Assign Ip address to Cisco L2 switch

SVI on Cisco Integrated Services Routers is designed to provide basic Layer 3 functions for the Layer 2 switch ports that belong to a specific VLAN. The SVI does not provide the same feature set and functions as the integrated Layer 3 Ethernet ports of the integrated services routers and should not be used to entirely replace the Layer 3 Ethernet ports. Customer who need additional Layer 3 Ethernet ports for their Integrated Services Routers may consider the use of 1- and 2-Port Fast Ethernet High-Speed WIC for modular ISR platforms. The guidelines presented in this document summarize feature support considerations for an Integrated Services Router deployment that uses SVIs.

Reference.

http://www.cisco.com/en/US/prod/collateral/routers/ps5853/prod_white_paper0900aecd8064c9f4_ps5855_Products_White_Paper.html

As you mentioned 2960 is L2 switch and can have only one SVI for management purpose and for troubleshooting purposes.

"As you mentioned 2960 is L2 switch and can have only one SVI for management purpose ". So why it let me assign IP addresses to the VLANs.

You can have as many VLANs as you want, and you can assign an IP address to a VLAN, but when you assign an IP to a VLAN, any other IP address on other vlans will be disabled.  The IP address is for management only, and it's to be used as a gateway, but it can be on any VLAN...

I think if you already have a VLAN interface with an IP, and you enable a second IP, the first VLAN interface is administratively shutdown.   (Not the vlan itself, just the vlan ip interface)

Does that clarify?

I did not have any devices connected to the ports. But I assigned the IP addresses to 3 vlans. I did the show ip int br and all the vlans are up.

interface Vlan1
 ip address 10.1.1.1 255.255.255.0
!
interface Vlan10
 ip address 10.10.10.1 255.255.255.0
!
interface Vlan20
 ip address 10.20.20.1 255.255.255.0
!

switch#sh ip int br
...
Vlan1                  10.1.1.1        YES manual up                    down
 
Vlan10                 10.10.10.1      YES manual up                    down
 
Vlan20                 10.20.20.1      YES manual up                    down

Interesting..  I think that's a change from the old switches..  I just remember thinking "why did my other vlan go down?"

I'd say you're still not going to get it to ROUTE - it may be that you just will have access to the switch from any vlan, for management purposes...

Yes I cannot route because it won't let me do any static route command or the switch IP ROUTING command. But it is interesting that you can configure the SVI... Well, I am not sure that I cal it a SVI because I cannot do any routing.

I remember going through some problems, because on the layer-2 switch, I think you have to use a "default-gateway" command, instead of a route 0.0.0.0 0.0.0.0 type command for your gateway, and it was confusing me in a similar situation..   (Doing this from memory, so might have that wrong!!)

"basic Layer-3 ", can you elaborate on that? Thx

For a L2 switch only a mgmt IP address is required along with a default gateway configuration. Assignment of IP's on multiple SVI can only be used for connectivity testing purposes.

For example, you need to test IP reachability within a particular VLAN - creating an additional SVI on the switch could aid with this.