Under the terms of the Good Friday Agreement, the Stormont Assembly and Executive are linked with a series of north-south and east-west bodies. The intention was to give institutional recognition to nationalists' Irish and unionists' British identity.
The North South Ministerial Council (NSMC) is based in Armagh. Its secretariat is headed by two senior officials, one appointed by the Northern Ireland Executive, the other by the Irish government.
The council meets regularly either in full or plenary session, or in what are known as institutional or sectoral meetings. At the full meetings, the Northern Ireland Executive is normally represented by the first minister, deputy first minister and a range of their departmental colleagues.
Sectoral meetings of the NSMC deal with specific issues like education or agriculture. The Irish government is represented by the minister or the minister of state responsible for that sector, while Stormont is represented by two ministers on a cross-community basis, one normally being the executive minister with responsibility for that sector.
At institutional meetings, the Irish foreign minister meets Stormont's first and deputy first ministers.
The Good Friday Agreement created six north-south bodies with a remit to operate on an all Ireland basis.
The bodies are funded by the two administrations, north and south. They cover inland waterways, food safety, trade and business, EU programmes, the Irish and Ulster Scots languages, and agencies looking after the Foyle and Carlingford loughs.
'Totality of relationships'
In addition, the Agreement set out six broad areas for north-south cooperation: agriculture, education, environment, health, tourism and transport.
The British Irish Council (BIC) currently has no permanent headquarters. At a meeting in November 2009, ministers could not decide between competing bids from Cardiff and Edinburgh.
The council brings together eight administrations: the UK, Ireland, Northern Ireland, Scotland, Wales, Jersey, Guernsey and the Isle of Man.
It was established under the Good Friday Agreement "to promote the harmonious and mutually beneficial development of the totality of relationships among the peoples of these islands". The BIC meets at summit level at least once a year, while ministers and officials meet more regularly.
At BIC meetings, ministers discuss a number of topics of mutual interest, with individual members taking responsibility for nine broad areas.
The Republic of Ireland takes the lead on the misuse of drugs, the UK on environmental matters, the Isle of Man on e-health or telemedicine, Jersey on the knowledge economy, Scotland and Wales on social inclusion, Guernsey on tourism, Northern Ireland on transport, Wales on indigenous, minority or lesser used languages, and Scotland on demography.
Although the BIC promotes cooperation in these areas of mutual interest, it cannot make or enforce any laws or regulations of its own.