Diffusing Update Algorithm DUAL - EIGRP English CCNA Tutorials - ENGLISH

Описание: Diffusing Update Algorithm(DUAL)

EIGRP→ Enhanced Interior Gateway Routing Protocol uses DUAL→ for selection and maintaining the best path to each remote network

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It helps to converge amazingly fast
Vital task done by EIGRP with the help of DUAL
→ Figure out a backup route if there’s one available
→ support VLSM(variable Length subnet masks)
→ Perform dynamic route recoveries
→ Query neighbours for unknown alternative routes
→ send out queries for an alternative route


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It enables EIGRP to converge amazingly fast

This happens in two fold
1 . Maintains a copy of all the neigbour’s route so that if best one goes down another one can be set up by scanning the topologu table
2 . It this does’nt work out EIGRP router will ask their neigbour’s for help finding the best path


IN EIGRP the propagation happens not happens on the entire network but only happens as far as needed


3 Critical conditions must be met for DUAL

1 . New Neigbours are discovered or declared dead in a finite time or pre defined time
2 . All transmitted messages are received correctly
3 . All changes and messages are processed in the order they are detected

RTP provides a reliable method of communication between routers
While DUAL selects and maintains information about the best paths