Q-Logic 16HA user manual Mesh Topology, Mesh Fabric Size, Mesh Latency

Mesh Topology

Mesh Topology

The term “mesh” indicates that each chassis has at least one T_Port directly connected to each other chassis.

In fabrics containing two or three chassis, Cascade-with-a-loop topology and Mesh topology are exactly the same. Note in Figure 5-2that you could take any three chassis and their interconnections and draw them in a row with a loop back from the last chassis to the first chassis (the same as Cascade-with-a-loop).

Figure 5-2 Mesh Example

Mesh Fabric Size

SANbox-16 chassis connected in Mesh topology expand from two chassis to a maximum of nine chassis. With each chassis using eight T_Ports for chassis inter- connection, then each chassis will have 8 user ports remaining. Figure 5-2shows an example of mesh interconnections.

Using four to eight chassis, Cascade-with-a-loop topology can result in more user ports than Mesh topology.

Using six or more chassis, Multistage topology can result in more user ports than Mesh topology. Multistage topology is described later in this manual.

Mesh Latency

Each Chassis will route traffic through the path of the least number of chassis hops to the destination chassis. A chassis will route traffic through other paths only if all links in the closest direction fail.

Latency to any port on the same chassis is one chassis hop.

Latency to any port on any other chassis is two chassis hops (counting the source chassis). This is the same latency as two or three chassis connected in Cascade - with-a-loop. It is better than Multistage. Multistage has three hops to any IO/T chassis.

SANbox-16HA Fibre Channel Switch		Multi-Chassis Fabrics 5-9
Installer’s/User’s Manual	59005-03 Rev. A