Systems network architecture

(SNA) IBM's proprietary high level networking protocol standard, used by IBM and IBM compatible mainframes. Also referred to as "Blue Glue", SNA is a bletcherous protocol once widely favoured at commercial shops. The official IBM definition is "that which binds blue boxes together." It may be relevant that Blue Glue is also a 3M product commonly used to hold down carpets in dinosaur pens.

Free Online Dictionary of Computing