# 6.5. Setting options

## 6.5.1. Thinktimes, SSL, Buffers

Default values can be set-up globally: `thinktime` between requests in the scenario, SSL cipher algorithms (use ssl:cipher_suites(openssl). to get a list of available ciphers), TCP/UDP buffer sizes (the default value is 32KB). These values overrides those set in session configuration tags if override is true.

    <option name="thinktime" value="3" random="false" override="true"/>
    <option name="ssl_ciphers"
            value="EXP1024-RC4-SHA,EDH-RSA-DES-CBC3-SHA"/>
    <option name="tcp_snd_buffer" value="16384"></option>
    <option name="tcp_rcv_buffer" value="16384"></option>
    <option name="udp_snd_buffer" value="16384"></option>
    <option name="udp_rcv_buffer" value="16384"></option>

Added in version 1.6.0.

You can disable the SSL session cache (it is enabled by default)

    <option name="ssl_reuse_sessions" value="false"/>

You can specify which SSL protocol you want use. Use ssl:versions(). to get a list of available ssl protocols.

    <option name="ssl_versions" value="'tlsv1.2'"/>

You can also use the command line option `-L <value>` to change the session lifetime in the cache (10mn by default); value must be in seconds.

You can also change the way Tsung starts remote beams. By default, Tsung will start at most 20 ssh process per core of the controller. If you manage hundreds of clients, you may want to raise this value with `max_ssh_startup_per_core` (or decrease it if you wish)

    <option name="max_ssh_startup_per_core" value="100"/>

Added in version 1.8.0.

You can disable the Server Name Indication feature of TLS (it is enabled by default).

    <option name="ssl_disable_sni" value="true"/>

## 6.5.2. Timeout for TCP connections

Added in version 1.6.0.

You can specify a timeout in milliseconds for establishing a TCP connection. The default is `infinity`.

    <option name="connect_timeout" value="5000" />

You can also change the timeout on a per-session basis using `set_option`.

    <set_option name="connect_timeout" value="1000" />

You can also enable the TCP REUSEADDR option globally:

    <option name="tcp_reuseaddr" value="true" />

## 6.5.3. IP transparent

Added in version 1.7.0.

This option is used to set the IP_TRANSPARENT option on the TCP socket

    <option name="ip_transparent" value="true" />

This can be useful to use when IPs are not configured on the client host (see also iprange)

## 6.5.4. IP bind address no port

Added in version 1.8.0.

This option is used to set the IP_BIND_ADDRESS_NO_PORT option on the TCP socket

    <option name="ip_bind_address_no_port" value="true" />

The kernel will choose the local port at connect time instead of bind time, making it more scalable

## 6.5.5. Retry Attempts and Timeouts

Added in version 1.6.0.

You can specify the amount of retry attempts made by Tsung. The default is `3`.

    <option name="max_retries" value="5" />

To disable retries entirely, set the value to `0`.

In addition, the option `retry_timeout` (in milliseconds; defaults to `10`) is used to implement a simple back-off algorithm (`retry * retry_timeout`).

    <set_option name="retry_timeout" value="1000" />

## 6.5.6. Timeout for acknowledgments of messages

This is used to set the idle timeout(used for ‘parse’ and ‘local’ ack) and global ack timeout(used for ‘global’ ack). By default, idle timeout will be 10min(600000) and global ack timeout will be `infinity`. This value can be changed like this:

    <option name="idle_timeout" value="300000"></option>
    <option name="global_ack_timeout" value="6000000"></option>

## 6.5.7. Hibernate

Added in version 1.3.1.

The option `hibernate` is used to reduced memory consumption of simulated users during thinktimes. By default, hibernation will be activated for thinktimes higher than 10sec. This value can be changed like this:

    <option name="hibernate" value="5"></option>

To disable hibernation, you must set the value to `infinity`.

## 6.5.8. Rate_limit

Added in version 1.4.0.

`rate_limit`. This will limit the bandwidth of each client (using a token bucket algorithm). The value is in KBytes per second. You can also specify a maximum burst value (eg. `max='2048'`). By default the burst size is the same as the rate (1024KB in the following example). Currently, only incoming traffic is rate limited.

    <option name="rate_limit" value="1024"></option>

## 6.5.9. Ports_range

If you need to open more than 30000 simultaneous connections on a client machine, you will be limited by the number of TCP client ports, even if you use several IPs (this is true at least on Linux). To bypass this limit, Tsung must not delegate the selection of client ports and together with using several IP for each client, you have to defined a range for available clients ports, for ex:

    <option name="ports_range" min="1025" max="65535"/>

## 6.5.10. Setting the seed for random numbers

If you want to use a fixed seed for the random generator, you can use the `seed` option, like this (by default, Tsung will use the current time to set the seed, therefore random numbers should be different for every test).

    <option name="seed" value="42"/>

## 6.5.11. Path for BOSH

You can use the following config option for setting the path to BOSH request:

    <option name="bosh_path" value="/http-bind/"/>

## 6.5.12. Websocket options

When you use Websocket as a server type, you can set the following options for Websocket:

    <option name="websocket_path" value="/chat"/>

    <!-- send websocket data with text frame, default binary-->
    <option name="websocket_frame" value="text"/>
    <option name="websocket_subprotocols" value="chat, superchat"/>

Use `websocket_path` for setting the path of the websocket request; use `websocket_frame` for setting the frame type(option type: binary and text, and binary as default) of the sending websocket data. Use `websocket_subprotocols` for setting the `Sec-WebSocket-Protocol` header.

## 6.5.13. XMPP/Jabber options

Default values for specific protocols can be defined. Here is an example of option values for Jabber/XMPP:

    <option type="ts_jabber" name="global_number" value="5" />
    <option type="ts_jabber" name="userid_max" value="100" />
    <option type="ts_jabber" name="domain" value="jabber.org" />
    <option type="ts_jabber" name="username" value="myuser" />
    <option type="ts_jabber" name="passwd" value="mypasswd" />
    <option type="ts_jabber" name="muc_service" value="conference.localhost"/>

Using these values, users will be `myuserXXX` where XXX is an integer in the interval [1:userid_max] and passwd `mypasswdXXX`

If not set in the configuration file, the values will be set to:

- global_number = 100

- userid_max = 10000

- domain = erlang-projects.org

- username = tsunguser

- passwd = sesame

Other options are available if you prefer to use a CSV file for username/password, see Reading usernames and password from a CSV file.

You can also set the `muc_service` here (see previous example).

## 6.5.14. HTTP options

For HTTP, you can set the `UserAgent` values (available since Tsung 1.1.0), using a probability for each value (the sum of all probabilities must be equal to 100)

    <option type="ts_http" name="user_agent">
      <user_agent probability="80">
         Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.8) Gecko/20050513 Galeon/1.3.21
      </user_agent>
      <user_agent probability="20">
        Mozilla/5.0 (Windows; U; Windows NT 5.2; fr-FR; rv:1.7.8) Gecko/20050511 Firefox/1.0.4
      </user_agent>
    </option>

## 6.5.15. AMQP options

You can set the AMQP heartbeat timeout; for example to set it to 30s (default is 600s), add:

    <option type="ts_amqp" name="heartbeat" value="30" />