This is a fixed layout with a fixed header and footer height.

This cell will be horizontally centered until your browser window is too small. Vertically, content will push the footer if your browser window becomes too small. Scrollbars are used when required.

Fixed width layout may suit better when you have a combination of text and images because they will remain in proportion to each other, not your browser window. In this layout, the content will stay a constant horizontal size.

Notice how the footer stays at the bottom when the cell is larger than the content.

Try it by resizing your browser window.