facilitate re-addressing all neighbors of a switch

[ruck94301]

thread558-1216774

I want to move a set of equipment from one network to another. They are all connected via a Cisco 2960 switch, in either vlan 1 or vlan 2. Actually, I want to provide a set of instructions for my field service rep to execute at customer site. I'm concerned that during cutover, after reassigning address to Host1, Host1 drops out of sight until last step (reconfigure the switch).

My first thought was:
Add a 2nd IP address -- the new one -- to the PC we're working from, and add some more vlans (new network) on top of the existing ones on the switch, then we'll be able to keep in touch with each computer as it's cut over. Finally wrap up by removing the original vlans and removing the original IP address from the PC.
But now I am thinking the 2960 won't allow me to give its ports access both networks at the same time.

Any recommendations? Purpose is to be able to maintain contact with the computers during the transition.

What if I set netmask to 0.0.0.0 for the switch vlans during the transition? Does that make sense?
Thanks for any comments.

P.S.
I have a Cisco 2960, with 16 ports on vlan 1 and 8 ports on vlan 2. There are approx 8 interfaces in use.
+ the PC I'm on (through which I am telnet-ing to the switch in order to configure)
+ a Cisco 1811 router (under my control)
+ and approx 6 other computers.

 

[burtsbees]

But now I am thinking the 2960 won't allow me to give its ports access both networks at the same time."

Why not create the vlans with a supernet address that contains both old and new vlans? Is that possible, or are the old and new addressing schemes not contiguous or even anywhere NEAR eachother (like a different class)?

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!

 

[ruck94301]

> Why not create the vlans with a supernet address that
> contains both old and new vlans? Is that possible, or are
> the old and new addressing schemes not contiguous or even
> anywhere NEAR eachother (like a different class)?

Presently, the plan is that old & new are different even at the 1st bit -- moving from 192.168.0.0/16 to 10.10.0.0/16 .
But I think I was trying to ask something quite similar to what you are suggesting... if I set netmask 0.0.0.0 on the switch vlans, then isn't that the ultimate "supernet" (sorry, I don't know proper use of that term) which would indeed cover both old & new network addresses?
After transition is complete, then I would change the address and netmask for vlans to the new.
Burtsbees -- thanks for replying, this might work, huh?

 

[burtsbees]

Well, maybe, but perhaps another solution would be to put the new vlan addresses on the unused ports (you said only 8 are in use right now), and that way all you would have is a very short down time.

Also, make SURE that you do

interface range fa0/1 - 24
spanning-tree portfast

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!

 

[ruck94301]

stepping back...
I realize now I don't need to worry about the switch VLAN configuration at all. I can add a 2nd address to the PC on vlan1 and then be able to reach all other vlan1 hosts at their new address as I cut them over one by one. Likewise on vlan2. The switch won't care. At some point I'll change the switch's address, but again, no need to add vlans. It's all good.

 

[burtsbees]

I would have told you that had I known it was an option...alternate config in XP Pro, or dual NICs?

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!

 

[ruck94301]

> alternate config in XP Pro, or dual NICs?

Neither
"Logical" multi-homing.
I gave the single NIC two IP addresses.
It's supported in XP Pro, see simple instructions in this microsoft doc:

http://technet.microsoft.com/en-us/library/bb457118.aspx

(long page, look about 15% down)


Configuring Multiple IP Addresses on a Network Adapter

Multihoming involves the placement of more than one network adapter in a single computer. In addition, Windows XP Professional supports logical multihoming, by which multiple addresses are assigned on a single network adapter. This configuration is useful in an environment in which a single physical network is logically divided into subnets.

To configure a multihomed system using a single network adapter

...