could you please send me a short guide how to delegate a zone subnet (class) to different NS.

I have a zone  i.e.  0.10.in-addr.arpa.zone

where I would like to delegate a part of the zone 10.0.0.104/29  (255.255.255.248) to different NS. It includes 8 IP addresses (10.0.0.104, 10.0.0.105, 10.0.0.106 .... 10.0.0.111)

then I create a record in the mentioned zone like 

104/29.0.0.10.in-addr.arpa. 300 NS my.test.server.

I tried to understand the syntax in RFC 2317 (https://tools.ietf.org/html/rfc2317) but it seems to be wrongly implemented from my side.

When I tried to "dig" records I have to ask next IP address in the row not like dig -x 10.0.0.105 bud like dig -x 10.0.0.104/29.105

Many thanks for the clarification,

best regards

Milan.