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Redundancy , Load balancing and Load sharing deference


hi guys

im really  confuse about those.

redundacy have load balancing and load sharing.


1.load balancing mean  is traffic going out to one destination by multi path.

   the multi path are used same traffic rate.

   - example Routing Protocol.

2. load sharing mean is almost same with load balancing but

   load sharing dosen't consider about destination just going out by multi path.

actually i saw  load sharing in the HSRP but im not sure that mean.

so anyone could tell me straight.

4 Replies 4

Cisco Employee
Cisco Employee


let assume you have two destinations and are reachable by 4 links. You have total 16 packets which will travel from localtion A to B.

A  ----Link 1----B

    ----Link 2 ---

    ----Link 3----

    ------Link 4---

During case of load balancing all the 16 packets will equally distributed by 4 links and each link will be having 4 packets.

Definition: Load balancing is a mechanism that helps to make networks more efficient. It distributes the processing of traffic evenly across a network with multiple-paths, in order to get optimal resource utilization, maximize throughput, and minimize response time.

Load Balancing

A  ----Link 1-(4 packets)---B

    ----Link 2 -(4 packets)--

    ----Link 3--(4 packets)--

    ------Link 4-(4 packets)--

During the case of load sharing all packets could travel the on link. Sometimes this could create a congestion on link too.

Definition: It is inherent in the forwarding process of a router to share the forwarding of traffic, if the routing table has multiple paths to a destination. If equal paths, the forwarding process will decide the manner of forwarding, still with the possibility of unbalanced forwarding. If unequal paths, the traffic is distributed inversely proportionally to the cost of the routes. That is, paths with lower costs (metrics) are assigned more traffic, and paths with higher costs are assigned less traffic.


shivlu jain

thanks shivlu jain.

im steal confuse. so i ask one more question.

load balancing is clear.

but sharing

During the case of load sharing all packets could travel the on link. Sometimes this could create a congestion on link too

whats that mean "on link" ?

(sharing)  load sharing time to select link 2 and ttaffic ging out only link 2

A  ----Link 1-( packets)---B

    ----Link 2 -(16 packets)--

    ----Link 3--( packets)--

    ------Link 4-( packets)--

in this situation. load sharing can select any link.

and use only one link?

am i right?


this is the switching process which takes care of the load-sharing:

-process switching: load shares per packet so for equal cost paths,one packet will go one way and next packet will go the other way

-fast switching: load shares per destination IP so all traffic going to one IP will take the same path

-CEF switching: load shares per flow( src-dst IP pair) and that is the CEF hashing algorithm which decides which flow

                        will take which path( so in this case me may have a lot of traffic on one link only and few on the other)



Don't forget to rate helpful posts.

Don't forget to rate helpful posts.

thanks for your helpful cadet alain

can i think like that?.

the load balancing is used in routing protocol.

the load sharing is used in swhitching proccess.

and switching proccess have 3 ways

and those things almost same.


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