Interface and Router Clock Sources

When configuring the routing platform, you can configure the transmit clock on each interface; the transmit clock aligns each outgoing packet transmitted over the routing platform's interfaces. For both the routing platform and interfaces, the clock source can be the routing platform's internal stratum 3 clock, which resides on the control board, or an external clock that is received from the interface you are configuring. For example, interface A can transmit on interface A's received clock (external, loop timing) or the stratum 3 clock (internal, line timing). Interface A cannot use a clock from any other source.

By default, each interface uses the routing platform's internal stratum 3 clock. To configure the clock source of each interface, include the clocking statement at the [edit interfaces interface-name] hierarchy level:

[edit interfaces interface-name]

clocking (internal | external);

Figure 3 illustrates the different clock sources.

Figure 3: Clock Sources