Converting catOS configs to native

Unanswered Question
Jun 23rd, 2007

A hybrid L3 switch has a port connected to the fastethernet interface of a router.

On the hybrid's msfc, a vlan interface is configured and the L2 port is placed in that vlan, thereby creating a routed link between the switch and the router.

Now, I need to migrate that connection to a 6500 running native IOS. So, here is my question:

How do I do it?

Do I create the vlan interface on the native IOS switch and place an interface in that vlan and just connect the rouer.



interface vlan 2

ip address

interface gigebitethernet 2/1


switchport access vlan 2

And then just connect ge2/1 to the router's ethernet interface? [This is the way its done on catOS switches because there are no physical L3 interfaces]

-- OR DO OPTION #2? --

interface gigabitethernet 2/1

no switchport

ip address

And then connect 2/1 to the router's ethernet interface?

Which is the correct way to do it on a switch running native IOS?

I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 4 (1 ratings)
mohammedmahmoud Sat, 06/23/2007 - 22:57


Both options are valid for both cases either when running Native or Hybrid, i'd go for option2, since this is a point-to-point link between the switch and the router then i'd go for a routed interface rather than using SVI interface.


Mohammed Mahmoud.

lamav Sun, 06/24/2007 - 03:49

Thanks MM.

OK, so just speaking of Native IOS, you are saying that both option 1 and option 2 will work on a native IOS switch to create an L3 link between the switch interface and the router?

You know something funny, I cant seem to find any literature on Cisco's website that addresses this scenario. You can find tons of informtaion on vlans, inter-vlan routing, etc, but nothing ever that addresses the situation in which one wants to create L3 links to another device using catOS and how it is different from native IOS.

Are there any advantages/disadvantages to either of the 2 approaches?


mohammedmahmoud Sun, 06/24/2007 - 04:31


Using routed interfaces instead of SVI interfaces has the benefit of preventing any spanning tree issues from affecting the routing between your devices.

Cisco documents contains a lot of details but needs you to sail into its sea and be patient :)


Mohammed Mahmoud.


This Discussion