Pakistani Case Study 2010-2011

Introduction

In 2010, following a series of workshops and site visits, the team at SEECS/NUST and SLAC has worked with Pakistan’s Education and Research Network (PERN) and Pakistani Universities to put together an end-to-end (E2E) network monitoring infrastructure for PERN connected higher education sites. So far they have installed the PingER monitoring tools and started gathering data at 18 sites in Pakistan. In addition they are working on a further 8 monitoring sites. This includes 4 sites (SEECS/NIIT, COMSATS, PERN and NCP/Quaid-i-Azam) which have been in place for a longer time. Over the last year the number of monitoring host – remote host pairs (both in Pakistan) has increased from about 30 to over 220.

The figure below shows the main regions where the hosts are located and how the regions are connected by PERN:

The difficulty of the installations has varied host to host. The technical installation has been simple and not resulted in delays. The delays between deciding to install a monitoring host and gathering measurements from the host have mostly been due to: machine availability; getting administrative approval within university; and delays in making the DNS record entry. The table below shows the history of the installations:

In addition work is in progress to install: BUITMS in Quetta, Bolochistan; Sind Agriculture University Tandojam in Karachi, Sind; NCEMB University in Punjab, Lahore; Virtual University Lahore, Ounjab; Air University in Islamabad, Punjab, Kinnaired College for Women in Lahore, Punjab.

The growth in the number of monitors and host pairs being monitored over 2010, is seen below (spreadsheet):

Using PingER, the monitoring hosts ping each remote host with 10 pings every 30 minutes. From this data we are able to measure minimum and average Round Trip Times (RTT), jitter, loss, unreachabilty and derive throughput and Mean Opinion Score (MOS). The data is gathered from the monitoring sites on a daily basis by archiving and analysis sites at SEECS (this was also set up in the last 18 months), SLAC and FNAL.

RTT and Losses for 2010

To try and show the network performance trends within Pakistan in 2010 Amber created a graph showing the inter-regional average RTT performance over the whole year.

Understanding the large variations Jan-Apr 2010

We were concerned about the large variations seen in January 210 through May 2010. Zafar suggested the problem might be to do with the congestion of the links. Jitter (Inter Packet Delay Variation - IPDV) tends to be a good indicator of queuing/congestion, so he suggested looking at this.

The IPDV shows similar behavior to the average RTT:

 
We then looked to see what portion of the larger IPDV early in the year was related to adding now monitoring and remote hosts. If we select the same host-pairs in both say Nov 2010 and April 2010 then the improvement ((ipdv(Apr)-ipdv(Nnov))/ipdv(Apr) in IPDV is about 47%. Thus things have improved with lower IPDVs for the selected host pairs.  

Unfortunately we do not have traceroutes between all the sites to see if they have changed over time. 

Comparing for Nov 2010 the average IPDV for all pairs with that for just the pairs in both April 2010 and November 2010 one gets 5.13ms verses 4.58. Thus some of the reduction appears to be due to the new hosts added.

, prior to this there are less than 100. It is suspected that this is partially the cause of the more stable values of IPDV following this date.

Returning to the average RTT graph, we believe it is less confusing to mainly focus on the data from May 2010 onwards, in order to remove the effects of small statistics. In this case, the average RTTs from Jun through November 2010 have been pretty flat.

Differences in RTTs for regions

Looking at the data for November 2010 it is seen that the average RTts to Karachi and Lahore are two to three times less than those to Quetta, Islamabad and Peshawar. This needs to be investigated.