# &adminguide;

## Overview

The Least Cost Routing (LCR) module implements capability to serially forward a request to one or more gateways so that the order in which the gateways is tried is based on admin defined "least cost" rules.

The LCR module supports many independent LCR instances (gateways and least cost rules). Each such instance has its own LCR instance identifier. Identifiers of normal LCR instances are positive integers. Gateways may belong to special LCR instance with identifier 0 meaning that such gateways belong to all normal LCR instances.

For the purpose of facilitating least cost routing of requests, each gateway of an LCR instance is associated with one or more <prefix, from uri pattern, from uri userpart, request uri pattern, priority, weight> tuples. A gateway matches a request if user part of Request-URI matches "prefix", caller URI matches "from_uri" pattern, caller URI userpart matches mtree with "mt_value", and callee URI matches "request_uri" pattern in a tuple that is associated with the gateway.

When the function load_gws() is called, matching gateways (that are not currently designated as defunct) are ordered for forwarding purposes as follows:

1. according to longest Request-URI user part match

2. according to tuple's priority

3. according to tuple's randomized weight

or, if priority_ordering parameter is set to value 1, as follows:

1. according to tuple's priority

2. according to tuple's randomized weight

A tuple can be marked as a "stopper" tuple. If a "stopper" tuple matches, then matching stops at it and all other tuples with shorter prefixes are not considered.

Prefix is a string of characters or NULL. From-URI pattern and Request-URI pattern are regular expressions (see 'man pcresyntax' for syntax), an empty string, or NULL. An empty or NULL From-URI pattern, Request-URI pattern or prefix matches anything. Smaller priority value means higher priority (highest priority value being 0 and lowest being 255).

Weight is an integer value from 1 to 254. Weight implementation is fast, but unfair favoring larger weight values at the expense smaller ones. For example, if two gateways have weights 1 and 2, probability that the gateway with weight 1 is tried first is 1/4, not 1/3. Two scripts are provided in lcr/utils directory that can be used to check the probabilities resulting from a given set of weight values. Same can be done with command 'kamctl eval_weights'.

The function next_gw() can then be used to select one gateway at a time for forwarding. Upon each call, unless "dont_strip_or_prefix_flag" flag is set, user part of the original Request-URI is first stripped by the number of characters as specified by the gateway's strip count and then prefixed by the gateway's prefix. Upon each call, if a gateway's hostname is NULL, Request-URI will be rewritten based on gateway's URI scheme, IP address, port, parameters, and transport protocol. If hostname is not NULL and IP address is NULL, Request-URI will be rewritten based on the gateway's URI scheme, hostname, port, parameters and transport protocol. If both hostname and IP address are not NULL, Request-URI will be rewritten based on gateway's URI scheme, hostname, and parameters, and destination URI is set based on gateway's URI scheme, IP address, port, and transport protocol.

Valid URI scheme values are NULL = sip, 1 = sip and 2 = sips. Currently valid transport protocol values are NULL and 0 = none, 1 = udp, 2 = tcp, 3 = tls, and 4 = sctp.

As a side effect of gateway selection, selected gateway's tag and flags (that may contain information about the gateway and its capabilities) are stored to tag_avp and flags_avp, respectively, if the corresponding module parameter has been defined. In the same way, rule_id_avp, if defined, contains the id of the rule that selected the gateway.

## Dependencies

### &kamailio; Modules

The following modules must be loaded before this module:

- A database module like mysql, postgres or dbtext.

- mtree module if mt_pv_values parameter is set.

### External libraries or applications

The following libraries or applications must be installed before running &siprouter; with this module:

- libpcre

## Parameters

### `db_url` (string)

&url; of the database table to be used.

Default value is &defaultrodb;.

#### Setting `db_url` module parameter

    ...
    modparam("lcr","db_url","&exampledb;")
    ...

### `lcr_gw_table` (string)

Name of the table holding gateways definitions.

Default value is lcr_gw.

#### Setting `lcr_gw_table` module parameter

    ...
    modparam("lcr", "lcr_gw_table","gw")
    ...

### `id_column` (string)

Name of the auto-increment, primary key column. Common to all lcr module tables.

Default value is id.

#### Setting `id_column` module parameter

    ...
    modparam("lcr", "id_column", "row_id")
    ...

