The comments summary:

Summary created by Wireshark  (Git Rev Unknown from unknown)

    File: 
       Name: /.../netsec-assignment2-S4498062/exercise3/outputnetsec-01.cap
       Length: 161961977 bytes
       Format: Wireshark/tcpdump/... - pcap
       Encapsulation: IEEE 802.11 Wireless LAN
       Packet size limit: 65535 bytes
    
    
    Time:
       First packet: 2015-09-11 08:52:12
       Last packet: 2015-09-11 09:16:57
       Elapsed: 00:24:45
    
    
    Capture:
    
       Unknown interface:
          Dropped packets: unknown
          Capture filter: unknown
          Link type: IEEE 802.11 Wireless LAN
          Packet size limit 65535 bytes
    
    Statistics:
       Packets: 543544
       Between first and last packet:1485.708 sec
       Avg. packets/sec: 365.849
       Avg packet size: 281.974 bytes
       Bytes: 153265265
       Avg bytes/sec: 103159.778
       Avg Mbit/sec: 0.825

In Statistics > Conversations, we see the most active clients:

    "Address A","Address B","Packets","Bytes","Packets A→B","Bytes A→B","Packets A←B","Bytes A←B","Rel Start","Duration","bps A→B","bps A←B"
    "Allnet_0c:f7:8c","Allnet_0c:f7:93","94165","80983864","55537","77358388","38628","3625476","-0.000004000","1485.6989","416549.48","19522.00"
    "Allnet_0c:ee:ed","Allnet_0c:f7:93","109921","67395252","65601","6130612","44320","61264640","-0.000003000","1485.7076","33011.14","329888.01"
    "Allnet_0c:ee:ed","Allnet_0c:f7:8c","8739","999840","4098","479032","4641","520808","0.066556000","1485.1628","2580.36","2805.39"
    "AsustekC_89:8c:10","IntelCor_25:1b:e2","1080","106920","1080","106920","0","0","6.014339000","1476.0891","579.48","N/A"
    "AsustekC_89:8c:10","Azurewav_8d:55:58","292","28908","292","28908","0","0","47.326149000","1380.3753","167.54","N/A"
    "AsustekC_89:8c:10","IntelCor_ed:f2:0b","233","23067","233","23067","0","0","40.717828000","1408.6099","131.01","N/A"
    "AsustekC_89:8c:10","LgElectr_65:c2:1e","186","18414","186","18414","0","0","196.765954000","1089.9483","135.16","N/A"
    "AsustekC_89:8c:10","50:a7:2b:79:98:e7","134","13266","134","13266","0","0","1037.606722000","60.9406","1741.50","N/A"
    "AsustekC_89:8c:10","HonHaiPr_4a:b3:b3","76","7524","76","7524","0","0","21.791043000","1329.0226","45.29","N/A"
    "IntelCor_a3:19:61","AsustekC_89:8c:10","76","7524","0","0","76","7524","697.795714000","679.1029","N/A","88.63"
    "IntelCor_e2:52:c0","AsustekC_89:8c:10","48","4752","0","0","48","4752","159.485889000","1289.6303","N/A","29.48"
    "Azurewav_4a:18:ef","AsustekC_89:8c:10","47","4653","0","0","47","4653","110.878660000","1320.6467","N/A","28.19"
    "34:fc:ef:a4:20:02","AsustekC_89:8c:10","42","4158","0","0","42","4158","298.310273000","949.5807","N/A","35.03"
    "AsustekC_89:8c:10","Jolla_01:30:c6","40","3960","40","3960","0","0","569.697859000","197.4624","160.44","N/A"
    "AsustekC_89:8c:10","SonyMobi_44:eb:da","30","2970","30","2970","0","0","61.584704000","60.0957","395.37","N/A"
    "SamsungE_34:6b:88","AsustekC_89:8c:10","26","2574","0","0","26","2574","253.012801000","408.3589","N/A","50.43"
    "AsustekC_89:8c:10","SamsungE_55:3b:c3","23","2277","23","2277","0","0","200.722946000","856.3267","21.27","N/A"
    "SamsungE_6e:9a:01","AsustekC_89:8c:10","17","1683","0","0","17","1683","11.333827000","304.7486","N/A","44.18"
    "AsustekC_89:8c:10","SamsungE_41:25:74","13","1287","13","1287","0","0","904.035331000","20.4690","503.00","N/A"
    "AsustekC_89:8c:10","Apple_35:43:18","9","891","9","891","0","0","259.246274000","501.2417","14.22","N/A"
    "SimTechn_64:6a:a5","AsustekC_89:8c:10","7","693","0","0","7","693","596.423938000","654.5950","N/A","8.47"
    "SamsungE_8f:28:47","AsustekC_89:8c:10","7","693","0","0","7","693","1276.488448000","0.0077","N/A","721875.00"
    "AsustekC_89:8c:10","Apple_9c:bc:42","6","594","6","594","0","0","1376.221698000","0.0159","299395.16","N/A"
    "Htc_76:de:49","AsustekC_89:8c:10","3","297","0","0","3","297","890.820803000","0.0205","N/A","116009.96"
    "HuaweiTe_ba:27:00","AsustekC_89:8c:10","3","297","0","0","3","297","1163.479234000","0.0036","N/A","662576.69"
    "AsustekC_89:8c:10","SamsungE_27:7b:4a","2","198","2","198","0","0","851.540162000","0.0195","81418.66","N/A"
    "AsustekC_89:8c:10","Broadcast","1","105","1","105","0","0","0.000003000","0.0000","N/A","N/A"
    "AsustekC_89:8c:10","Motorola_2c:ab:db","1","99","1","99","0","0","1004.081411000","0.0000","N/A","N/A"
    "AsustekC_89:8c:10","IntelCor_4f:b6:a9","1","99","1","99","0","0","1148.830019000","0.0000","N/A","N/A"

Clearly, Allnet_0c:{f7:8c,ee:ed,f7:93} are the most active.

The protocol hierarchy only shows 802.11 and its data. We're using an encrypted capture, so Wireshark cannot distinguish the different protocols (as explained in exercise3a).