content_image/1013773.jpg
## 2.2.3 Edge-core-edge topology 

Edge-core-edge is the most scalable topology, it is used for installations where a core-edge fabric made up of multislot director-class SAN switches is insufficient. This design is useful for large, multiclustered system installations. Similar to a regular core-edge, the edge switches can be of any size, and multiple ISLs must be installed per switch. 

Figure 2-4 shows an edge-core-edge topology with two different edges, one of which is exclusive for the FlashSystem and high-bandwidth servers. The other pair is exclusively for servers. 

<img src='content_image/1013773.jpg'>

Edge-core-edge fabrics allow better isolation between tiers. For additional information, see 2.2.6, “Device placement” on page 19. 

