valn on an existing network

[mahimakundu1]

I have recently joined a company, and they  have below network topology.

There are these vlans defined with Ip routing enabled.

interface vlan 4
name "Four"
routing
ip address 192.168.4.77 255.255.255.0
exit
interface vlan 10
name "Infrastructure"
routing
ip address 10.10.0.1 255.255.255.0
exit
interface vlan 20
name "Infrastructure"
routing
ip address 10.20.0.1 255.255.255.0
exit
interface vlan 30
name "Infrastructure"
exit
interface vlan 40
name "Infrastructure"
exit
interface vlan 50
name "Corporate Desktop"
exit
interface vlan 60
name "Dev Domain"
routing
ip address 10.0.80.1 255.255.240.0
exit
interface vlan 70
name "R and D Domain"
exit
interface vlan 80
name "Support Domain"
exit
interface vlan 90
name "QA Domain"
routing
ip address 10.0.128.1 255.255.240.0
exit
interface vlan 192
name "Current Corp Domain"
routing
ip address 192.168.1.177 255.255.252.0
exit

Then there is a default route to firewall ip route 0.0.0.0 0.0.0.0 192.168.1.77
All the hosts in the environment have firewall as the default  gateway.

All the switches Data6, data5, data4, data3, data2, data1 are on native vlan's with 192.168.0.0/22 subnet and firewall as default gateway

Now The issue is that the network is really slow and they want to seggregate servers on a different vlan which are now present o 192 ip address range.

Is there any way to create VLANs without changing IP addresses of all the hosts

Also they want to migrate it to 10.0.0.0 network to increase number of hosts for future. is it really necessary?

Now my issue is can I seggregate the network without reassigning Ip's to all the hosts on the network?

And what can be the reason for network slowness?

And if i need to reassign ip to all the host and servers will i have to change all nat policies and access lists, there are currently 330 access lists and 250 nat policies.

[Bilal Nawaz]

You can create vlans no problem, however each vlan will need its own subnet range, so no, there isn't a way to create vlan without changing ip address or subnet mask/default GW of all hosts.

Migrating to a 10 network could be good or unnecessary depending on your environment, follow ip addressing assignment best practices by researching it.

Well you could calve up your existing /22 in to smaller networks i guess? but you will have to change the mask and default gateway of all your hosts including the FW.

Slowness, hmm, depending on what these hosts are doing, they could be generating a lot of broadcast traffic, which isn't really needed. There could be a whole bunch of things for slowness. Check the link utilisations of links, CPU, memory etc... to see where the bottleneck is.

If you re-IP your network, its extremely likely you will have to edit your security policies, especially if you move on to a 10 network scheme.