Have 4 distribution routers, A, A1, B and B1. These are connected by gig links. Access routers has links to A or B. If failure, access-routers will be "moved" to A1 or B1. The rest of the core, distribution is connecting to both A, A1, B and B1. The address space for the access routers is planned for summarization. Is it good design to implement a common ip eigrp summary at the links towards the core/distribution (the same ip summary eigrp statements for A, A1, B and B1) - and no summary between A, A1, B and B1?