Copyright © 2005-2008 Voice Sistem SRL
Copyright © 2009-2012 www.opensips-solutions.com
| Revision History | |
|---|---|
| Revision $Revision: 8834 $ | $Date: 2012-03-22 19:43:49 +0100 (Thu, 22 Mar 2012) $ |
Table of Contents
db_url(str)drd_table(str)drr_table(str)drg_table(str)drc_table(str)ruri_avp (str)gw_id_avp (str)gw_attrs_avp (str)rule_id_avp (str)rule_attrs_avp (str)rule_prefix_avp (str)carrier_id_avp (str)carrier_attrs_avp (str)define_blacklist (str)default_group (int)force_dns (int)probing_interval (integer)probing_method (string)probing_from (string)probing_reply_codes (string)use_domain (int)drg_user_col (str)drg_domain_col (str)drg_grpid_col (str)List of Examples
db_url parameterdrd_table parameterdrr_table parameterdrg_table parameterdrc_table parameterruri_avp parametergw_id_avp parametergw_attrs_avp parameterrule_id_avp parameterrule_attrs_avp parameterrule_prefix_avp parametercarrier_id_avp parametercarrier_attrs_avp parameterdefine_blacklist parameterdefault_group parameterforce_dns parameterprobing_interval parameterprobing_method parameterprobing_from parameterprobing_reply_codes parameteruse_domain parameterdrg_user_col parameterdrg_domain_col parameterdrg_grpid_col parameterdo_routing usageroute_to_carrier usageroute_to_gw usageuse_next_gw usagegoes_to_gw usageis_from_gw usagedr_disable() usagedr_gw_status usagedr_carrier_status usageDynamic Routing is a module for selecting (based on multiple criteria) the best gateway/destination to be used for delivering a certain call. Least Cost Routing (LCR) is a special case of dynamic routing - when the rules are ordered based on costs. Dynamic Routing comes with many features regarding routing rule selection:
prefix based
caller/group based
time based
priority based
, processing :
stripping and prefixing
default rules
inbound and outbound processing
script route triggering
and failure handling:
serial forking
weight based GW selection
random GW selection
GW probing for crashes
The dynamic routing implementation for OpenSIPS is designed with the following properties:
routing info (destinations, carriers, rules, groups) are stored in a database and loaded into memory at start up time; reload at runtime via an Management Interface command.
weigth-based or random selection of the destinations (from a rule or from a carrier), failure detection of gateways (with switching to next available gateway).
able to handle large volume of routing info (10M of rules) with minimal speed/time and memory consumption penalties
script integration - Pseudo variables support in functions; scripting route triggering when rules are matched
bidirectional behavior - inbound and outbound processing (strip and prefixing when sending and receiving from a destination/GW)
blacklisting - the module allows definition of backlists based on the destination IPs. This blacklists are to be used to prevent malicious forwarding to GWs (based on DNS lookups) when the script logic does none-GE forwarding (like foreign domains).
There were several tests performed regarding the performance of the module when dealing with a large number of routing rules.
The tests were performed with a set of 383000 rules and to values were measured:
time to load from DB
used shared memory
The time to load was varying between 4 seconds and 8 seconds, depending of the caching of the DB client - the first load was the slowest (as the DB query hits the disk drive); the following are faster as data is already cached in the DB client. So technically speaking, the time to load (without the time to query which is DB type dependent) is ~4 seconds
After loading the data into shared memory ~ 96M of memory were used exclusively for the DR data.
DR engine uses several concepts in order to define how the routing should be done (describing all the dependecies between destinations and routing rules).
These are the end SIP entities where actually the traffic needs to be sent after routing. They are stored in a table called “dr_gateways”. Gateway addresses are stored in a separate table because of need to access them independent of Dynamic Routing processing (e.g., adding/ removing gateway PRI prefix before/after performing other operation -- receiving/relaying to gateway).
In DR, a gateway is defined by:
id (string)
SIP address (SIP URI)
type (number to allow to group GW based on purpose, like inbound, outbound, etc)
prefix (string) to be added to dialled number
attributes (not used by DR engine, but only pushed to script level when routing to this GW)
probing mode (how the GW should be probed at SIP level - see the probing chapter)
The Gateways are to be used from the routing rule or from the carrier definition. They are all the time referred by their ID.
The carrier concept is used if you need to group gateways in order to have a better control on how the GWs will be used by DR rules; like in what order the GWs will be used.
