Switch Meshing

Introduction

 

Finding the Fastest Path. Using multiple switches redundantly linked

 

together to form a meshed switch domain, switch meshing dynamically

 

distributes traffic across load-balanced switch paths by seeking the fastest

 

paths for new traffic between nodes. In actual operation, the switch mesh

 

periodically determines the best (lowest latency) paths, then assigns these

 

paths as the need arises. The path assignment remains until the related MAC

 

address entry times out. The mesh sees later traffic between the same nodes

 

as new traffic, and may assign a different path, depending on conditions at the

 

time. For example, at one time the best path from node A to node B is through

 

switch 2. However, if traffic between node A and node B ceases long enough

 

for the path assignment to age out, then the next time node A has traffic for

 

node B, the assigned path between these nodes may be through switch 3 if

 

network conditions have changed significantly.

 

 

N o t e

The mac-age-timeparameter determines how long an inactive path assignment

 

remains in memory. Refer to “Reconfigure the Age Time for Learned MAC

 

Addresses” on page 6-13.

 

Because Redundant Paths Are Active, Meshing Adjusts Quickly to Link

 

 

Failures. If a link in the mesh fails, the fast convergence time designed into

 

meshing typically has an alternate route selected in less than a second for

 

traffic that was destined for the failed link.

 

Meshing Allows Scalable Responses to Increasing Bandwidth

 

Demand. As more bandwidth is needed in a LAN backbone, another switch

 

and another set of links can be added. This means that bandwidth is not limited

 

by the number of trunk ports allowed in a single switch.

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