HTTP Traffic Generator

src/http/docs/http.rst

+.. include:: replace.txt
+
+HTTP Traffic Generator
+------------
+
+HTTP traffic generator is one traffic model to generate web-like traffic and have different options to tune and generate HTTP traffic.
+
+This model was developed by·
+`the ResiliNets research group <http://www.ittc.ku.edu/resilinets>`_
+at the University of Kansas.··
+
+Overview
+*********************
+·
+ The implementation of HTTP traffic generator composes mainly four parts:
+·
+ 1. Client
+ 2. Server
+ 3. Runtime Variable
+ 4. Distribution Generation (Notification to Statistics Research, Bell Labs, Lucent Technologies and The University of North Carolina at Chapel Hill)
+·
+ The major classes include:·
+·
+ Class http::HttpClient implements the functions needed to initiate the transport connections to the HTTP server and the random variables generation functions
+
+ Class http::HttpServer implements the functions to receive the connection from HTTP clients and establish the connection, receive HTTP packets received by the HTTP client
+
+ Class http::HttpDistribution implements functions to take use of the distribution functions generated parameters and use them in the·
+
+ Class http::HTTPRandomVariableBase defines the major distribution functions to generate the parameters used in the HTTP traffic model
+
+ Class http::RuntimeVariable is used to save the random variables generated by the HTTPRandomVariableBase and save in the RuntimeVariable table entries.  They will be used by both HTTP clients and servers.
+
+ Class http::HttpSeqHeader is the header to distinguish different transport segments from a single HTTP packet
+
+ When the traffic generator starts, the http client initialize connections to http server, after the connection has established,
+ the client calls the distribution generation module and generates empirical parameters involved with http operation. For example,
+ request size, response size, request gap time, server delay time, total objects per page, total pages per web session. All those
+ parameters will be saved in runtime variable model, which can be accessed by both the http client and server. Based on the parameters
+ saved in runtime variable, the client and server will generate http traffic which can represent real-world http traffic.
+
+ This traffic generator is capable of generating both HTTP 1.0 traffic and HTTP 1.1 traffic.  When HTTP 1.0 mode is used, each http request
+ will wait until the previous http transaction is over, while HTTP 1.1 will do pipelining, which means it sends multiple http requests·
+ without waiting for previous responses; however, parallel connections is not yet supported.
+

[Nicola Baldo, 2012/07/25 09:00:43]

Any detailed info on the statistical model that is implemented in the generator?
This is the most important piece of information that one would expect to appear
here.

+Work Modes
+*****************
+
+ There are two working modes: automatic and manual. When automatic mode is used, it generates the variables based
+ on predefined distribution functions. While the manual mode will need the users to pass in variables for the
+ model to generate HTTP traffic.
+
+ This module does not use the built in tracing module of ns-3, it generated its own files to record the parameters generated from
+ distribution functions as well as the simulation results.  The reason for this choice is that some of the metrics we use cannot be represented
+ by the ns-3 built in tracing module.  For example, the Web Page Delivery Delay needs to identify the time it takes a whole HTTP object·
+ to deliver to the destination.  The build tracing module in ns-3 can only monitor the time it takes for the single transport segment to reach
+ the destination.  This is the reason we choose to use the text-based tracing of the module.  Furthermore, the tracing module is carefully tested·
+ and validated.·
+
+ There are two metrics to record the results:
+ 1. Object Delivery Ratio (ODR)
+ 2. Web Page Delivery Delay
+
+ Notes:
+ The time recorded as parameters are all in milliseconds
+
+HTTP Instructions
+*****************
+
+To have a node run HTTP, the easiest way would be to use the ClickInternetStackHelper

[Nicola Baldo, 2012/07/25 09:00:43]

ClickInternetStackHelper???

+class in your simulation script. For instance::
+
+  HttpHelper http;
+  http.Install (http, adhocNodes);
+
+The example scripts inside ``src/http/examples/`` demonstrate the use of HTTP based nodes
+in different scenarios. The helper source can be found inside ``src/http/helper/http-helper.{h,cc}``
+
+Examples
+********
+
+The example can be found in ``src/http/examples/``:
+
+* http.cc use HTTP as traffic generator.  This example uses basic settings to make it simple to use.  Advanced settings have been commented out.
+
+
+Validation

[Nicola Baldo, 2012/07/25 09:00:43]

I would call this just "Testing".

+**********
+
+This model has been tested as follows:
+
+* Unit tests have been written to verify the internals of DSR. This can be found in ``src/http/test/http-test-suite.cc``. These tests verify whether the methods inside DSR module which deal with packet buffer, headers work correctly.

[Nicola Baldo, 2012/07/25 09:00:43]

DSR?

+* Simulation cases similar to [1] have been tested and have comparable results.

[Nicola Baldo, 2012/07/25 09:00:43]

"have comparable results" with what? [1] seems to describe the same model that
is being reviewed here, and I see no comparison with other data there.

+* Random variable validation cases have been conducted to fit the proposed distribution function for each http parameter

[Nicola Baldo, 2012/07/25 09:00:43]

this sentence is not clear, and what you do is not evident from the test
program. Can you please explain better?

+··
+References
+**********
+
+[1] BibTeX for the http performance paper:·
+@inproceedings{cheng:2011:PCO,
+        Address = {Las Vegas, NV},
+        Author = {Yufei Cheng and Egemen K. \c{C}etinkaya and James P.G. Sterbenz},
+        Booktitle = {Proceedings of the International Telemetering Conference ({ITC})},
+        Month = {October},
+        Title = {Performance Comparison of Routing Protocols for Transactional Traffic over Aeronautical Networks},
+        Year = {2011}}
+