What are proprietary protocols?

the Proprietary Protocol , the one not mange by international origination like IEEE or IETF in other words it is not open protocol her is the most famous Proprietary Protocol

1- CDP

2- EIGRP

3- GLBP

4- HSRP

5- ISL

6-PAgP

all this protocol created  by cisco systems

protocols that are developed by organizations privatley to operate on any vendor hardware.

proprietary protocols are the protocols owned by and company, organization or individuals, the owner can control their protocols or impose restrictions and limit implementations. e.g. Skype protocol and Microsoft Exchange Server.

Depends on the type of company and the network that is managed .In addition to the presence of several factors, the most important is the safety within the network. Sometimes we need protocols such as EIGRP property Cisco protocols company in order to protect and transfer data sometimes choose other protocols depending on what the companies want