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Introduction

We worked with UNIMAS folks to set uyp a monitoring host at pinger.unimas.my. We noticed that there were severe diurnal variations to most hosts measureed from UNIMAS. We suspected that maybe UNIMAS itself is congested. Since congestion is usually an edge effect since the backbones are well provisioned, We looked at the Round Trip Times (RTTs) from SLAC which is not congested.

this was reported by Nara to their network folks

Dear Harun,

We are doing a joint project with Stanford and looks like their testing indicates that our network is congested. Can you check?

I don't want them to move their main link to UM because of this.

Harun responded Nov 8:

Thanks to let us know. The network capacity to internet 200Mbps is almost fully utilised especially during office hour.
everyday an average of 170 -180Mbps is being used.
but so far the performance still ok because we shape the bandwidth accordingly and we are monitoring the usage.

FYI, TM has already agreed in giving us 500Mbps POC bandwidth for a period of one week. the exercise will be done on the 3rd till 9th December 2012.
The POC will roughly show us the actual bandwidth for the community and to be discussed in TECIS for upgrade proposal.

Thanks & Regards

HARUN MAKSOM
Head
Centre for ICT Services (CICTS)
Universiti Malaysia Sarawak

Les responded

That sounds very interesting. I assume all traffic will take the new, faster link. Otherwise I hope you will be able to route the pinger traffic via the faster link. Harun says you are shaping the traffic which avoids some of the problems. Looking at the RTT plots (see below) from SLAC to UNIMAS the diurnal changes were much larger (200ms light use periods and multiple seconds heavy use periods) in October. I wonder if the shaping was applied in late October early November, thus accounting from the lower diurnal changes (indicating less congestion) recently. If so identifying the changes in performance maybe a bit more interesting, i.e. improvement with 100Mbps link by adding traffic shaping, and improvement with 500Mbps link with and without shaping. Can this be done, i.e. add and remove the shaping for the PingER host. This will be an interesting application of the use of PingER.

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