### `lcr_id_column` (string)

Name of the column holding the identifier of an LCR instance. Common to all lcr module tables. In lcr_rule and lcr_rule_target tables, value of the column is integer from 1 to lcr_count. In lcr_gw table, value of the column is from 0 to lcr_count.

Default value is lcr_id.

#### Setting `lcr_id_column` module parameter

    ...
    modparam("lcr", "lcr_id_column", "lcr_identifier")
    ...

### `gw_name_column` (string)

Name of the column holding gateway's name for documentation purpose.

Default value is gw_name.

#### Setting `gw_name_column` module parameter

    ...
    modparam("lcr", "gw_name_column", "name")
    ...

### `ip_addr_column` (string)

Name of the column holding the IPv4 or IPv6 address of the gateway.

Default value is ip_addr.

#### Setting `ip_addr_column` module parameter

    ...
    modparam("lcr", "ip_addr_column", "ip")
    ...

### `hostname_column` (string)

Name of the column holding gateway's hostname that is used in Request-URI hostpart, when request is sent to the gateway.

Default value is hostname.

#### Setting `hostname_column` module parameter

    ...
    modparam("lcr", "hostname_column", "host")
    ...

### `port_column` (string)

Name of the column holding the port number of the gateway.

Default value is port.

#### Setting `port_column` module parameter

    ...
    modparam("lcr", "port_column", "port")
    ...

### `params_column` (string)

Name of the column holding gateway's parameters that is used in Request-URI, when request is sent to the gateway.

Default value is params.

#### Setting `params_column` module parameter

    ...
    modparam("lcr", "params_column", "parameters")
    ...

### `uri_scheme_column` (string)

Name of the column holding the uri scheme of the gateway.

Default value is uri_scheme.

#### Setting `uri_scheme_column` module parameter

    ...
    modparam("lcr", "uri_scheme_column", "uri_scheme")
    ...

### `transport_column` (string)

Name of the column holding the transport protocol to be used for the gateway.

Default value is transport.

#### Setting `transport_column` module parameter

    ...
    modparam("lcr", "transport_column", "trans")
    ...

### `strip_column` (string)

Name of the column holding the number of characters to be stripped from the front of Request-URI user part before inserting tag.

Default value is strip.

#### Setting `strip_column` module parameter

    ...
    modparam("lcr", "strip_column", "strip_count")
    ...

### `tag_column` (string)

Name of the column holding gateway specific tag string that is added to Request URI userpart after stripping.

Default value is tag.

#### Setting `tag_column` module parameter

    ...
    modparam("lcr", "tag_column", "gw_tag")
    ...

### `flags_column` (string)

Name of the column holding gateway specific flag values.

Default value is flags.

#### Setting `flags_column` module parameter

    ...
    modparam("lcr", "flags_column", "gw_flags")
    ...

### `defunct_column` (string)

Name of the column holding UNIX timestamp telling the time until which the gw is considered as defunct. If timestamp value is 4294967295 (= max UNIX timestamp value) or greater, gw is considered currently unused and is not loaded into memory at all.

Default value is defunct.

#### Setting `defunct_column` module parameter

    ...
    modparam("lcr", "defunct_column", "defunct_until")
    ...

### `lcr_rule_table` (string)

Name of the table holding the LCR rules.

Default value is lcr_rule.

#### Setting `lcr_rule_table` module parameter

    ...
    modparam("lcr", "lcr_rule_table", "rules")
    ...

### `prefix_column` (string)

Name of the column in lcr_rule and lcr_gw tables holding prefix of Request-URI user part and prefix of gateway, respectively.

Default value is prefix.

#### Setting `prefix_column` module parameter

    ...
    modparam("lcr", "prefix_column", "number_prefix")
    ...

### `from_uri_column` (string)

Name of the column holding the From (caller's) URI.

Default value is from_uri.

#### Setting `from_uri_column` module parameter

    ...
    modparam("lcr", "from_uri_column", "caller_uri")
    ...

### `mt_tvalue_column` (string)

Name of the column holding mtree tvalue.

Default value is mt_tvalue.

#### Setting `from_uri_column` module parameter

    ...
    modparam("lcr", "mt_tvalue_column", "tree_value")
    ...

### `request_uri_column` (string)

Name of the column holding the regular expression to match against the complete request URI (including the "sip:" prefix).

Default value is request_uri.

