iOS users expect navigation buttons to exist at the bottom of the screen. Great examples of this include Photos, Music, App Store, etc. Note that if you have too many tabs in the
UITabBarController, the last tab will be replaced with a "More" tab that allows the user to see all other tabs that aren't visible in the tab bar. Place your most often used or important tabs in the tab bar, and all others can go into More. You could also implement your own "More" tab to control its appearance.
I would not place such menu buttons below a navigation bar (like android). Additionally, users expect buttons in navigation bars will affect the content that's on screen, not provide any navigational utilities, so I wouldn't implement those there either.
I'll also note that Apple strongly recommends against using a hamburger icon that pulls out a sidebar to provide buttons to navigate.