NSH-Network Service Header
Network Service Header (NSH) is a protocol designed to create dynamic service graphs. NSH lets you construct a service path without any network changes. It is a data plane protocol, that is, NSH included, on the wire, with network packets. NSH is an open protocol, and has been accepted by the IEFT as a draft standard. In addition to Cisco and Intel, other vendors and operators are co-authors of the protocol specification.
Service graphs enable network operators to dynamically deploy and scale service offerings for their customers without changing the physical network topology. More generally, a service graphs has the branching property where flows can be steered into different paths so that very flexible topologies can be built. Service graphs using NSH also enable the sharing of extra information (such as subscriber ID, application type, etc.) – dubbed metadata – between nodes in the graphs chain for policy enforcement and any other usage required at the service level.
NSH enables the following capabilities:
- Automatically, dynamically create new services from shared resources (service nodes/functions) as needed.
- Dynamically modify traffic steering (for example; a DPI can re-write the SPI based on outcome of application identification).
- Provide complete end-to-end visibility, OAM, trouble shooting and performance management.
- Dynamically change the data path to alter the service chain without touching the network topology.
In short, NSH makes SDN (Software Defined Networking) easy and provide tangible benefits by speeding and simplifying service creation and service modification.