JUNOS High Availability

Are You In or Out?

When you are developing a monitoring and management scheme, it is important to consider the method that the tools use to access the chassis. There are two distinct approaches to network management: in band and Out of Band (OoB).

In-Band Management

With in-band management, management traffic shares interfaces, links, and other resources with customer traffic. This method is more economical up front because you do not need to purchase additional equipment to support the management network. However, the risks associated with this form of management make it inappropriate for most networks with high availability requirements. The main issue is that when the network is having problems, the router may become inaccessible to management tools.

Out-of-Band Management

With OoB management, you independently provision interfaces and links for the management traffic so that no links are shared with customer traffic. This method requires a greater capital expense, but has a few advantages over in-band management:

• Dedicated interfaces result in clean separation of management traffic from other forms of traffic, and simplify troubleshooting.

• Problems impacting the production network do not automatically degrade the ability to manage the chassis, as is the case with in-band management.

OoB management essentially results in the creation of a second network for the sole purpose of monitoring the production network. Most administrators agree that this is by far the most reliable way to effectively ...