#### Setting `request_uri_column` module parameter

    ...
    modparam("lcr", "request_uri_column", "callee_uri")
    ...

### `stopper_column` (string)

Name of the column holding rule's stopper attribute.

Default value is stopper.

#### Setting `stopper_column` module parameter

    ...
    modparam("lcr", "stopper_column", "stop")
    ...

### `enabled_column` (string)

Name of the column telling is the rule is currently enabled or disabled.

Default value is enabled.

#### Setting `enabled_column` module parameter

    ...
    modparam("lcr", "enabled_column", "in_use")
    ...

### `lcr_rule_target_table` (string)

Name of the table holding information about the LCR rule targets (gateways).

Default value is lcr_rule_target.

#### Setting `lcr_rule_target_table` module parameter

    ...
    modparam("lcr", "lcr_rule_target_table", "rules")
    ...

### `rule_id_column` (string)

Name of lcr_rule_target_table column containing an id of lcr_rule table.

Default value is rule_id.

#### Setting `rule_id_column` module parameter

    ...
    modparam("lcr", "rule_id_column", "rule")
    ...

### `gw_id_column` (string)

Name of lcr_rule_target_table column containing an id of lcr_gw table.

Default value is gw_id.

#### Setting `gw_id_column` module parameter

    ...
    modparam("lcr", "gw_id_column", "gw")
    ...

### `priority_column` (string)

Name of the column holding the priority of the rule target.

Default value is priority.

#### Setting `priority_column` module parameter

    ...
    modparam("lcr", "priority_column", "priority")
    ...

### `weight_column` (string)

Name of the column holding weight of rule target.

Default value is weight.

#### Setting `weight_column` module parameter

    ...
    modparam("lcr","weight_column", "target_weight")
    ...

### `lcr_count` (integer)

Maximum value of lcr_id.

Default value is 1.

#### Setting `lcr_count` module parameter

    ...
    modparam("lcr", "lcr_count", 10)
    ...

### `gw_uri_avp` (AVP string)

Internal AVP that load_gws() function uses to store information of matching gateways.

There is NO default value, thus this variable must be defined in &siprouterconfig;.

#### Setting `gw_uri_avp` module parameter

    ...
    modparam("lcr", "gw_uri_avp", "$avp(lcr_gwuri)")
    ...

### `ruri_user_avp` (AVP string)

Internal AVP that next_gw function uses to store Request-URI user for subsequent next_gw calls.

There is NO default value, thus this variable must be defined in &siprouterconfig;.

#### Setting `ruri_user_avp` module parameter

    ...
    modparam("lcr", "ruri_user_avp", "$avp(lcr_ruri_user)")
    ...

### `tag_avp` (AVP string)

If defined, an AVP where successful next_gw and from_gw functions store gateway's tag.

There is NO default value, i.e, if not defined, gateway's tag is not stored anywhere.

#### Setting `tag_avp` module parameter

    ...
    modparam("lcr", "tag_avp", "$avp(lcr_tag)")
    ...

### `flags_avp` (AVP string)

If defined, an AVP where successful next_gw and from_gw functions store gateway's flags.

There is NO default value, i.e, if not defined, gateway's flags are not stored anywhere.

#### Setting `flags_avp` module parameter

    ...
    modparam("lcr", "flags_avp", "$avp(lcr_flags)")
    ...

### `rule_id_avp` (AVP string)

If defined, an AVP where successful next_gw and from_gw functions store matching rule's id.

There is NO default value, i.e, if not defined, matching rule's id is not stored anywhere.

#### Setting `rule_id_avp` module parameter

    ...
    modparam("lcr", "rule_id_avp", "$avp(lcr_ruleid)")
    ...

### `mt_pv_values` (AVP string)

If defined and mt_value is given for a rule, load_gws() matches caller URI userpart to a mtree given as mtree parameter.

If defined, must have the same value as mtree module pv_values parameter.

There is NO default value.

#### Setting `tag_avp` module parameter

    ...
    modparam("lcr", "mt_pv_values", "$avp(lcr_mt_values)")
    ...

### `mtree` (string)

Name of mtree to which load_gws() matches caller URI userpart.

Default value is "lcr".

#### Setting `mtree` module parameter

    ...
    modparam("lcr", "mtree", "caller_tree")
    ...

### `defunct_capability` (integer)

Tells if defunct capability of (non-responsive) gateways is supported. Non-zero value turns on defunct capability.

