TRex Virtual Machine setup and basic usage
===========================================
:author: Dan Klein 
:email: <danklei@cisco.com> 
:revnumber: 1.0
:quotes.++:
:numbered:


== Introduction

=== TRex traffic generator

TRex traffic generator is a tool design the benchmark platforms with realistic traffic.
This is a work-in-progress product, which is under constant developement, new features are added and support for more router's fuctionality is achieved.

One of the innovative tools through which TRex can be learned and tested during development is a virtual machine instance, fully simulating TRex without the need of any additional hardware.


==== TRex Virtual Machine

The TRex Virtual Machine is based on Oracle's Virtual Box freeware.

It is designed to enable TRex newbies to explore this tool without any special resources, and no single network cable attached. Moreover, is requires no internet or outer network connectivity.


== Setup and Usage

=== Setup

In order to use TRex VM, there are several super-easy steps to follow:

  . Download and install Oracle VM Virtual Box Manage https://www.virtualbox.org/wiki/Downloads[(VB download link)]. + 
    During the installation you'll be asked to allow the installation of system devices component interactions. Allow it.
  . Download the latest TRex VM by http://trex-tgn.cisco.com/trex/T_Rex_162_VM_Fedora_21.ova[clicking on this link].
  . Open Oracle VM Virtual Box application installed at step 1.
  . Under 'File' tab, select 'Import Appliance' (`ctrl+I` shorthand can be used as well). The following screen will apear:

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  . Browse and select the .ova file you have downloaded at step 2, and click 'continue'.
  . Click 'Next, and then make sure that the 'Reinitialize the MAC address of all network cards' checkbox is **not selected**.
  . Click 'import' and wait for the import process to finish.
  . **That's it! you're all good and set to go!**


=== Launching and logging into the machine

Let's get started with running TRex!

First, launch the virtual machine by selecting it in the VM's menu and hitting 'Start' button.

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[IMPORTANT]
====
You may encounter with "VT-x is disabled" error, similar to the image below. +
In that case, please refer to https://www.virtualbox.org/ticket/4130[this link] and follow the provided steps to overcome this issue.
====

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<<<<<

Next, once the machine is finished booting, login to the machine using the following credentials:

  - Username: `trex`

  - Password: `trex`

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TIP: a remote connection to the machine from anywhere in the hosting machine can be achieved by the following command: +
 `ssh -p 3022 trex@127.0.0.1`

=== Running TRex traffic generator

Finally, we're ready to do some TRex magic. This is super easy and can be achived be the following steps:

  1. Change dir to latest version supplied using: `cd /home/trex/v1.62/`.

  2. Run your desired TRex command. 

IMPORTANT: When launching a TRex command pay attention make sure that: +
  1. use `sudo` prefix at the beggining of the command. +
  2. Specify the `-f` argument first among all arguments.


For example, let's run TRex with DNS traffic generation and no latency. The Runnning command is:

----
[trex@localhost v1.62]$ sudo ./t-rex-64 -f cap2/dns.yaml -d 100 -m 1 --nc
Starting  TRex 1.62 please wait  ...
found configuration file at /etc/trex_cfg.yaml
zmq publisher at: tcp://*:4500

...
<1>
...

-Per port stats table
      ports |               0 |               1
 -----------------------------------------------------------------------------------------
   opackets |              17 |              17
     obytes |            1241 |            1513
   ipackets |              17 |              17
     ibytes |            1513 |            1241
    ierrors |               0 |               0
    oerrors |               0 |               0
      Tx Bw |     582.35  bps |     709.99  bps

-Global stats enabled
 Cpu Utilization : 0.8  %  0.0 Gb/core
 Platform_factor : 1.0
 Total-Tx        :       1.29 Kbps
 Total-Rx        :       1.29 Kbps
 Total-PPS       :       1.99  pps
 Total-CPS       :       1.00  cps

 Expected-PPS    :       2.00  pps
 Expected-CPS    :       1.00  cps
 Expected-BPS    :       1.30 Kbps

 Active-flows    :        0  Clients :      511   Socket-util : 0.0001 %
 Open-flows      :       17  Servers :      255   Socket :       17 Socket/Clients :  0.0
 drop-rate       :       0.00  bps
 current time    : 18.7 sec
 test duration   : 81.3 sec
----
<1> Output prompt continues (trimmed for reader's comfort).

