Mike Hearn's initial wiki article for Micropayment channels is unidirectional, i.e. the payment can flow only from one party to another and not in the reverse direction.

Example 7, https://en.bitcoin.it/wiki/Contracts

Is there a protocol that allows micropayments to flow in both directions? The solution of creating 2 channels with Bitcoins locked up by both parties is obviously valid, and I am looking for something different.

Is there a way by which, only one party locks up bitcoins, opens up a channel with another party, and the micropayments can flow in both directions?

Here is proposed an alternative architecture called "The Internet of Money (IoM)" to build a Ripple like system with the following differences:

1. No in-built math based currency.

2. No requirement for a singular consensus process. Gateways use a decentralized consensus pool, outside their control, to run their ledger. We replace a singular consensus process (Ripple) with multiple ones, and make up for the disadvantage at higher protocol layers. This simplifies the Ripple consensus engineering challenge.

Reading the Bitcoin technical forum with its numerous resident geniuses has been the best educational experience of my life. I welcome everyone to post comments, questions and point out mistakes / errata. Please bear in mind that the document is an early draft.

Current document version is 0.2.9, please discard the old versions.

Version published through google docs: https://docs.google.com/document/d/1Bc-kZXROTeMzG6AvH7rrTrUy24UwHoEcgiL7ALHMO0A/pub

An aesthetically better pdf version: http://issuu.com/meherroy/docs/an_architecture_for_the_internet_of/01
Pdf works best with Chrome.

A third backup, suitable to download the file: https://www.scribd.com/doc/241975638/An-Architecture-for-the-Internet-of-Money

Comprehensively crediting work that came previously is always a challenge; omissions (if any) should be treated as arising out of ignorance.

Hyperledger thread for the same: http://forum.hyperledger.com/t/an-architecture-for-the-internet-of-money/157