MME is a component of LTE network which mainly takes care of the following functionalities:
- Mutual authentication of UE
- NAS security
- Default bearer establishment
- Tracking area management
and so many other features of LTE technology.
If your requirement is just to support few user, MME can be run on simple desktop machine which has support of underlying protocols.
If MME is going to be deployed to serve million of user then your desktop machine won't be able to meet performance that's why a different set of telecom specific hardware would be used and then MME will be run of that machine. Typically ATCA is known as telecom hardware and high performance computing blades are used to meet the performance.
Conclusion: MME is a software component which can be modified based on the underlying hardware. One more thing I would like to add here. Now and days, Hard independent software are being developed and will be used under the virtualization technology.