What is the definition of "load" in a network?

hitmenhitmen Banned Posts: 133
Why is the highest load taken for an EIGRP update message?

Assuming my left arm carries 5kg while my right arm carries 10kg. Should the lowest value be taken since we are assuming the worst case scenario?

Can anyone explain load as a metric component?


  • networker050184networker050184 Mod Posts: 11,962 Mod
    Load refers to the amount of traffic on an interface.
    An expert is a man who has made all the mistakes which can be made.
  • fredrikjjfredrikjj Member Posts: 879
    hitmen wrote: »
    Why is the highest load taken for an EIGRP update message?
    Can anyone explain load as a metric component?

    I'm writing this off the top of my head without research because I got no time for that. Feel free to correct me

    The EIGRP metric components were designed to be backwards compatible with Cisco's older protocol IGRP. IGRP worked similarly to RIP in that an update of the full routing information was sent periodically. Each time an update was sent it took a snapshot of the metric components and because of that, it made more sense to take load into account. Theoretically, this would allow the network to adapt to changes in the load each time an update was sent. I have no idea if this was used in reality.

    EIGRP does not send periodic updates. Once two routers have exchanged information, only changes (prefix up/down) are sent (unless you manually add offset lists and fitlersr and so on). In a stable network therefore, the load in the composite metric will only reflect the load at the point when the routers originally exchanged routes; changes in the load do not make EIGRP send a new update. So basically, it's more less useless and the default k-values used creates a metric formula where load isn't taken into account when calculating the total metric. Potentially it's even worse than useless because if you happen to have a temporarily heavily loaded link when the updates are exchanged, that link will have an inflated metric that remains so even after the load has returned to normal.
Sign In or Register to comment.