Executive Overview

A total of six new POP nodes are added in Lahore, Karachi and Islamabad, two each. This helped in better POP to POP intraregional analysis and gave more reliability to measurements. Some POP nodes have unreachability issues for example ISL QAU, LHR GCU and KHI CPSP. Peshawar Region has highest RTT when accessed from any of the other regions.  Also, Peshawar to Islamabad RTT is higher than Peshawar to Karachi RTT. A clear difference of RTT in forward and reverse direction is seen for Intraregional POP in ISL and Lahore. Multan and Faisalabad POP have RTT from Islamabad. Islamabad to Karachi RTT is better than Islamabad to Lahore and Peshawar. Islamabad to Jamshoro POP has high RTT and IPDV each month. NEDUET and GIKI were unreachable all the time.

POP to POP Analysis

We study the performance evaluation in terms of link stability through the data collected by various monitoring sites running through the remote nodes that are deployed at PERN-POPs. The link stability is examined for by means of different performance evaluation metrics that include the throughput, the average and minimum Round Trip Time (RTT), the nodes unreachability and the corresponding packet loss observed. This study includes the performance evaluation between POP to POP nodes and between POP to Non-POP nodes, for the months June-November 2011. Some of the unpredictable situation in the network is supported by use of outliers presented at the end.

The POP to POP node pairs increased from September to October as we added 2 new POP nodes in each of Islamabad, Karachi and Lahore region. Figure 1 shows the increase in POP to POP node pairs. Throughput of POP to POP also increased over six months. Figure 2 shows the increase in POP to POP throughput from June to November. The black line shows the exponential increase trend line. It is observed that new POP nodes were added in three regions which already had one POP node each; resulting in high POP to POP throughput when the Node pairs are within the same region. As a result POP to POP throughput increased as shown in Figure 2.

Inter Region POP to POP Analysis

Overall POP to POP performance was affected by the RTTs. We analyze the average Round Trip Time (RTT) where we take the PERN node deployed at Fatima Jinnah Women University (FJWU) Islamabad as the monitoring node and all the other POP nodes as remote nodes that are being observed. Figure 1 shows the average RTT observed during the months September 2011 to November 2011. It can be observed that the tendency of the RTTs for various months intended for various cities remain identical with a very small variations. As an example, the average RTT observed form FJWU to Karachi HQ (green line with triangles) for the months September-November is 26.59ms, 25.22ms, and 25.14ms. The same tendency is also followed by the other remote sites. Giving a close look to RTTs, it is observed that:

• ISL HQ to Jamshoro Average RTT increased from 45ms in Sep to 91 ms in November. However, its min RTT reduced from 36.3ms in August to 26.8ms in September and remained almost same for the coming months. This increased Avg RTT resulted in reduced throughput.
• RTT for Karachi POPs is very stable throughout the analyzed months.
• The average RTT from FJWU to Quaid-e-Azam University, Islamabad (Islamabad-QAU) is very small (with an average of 0.91ms) compared to the other remote sites.
•  A significant difference in average and Min RTTs is seen for KHI POP, Multan POP and Jamshoro POP. This can be seen in figure 3.

Packet loss and throughput from FJWU POP to other POPs is shown in the tables and average and Minimum RTT is shown in the graphs to identify the nodes with high RTTs.

Intra Regional POP to POP Analysis

Islamabad, Lahore and Karachi regions have three POP nodes each. Intraregional analysis is therefore carried out on these regions. In the tables below, Intra-regional POP performances are evaluated. Each metirc is compared with itself throughout the table (within its column) and colored based on the comparative value. Green shows good values while red shows bad values. It is seen that

• ISL HQ to FJWU unreachability is 12.09% in October however, ISL FJWU to ISL HQ unreachability in October is 0 %.  Similarly, it is seen that FJWU was unable to reach QAU in september for 74% of time however, QAU POP wasunable to reach FJWU 3.7% of time.
• HEC NOC to FJWU and QAU has different RTTs in forward and reverse direction.
• Karachi POP to POP RTT is same in forward and reverse directions however we see a difference in average RTT in Islamabad and Lahore region.

POP to NON POP Analysis

An aerial view of Average RTT of Pakistan shows that the RTTs for Peshawar region are high as compared to other regions.  Multan and Faisalabad POP nodes also show high RTT. Figure 3 shows the average RTTs from SEECS to other nodes in Pakistan with colors of line showing the average RTT for that link.
Figure 3: SEECS to Pakistan Average RTT
Mean Opinion Score (MOS ) is used as the measurement for VoIP. It is a good measure to know which links are good and which ones are bad. Within Pakistan MOS value for all of the links is above 4.1 (which is excellent for VOIP communication). In figure 4 it is seen that MOS (red markers) were not affected much by addition of new nodes (green line shows node pairs). MOS shows that, Pakistan to Pakistan VOIP communication should not be a problem.
Figure 4: Pakistan to Pakistan MOS with Node Pairs

POP to Non-POP Inter-region Analysis

We now examine the POP to Non-POP region performance in order to understand the inter region PERN performance, we chose one reliable node (least unreachable, generally POP node) in a region and try to see how non-POP nodes in other regions look from this node. We have divided all Pakistani nodes in 5 regions, Lahore, Islamabad, Karachi, Peshawar and Quetta. Following are the interesting findings:

1. UETTAXILA performs consistently bad in Islamabad region followed by HEC POP Islamabad node.
2. NEDUET remained unreachable in Sep, Oct and November.
3. IPDV from ISL to Jamshoro is very high (75ms) which results in bad throughput.
4. ISRA University improved its RTT from 65 ms in Sept to 31ms in November.
5. Kinnaird College was unreachable more than 70 % of times with high IPDV. On Nov 20^th there was a spike of Average RTT of 8029.49ms which increased the average RTT to 431ms for the month.
6. Lahore GCU POP node was also unreachable 45.46% and 32.33% in Oct and Nov respectively.
7. In Peshawar Region USTB, Kohat and CAE had high RTT. Kohat had high IPDV of 15ms every month. GIKI was unreachable all the times in Sept, Oct and Nov.
8. Karachi to Karachi and Peshawar to Peshawar average RTT is high (18ms), while for the rest of the regions it is below 1ms.
9. Peshawar region showed worst performance when accessed from any of the regions, including itself.
10. Quetta to Quetta links show low RTT.
11. Peshawar to Islamabad and to Lahore RTT is higher than Peshawar to Karachi and to Quetta.
12. Multan POP, Faisalabad POP and QUEST (Sindh) showed high RTTs.

NOTE: In the tables below, the values are colored while compared to the values of all the regions for the same metric. Color variation is from Red being bad values to Green being good values.