Lectures notes for 2010 - KTH

IGRP Metrics
• a vector of metrics each with a 24 bit value
K 1
K
• composite metric is ⎛------
⎞ 2
+ ⎛------
⎞ ⋅ R, where K 1 and K 2 are constants,
⎝ B ⎠ ⎝ D ⎠
B the unloaded path bandwidth, D a topological delay, and R is
reliability
• also we pass the hop count and Maximum Transmission Unit values
K 1 is the weight assigned to bandwidth (by default 10,000,000)
K 2 is the weight assigned to delay (by default 100,000)
If up to 4 paths are with in a defined variance of each other, Cisco’s IOS
(Internetwork Operating System) will split the traffic across them in inverse
proportion to their metric.
Maguire IGRP Metrics 7: 22 of 70
maguire@kth.se 2010.03.21 Internetworking/Internetteknik