Now, lets review the generated packets as they observed footnoteref:[<1>,The given output represents the output begining.] by our promiscuous interface (interface #2):

----
[trex@localhost ~]$ sudo tcpdump -i enp0s8
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on enp0s8, link-type EN10MB (Ethernet), capture size 262144 bytes
09:38:53.953651 IP 16.0.0.2.1024 > 48.0.0.2.domain: 48 A? www.cisco.com. (31)
09:38:53.963969 IP 48.0.0.2.domain > 16.0.0.2.1024: 48* 1/0/0 A 100.100.100.100 (47)
09:38:54.960361 IP 16.0.0.3.1024 > 48.0.0.3.domain: 48 A? www.cisco.com. (31)
09:38:54.970358 IP 48.0.0.3.domain > 16.0.0.3.1024: 48* 1/0/0 A 100.100.100.100 (47)
09:38:55.967200 IP 16.0.0.4.1024 > 48.0.0.4.domain: 48 A? www.cisco.com. (31)
09:38:55.977222 IP 48.0.0.4.domain > 16.0.0.4.1024: 48* 1/0/0 A 100.100.100.100 (47)
09:38:56.975355 IP 16.0.0.5.1024 > 48.0.0.5.domain: 48 A? www.cisco.com. (31)
09:38:56.985379 IP 48.0.0.5.domain > 16.0.0.5.1024: 48* 1/0/0 A 100.100.100.100 (47)
09:38:57.981659 IP 16.0.0.6.1024 > 48.0.0.6.domain: 48 A? www.cisco.com. (31)
09:38:57.992358 IP 48.0.0.6.domain > 16.0.0.6.1024: 48* 1/0/0 A 100.100.100.100 (47)
09:38:58.990979 IP 16.0.0.7.1024 > 48.0.0.7.domain: 48 A? www.cisco.com. (31)
09:38:59.000952 IP 48.0.0.7.domain > 16.0.0.7.1024: 48* 1/0/0 A 100.100.100.100 (47)
09:39:00.009403 IP 16.0.0.8.1024 > 48.0.0.8.domain: 48 A? www.cisco.com. (31)
09:39:00.019456 IP 48.0.0.8.domain > 16.0.0.8.1024: 48* 1/0/0 A 100.100.100.100 (47)
09:39:01.015810 IP 16.0.0.9.1024 > 48.0.0.9.domain: 48 A? www.cisco.com. (31)
----


Let's have a look at another example. +
We want to run TRex with simple http traffic generation. The running command will look like this:

----
[trex@localhost v1.62]$ sudo ./t-rex-64 -f cap2/http_simple.yaml -d 100 -l 1000 -m 1 --nc
Starting  TRex 1.62 please wait  ...
found configuration file at /etc/trex_cfg.yaml
zmq publisher at: tcp://*:4500

...
<1>
...

-Per port stats table
      ports |               0 |               1
 -----------------------------------------------------------------------------------------
   opackets |           40983 |           41946
     obytes |         2563951 |         6015664
   ipackets |           41946 |           40983
     ibytes |         6015664 |         2563951
    ierrors |               0 |               0
    oerrors |               0 |               0
      Tx Bw |     520.83 Kbps |       1.27 Mbps

-Global stats enabled
 Cpu Utilization : 3.1  %  0.1 Gb/core
 Platform_factor : 1.0
 Total-Tx        :       1.79 Mbps
 Total-Rx        :       1.79 Mbps
 Total-PPS       :       2.11 Kpps
 Total-CPS       :       2.84  cps

 Expected-PPS    :     102.71  pps
 Expected-CPS    :       2.78  cps
 Expected-BPS    :     764.51 Kbps

 Active-flows    :        0  Clients :      255   Socket-util : 0.0000 %
 Open-flows      :      107  Servers :    65535   Socket :        0 Socket/Clients :  0.0
 drop-rate       :       0.00  bps
 current time    : 39.6 sec
 test duration   : 60.4 sec

-Latency stats enabled
 Cpu Utilization : 1.0 %
 if|   tx_ok , rx_ok  , rx   ,error,    average   ,   max         , Jitter ,  max window
   |         ,        , check,     , latency(usec),latency (usec) ,(usec)  ,
 ----------------------------------------------------------------------------------------
 0 |  39490,  39489,      0,   0,       1276  ,  106714,      91      |  1737  1880  
 1 | 39490,   39490,      0,   0,        226  ,  107619,     203      |  1694  1041  

----

<1> Output prompt continues (trimmed for reader's comfort).