Basically, a carrier is a set of gateways which have its own sorting algorithm and its own attribute string. They are by default defined in the “dr_carriers” table.
In DR, a carrier is defined by:
id (string)
list of gateways with/without weights (string) (Ex:“gw1=10,gw4=10” or “gw1,gw2”
flags : 0x1 - use weight for sorting the list and not definition order; 0x2 - use only the first gateway from the carrier (depending on the sorting); 0x4 - disable the usage of this carrier
attributes (not used by DR engine, but only pushed to script level when routing to this carrier)
The Carriers are to be used only from the routing rule definition. They are all the time referred by their ID.
These are the actual rule which control the routing - like based on different criterias (prefix, time, priority, etc) they will decide to which gateways the call will be sent.
Default name for the table storing rule definitions is “dr_rules”.
In DR, a carrier is defined by:
group (list of numbers) - rules can be grouped (a rule may belong to multiple groups in the same time ) and you can use only a certian group at a point; like having a “premium” or “standard” or “interstate” or “intrastate” groups of rules to be used in different cases
prefix (string with digits only) - prefix to be used for matching this rule (longest prefix matching)
time validity (time recurrence string) - when this rule is valid from time point of view (see RFC 2445)
priority (number) - prority off the rule - higher value, higher priority (see rule section alg)
script route ID (string) - if defined, then execute the route with the specified ID when this rule is matched. That's it, a route which can be used to perform custom operations on message. NOTE that no modification is performed at signaling level and you must NOT do any signalling operations in that script route
list of GWs/carriers (string) - a comma separated list of gateways or carriers (defined by IDs) to be used for this rule; the carrier IDs are prefixed with “#” sign. For each ID (GW or carrier) you may specify a weight. For how this list will be interpreted (as order) see the rule selection section. Example of list: “gw1,gw4,#cr3” or “gw1=10,gw4=10,#cr3=80”
attributes (not used by DR engine, but only pushed to script level when this rule matched and been used)
More on time recurrence:
A date-time expression that defines the time recurrence to match for current rule. Time recurrences are based closely on the specification of recurring intervals of time in the Internet Calendaring and Scheduling Core Object Specification (calendar COS), RFC 2445. The set of attributes used in routing rule specification is subset of time recurrence attributes.
The value stored in database has the format of: <dtstart>|<duration>|<freq>|<until>|<interval>|<byday>|<bymonthday>|<byyearday>|<byweekno>|<bymonth>
When an attribute is not specified, the corresponding place must be left empty, whenever another attribute that follows in the list has to be specified.
The module can be used to find out which is the best gateway to use for new calls terminated to PSTN. The algorithm to select the rule is as follows:
the module discovers the routing group of the originating user. This step is skipped if a routing group is passed from the script as parameter.
once the group is known, in the subset of the rules for this group the module looks for the one that matches the destination based on "prefix" column. The set of rules with the longest prefix is chosen. If no digit from the prefix matches, the default rules are used (rules with no prefix)
within the set of rules is applied the time criteria, and the rule which has the highest priority and matches the time criteria is selected to drive the routing.
Once found the rule, it may contain a route ID to execute. If a certain flag is set, then the processing is stopped after executing the route block.
The rule must contain a chain of gateways and carriers. The module will execute serial forking for each address in chain (in which order the destinations will be tried, depends on the defintion order or depends on the weights (weights selection must be enabled). The next address in chain is used only if the previously has failed.
With the right gateway address found, the prefix (PRI) of the gateway is added to the request URI and then the request is forwarded.
If no rule is found to match the selection criteria an default action must be taken (e.g., error response sent back). If the gateway in the chain has no prefix the request is forwarded without adding any prefix to the request URI.
The module has the capability to monitor the status of the destinations by doing SIP probing (sending SIP requests like OPTIONS).
For each destination, you can configure what kind of probing should be done (probe_mode column):
(0) - no probing at all;
(1) - probing only when the destination is in disabled mode (disabling via MI command will competely stop the probing also). The destination will be automatically re-enabled when the probing will succeed next time;
(2) - probing all the time. If disabled, the destination will be automatically re-enabled when the probing will succeed next time;
A destination can become disabled in two ways:
The following modules must be loaded before this module:
a database module.
tm module.
The database url.
Default value is “NULL”.
Example 1.1. Set db_url parameter
...
modparam("drouting", "db_url",
"mysql://opensips:opensipsrw@localhost/opensips")
...
The name of the db table storing gateway addresses.
Default value is “dr_gateways”.
The name of the db table storing routing rules.
