Instant messaging interoperability between disparate service providers

An apparatus comprising a processor and memory, the memory storing processor-executable logic comprising:

• interface logic that receives, at a stateless gateway server comprised within a primary service provider network, communication related to a client of the primary service provider network and at least one of a plurality of external instant messaging service provider networks, the communication comprising subscribe requests and unsubscribe requests;
• use logic that uses, at the stateless gateway server, a buddy store associated with the stateless gateway server, the buddy store storing primary network buddies of external users, wherein the primary network buddies are associated with the primary service provider network and the external users are associated with the at least one of the plurality of external instant messaging service provider networks;
• identifying logic that identifies, at the stateless gateway server, a primary network buddy via the client that logs in to the primary service provider network;
• interface logic that receives, at the stateless gateway server, upon logging in of the primary network buddy, at least one of a subscription request from the external users to subscribe to presence states of the logged-in primary network buddy and a subscription request from the client to subscribe to presence states of the external users;
• and
• subscribing logic that allows, at the stateless gateway server, at least one of subscription of the external user to the presence states of the logged-in primary network buddy and subscription of the client to the presence states of the external users.

A method comprising:

• receiving, at a stateless gateway server comprised within a primary service provider network, communication related to a client of the primary service provider network and at least one of a plurality of external instant messaging service provider networks, the communication comprising subscribe requests and unsubscribe requests;
• using, at the stateless gateway server, a buddy store associated with the stateless gateway server, the buddy store storing primary network buddies of external users, wherein the primary network buddies are associated with the primary service provider network and the external users are associated with the at least one of the plurality of external instant messaging service provider networks;
• identifying, at the stateless gateway server, a primary network buddy via the client that logs in to the primary service provider network;
• receiving, at the stateless gateway server, upon logging in of the primary network buddy, at least one of a subscription request from the external users to subscribe to presence states of the logged-in primary network buddy and a subscription request from the client to subscribe to presence states of the external users;
• and
• allowing, at the stateless gateway server, at least one of subscription of the external user to the presence states of the logged-in primary network buddy and subscription of the client to the presence states of the external users.

A non-transitory computer-readable storage medium tangibly encoded with computer-executable instructions, that when executed by a processor associated with a computing device, perform a method comprising:

• receiving, over a primary service provider network, communication related to a client of the primary service provider network and at least one of a plurality of external instant messaging service provider networks, the communication comprising subscribe requests and unsubscribe requests;
• using a buddy store associated with a stateless gateway server, the buddy store storing primary network buddies of external users, wherein the primary network buddies are associated with the primary service provider network and the external users are associated with the at least one of the plurality of external instant messaging service provider networks;
• identifying a primary network buddy via the client that logs in to the primary service provider network;
• receiving upon logging in of the primary network buddy, at least one of a subscription request from the external users to subscribe to presence states of the logged-in primary network buddy and a subscription request from the client to subscribe to presence states of the external users;
• and
• allowing at least one of subscription of the external user to the presence states of the logged-in primary network buddy and subscription of the client to the presence states of the external users.