ALERT

[FREE DEMO] Deploy Your Enterprise Cloud in Minutes

Diffusing Update Algorithm (DUAL)

Definition - What does Diffusing Update Algorithm (DUAL) mean?

A diffusing update algorithm (DUAL or DUAL finite state machine) is a convergence algorithm that dictates a routing protocol used by Cisco’s proprietary Enhanced Interior Gateway Routing Protocol (EIGRP) to prevent routing loops via a continuous route computation.

A DUAL finite state machine (FSM) consists of many different states and scenarios. The DUAL protocol scans all routes to track the optimal path, in terms of efficiency and cost. Then, it adds that path in the routing table. DUAL FSM also manages backup routes, in case the primary and most efficient route is lost.

This term is also known as the DUAL finite state machine (DUAL FSM).

Techopedia explains Diffusing Update Algorithm (DUAL)

Routing protocols use several techniques to prevent any loop, which is an unreachable destination causing data packets to bounce back. Loops must be prevented because they hamper the performance of the entire network. Looped packets may have to be retransmitted to ensure that transmission is not due to overflow or other delivery failure.

UDP loops can be persistent, as there is no feedback on receipt. So, a sending application may keep sending packets into a network black hole. These receive data at full speed of the line, causing network performance degradation. Distance vector routing protocols, such as EIGRP, use several techniques to avoid looping, including the diffusing update algorithm.

DUAL avoids looping and uses an algorithmic calculation to ascertain best and alternate paths.

DUAL maintains several metrics about the paths, including the successor, feasible distance, feasible successor, reported distance and feasible condition.

Techopedia Deals

Connect with us

Techopedia on Linkedin
Techopedia on Linkedin
Tweat cdn.techopedia.com
"Techopedia" on Twitter


'@Techopedia'
Sign up for Techopedia's Free Newsletter!

Email Newsletter

Join thousands of others with our weekly newsletter

Resources
The 4th Era of IT Infrastructure: Superconverged Systems
The 4th Era of IT Infrastructure: Superconverged Systems:
Learn the benefits and limitations of the 3 generations of IT infrastructure – siloed, converged and hyperconverged – and discover how the 4th...
Approaches and Benefits of Network Virtualization
Approaches and Benefits of Network Virtualization:
Businesses today aspire to achieve a software-defined datacenter (SDDC) to enhance business agility and reduce operational complexity. However, the...
Free E-Book: Public Cloud Guide
Free E-Book: Public Cloud Guide:
This white paper is for leaders of Operations, Engineering, or Infrastructure teams who are creating or executing an IT roadmap.
Free Tool: Virtual Health Monitor
Free Tool: Virtual Health Monitor:
Virtual Health Monitor is a free virtualization monitoring and reporting tool for VMware, Hyper-V, RHEV, and XenServer environments.
Free 30 Day Trial – Turbonomic
Free 30 Day Trial – Turbonomic:
Turbonomic delivers an autonomic platform where virtual and cloud environments self-manage in real-time to assure application performance.