RAD Data comm IPmux-16 operation manual External Network Timing, Single Source Clock Network

Chapter 1 Introduction IPmux-16Installation and Operation Manual

•Adaptive: In this mode, the E1 or T1 Tx clock is regenerated using the Adaptive method. In this method, the fill level of the buffer receiving packets is monitored. If the buffer begins to overfill, the regenerated clock frequency increases to avoid overflow. If the buffer begins to empty, the clock decreases to avoid underflow.

•Internal Clock: In this mode, the Transmit (Tx) clock is received from an internal oscillator. This mode is useful for testing and diagnostic purposes.

Each of the clocks must be configured correctly on both the Receive and Transmit ends to ensure proper operation and prevent pattern slips.

The following paragraphs describe typical timing schemes and their correct timing mode settings in order to achieve end-to-end synchronization.

External Network Timing

When an external network is used to synchronize the E1/T1 devices, all the IPmux-16 units should be configured to work in loopback mode (see the following illustration). This topology enables any-to-any connectivity; as in the following illustration, all three IPmux-16s have direct E1/T1 connectivity. In this timing configuration both mesh and star bundle connection topologies are supported.

Clock from External Distribution Network

				E1/T1
E1/T1				E1/T1
		IP over	IPmux-16	LBT Mode	E1/T1 Device
E1/T1		Ethernet
	IPmux-16
E1/T1 Device				E1/T1
LBT Mode				E1/T1
			IPmux-16		E1/T1 Device
				LBT Mode

Figure 1-6. IPmux-16 in Loopback Timing Mode

Single Source Clock Network

When a common clock is not available on all the ends of the network:

•E1/T1 Device Configuration:

One of the E1/T1 devices connected to the IPmux-16 should work as the master clock while the others work in loopback timing.

•IPmux-16 Configuration:

The IPmux-16 E1/T1 ports connected to the master clock E1/T1 device work in loopback timing, while the far-end IPmux-16s work in Adaptive mode.

1-8 Functional Description