The IIHF Sport Regulations downloadable here explains the seeding, and game schedules and stuff:
http://www.iihf.com/iihf-home/sport/iihf-rule-book.html
To quote:
If in the previous championship pool all positions of the participating teams were decided, the teams will keep their ranking numbers as seeding numbers for the next championship. Only the relegated team will get the top seeding number in the lower pool, whereas the promoting winner from the lower pool will get the bottom seeding number in the higher pool.
If in a championship pool, which was played in two or more groups where all teams have not played each other and all final placing of teams were not decided, then the missing seeding numbers will be allotted by use of the following criteria in the order presented:
1. Higher position in the group,
2. Higher number of points,
3. Better goal difference,
4. Higher number of goals scored for,
5. Better seeding number in the previous championship
Should the number of teams in the groups be different or in special circumstances, the IIHF Competition Committee will prepare an appropriate solution for consideration of IIHF Council. The IIHF Council shall have the option to amend the seeding numbers with the agreement of the majority of participating national associations to accommodate special requirements of an organizer or for geographical considerations.
If a championship pool consists of two groups to take place in two countries whose teams are seeded into the same group, the hosting country team in the lower position will switch its position with the team in the same position of the other group.
Examples for Seeding of Teams into Groups for an IIHF Championship Event
The following are examples demonstrating the use of seedings to produce a game schedule using a regular seeding format and a seeding by draw format.
1. Regular Seeding into 2 Groups:
Group A Group B
1 2
4 3
5 6
8 7
etc.
The organising member national association will prepare the game schedule for the respective
IIHF Championship in accordance with the IIHF Sport Regulations. This game proposal is to
be approved by the participating national associations. If not agreed then the IIHF Council will
make the final decision. (Page 9)