Default value is 0.

#### Setting `defunct_capability` module parameter

    ...
    modparam("lcr", "defunct_capability", 1)
    ...

### `lcr_id_avp` (AVP string)

Internal AVP that load_gws() function uses to store LCR instance identifier of loaded gateways. Only needed if gateway defunct capability has been activated.

There is NO default value.

#### Setting `lcr_id_avp` module parameter

    ...
    modparam("lcr", "lcr_id_avp", "$avp(lcr_id)")
    ...

### `defunct_gw_avp` (AVP string)

Internal AVP that next_gw() function uses to store internal index of the selected gateway for later use by defunct_gw() function. Only needed if gateway defunct capability has been activated.

There is NO default value.

#### Setting `defunct_gw_avp` module parameter

    ...
    modparam("lcr", "defunct_gw_avp", "$avp(lcr_defunct_gw)")
    ...

### `lcr_rule_hash_size` (integer)

Defines the size of hash table used to store LCR rules. Hashing is done based on rule's prefix. Larger value means less collisions with other prefixes. Hash size value should be a power of 2.

Default value is 128.

#### Setting `lcr_rule_hash_size` module parameter

    ...
    modparam("lcr", "lcr_rule_hash_size", 1024)
    ...

### `lcr_gw_count` (integer)

Defines the maximum number of gateways in lcr_gw table.

Default value is 128.

#### Setting `lcr_gw_count` module parameter

    ...
    modparam("lcr", "lcr_gw_count", 1024)
    ...

### `dont_strip_or_prefix_flag` (integer)

Defines the flag number used to tell if stripping and tagging is done for the selected gateway.

Default value is -1 meaning that the flag is not defined.

#### Setting `dont_strip_or_prefix_flag` module parameter

    ...
    modparam("lcr", "dont_strip_or_prefix_flag", 10)
    ...

### `priority_ordering` (integer)

Defines how matching gateways are ordered (see Overview section).

Default value is 0.

#### Setting `priority_ordering` module parameter

    ...
    modparam("lcr", "priority_ordering", 1)
    ...

### `fetch_rows` (integer)

The number of the rows to be fetched at once from database when loading data from lcr_rule table. This value can be used to tune the load time at startup. For 1MB of private memory (default) it should be below 3750. In order for this parameter to have effect, the database driver must support fetch_result() capability.

Default value is 1024.

#### Set `fetch_rows` parameter

    ...
    modparam("lcr", "fetch_rows", 3000)
    ...

### `ping_interval` (integer)

Interval in seconds for sending OPTIONS ping requests to gateways that, due to failures, have been marked as inactive by inactivate_gw() function call. If an inactive gateway later gives a valid response (see `ping_valid_reply_codes`) to a ping request, it is marked again as active.

If value of this parameter is greater than zero, tm module must have been loaded and parameters `lcr_id_avp` and `defunct_gw_avp` must have been defined. Value 0 disables sending of OPTIONS ping requests to failed gateways.

Default value is 0.

#### Set `ping_interval` parameter

    ...
    modparam("lcr", "ping_interval", 15)
    ...

### `ping_inactivate_threshold` (integer)

Tells after how many failures (= inactivate_gw() function calls) a gateway is marked as inactive.

Default value is 1, i.e., gateway is inactivated after first failure.

#### Set `ping_inactivate_threshold` parameter

    ...
    modparam("lcr", "ping_inactivate_threshold", 3)
    ...

### `ping_valid_reply_codes` (string)

A comma separated list of SIP reply codes, which are accepted as valid replies to OPTIONS ping requests. Reply codes 2xx are by default accepted as valid replies and they don't need to be listed here.

Default value is , i.e., only 2xx replies are considered as valid replies.

#### Set `ping_valid_reply_codes` parameter

    ...
    modparam("lcr", "ping_valid_reply_codes", "403,405,501")
    ...

### `ping_from` (string)

From URI used in OPTIONS ping requests.

Default value is sip:pinger@localhost.

#### Set `ping_from` parameter

    ...
    modparam("lcr", "ping_from", "sip:proxy.operator.com")
    ...

### `ping_socket` (string)

Socket to be used for sending OPTIONS ping request. If not set or set to , default socket is used.

Default value is .

