Precision Time Protocol (PTP) over Link Aggregation Group (LAG)

Link Aggregation is a mechanism of combining multiple physical links into a single virtual link to achieve linear increase in bandwidth and to provide redundancy in case one of the links fails.

Link Aggregation is a mechanism of combining multiple physical links into a single virtual link to achieve linear increase in bandwidth and to provide redundancy in case one of the links fails. The virtual link is referred as Aggregated Ethernet (AE) interface or Link Aggregation Group (LAG). Junos OS supports PTP (IPv4 and Ethernet) over LAG based on the recommendation in ITU-T-G.8275.1.

For each aggregated Ethernet link configured as PTP timeTransmitter or timeReceiver, you can specify one member link of the aggregated Ethernet bundle as primary and another as secondary. PTP switches over to the secondary member in the aggregated Ethernet bundle when the primary aggregated Ethernet link is down. For providing both link-level and FPC-level redundancy, the primary and secondary interfaces of the aggregated Ethernet bundle must be configured on separate line cards. If both primary and secondary are configured on the same line card, it would provide only link-level redundancy.

PTP timeTransmitter streams are created on the FPC on which the timeTransmitter interface is present. Announce and sync packets are transmitted on this active PTP aggregated Ethernet link. The line card on the PTP timeReceiver containing this active PTP aggregated Ethernet link will receive announce and sync packets from the remote timeTransmitter.

Junos OS also supports Hybrid over LAG. When primary and backup SyncE Interfaces are present on same line card, hybrid over LAG is supported.

See the Feature Explorer page to confirm platform and release support for specific features.