 Institutionally, the arbitral tribunal is often made of three or five arbitrators. Sometimes states agree on a single arbitrator or umpire, but this is quite exceptional today. Three is the default number under PCA rules. Each party has the right to appoint one arbitrator or two arbitrators if the tribunal has five members. Parties may not appoint one of their national as arbitrator. The presiding arbitrator is then appointed by the party appointed arbitrators. And if they fail to agree, or if one of the parties fails to appoint its own arbitrators in due course, the procedural rules agreed upon by the parties usually provide that for instance the PCA Secretary General or the President of the International Court of Justice or any neutral authority like the Secretary General of the United Nations has the power to appoint the missing members of the tribunal. Once the tribunal is constituted, it conducts the procedure according to the rules of procedure agreed by the parties. And very often the respondent will want to raise jurisdictional objections and the procedure will bifurcate in the sense that before hearing the case on the merits the parties will exchange arguments in writing and orally about the competence of the tribunal to entertain the dispute and the tribunal will have to deliver an award about its jurisdiction. An essential principle in that regard is that the tribunal always has what is called the compétence de la compétence which means that even if it has no jurisdiction to hear the claim on the merits, the tribunal has at least the competence to decide on its own jurisdiction and to decline it eventually. If it decides that it has no jurisdiction, that's the end of the matter. But if the tribunal decides that it has jurisdiction, then the case proceeds to the merits and during that second phase the parties will present their views in writing and orally about the merits of the claims. And of course the parties will submit evidence to substantiate their claims and sometimes experts or witnesses may be called in. The awards are final and binding on the parties. Those states must consent to arbitration and because arbitral tribunals are often called when the procedure bifurcates to assess and check their jurisdiction, states rarely fail to implement binding awards. And in this course there is no need to enter into the details of the possible annulment of arbitral awards but suffice it to say that the grounds for annulment are usually considered to be rather limited and limited to excessive power that is going well beyond what was agreed under the Compromis or the Compromissory Clause. Corruption of a tribunal member is also a ground formality or sound departure from the procedural rules including the failure to state the reasons for the award. The parties must bear the costs of arbitration including the arbitrator's fees and this is a disadvantage of arbitration but the advantage of arbitration is that it can be tailored exactly according to the needs of the parties. Arbitration is flexible and fairly speedy and the parties may agree also to keep it confidential. And this latter aspect may sound unacceptable at a time when transparency is rightly praised as an essential requirement in public affairs but confidentiality may have the advantage of bringing the parties closer together in the course of the proceedings. If the dispute is politically sensitive for the domestic audience and if the press is present in the room the tone used by states and by their councils can be very different and less compromising than if the proceedings are kept confidential. Most of the time arbitral tribunals are established to settle one claim and the arbitral tribunal is not permanent. However some arbitral tribunals have been established to settle hundreds of claims and have existed for decades and most notably this is the case of the Iran-U.S. claims tribunal established under the Algiers agreements of 1981 to settle the claims resulting from the Iranian revolution of 1979. The tribunal has finalized nearly 4,000 cases that mostly related to claims by individuals and corporations but it must still decide on large and complex claims between the U.S. and Iran and it still exists. When an arbitral tribunal serves over such a long period of time it develops an institutional history and also judicial consistency. Such consistency is not necessarily present between the awards rendered by different tribunals in different cases and in different contexts. However some awards are considered as landmark cases and decisions and they are referred to in many proceedings.