Default value is “dr_rules”.
The name of the db table storing groups.
Default value is “dr_groups”.
The name of the db table storing definitions of the carriers that will be used directly by the routing rules.
Default value is “dr_carriers”.
The name of the avp for storing Request URIs to be later used (alternative destiantions for the current one).
Default value is “$avp(0xad346b2f)”.
Example 1.6. Set ruri_avp parameter
...
modparam("drouting", "ruri_avp", '$avp(dr_ruri)')
modparam("drouting", "ruri_avp", '$avp(33)')
...
The name of the avp for storing the id of the current selected gateway/destination - once a new destination is selected (via the use_next_gw() function), the AVP will be updated with the ID of the new selected gateway/destination.
Default value is “$avp(0xad346b30)”.
Example 1.7. Set gw_id_avp parameter
...
modparam("drouting", "gw_id_avp", '$avp(gw_id)')
modparam("drouting", "gw_id_avp", '$avp(334)')
...
The name of the avp for storing the attributes of the current selected destination/gateway - once a new destination is selected (via the use_next_gw() function), the AVP will be updated with the attrs of the new used destination.
Default value is “NULL”.
Example 1.8. Set gw_attrs_avp parameter
...
modparam("drouting", "gw_attrs_avp", '$avp(gw_attrs)')
modparam("drouting", "gw_attrs_avp", '$avp(67)')
...
The name of the avp for storing the id of the current matched routing rule (see dr_rules table).
Default value is “NULL”.
Example 1.9. Set rule_id_avp parameter
...
modparam("drouting", "rule_id_avp", '$avp(rule_id)')
modparam("drouting", "rule_id_avp", '$avp(335)')
...
The name of the avp for storing the attributes of the current matched routing rule (see dr_rules table).
Default value is “NULL”.
Example 1.10. Set rule_attrs_avp parameter
...
modparam("drouting", "rule_attrs_avp", '$avp(rule_attrs)')
modparam("drouting", "rule_attrs_avp", '$avp(66)')
...
The actual prefix that matched the routing rule (the part from RURI username that matched the routing rule).
Default value is “NULL”.
Example 1.11. Set rule_prefix_avp parameter
...
modparam("drouting", "rule_prefix_avp", '$avp(dr_prefix)')
...
AVP to be populate with the ID string for the carrier the current GW belongs to.
Default value is “NULL”.
Example 1.12. Set carrier_id_avp parameter
...
modparam("drouting", "carrier_id_avp", '$avp(carrier_id)')
...
AVP to be populate with the attributes string for the carrier the current GW belongs to.
Default value is “NULL”.
Example 1.13. Set carrier_attrs_avp parameter
...
modparam("drouting", "carrier_attrs_avp", '$avp(carrier_attrs)')
...
Defines a backlist based on a list of GW types - the list will contain the IPs (no port, all protocols) of the GWs with the specified types.
Multiple instances of this param are allowed.
Default value is “NULL”.
Example 1.14. Set define_blacklist parameter
...
modparam("drouting", "define_blacklist", 'bl_name= 3,5,25,23')
modparam("drouting", "define_blacklist", 'list= 4,2')
...
Group to be used if the caller (FROM user) is not found in the GROUP table.
Default value is “NONE”.
Force DNS resolving of GW/destination names (if not IPs) during startup. If not enabled, the GW name will be blindly used during routing.
Default value is “1 (enabled)”.
How often (in seconds) the probing of a destination should be done. If set to 0, the probing will be disabled as functionality (for all destinations)
Default value is “30”.
The SIP method to be used for the probing requests.
Default value is “"OPTIONS"”.
The FROM SIP URI to be advertised in the SIP probing requests.
Default value is “"sip:prober@localhost"”.
Example 1.19. Set probing_from parameter
...
modparam("drouting", "probing_from", "sip:pinger@192.168.2.10")
...
A comma separted list of SIP reply codes. The codes defined here will be considered as valid reply codes for probing messages, apart for 200.
Default value is “NULL”.
Example 1.20. Set probing_reply_codes parameter
...
modparam("drouting", "probing_reply_codes", "501, 403")
...
Flag to configure whether to use domain match when querying database for user's routing group.
Default value is “1”.
The name of the column in group db table where the username is stored.
Default value is “username”.
The name of the column in group db table where the domain is stored.
Default value is “domain”.
Function to trigger routing of the message according to the rules in the database table and the configured parameters.
This function can be used from REQUEST_ROUTE and FAILURE_ROUTE.
