merging old it infrastructure with new it infrastructure

[anoop.verma]

Hi,

I am a network eng. and my question is related to "merging old it infrastructure with new it infrastructure ".

recently we have build new data center for our company and i want to merger the old it infra with the new.

attached is the old infra.

new infra is as below :-(dhcp)

dc--------mpls------> router 2951---------->switch2960.(user: 200, internet BW: 10 mbps)  (subnet 22, class a)

old is:-(static ip on entities)

isp internet--------router 2600--------firewall----------L3 switch 3750---------L2 switch 2960  (user: 200, internet BW: 45mbps) (subnet 24, class a)

I want user can access isp internet as well as dc same time.

i don't want to change the ip on host pc.

Need your expert advice.Thanks in advance.

[Philip D'Ath]

There isn't quite enough info your your diagram for me to figure everything out.

The Cisco 3750 is being replaced by a Cisco 2951, or is the Cisco 3750 being retained?  If the Cisco 3750 is going, move it's IP address onto the Cisco 2951.  Then everyone can maintain their current IP addressing, and since they are going via the 2951 will start using the new Internet circuit.

If the Cisco 3750 is staying, then connect it and the Cisco 2951 together, and change the default route on the Cisco 3750 to point to the Cisco 2951.