Overview

The IPSMGW uses a Cassandra database for storing Third Party Registration data, Routing Information, generating Message References, and tracking Registration Ownership. During Installation the user is asked to enter connection details for the Cassandra Database.

How it works

The Cassandra Storage system uses the Cassandra CQL RA to create, update and remove entries from a Cassandra Database cluster.

Note For information about the Cassandra CQL RA’s architecture and configuration, see the Cassandra CQL Resource Adaptor Guide.

Cassandra Database Configuration

The administrator is required to download and set up a Cassandra Database. The Sentinel IP-SM-GW installer does not perform this function on the behalf of the user. It is required that the installed version of Cassandra be 2.0.17+ or 2.1.17+.

OpenCloud recommends reading Cassandra’s Getting Started page.

For a test system, a single Cassandra Database instance may be sufficient if redundancy is not a requirement.

Minimal production recommendations

For a minimal production system, in order to tolerate a single failure in the Cassandra Database there should be at least three nodes configured per site. The Cassandra replication factor should be three.

Higher replication factors can be used on larger clusters. The recommended consistency level for this storage system is the LOCAL_QUORUM consistency level. All read and write queries are programmed to use LOCAL_QUORUM as the consistency level.

It is assumed that in a multi-site deployment, an appropriate Snitch and Topology Strategy are used. As a basis, we suggest use of the NetworkTopologyStrategy and GossipingPropertyFileSnitch, then reading the relevant links below to review this selection.

There are several recommended links to review when planning a deployment.

Configuration aspect Cassandra documentation link

Planning a Cassandra deployment

Recommended settings for Cassandra

Some anti-patterns, or things to not do with Cassandra

Cassandra Consistency levels and replication factors - in particlar read the LOCAL_QUORUM section

Cassandra Snitches - read this when configuring a single site or multi-site deployment

Cassandra Topology Strategies - read this when configuring a single site or multi-site deployment

Performance recommendations

OpenCloud recommend that Cassandra’s Data directory and Commit log directories are on different physical devices (e.g. different disks). If this is not possible, then different partitions on the same device is acceptable. OpenCloud performance testing shows that there are benefits using different partitions on the same device when there are 1000 or more Cassandra DB transactions per second.

Sentinel IP-SM-GW Configuration for Cassandra

Each insert and update in the database uses Cassandra’s 'time to live' feature, automatically removing stale data from the database. The TTL is set in seconds. It is always calculated to be greater than the largest expiry for a First Party Registration.

3rd-Party Registration TTL

The TTL is defined as the largest expiry from First Party Registration plus a configured time. The configured time value is defined in the Profile Table CassandraSubscriberDataStoreConfig. It is scoped by a Sentinel Selection Key. The value is stored in the attribute named CassandraTTL. The default value is 1800 seconds (30 minutes).

Routing Info TTL

For Routing Info the TTL is configured in IPSMGWRoutingInfoCassandraConfigProfileTable. The value is stored in the attribute named CassandraTTL. The default value is 120 seconds.

Registration Ownership TTL

For Registration Ownership the TTL is defined as the largest expiry from Third Party Registration plus a configured time. The configured time value is defined in IPSMGWRegistrationTrackingCassandraConfigProfileTable. It is scoped by a Sentinel Selection Key. The value is stored in the attribute named CassandraTTL. The default value is 1800 seconds (30 minutes).

Sentinel IP-SM-GW Data Schema

Cassandra’s tables exist in a 'keyspace', which, for illustrative purposes, can be thought of as a 'database' in SQL implementations. Creating a keyspace is simple, but some considerations are present.

Third Party Registration

  • The keyspace must be named opencloud_thirdparty_reg

  • For a production environment, the keyspace can be created such that it is replicated. A sample CQL command for creating such a keyspace is:

CREATE KEYSPACE IF NOT EXISTS opencloud_thirdparty_reg WITH REPLICATION={'class' : 'SimpleStrategy' ,'replication_factor' : 3 };
  • For testing purposes, replication may not be necessary. A sample CQL command for creating such a keyspace is:

CREATE KEYSPACE IF NOT EXISTS opencloud_thirdparty_reg WITH REPLICATION={'class' : 'SimpleStrategy' ,'replication_factor' : 1 };

Once a keyspace is created, the required tables can be created. The following CQL statements provide both the structure and insight into the tables that are required.

