Router Switch management Design

[Manindersinghnegi]

Hi All,

We are redesigning the Management of of offices network devices.

network is like below

Vlan 300-----SW--10.1.1.1----------10.1.1.2 Router----WAN

we will configure reverse static router for 192.168.1.0/24 in router.

Option 1

- User separate management vlan i.e. 300( 192.168.1.0/24)for Switches access.

- Use loopback 192.168.2.1/32 router management.

But in this case we will be  using 2 different subnets for offices network devices management.

Option 2

- User separate management vlan i.e. 300( 192.168.1.0/24)for Switches access.

- Create loopback 192.168.1.1/32  for router management and rest of IP for switch management.

-Advertise both 192.168.1.0/24 and 192.168.1.1/32 in BGP, if Switch goes then at least we can access router on 192.168.1.1

Do you think option 2 is feasible solution, if we want to use single management subnet for network devices?

[MHM Cisco World]

Option 2 not correct' the same IP subnet can not be in different l3 Device that interconnect by l3 link.

So you need to use op1 

MHM

[Manindersinghnegi]

@MHM Cisco World   can you shed some light what issue can occur using option 2 in Network?

[MHM Cisco World]

IP overlapping in your network

Two devices not direct connect using same subnet

That not correct.

MHM

[Manindersinghnegi]

I want when my switches goes down, then also I can access of routers on loopback

I am just trying to figure out what can be issue with below config in production environment?

RTR--10.1.1.1-------------10.1.1.2 SWT01

RTR01

int loopback
ip addresss 192.168.1.1/32

Router bgp 300
network 192.168.1.1/32
Network 192.168.1.0/24

ip route 192.168.1.0/24 next-hop 10.1.1.2 track xxx

SWT01

interface vlan 300
ip addresss 192.168.1.3/24

[MHM Cisco World]

from Out to SW 
packet reach router why router forward packet to SW if it have direct connect ?
the router will drop the packet and you can not connect to SW

MHM

[M02@rt37]

Hello @Manindersinghnegi 

Option 2 isn't viable because the same IP subnet cannot exist on different Layer 3 devices connected by an L3 link without causing routing conflicts.

Therefore, Option 1 is the correct approach. You use VLAN 300 (192.168.1.0/24) for switch management and a separate loopback interface (192.168.2.1/32) for router management. This ensures proper L3 separation between the devices, avoiding subnet overlap. You can then configure a static route for 192.168.1.0/24 on the router and, if needed, advertise both subnets (192.168.1.0/24 and 192.168.2.1/32) in BGP for full network reachability.