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Convergence is not a unique process from one determinate protocol, a common characteristic is that process occur as result of change in topology. Once time I found a better definition but I lost it :\

My question is, Can I say that Convergence is the time it takes to run the algorithm for accomplishing a task?

Edit: accomplishing a task .. when occur a change in topology

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  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide your own answer and accept it. – Ron Maupin Aug 6 '17 at 20:44
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Your definition might be somewhat too generic in the networking space. "Accomplishing a task" would have to be adapted based on the scenario

The Linux Information Project provides a clear definition for convergence.

Convergence occurs as a result of a change in network topology, i.e., a link becoming available or unavailable. When this occurs, each router independently runs a routing algorithm to recalculate metrics and build a new routing table based on this information. Once all the routing tables have been updated, convergence is complete.

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  • I did that definition, trying explain these "tasks", like Spanning Tree "happens when bridges and switches have transitioned to either the forwarding or blocking state", so changes in topology – TMoraes Oct 14 '15 at 21:34
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most of the time convergence is describe turning from certain state to another state through multiple states like routing or even like spanning tree . if we have 4 states like spanning tree blocking->lessening->learning->forwarding so turning from blocking to forwarding that what is called full convergence but if the process interrupted in any certain state that can't be called convergence and the whole of the process will rebuild after certain time

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  • I tought it, but I would like to confirm my question, What do you think? – TMoraes Oct 14 '15 at 21:47
  • i think state is more suitable than algorithm , cause algorithm describe between two states but state describe a result . you can think of it like list of check boxes . – Gadeliow Oct 14 '15 at 21:50
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In routing, convergence is the act of the routers updating their routing tables to reflect a topology change, and it is done when all the routing tables have been updated.

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  • Its happens with Layer 2 too in Spanning Tree, but all this have regarding with time performance – TMoraes Oct 14 '15 at 21:30
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    Yes, layer-2 STP converges, too.. That is why I prefaced it with "In routing." You can make a direct inference with STP by saying convergence begin with the topology change is detected and lasts until all the switches have updated all ports to reflect the new topology. – Ron Maupin Oct 14 '15 at 21:35
  • Nice, but about "time it takes to run the algorithm" Can I trust it? Because, it makes sense right? – TMoraes Oct 14 '15 at 21:40
  • If you are speaking about a single device, its convergence is done when it has run the algorithm. I may be more accurate to say that its done when all the affected devices have run the algorithm. You can see this in routers when the first one doesn't tell its neighbors about the change until it has updated its own routing table; convergence is done when the last affected router has updated its routing table. – Ron Maupin Oct 14 '15 at 21:58
  • I agree. Yes I'm saying about a single device, its algorithm will accomplish a determinate function, because there was a change in topology! – TMoraes Oct 14 '15 at 22:10

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