Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 What causes... Lack of bandwidth multiple flows are competing for a limited amount of bandwidth Too much delay -packets have to traverse many network devices and links that add up to the overall delay,and/or long queueing delay at routers (congestion) Variable delay sometimes there is a lot of other traffic which results in more delay Drops-packets have to be dropped when a link is congested (congestion) 2616009:Network Traffic Engineering 1:Overview Page.62616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 1: Overview Page.6 What causes ... - Lack of bandwidth – multiple flows are competing for a limited amount of bandwidth - Too much delay – packets have to traverse many network devices and links that add up to the overall delay, and/or long queueing delay at routers (congestion) - Variable delay – sometimes there is a lot of other traffic which results in more delay - Drops – packets have to be dropped when a link is congested (congestion)