Background: Know: Recognize:
Separate Phy for NM
In- band management: For in- band management, management control information and data information are transmitted in one physical layer . It is cheaper compared to out- of- band management, but both management and data tranmission cannot work when network fails.
Out- of- band management: When we separate Phy for NM, we get out- of- band management. There is a dedicated management network to separate the system administrator and production network. In addition, routers provide the “ Console ” port to establish a production network outside of a dedicated management network, where production traffic and management traffic will no longer share the same physical channel. It is safer and more robust than in- band management as Production networks and management networks are completely independent with each other.
Compare: If we compare Network Management to a street, in- band management is just like a street shared by pedestrians and vehicles. Once it blocks, it's not easy to remove the obstacles. Out- of- band is like a street separating sidewalk and driveway. Once the driveway blocks, we could go through sidewalk to remove obstacles and prevent transportation failure.
Reference: 1. http://en.wikipedia.org/wiki/Out-of-band_management