and gigabit Networks would be connected thru gigabit ethernet port which is available on one of bakbone ATM Marconi switch. Now here is as vlan 1 is already there on ATM switches on range 140.140.x.x/16, also vlan 1 is there on one of the 6500 with the same subnet i would be connecting new 6500 with subnet 10.x.x.x with old 6500.

Question is can i have vlan 1 on subnet 140.140.x.x on old network and vlan 1 on the new network(10.x.x.x/24), and these old 6500 and new 6500 would be connected thru a PTP link.

Regards

  • Other Network Infrastructure Subjects
5 REPLIES

Re: Different subnets to VLAN 1

Just trying to understand the configs.

How will these 2 networks be connected ? through switchports (trunks?)? or router ports?

Im not sure if I got it right, but if you are going to route between those 2, I dont see how these vlans would affect each other.

Let me know.

Regards,

Vlad

New Member

Re: Different subnets to VLAN 1

These 2 networks would be connected thru Layer 3 Link not thru trunk.

Regards

Ashish

Silver

Re: Different subnets to VLAN 1

If the Marconi and Catalyst networks are connected via a point-to-point Layer3 link only (no trunking, no SVI), then VLAN1 will not be a problem. The Marconi network will have no knowledge of the Catalyst network vlan configuration, it will just see IP routes.

Make sure you configure the 6509 port connecting to Marconi with 'no switchport'.

Please rate all helpful posts.

Regards,

Brad

New Member

Re: Different subnets to VLAN 1

Hi Brad

These ASX 1000 switches are not L3 capable and marconi and 6509 is connected thru a switch port and bothe the ports are in vlan1 with the same subnet range, as ASX 1000 is a pure L2 ATM switch in my case i can not define L3 PTP links on it.

Regards

Ashish

New Member

Re: Different subnets to VLAN 1

I would also like to know this answer. The one thing that might be different for me, though I'm not sure, is that my network is connected there serial. So if anyone could answer this question, it would be greatly appreciated! Thanks!

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