Routing

Hi ,
i have a question about routing / switching.

I have two MX router, one is old und the other is new.
I have some irb on the old mx and I must use this network for a short time on my new mx to  use this network on both routern.
When all connections heve beein moved to  the new mx,  i can delete the old mx and move the irb to the new mx.
How can I do this......
When you need i picture or other information call me back.
Thanks for all
Thomas

Hello

Yes You need to provide more data because what you described tells me nothing completely at least to me so even if I wanted to I can't help you 

HI,
i have make a picture and i hope that can explain my question.
I want to use an IRB on the old mx as layer 2 vlan on my new mx.
When i have connected the switches on my new mx, i can turn off the old mx and i make the irb on my new mx

Yes you can do that.  The IRB on the new MX will probably have a new MAC Address, so the ARP caches in the clients should update automatically.  I forget if IRB sends out a G-ARP (gratuitous).  This type of throw is usually painless, but stale arp caches on clients could pose a problem.