HPE Network Design Best Practice

[ABZ78]

We have 28  HP 5412 ZL2 switches configured with Routing.  1 is the Core router which connects the to the other 27 rourters via individual 10GB dark fiber lines.  Each Router is its own spanning root for its site. The Core router is also connected to our ISP and has another connection to our SAN and Servers.  So all DHCP, DNS, Internet, etc come through the core router.

Currently each 5412 has is on the same VLAN.  For example:

The core router has the following vlan config for the 28 routers. 

Vlan 100
name: remote sites uplink
ip address 10.100.1.1  255.255.0.0
tagged A1-A8, B1-B8, C1-C8, D1-D8, E1-4

and the remote site routers have the following VLAN configs

Site 2
-------
Vlan 100
name: remote site uplinks
ip address 10.100.2.1 255.255.0.0
tagged A1

Site 3
-------
Vlan 100
name: remote site uplinks
ip address 10.100.3.1 255.255.0.0
tagged A1

Site 4
-------
Vlan 100
name: remote site uplinks
ip address 10.100.4.1 255.255.0.0
tagged A1

All remote sites have default route back to core.    0.0.0.0/ 0.0.0.0 - 10.100.1.1

My question is can this be problematic by having 28 routers on a single broadcast domain?

Would it be better or worse if I used something like such between the sites:

Core Router
--------------
Vlan 102
name: uplink remote site 2
ip address 10.100.2.1 255.255.255.252
untagged A1

Vlan 103
name: uplink remote site 3
ip address 10.100.3.1 255.255.255.252
untagged A2

Vlan 104
name: uplink remote site 4
ip address 10.100.4.1 255.255.255.252
untagged A3

Remote Site 2 Router
-------------------------
Vlan 102
name: uplink to Core Router
ip address 10.100.2.2 255.255.255.252
untagged A1

0.0.0.0 / 10.100.2.1 

Remote Site 3 Router
-------------------------
Vlan 103
name: Uplink to Core Router
ip address 10.100.3.2 255.255.255.252
untagged A1

0.0.0.0 / 10.100.3.1 

Remote Site 4 Router
-------------------------
Vlan 104
name: uplink to Core Router
ip address 10.100.4.2 255.255.255.252
untagged A1

0.0.0.0 / 10.100.4.1 

[Parvez_Admin]

Hello @ABZ78 

HPE Networking forum has moved. For HPE networking and Aruba product queries, request you to visit and post your query in the Aruba Airheads Community using the link below:

https://community.arubanetworks.com/discussion

You can refer to the below link aswell for more details:

HPE Networking forum migration to Aruba Airheads c... - Hewlett Packard Enterprise Community