Once again, lets review the generated packets as they observed footnoteref:[<1>] by our promiscuous interface (interface #2):

----
[trex@localhost ~]$ sudo tcpdump -a -i enp0s8
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on enp0s8, link-type EN10MB (Ethernet), capture size 262144 bytes
19:31:46.650426 IP 16.0.0.1.1024 > 48.0.0.1.http: Flags [S], seq 404375002, win 32768, options [mss 1460], length 0
19:31:46.650439 IP 16.0.0.1.17 > 48.0.0.1.80: sctp (1) [Bad chunk length 0]
19:31:46.650442 IP 48.0.0.1.17 > 16.0.0.1.80: sctp (1) [Bad chunk length 0]
19:31:46.650445 IP 16.0.0.1.17 > 48.0.0.1.80: sctp (1) [Bad chunk length 0]
19:31:46.652458 IP 48.0.0.1.17 > 16.0.0.1.80: sctp (1) [Bad chunk length 0]
19:31:46.652462 IP 16.0.0.1.17 > 48.0.0.1.80: sctp (1) [Bad chunk length 0]
19:31:46.652465 IP 48.0.0.1.17 > 16.0.0.1.80: sctp (1) [Bad chunk length 0]
19:31:47.152768 IP 16.0.0.1.17 > 48.0.0.1.80: sctp (1) [Bad chunk length 0]
19:31:47.152788 IP 48.0.0.1.17 > 16.0.0.1.80: sctp (1) [Bad chunk length 0]
19:31:47.153796 IP 16.0.0.1.17 > 48.0.0.1.80: sctp (1) [Bad chunk length 0]
19:31:47.153801 IP 48.0.0.1.17 > 16.0.0.1.80: sctp (1) [Bad chunk length 0]
19:31:47.154803 IP 48.0.0.2.http > 16.0.0.2.1024: Flags [P.], seq 404419110:404420570, ack 404375252, win 32768, length 1460
19:31:47.154823 IP 48.0.0.2.http > 16.0.0.2.1024: Flags [P.], seq 1460:2920, ack 1, win 32768, length 1460
----

[NOTE]
See http://trex-tgn.cisco.com/trex/doc/trex_book.pdf[TRex full manual] for a complete understading of the tool features and options.

=== Updating TRex

See http://trex-tgn.cisco.com/trex/doc/trex_manual.html#_obtaining_the_trex_package[Related manual] section

=== TRex Live monitoring

Once we have TRex up and running, we can enjoy the benefit of having live monitoring on its performance, using TRexViewer application footnote:[Supported only on Windows OS]



This can be easily done by following these steps:
  0. Download the latest version of TrexViewer application and install it using http://trex-tgn.cisco.com/trex/client_gui/setup.exe[this link].

  1. Start the application and fill in the following: + 
    - Trex ip: `127.0.0.1:4500`

  2. Click the play button.

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  3. **That's it!** +
     Now the live data from TRex will be displayed on the screen.

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[NOTE]
Make sure TRex is running, otherwise data will not be available at TRexViewer.

=== Architecture and network design

Since no hardware is used, TRex simulates traffic using a virtual internal network, named 'trex_intnet'.

The following figure describes the virtual "wiring" of the virtual machine to support TRex traffic simulation.

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The VM runs TRex with single client and single server port. The traffic generated by each of those ports are switched over the 'trex_intnet' virtual network and received by the other side.

TRex identifies only the packets which were dedicately sent by one of those traffic ports and receives them in the other port. Hence, packets generated by client port will be received by the server port and vice versa.

Ontop, network adapter #4 used to [underline]#listen# to all traffic generated by both of TRex's ports, therefore it is very useful in providing live data of the generated flows over the network.
