Configuring the Global Navigation Satellite System
In typical telecom networks, synchronization works in a hierarchal manner where the core network is connected to a stratum-1 clock. The stratum-1 clock is then distributed along the network in a tree-like structure. However, with a GNSS receiver, clocking is changed to a flat architecture, where access networks can directly take clock from satellites in sky by using an on-board GPS chip.
IOS XR NCS-55A2-MOD-SE-S Router now uses a satellite receiver, also called the Global Navigation Satellite System (GNSS), as the new timing interface.
To optimize the GNSS system, it requires all the systems to share a common time scale and coordinated system. If all the systems do not have a common time, the receiver sees a time offset and then the receiver will have to select only one constellation having common time scale. Then there will be a requirement to add more satellites to increase the coverage of the constellation itself.
This capability simplifies network synchronization planning, provides flexibility and resilience in resolving network synchronization issues in the hierarchical network.
These Cisco IOS XR routers now support on board GNSS receiver to recover time.