USE opencloud_thirdparty_reg;

CREATE TABLE IF NOT EXISTS REGISTRATIONDATA(
    callid text,                    //The callid used for registration
    defaultpublicid text,           //The default IMS Public ID
    privateid text,                 //The IMS Private ID
    associateduris list<text>,      //The Associated URIs
    contacts set<text>,             //Registered Contacts
    visitednetworkid text,          //P-Visited-Network-ID header from registration
    creationtime timestamp,         //The registration creation datetime
    expires int,                    //The time this registration expires in seconds
    expirytime timestamp,           //The registration expiration datetime
    tempgruu text,                  //Temporary GRUU defined in the Contacts
    gruu text,                      //The GRUU in the Contacts
    cmsisdn text,                   //The Correlation MSISDN
    stnsr text,                     //The Session Transfer Number for Single Radio
    isuesrvcccapable boolean,       //Whether the ue has capability UE-SRVCC-CAPABILITY-SUPPORTED
    paccessnetworkinfo list<text>,  //P-Access-Network-Info header from registration
    currentatusti text,             //Current ATU-STI, from initial registration
    atcfmgmturi text,               //ATCF Management URI, from initial registration
    atcfpathuri text,               //ATCF path URI, from initial registration
    extensions map<text,text>,      //Extensions map
    primary key(callid)
)
WITH gc_grace_seconds = 172800; // 2 days

CREATE TABLE IF NOT EXISTS ASSOCURIS(
    impu text,                      //A referenced IMS Public ID
    callid text,                    //The callid used for registration
    isdefault boolean,              //Flag indicating if this IMPU is the default public ID
    defaultpublicid text,           //The default IMS Public ID
    privateid text,                 //The IMS Private ID
    regstate text,                  //Registration state: active, terminated or unknown
    creationtime timestamp,         //The registration creation datetime
    expires int,                    //The time this registration expires in seconds
    expirytime timestamp,           //The registration expiration datetime
    cmsisdn text,                   //The Correlation MSISDN
    associateduris list<text>,      //The Associated URIs
    contacts set<text>,             //Registered Contacts
    isuesrvcccapable boolean,       //Whether the ue has capability UE-SRVCC-CAPABILITY-SUPPORTED
    visitednetworkid text,          //P-Visited-Network-ID header from registration
    paccessnetworkinfo list<text>,  //P-Access-Network-Info headers from registration
    currentatusti text,             //Current ATU-STI, from initial registration
    atcfmgmturi text,               //ATCF Management URI, from initial registration
    atcfpathuri text,               //ATCF path URI, from initial registration
    extensions map<text,text>,      //Extensions map used to store PATH information
    primary key(impu,callid)
)
WITH gc_grace_seconds = 172800; // 2 days

IP-SM-GW Routing Information and Registration Ownership

  • The keyspace for routing information must be named opencloud_ipsmgw_routing_info

  • The keyspace for registration ownership must be named opencloud_ipsmgw_registration_ownership

  • For a production environment, the keyspace can be created such that it is replicated. A sample set of CQL commands for creating these keyspaces is:

CREATE KEYSPACE opencloud_ipsmgw_routing_info WITH REPLICATION={'class' : 'NetworkTopologyStrategy' ,'replication_factor' : 3 };
CREATE KEYSPACE opencloud_ipsmgw_registration_ownership WITH REPLICATION={'class' : 'NetworkTopologyStrategy' ,'replication_factor' : 3 };
  • For testing purposes, replication may not be necessary. A sample set of CQL commands for creating these keyspaces is:

CREATE KEYSPACE opencloud_ipsmgw_routing_info WITH REPLICATION={'class' : 'SimpleStrategy' ,'replication_factor' : 1 };
CREATE KEYSPACE opencloud_ipsmgw_registration_ownership WITH REPLICATION={'class' : 'SimpleStrategy' ,'replication_factor' : 1 };

Once the keyspaces are created, the required tables can be created. The following CQL statements provide both the structure and insight into the tables that are required.

USE opencloud_ipsmgw_routing_info;

CREATE TABLE IPSMGWROUTINGINFO(
    mtcorrelationid text,           //The mtcorrelationid used as the address of the SRI SM response
    appcontext text,                //The application context of the stored SRI SM response
    srismarg blob,                  //The SRI SM request that is stored as a byte array
    srismres blob,                  //The SRI SM response that is stored as a byte array
    msisdn text,                    //The MSISDN retrieved from the SRI SM request
    imsi text,                      //The IMSI retrieved from the SRI SM response
    uuid uuid,                      //The UUID generated for SAS correlation
    primary key(mtcorrelationid)
)
WITH gc_grace_seconds = 14400; // 4 hours

CREATE TABLE IPSMGWGenerateMessageReference(
    imsi text,                      //MSISDN from the MT FSM (previously used IMSI as key, but not always available)
    messagereference bigint,        //The message reference counter to use when forwarding an RpData - it will be modulo 256 so we actually loop through 0 - 255
    primary key(imsi)
)
WITH gc_grace_seconds = 14400; // 4 hours

USE opencloud_ipsmgw_registration_ownership;

CREATE TABLE IPSMGWRegistrationOwnership(
    msisdn text,                 //MSISDN of the subscriber
    ipsmgwsitegt text,           //GT of the IPSMGW site that handled the registration for the subscriber
    writetime timestamp,         //The time that this record was written
 primary key(msisdn,ipsmgwsitegt)
)
WITH gc_grace_seconds = 172800; // 2 days

The schemas are used by these features:

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Sentinel IP-SM-GW Version 3.1.0