interface vlan

Unanswered Question
Oct 3rd, 2010

Hello everyone

For access layer (Layer 2) we do configure management IP address to the access switch.

And, for distribution layer (Layer 3) we do also configure management IP address to the distribution switch.

Is there any difference between the Layer 2 and Layer 3 management IP address?

As we know in order to configure switch management IP address we need to issue below command line:-

interface vlan 1000

  description Managemnt_IP

  ip address x.x.x.x. 255.255.255.0

  no shut

We configure interface vlan at Layer 3 switch, but we can also configure interface vlan at Layer 2 switch???????

I have this problem too.
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Peter Paluch Sun, 10/03/2010 - 00:42

Lim,

Is there any difference between the Layer 2 and Layer 3 management IP address?

No, there is no difference. By creating interface VLAN X (we call it SVI - Switched Virtual Interface), you are simply assigning the computer inside the switch to a particular VLAN and you are assigning it an IP address.

We configure interface vlan at Layer 3 switch, but we can also configure interface vlan at Layer 2 switch???????

Sure, why not? As I said, in each switch there is a computer you need to talk to when you are managing the switch, and which orchestrates all the processes running on a switch. Just as with any other station connected to the switch, also the internal computer of the switch must belong to a particular VLAN and have an IP address from the range assigned to that VLAN. The way to assign the internal computer to a VLAN is to create the SVI for it and assign it an IP address. As simple as that

Best regards,

Peter

Lim Seow Hua Sun, 10/03/2010 - 00:50

Thanks for the info.

As i know for Layer 2 access switch we configure management IP address to it by issuing

interface vlan 1000

ip address 172.21.x.x. 255.255.255.0

no shut

We can know that this is the management IP for the switch as in the access switch we only configuer one interface vlan.

But how about Layer 3 management IP address? As in the Later 3 distribution we can create as many as SVI as we want. But how does the switch can know that which SVI is the managment IP address for the switch?

Peter Paluch Sun, 10/03/2010 - 01:01

Lim,

But how about Layer 3 management IP address? As in the Later 3 
distribution we can create as many as SVI as we want. But how does the 
switch can know that which SVI is the managment IP address for the 
switch?

The answer is - it does not matter. For Catalyst switches, there is no such thing as a separate management IP address. All IP addresses assigned to a device are management IP addresses. What is the management IP address, anyway? By definition, it is an IP address you can connect to in order to manage the device remotely. Now, if a device has 5 IP addresses, you can connect to it using any of these 5 IPs, right? From this it follows that any IP address assigned to a device can be considered a management IP address.

Some vendors (not Cisco) actually allow you to define a special IP address (they use to call it a management IP address) for remote management and they impose some additional restrictions on how this IP address can be reached. This concept has not been adopted for Cisco switches. Cisco switches simply are assigned IP addresses - one or more - and each of their IP addresses can be used for their remote management.

Best regards,

Peter

Lim Seow Hua Sun, 10/03/2010 - 01:51

Thanks. I get what you mean and i have test this by telnetting to the each Layer 3 switch SVI and I able to get to the switch

"Some vendors (not Cisco) actually allow you to define a special IP  address (they use to call it a management IP address) for remote  management and they impose some additional restrictions on how this IP  address can be reached. This concept has not been adopted for Cisco  switches. Cisco switches simply are assigned IP addresses - one or more -  and each of their IP addresses can be used for their remote management."

What is the vendor allow to define a special address for remote management and how do they configure this ?

Peter Paluch Sun, 10/03/2010 - 02:00

Lim,

What is the vendor allow to define a special address for remote management and how do they configure this ?

You understand that I cannot possibly enumerate all vendors and their own ways to assigning an IP address to their device HP ProCurve switches use a very similar way to Cisco - they define the IP address inside the VLAN definition itself (they do not have SVIs in the same form as Catalysts). I have not worked extensively with other vendors' devices.

Best regards,

Peter

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