#### Set `ping_socket` parameter

    ...
    modparam("lcr", "ping_socket", "192.98.102.10:5060")
    ...

## Functions

### `load_gws(lcr_id[, uri_user[, caller_uri]])`

Loads attributes of matching gateways to gw_uri_avp (see Overview section). Argument lcr_id specifies the used LCR instance. It can be a positive integer or a pseudo variable containing an integer value. If uri_user is given, it is used, instead of Request-URI user part, to look for matching gateways. Caller's URI may be given by caller_uri argument. If caller_uri argument is omitted, it defaults to empty string. Both uri_user and caller_uri argument may be a string or a pseudo variable containing a string value.

Returns 1 if at least one matching gateway was found, 2 if no matching gateways was found, and -1 on error.

Execution time of load_gws() function is O(N) * O(M), where N is number of different prefix lengths and M is number of collisions for matching prefix(es) in lcr rules hash table of the LCR instance.

This function can be used from REQUEST_ROUTE.

#### `load_gws` usage

    ...
    if (!load_gws(1, $rU, $var(caller_uri))) {
    	sl_send_reply("500", "Server Internal Error - Cannot load gateways");
    	exit;
    };
    ...

### `next_gw()`

Upon first call, fetches attribute values stored in first gw_uri_avp, destroys that AVP, and rewrites Request-URI and possibly also destination URI as described in the Overview section. Saves user part of Request-URI into ruri_user_avp for use in subsequent next_gw() calls.

Upon subsequent calls, does the same as in above, but takes user part of Request-URI from ruri_user_avp.

As a side effect, stores gateway's tag and flags to tag_avp and flags_avp, respectively, if the corresponding module parameter has been defined. In the same way, rule_id_avp, if defined, contains the id of the rule that selected the gateway.

Returns 1 on success and -1 if there were no gateways left or if an error occurred (see syslog).

Must be preceded by successful load_gws() call.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `next_gw` usage from a route block

    ...
    if (!next_gw()) {
    	sl_send_reply("503", "Service not available - No gateways");
    	exit;
    };
    ...

#### `next_gw` usage from a failure route block

    ...
    if (!next_gw()) {
    	t_reply("503", "Service not available - No more gateways");
    	exit;
    };
    ...

### `inactivate_gw()`

Inactivates the gateway denoted by lcr_id_avp and defunct_gw_avp (which were set by previous next_gw() call). Use of this function requires that `ping_interval` module parameter has been set to a positive value allowing an inactivated gateway to be automatically activated by a positive response to OPTIONS ping request.

Returns 1 on success and -1 in case of error (see syslog).

This function can be used from REQUEST_ROUTE and FAILURE_ROUTE.

#### `inactivate_gw` usage

    ...
    failure_route [GW_FAILURE] {
    ...
        if (t_check_status("408|503")) {
            inactivate_gw();
        };
    ...

### `defunct_gw(period)`

Defuncts gateway denoted by lcr_id_avp and defunct_gw_avp (which were set by previuos next_gw() call) for a period of seconds given as argument. Argument must be a positive integer constant or a pseudo variable with positive integer value. Value of defunct column in database is not updated.

Returns 1 on success and -1 in case of error (see syslog).

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `defunct_gw` usage

    ...
    defunct_gw(60);
    ...

### `from_gw(lcr_id[, ip_addr, proto[, src_port]])`

Checks if request comes from IP address, transport protocol and source port specified for a gateway in LCR instance lcr_id. Fails if the LCR instance includes one or more gateways without IP address. IP address, transport protocol and source port to be checked are either taken from source IP address and port of the request or (if present) from ip_addr, proto and src_port arguments.

lcr_id can be an integer constant or a pseudo variable holding an integer value. ip_addr can be a string or a pseudo variable holding a string value. proto can be an integer constant (0 = ANY, 1 = UDP, 2 = TCP, 3 = TLS, 4 = SCTP) or a pseudo variable holding such an integer value. src_port can be an integer or a pseudo variable holding such an integer value.

If request comes from a gateway, gateway's tag and flags are stored as a side effect to tag_avp and flags_avp, respectively, if the corresponding module parameter has been defined. In the same way, rule_id_avp, if defined, contains the id of the rule that selected the gateway.

Returns 1 on success and -1 on failure or on error.

Execution time of from_gw() function is O(log N), where N is number of gateways in the LCR instance.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, ONREPLY_ROUTE.

