Compare In-Band and Out-of-Band Management Access

Both in-band and out-of-band management traffic are mapped to the management plane. There are two main methods of network management:

• In-band network management
• Out-of-band management (OOB).

In-band management is performed by connecting to the router via Telnet/SSH or using SNMP-based tools. In-band management is the most common method of network management, allowing actual data/production and management traffic to use the same path to communicate with different network nodes. In-band network management is inadequate for large-scale or mission-critical networks. When the network goes down, it compromises the reachability of network devices and poses a significant risk to your business and its operations. Out-of-band management (OOB) provides an alternative or secondary access method to avoid problems or get to the root cause of problems.

In-Band Management:

Devices are managed using protocols such as Telnet/SSH as part of in-band management. Identity-based access control is a commonly used method for enhancing security. It’s good practice to separate administrative traffic from production customer traffic. Create a management VLAN or loop back interface for other management tasks such as device monitoring, system logging, and SNMP. The following diagram shows in-band management.

Out-of-Band Management:

Alternate channels for network nodes are required when the network is down and no traffic is flowing. If network traffic goes down, you need a secure, remote emergency network access method to manage and troubleshoot your device. In-band management tools are inadequate for critical networks. OOB refers to management through an independent dedicated channel. OOB allows access if an alternate path to a network node is required.  The following diagram shows out of band management (OOB).

The following is the comparison between In-Band and Out-of-Band Management Access:

Parameter	In-band Management	Out-of-band Management
Access	Telnet/SSH is used for in-band access.	Consoles are used for OOB access.
Connection Speed	In-band connection speed is fast.	OOB connection speed is slow.
Depends on	In-band relies on the IP address and Telnet/SSH port number.	OOB relies on the IP address and port number specified in the OOB template.
Synchronous / Asynchronous	In-band is synchronous.	OOB is asynchronous.
Works	When a network link is active, in-band technology operates.	OOB is a backup method when a network is unavailable.
Connectivity	Use Putty or Secure CRT to establish in-band connectivity.	Terminal Access to establish out-of-band connectivity.