help: Disable split horizon on specified interface
create: vtysh -c "configure terminal" -c "interface $IFNAME" \
    -c "no ip rip split-horizon"
delete: vtysh -c "configure terminal" -c "interface $IFNAME" \
    -c "ip rip split-horizon"

commit:expression: ($VAR(../poison-reverse/) == ""); \
    "You cannot have 'split-horizon poison-reverse' enabled with 'split-horizon' disabled for $IFNAME"