#### `from_gw` usage

    ...
    if (from_gw(1, $avp(real_source_addr), 2, 5060) {
    	...
    };
    ...

### `from_any_gw([ip_addr, proto[, src_port]])`

Checks if request comes from IP address, transport protocol and source port specified for any gateway. Only LCR instances, where all gateways have IP address, are included in the test. IP address, transport protocol and source port to be checked are either taken from source IP address, transport protocol and source port of the request or (if present) from ip_addr, proto and src_port arguments. See from_gw() function for more info about the arguments.

If any gateway has the IP address, transport protocol and source port, function returns LCR identifier of the gateway. Returns -1 on error or if the request does not come from a gateway.

If request comes from a gateway, gateway's tag and flags are stored as a side effect to tag_avp and flags_avp, respectively, if the corresponding module parameter has been defined. In the same way, rule_id_avp, if defined, contains the id of the rule that selected the gateway.

Execution time of from_gw() function is M * O(log N), where M is number of LCR instances and N is average number of gateways in LCR instances.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, ONREPLY_ROUTE.

#### `from_gw` usage

    ...
    $var(lcr_id) = from_any_gw("192.168.1.1", 3, 5061);
    ...

### `to_gw(lcr_id[, ip_addr, proto])`

Checks if in-dialog request goes to IP address and transport protocol specified for a gateway in LCR instance lcr_id. Fails if LCR instance includes one or more gateways without IP address. IP address and transport protocol to be checked are either taken from Request-URI or (if present) from ip_addr and proto arguments. See from_gw() for more info regarding the arguments.

Returns 1 on success and -1 on failure and error.

Execution time of to_gw() function is O(log N), where N is number of gateways in the LCR instance.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `to_gw` usage

    ...
    if (to_gw("1")) {
    	...
    	exit;
    };
    ...

### `to_any_gw([ip_addr, proto])`

Checks if in-dialog request goes to IP address and transport protocol of any gateway. Only LCR instances, where all gateways have IP address, are included in the test. IP address and transport protocol to be checked are either taken from Request-URI or (if present) from ip_addr and proto arguments. See from_gw() for more info regarding the arguments.

Execution time of to_any_gw() function is M * O(log N), where M is number of LCR instances and N is average number of gateways in LCR instances.

If any gateway has the IP address, returns LCR identifier of the gateway. Returns -1 if request does not go to a gateway and on error.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.

#### `to_gw` usage

    ...
    if (to_any_gw("192.55.66.2", 1)) {
    	...
    	exit;
    };
    ...

## RPC Commands

### `lcr.reload`

Causes lcr module to re-read the contents of LCR tables into memory.

Name: lcr.reload

Parameters: none

#### `lcr.reload` RPC example

    		$ &sercmd; lcr.reload

### `lcr.dump_gws`

Causes lcr module to dump the contents of its in-memory gw table.

Parameters: none

#### `lcr.dump_gws` RPC example

    		$ &sercmd; lcr.dump_gws

### `lcr.dump_rules`

Causes lcr module to dump the contents of its in-memory lcr_rule and lcr_rule_target tables. Rules can be filtered by lcr_id or lcr_id and prefix. The filters are passed as optional parameters.

Parameters:

- lcr_id filter rules based on lcr_id.

- prefix filter rules based on prefix (prefixes shorter or equal to the give prefix) in addition to the previous lcr_id parameter.

#### `lcr.dump_rules` RPC example

    		$ &sercmd; lcr.dump_rules

### `lcr.load_gws`

Loads gateways and prints ids of matching ones in priority order.

Name: lcr.load_gws

Parameters: lcr_id uri_user [caller_uri request_uri]

#### `lcr.load_gws` RPC example

    		$ &sercmd; lcr.load_gws 2 s:0447058050

### `lcr.defunct_gw`

Defuncts gateway loaded into memory for a period of time (seconds) without a need to store gateway's defunct value into database and reload the tables.

Name: lcr.defunct_gw

Parameters: lcr_id gw_id period

#### `lcr.defunct_gw` RPC example

    		$ &sercmd; lcr.defunct_gw 1 4 120

## Known Limitations

In-memory LCR rules and gw tables are switched by two consecutive machine instructions. If lcr reload process is interrupted after the first one, in-memory gateway table does not match in-memory rule table until execution of lcr reload process is resumed.