Calculating Unscaled EIGRP Metrics

[surendrasinghtanwar667]

Hey while working on the EIGRP i have came across a topic of unscaled eigrp metric. In my topology my router is using classic metrics and wide metric but how this formula will work can someone help me out with this problem. ???

[Cristian Matei]

Hi,

   For whatever reason, maybe being a now OLD document, can't find it on Cisco site, however here it is in another location: https://studylib.net/doc/7099620/eigrp-wide-metrics---white-paper

    Long story short, unscaled BW formula is for backwards compatibility with routers / IOS versions that don't support wide metrics.

Best,

Cristian.

[surendrasinghtanwar667]

But i want to know that how this formula calculation works ??

[MHM Cisco World]

From Cisco press 

""Metric Backward Compatibility

EIGRP wide metrics were designed with backward compatibility in mind. EIGRP wide metrics set K₁ and K₃ to a value of 1 and set K₂, K₄, K₅, and K₆ to 0, which allows backward compatibility because the K value metrics match with classic metrics. As long as K₁ through K₅ are the same and K₆ is not set, the two metric styles allow adjacency between routers.

EIGRP is able to detect when peering with a router is using classic metrics, and it unscales the metric to the formula in Figure 2-13.

Figure 2-13 Formula for Calculating Unscaled EIGRP Metrics

This conversion results in loss of clarity if routes pass through a mixture of classic metric and wide metric devices. An end result of this intended behavior is that paths learned from wide metric peers always look better than paths learned from classic peers. Using a mixture of classic metric and wide metric devices could lead to suboptimal routing, so it is best to keep all devices operating with the same metric style.""

MHM

[paul driver]

Hello
Please review this post here: 

[SmileCocktail]

Hey! The unscaled EIGRP metric can be a bit tricky. It’s great that you’re looking into both classic and wide metrics. The key thing to remember is that unscaled metrics are based on the classic EIGRP formula but don't include the 256 scaling factor, which can affect your route calculations. You can start by applying the standard formula (bandwidth + delay) and then adjust it according to your needs. If you provide more details about your topology, I might be able to help you troubleshoot further! CFAHome