Synchronization and Deployment Guide
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Network topology
The traffic patterns on the network
The quality and configuration of the switches
Network topology
Every time a PTPv2 packet passes through a switch - jitter is potentially added. Therefore, the
number of switches between all base stations must be kept low. Because every individual base
station can assume the role as PTPv2 master or slave regardless of its position in the network
topology, a worst case position of master and slave must be considered when deploying the base
stations in the network. The figure below illustrates this with a core switch with two access
switches connected. Here the worst case path length is three switches.
Note: In the lab, the IP base stations have successfully been synchronized with 5 enterprise
LAN switches between master and slave.
Traffic Load
The traffic load on the switches will also affect the jitter. High traffic load and especially a large
number of large packets will increase the jitter. For example, a 1500 bytes data packet
introduces an immediate 120 usec delay on a 100 Mbps link.
It is recommended that the core network links provides higher bandwidth than the access links,
i.e. if the access links are 100 Mbps, the uplink and core network should be at least 1 Gbps. This
will alleviate the probability of traffic saturating the network path used for the base station
synchronization.
14169000 Version 9.3
October, 2016
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