Debian Ifupdown /etc/network/interfaces : network vs netmask

I came accross the following bit of network conf and the part I don't get is the keyword **network**. Given that netmask is fed, what is the purpose of network ? Disclaimer : I'm not a guru of network configuration, so sorry i the question seems dumb. On Debian Jessie(8)

auto eth0
iface eth0 inet static
        address xx.201.4.132
        netmask 255.255.255.192
        network xx.201.4.128
        gateway xx.201.4.129

auto eth1
iface eth1 inet static
        address xx.201.69.4
        netmask 255.255.255.192
        network xx.201.69.0

I searched thoroughly in the manpage, this keyword is never mentionned. I've seen a mention of it in the Debian Wiki page on Network Comfiguration but that's all: > ### Configuring the interface manually > > If you're configuring it manually then something like this will set the default gateway (network, broadcast and gateway are optional):