Media planning is an act of creating a plan that will make the advertisement successful, while media buying is related to the task of buying space and time slots in various media platforms. Media planning and buying are processes associated with the negotiating, strategizing and purchasing of ad placements, otherwise known as “inventory”. While planning which of the inventories to purchase, the planners must consider the products that are being advertised, the target audience, as well as the campaign goals. The media buyers manage the initial purchase and they are also responsible for making efforts that optimize the performance of these ads throughout the whole campaign lifecycle.

Media Planning
This should really be at the core of any media execution. It’s the creation of the strategy – and the media plan that exemplifies this strategy. The media planner is the person who helps their clients not only understand why they’re making key suggestions that pertain to media budgets, but also define how objectives can be met via planning.

A media planner is someone who might focus on writing and creating materials, versus managing a campaign’s day-to-day. Many planners evolved from being experienced buyers, and many also execute the media plans, or oversee that execution.

Media Buying
This is the biggest piece of a campaign’s execution, and takes up the largest percentage of labor for a media team. The buying phase is when the plan is put to the test and buyers spend their time first negotiating rates with media vendors to get as favorable a price possible, or to build out specific placements against objectives and performance goals.

When the buy is set, the buyer also executes the campaign and acts as a project manager – ensuring that all materials and assets are produced to spec, any financial obligations are covered, and generally oversees implementation and monitoring.

Media Planning Vs Media Buying
Both media buying and media planning can be considered to be subsets of media research. The media research also includes of other areas like marketing sources, creative sources, and media sources. Therefore, for conducting a successful media research, all the mentioned elements must be given due consideration. In order to ensure that a media campaign runs in the best possible manner, it is necessary to use both Media Planning and Media Buying in an effective way. Plenty of companies ignore the importance of one or the other, thereby not being able to reap the best benefits. It is not wise to jump to media buying straight ahead without effective planning, as that would only lead to a major investment without much result. One should also not think that only media planning without appropriate media buying would lead to optimum business promotion.

Source:
http://www.articlesfactory.com/articles/advertising/what-is-media-buying-and-planning.html
https://medium.com/@henrymiller789/media-planning-vs-media-buying-which-is-more-important-2bb88cb11b00
http://instratmedia.com/media-planning-vs-mediabuying