Muscle cramps can bring the strongest of athletes to his or her knees in just an instant. One minute you’re running along at a race pace and the next, your leg is overcome with an intense, clinching and unyielding pain.

This is a serious issue because you are, after all, developing code: each time you run the program and examine its output, you will want to write more code to tweak something, or to gain some different insight. Each time you make a small change to the code and run it, you will have to deal with its sluggishness which can get frustrating and impede progress. I will be using Python (3). Why Python? Apart from the well-known benefits of Python (open-source, relatively gentle learning curve, ubiquity, abundance of modules and so forth), it is also the case that Network Engineers are gaining expertise in this language and are using it in other areas of their work (device management and monitoring, workflow applications etc.). What modules?The argparse code to parse the command line is not shown below; please look at my argparse recipe book if you need help with using the argparse module. On sending, make sure you don't cross the size limits: MAX_UDP_SIZE = 65507 # https://en.wikipedia.org/wiki/User_Datagram_Protocol

print ( '##################################################################' ) print ( 'TCP session between client {} and server {}' . format ( client_ip_addr_port , server_ip_addr_port )) print ( '##################################################################' ) # Print format string The code below was written and executed on Linux (Linux Mint 18.3 64-bit), but the code is OS-agnostic; it should work as well in other environments, with little or no modification. you are given two pcaps, one gathered on a SPAN port on an access switch, and another on an application server a few L3 hops away. At some point the application server sporadically becomes slow (retransmits on both sides, TCP windows shrinking etc.). Prove that it is (or is not) because of the network. The printable_timestamp function is defined like this: import time def printable_timestamp ( ts , resol ): ts_sec = ts // resol ts_subsec = ts % resol ts_sec_str = time . strftime ( '%Y-%m-%d %H:%M:%S' , time . localtime ( ts_sec )) return '{}.{}' . format ( ts_sec_str , ts_subsec )The goal in this iteration of the code is to generate a graphical plot of the TCP Receive window on the Client. The end result is a graph that looks like this:

Use the argparse module to get the pcap file name from the command line. If your argparse knowledge needs a little brushing up, you can look at my argparse recipe book, or at any other of the dozens of tutorials on the web. import argparse import os import sys def process_pcap ( file_name ): print ( 'Opening {}...' . format ( file_name )) if __name__ == '__main__' : parser = argparse . ArgumentParser ( description = 'PCAP reader' ) parser . add_argument ( '--pcap' , metavar = '' , help = 'pcap file to parse' , required = True ) args = parser . parse_args () file_name = args . pcap if not os . path . isfile ( file_name ): print ( '"{}" does not exist' . format ( file_name ), file = sys . stderr ) sys . exit ( - 1 ) process_pcap ( file_name ) sys . exit ( 0 ) Vinegar is a very interesting food. Folk medicine has attributed everything from weight loss to increased energy to increased metabolism to the properties of this ancient condiment. For the purposes of stopping muscle cramps, it’s believed that the vinegar triggers a reflex that alerts our brains to tell our muscles to stop contracting and to relax. And, it’s believed to begin as soon as the vinegar touches receptors in the mouth. This means very fast cramp relief!pkt_data = {} pkt_data [ 'direction' ] = direction pkt_data [ 'ordinal' ] = last_pkt_ordinal pkt_data [ 'relative_timestamp' ] = this_pkt_relative_timestamp / \ Unfortunately, it’s not always clear to us why muscle cramps occur. There are hypotheses regarding hydration, electrolytes, bike-fit, form, over-training, and more. There are plausible reasons they seem to happen more in races than in training, when you’re pushing your body hardest. They also seem to plague some athletes more than others. In all these cases, it is immensely helpful to write a custom program to parse the pcaps and yield the data points you are looking for.