Router interfaces with 2 ip addresses

[jristo]

We have the following situation: We wish to impliment a network address change across the entire WAN, and wish to do this in phases. The first step would be to place a second IP address onto the router ports to allow us to still have connectivity under the old scheme, but also allow us to test on the new scheme.

To do this, the only solution I can come up with is to use sub interfaces and assign the IP's onto there.

My quesiton are

1) would this even work?

2) is there a better solution then the above?

Thanks

[vmiller · Accepted solution]

take a look at secondary IP addressing. It does give you a pathway to address migration, but does have some limitations.

[ashok_boin]

Because of you are saying WAN connectivity, it is better to change immediately to new IP addresses which will take less than 5min with proper planning.

[jristo]

With resepct to the previous posting about WAN connectivity and 5 minutes, that isn't the case and won't be that short a timeframe.

The entire WAN was stated to illistrate that this is not limited to one site, but to over 15 as well as the entire LAN ip address space as well.

It cannot be done in 5 minutes, nor would even just the WAN links being changed happen in that timeframe, due to the number of links, as well as testing being required.

[prafuljaded]

I would suggest you to first change the LAN IPs one site at a time and check for routes/connectivity(Verify by static routing/ routing protocols,access-lists).