+At present it's not possible to reallocate a block to a different router
+except by deallocating it first, which requires that none of its addresses
+be assigned. This is probably as it should be.
+
+sub replace_check {
+ my ( $new, $old ) = ( shift, shift );
+
+ unless($new->routernum == $old->routernum) {
+ my @svc = $self->svc_broadband;
+ if (@svc) {
+ return 'Block has assigned addresses: '.
+ join ', ', map {$_->ip_addr} @svc;
+ }
+
+ return 'Block is already allocated'
+ if($new->routernum && $old->routernum);
+
+ }
+
+ '';
+}
+