This section highlights some of the cross-connections types supported by Alcatel-Lucent 1665 DMX. For an in depth look at all cross-connections supported by the Alcatel-Lucent 1665 DMX, see Cross-connections in Chapter 6, System planning and engineering of this document.
Alcatel-Lucent 1665 DMX employs atomic cross-connections for all cross-connect provisioning. Atomic cross-connections are one-way cross-connections between logical ring channels which can be set up and taken down by a single command, and which cannot be broken down into smaller parts. Logical ring channels are the tributaries of a port or port protection group used for transmission in the absence of any line or equipment protection.
Low-speed tributary traffic is routed into the system and back out without being placed on the high-speed (OC-12, OC-48 or OC-192) interfaces. With a VLF Main pack (LNW59/LNW82/LNW504), all cross-connections use the switch fabric located on these packs. Any switch fabrics located on low-speed, tributary packs are disabled when VLF Mains are used.
With the VLF Mains, Alcatel-Lucent 1665 DMX can cross-connect any input on a circuit pack in a function or growth slot to any output on a circuit pack in the same or different function or growth slot. Both slots in a function group can be provisioned independently for working traffic, whether they are the same or different packs. Certain restrictions apply, see Very large fabric (VLF) engineering rules for more information.
These flexible cross-connect capabilities allow you to use a combination of add/drop and hairpinning of compatible payloads through a variety of interfaces. You can bring traffic in from one remote site and cross-connect it at the VT1.5, STS-1, STS-3c, STS-12c, STS-48c, or STS-192c level back out to other remote sites without consuming any capacity on the ring/line interface.
If hairpinning cross-connections are being provisioned between any interface and a 0x1 unprotected interface, 1-way cross-connections must be used. 1-waypr cross-connections are not allowed in 0x1 unprotected scenarios.
Bridge and roll cross-connections are coordinated activity between two NEs designed to move traffic from one facility to another, affecting service by a maximum of 10 milliseconds.
Bridging of an existing cross-connection consists of adding a one-way cross-connection with the same input tributary as that of an existing cross-connection, resulting in a 1x2 multicast from an input tributary to two output tributaries. Alcatel-Lucent 1665 DMX supports bridging for each of the supported SONET cross-connection rates. You can bridge any existing cross-connection to a second output port without impairing the existing signal. Conversely, either half of a bridged signal can be taken down without impairing the remaining cross-connected signal.
Alcatel-Lucent 1665 DMX provides the capability to change the location or source of the input tributary of a given cross-connection. Alcatel-Lucent 1665 DMX supports facility rolling for all supported signal rates as follows:
Disconnection of the circuit cross-connecting input tributary to output tributary
Cross-connection of either a new input tributary to the corresponding input tributary
With unprotected cross-connections on a UPSR Alcatel-Lucent 1665 DMX does not select the best signal from both rotations of a UPSR. Instead, traffic is added and dropped (locked) from one rotation of the ring only (provisionable). The main advantage of locked VT or DS3 cross-connections is the lack of UPSR switching which results in the ability to reuse time slots around a UPSR.
Alcatel-Lucent 1665 DMX has the ability to mix unprotected (locked), protected (unlocked), and pass-through VT1.5s within the same STS-1, and to allow both rotations of a ring to be used simultaneously.
Unprotected cross-connections are also supported to Ethernet VCGs.
The data specific multi-point cross-connect is a bidirectional cross-connection between two STS-1 Virtual Concatenation Groups (VCGs) on 100BASE-T or 1000BASE-X ports to two different ring interfaces.
Pipe mode is a fault monitoring and performance monitoring feature whereby each automatically adapts to changes in the constituent payload structure of a provisioned STS-n rate cross-connection. Fault and PM are based on the payloads carried within a cross-connection rather than the cross-connection rate. Path protection switching continues to operate at the provisioned cross-connect rate.
Alcatel-Lucent 1665 DMX also supports optical channel (OCH) cross-connections between dense wavelength division multiplexing (DWDM) compatible circuit packs/pluggable transmission modules. The OCH cross-connections are used to inform the network element about manual fiber connections.
| November 2011 | Copyright © 2011 Alcatel-Lucent. All rights reserved. |