Media Cross Connects

Media Cross-connects are physical layer switches that create connections from any port to any other port on the device. These devices are used in a variety of applications. A cross-connect is used primarily as an intelligent patch panel. Whereas with a typical patch panel, wires must be physically disconnected, moved, and reconnected to change the network configuration, with a cross-connect, the network administrator can make any desired configuration changes without touching the physical wires. This is accomplished by providing a fully programmable path between all the ports on the cross-connect.

• Media Cross Connect Overview

Applications

Fiber exchange points

Wherever large numbers of fiber strands come together in a junction place, cross-connects can be used to connect all the fibers together, allowing completely programmable connections. In many cases, these fiber strands are using CWDM to multiplex many streams or customers onto each fiber. In this case, cross-connects can be used together with passive Mux/Demuxes and 'colored' SFP optical interfaces to provide a completely configurable wavelength and fiber switch, allowing total control over which wavelength from each fiber is connected to which other fiber and wavelength.

Wire-once Enterprise

In many Enterprise wiring closets, the state of change is the normal state of affairs. Here, cross-connects can be used to replace the optical or copper patch panels so that any change in fundamental topology (for example, if a router or switch is added or removed, or simply needs a different connection) can be achieved by simply reprogramming the cross-connect, without the administrator having to physically touch any of the cables.

Test labs

Test labs administrators face several challenges that are eased with cross-connects. First, test operators need to use expensive test equipment efficiently. Cross-connects allow operators to share interfaces on a piece of test equipment that is located centrally. Additionally, someone constantly has to rewire or move cables around from place to place, which is cumbersome, and can interfere with test results. A programmable cross-connect allows total control over the entire test lab infrastructure, and enables the test operators quickly and easily to change the test setup.

Network simulation

Media Cross-connects dramatically simplify network simulation setup and reconfiguration by simply allowing a software programmable connection between the various devices on simulated network. Each device is attached to the cross-connect via as many connections as necessary, and the cross-connect is programmed and reprogrammed to create the desired network topology. A cross-connect can easily be used to simulate network outages or cable breaks as well. Ports on the cross-connect can also act as network analysis (or mirror) ports, allowing a single network analysis device to be used for any given protocol (Gigabit Ethernet or ATM, for example).

Video distribution via physical layer multicasting

Cross-connects can be used in a digital video distribution environment, such as an educational video network on a campus. The cross-connect broadcasts the video from a single source to all the other ports, using the port-to-multiport physical layer multicasting feature. In doing this, the digital signal is regenerated which allows a better quality signal than the traditional 'vampire-tap' approach. Additionally, using optical SFPs, fiber optic cabling can be used to reach long distances between devices, allowing a Metro-wide deployment of a single digital video source.