Specifications

Chapter 1 Introduction IPmux-4 Installation and Operation Manual

1-8 Functional Description

begins to empty, the Tx (toward the TDM device) clock decreases to avoid

underflow.

In this mode the regenerated clock is subject to network Packet Delay Variation and

may not comply with jitter and wander specifications.

• Internal Clock – in this mode, the Tx clock is received from an internal

oscillator.

• External Clock – in the four-port version of IPmux-4, port 4 can be used to

supply an external clock source. When one of the other ports (1, 2 or 3) is

configured to external clock, its Tx clock is taken from the Rx clock of port 4.

Network Timing Schemes

The following paragraphs describe typical timing schemes and their correct timing

mode settings in order to achieve end-to-end synchronization.

External Network Timing

All the edges of the network are synchronized according to an external network

clock source. This topology enables any-to-any connectivity, thus supporting both

mesh and star bundle connection topologies.

In the following application (see Figure 1-6), an External Clock Distribution

Network provides the clock to the E1/T1 devices. All three IPmux-4 units work in

LBT clock mode.

IP over

Ethernet

E1/T1 Device

E1/T1

E1/T1 Device

E1/T1

E1/T1 Device

E1/T1

Clock from

External

Distribution

Network

IPmux-4

Figure 1-6. IPmux-4 in Loopback Timing Mode

In the following application (see Figure 1-7), the External Clock Distribution

Network (GPS in this example) provides the clock directly to the IPmux-4 units

that are working in EXT clock mode.

Port 4’s Rx interface serves as the “Station Clock Port”. Port 4 should be set to

LBT clock mode. While the port (1–3) that is to work in External timing should be

set to EXT clock mode (since each port is autonomous, any of the ports can be

configured to either LBT or EXT clock mode).

Note

Order from: Cutter Networks

Ph:727-398-5252/Fax:727-397-9610