Comment 2 for bug 1350639

> Is there an API call we could use to dynamically determine if L3/routers is supported, rather than add another setting?
> This will also affects the Network Topology graph I think.
Thank you for pointing that out.

I think there is no API to do that and I found that hiding routers panel will affect the Network Topology.

https://bugs.launchpad.net/horizon/+bug/1292022
One of the reason why I reported this bug is that disabling router causes error on Horizon which is reported in above link.

So we decided to take workaround for using neutron quota function.
Like this:
$ sudo neutron quota-update --router=0
With setting, user cannot create routers.