PI addresses and BIRD

Hello, tell me please, to which interface I need to bind PI address? lo? eth0? I have 91.XXX.XXX.0/23 network and local address 172.11.22.1 (eth0). Can I make an alias on eth0 (ip addr add 91.XXX.XXX.1/23 dev eth0)? Or the right thing to do somehow different?