In a mesh topology,each switch is directly connected to other switches by using ISC.This topology promotes enhanced connectivity within SAN.When the number of ports on a network increases,the number of nodes that can participate & communicate also increases.
There are two types of Mesh Topology-
In Full Mesh every switch is connected to every other switch in topology.
Full Mesh topology may be appropriate when the number of switches involved in are small.
A typical deployment would involve upto four switches or directors with each of them servicing highly localized host to storage traffic.
In a full mesh topology , a maximum of one ISL or hop is required for host to storage traffic.
In a partial mesh topology,several hops or ISL may be required for the traffic to reach its destination.
Hosts and storage can be located anywhere in the fabric ,& storage can be localized to a director or a switch in both mesh topologies.
Thus for high availability solution ,full mesh topology is used.
In mesh one ISL for each host to storage
Total ports available = 17*16=272
So ISL required are 136 i.e.272/2
Each ISL requires / consume two ports available ports 272 ports
Thus 'zero'/'0' number of ports available for hosts.
free ports = total port -(total switch - ISL)
= 16-(17-1) =0