The function can take two optional parameters:
Example 1.25. do_routing usage
...
# all groups, sort on order
do_routing();
...
# group id 0, sort on order
do_routing("0");
...
# group id from $avp(10), sort on order
do_routing("$avp(10)");
...
# all groups, sort on weights
do_routing("","W");
...
# group id 2, sort on order, fallback rule
do_routing("2","F");
...
Function to trigger the direct routing to a given carrier. In this case the routing is not done prefix based, but carrier based (call will be sent to the GWs of that carrier, based on carrier policy)
This function can be used from REQUEST_ROUTE and FAILURE_ROUTE.
Function takes a single mandatory parameter, the ID of the carrier to be used (variables are accepted).
Example 1.26. route_to_carrier usage
...
if ( route_to_carrier("my_top_carrier") ) {
t_on_failure("next_gw");
t_relay();
exit;
}
...
Function to trigger the direct routing to a given gateway. Attributes and per-gw preocessing will be available.
This function can be used from REQUEST_ROUTE and FAILURE_ROUTE.
Function takes a single mandatory parameter, the ID of the gateway to be used (variables are accepted).
The function takes the next available destination (set by do_routing, as alternative destinations) and push it into RURI. Note that the function just sets the RURI (nothing more).
If a new RURI is set, the used destination is removed from the pending set of alternative destinations.
This function can be used from REQUEST_ROUTE and FAILURE_ROUTE.
The function returns true only if a new RURI was set. False is returned is no other alternative destinations are found or in case of internal processing error.
Function returns true if the destination of the current request (destination URI or Request URI) points (as IP) to one of the gateways. There no DNS lookups done if the domain part of the URI is not an IP.
This function does not change anything in the message.
This function can be used from REQUEST_ROUTE and FAILURE_ROUTE.
The function can take two optional parameters:
Example 1.29. goes_to_gw usage
...
if (goes_to_gw("1")) {
sl_send_reply("403","Forbidden");
exit;
}
...
The function checks if the sender of the message is a gateway from a certain group.
This function can be used from REQUEST_ROUTE and FAILURE_ROUTE.
The function can take two optional parameters:
Marks as disabled the last destination that was used for the current call. The disabling done via this function will prevent the destination to be used for usage from now on. The probing mechanism can re-enable this peer (see the probing section in the begining)
This function can be used from REQUEST_ROUTE and FAILURE_ROUTE.
Example 1.31. dr_disable() usage
...
if (t_check_status("(408)|(5[0-9][0-9])")) {
dr_disable();
}
...
Command to reload routing rules from database.
It takes no parameter.
MI FIFO Command Format:
:dr_reload:fifo_reply _empty_line_
Gets or sets the status (enabled or disabled) of a gateway. The function may take from 0 to 2 parameters. If none, it will list all gateways along with their status. If one parameter is provided, that must be the id of a gateway and the function will return the status of that gateway. If 2 parameters are provided, first must be the ID of the ID of a GW and the second must be the new status to be forced for that GW (0 - disable, 1 - enable).
MI FIFO Command Format:
:dr_gw_status:_reply_fifo_file_ GW_id status (optional) _empty_line_
Example 1.32. dr_gw_status usage
$ ./opensipsctl fifo dr_gw_status 2 Enabled:: no $ ./opensipsctl fifo dr_gw_status 2 1 $ ./opensipsctl fifo dr_gw_status 2 Enabled:: yes
Gets or sets the status (enabled or disabled) of a carrier. The function may take from 0 to 2 parameters. If none, it will list all carriers along with their status. If one parameter is provided, that must be the id of a carrier and the function will return the status of that carrier. If 2 parameters are provided, first must be the ID of the ID of a carrier and the second must be the new status to be forced for that carrier (0 - disable, 1 - enable).
MI FIFO Command Format:
:dr_carrier_status:_reply_fifo_file_ carrier_id status (optional) _empty_line_
Example 1.33. dr_carrier_status usage
$ ./opensipsctl fifo dr_carrier_status CR1 Enabled:: no $ ./opensipsctl fifo dr_carrier_status CR1 1 $ ./opensipsctl fifo dr_carrier_status CR1 Enabled:: yes
The module requires 4 table in OpenSIPS database: dr_groups, dr_gateways, dr_carriers, dr_rules. The SQL syntax to create them can be found in drouting-create.sql script in the database directories in the opensips/scripts folder. You can also find the complete database documentation on the project webpage, http://www.opensips.org/html/docs/db/db-schema-devel.html.