Alcatel-Lucent 1850 TSS-5 allows technicians to perform loopback tests on SONET/SDH and Ethernet interfaces.
The VLNC50/52/55 circuit packs support terminal and facility loopbacks on DS1/E1 and DS3/E3 ports. The VLNC60/61/62 circuit packs support terminal and facility loopbacks for DS1/E1 signals. The VLNC64 circuit pack supports terminal and facility loopbacks on SONET/SDH interfaces. The VLNC35 circuit pack supports terminal loopbacks on Ethernet ports. Active loopbacks are shown by the MN/ABN LED on the SYSCTL faceplate and in the alarm and status report. These loopbacks are individually controllable by the WaveStar® CIT or the OS interface.
Beginning in Release 7.2.2, Alcatel-Lucent 1850 TSS-5 supports Ethernet internal and line loopbacks on the VLNC42B in T-MPLS mode and VLNC61/62/64 circuit packs . These loopbacks are managed via the Web GUI.
There are two software-controlled electrical loopbacks.
The Facility loopback connects the DS1, DS3, E1, or E3 transmit side input to the corresponding receiver side output.
Cross-connect facility loopbacks are supported on the tributaries of the optical SONET/SDH ports of the VLNC50/52/55 circuit pack A tributary received on an optical interface is looped back, through the cross-connect fabric, to the same-numbered tributary in the transmit optical interface, and AIS is inserted downstream if the tributary is cross connected.
Low-speed DS1, DS3, E1, and EC-1 electronic loopbacks, directed toward the high-speed line (terminal loopbacks) connect the entire signal that is about to be passed-through the tributary interface to the DSX (in the case of DS1/E1/DS3/E3 signals) back toward the cross-connect fabric to the optical line. AIS is the output to the DSX. Alcatel-Lucent 1850 TSS-5 supports terminal loopbacks on VLNC35 Ethernet interfaces and terminal loopbacks on VLNC64 SONET/SDH interfaces.
Terminal loopbacks are used for installation and maintenance procedures to test the integrity of near and far-end interfaces as well as fibers and system circuitry.
Beginning in Release 7.2.2, Alcatel-Lucent 1850 TSS-5 supports terminal loopbacks on SONET/SDH main-{1-2}-1 ports on the VLNC64 circuit pack.
Front access to the optical connectors on the optical line interface unit (OLIU) circuit pack allows easy manual optical loopback. This loopback is performed by connecting a fiber jumper from the MAIN circuit pack output to its input. In some cases a lightguide buildout assembly is required to prevent receiver overload when performing loopbacks.
Beginning in Release 7.2.2, Alcatel-Lucent 1850 TSS-5 supports Ethernet internal and line loopbacks on the VLNC42B in T-MPLS mode and VLNC61/62/64. These loopbacks are managed via the Web GUI.
|
Circuit pack |
Ports |
Ethernet loopback |
|---|---|---|
|
VLNC42B in T-MPLS mode |
Optical Ethernet d{2}-{1-4} |
Internal |
|
Line | ||
|
Electrical Ethernet d{2}-{1-4} a-{9-28} a-{41-60} |
Internal | |
|
Line | ||
|
VLNC61, VLNC62, VLNC64 |
Ethernet d{1-2}-{1-2} |
Internal |
|
Line |
Internal loopbacks on electrical and optical Ethernet interfaces redirect packets that are about to be transmitted out of the interface back toward the switch at the physical layer.Alcatel-Lucent 1850 TSS-5 supports internal loopbacks on the Ethernet interfaces on the VLNC42B, VLNC61, VLNC62, and VLNC64 circuit packs.
Line loopbacks on electrical and optical Ethernet interfaces redirect packets that are received on the interface back out the interface at the physical layer. Alcatel-Lucent 1850 TSS5 supports line loopbacks on Ethernet interfaces on the VLNC42B, VLNC61, VLNC62, and VLNC64 circuit packs.
The VLNC50/52/55 and VLNC60/61/62 circuit packs support inband-requested DS1 loopbacks. Inband-requested DS1 loopbacks can be provisioned using either inband signal control (ISC) patterns or a bit-oriented codes (BOC) within the DS1 signal received from the DSX (VLNC50/52/55 and VLNC60/61/62) or optical fiber (VLNC50/52/55). The ability to respond to inband loopback requests is provisionable on a per-port, per-direction basis, and is by default disabled. If inband loopbacks are enabled in either direction, then command-based loopbacks are denied. If inband loopbacks are disabled while inband-requested loopbacks are active, the loopbacks are released.
The VLNC50/52/55 circuit packs support Far End Alarm Channel (FEAC) requested DS1 and DS3 facility loopbacks on the channelized, C-bit framed, b-3 DS3 port. The FEAC-requested loopbacks are provisioned using FEAC codes within the b-3 DS3 signal received from the DSX. The ability to respond to FEAC loopback requests is provisionable on the b-3 DS3 port only, and is by default disabled. If FEAC-requested loopbacks are enabled, then WaveStar® CIT-based facility loopbacks (VLNC50/52/55) are denied. Terminal loopbacks are not denied. If FEAC-requested loopbacks are disabled while a FEAC-requested loopback is active, the loopback is released.
Beginning in Release 7.1, the VLNC40/42/42B circuit packs support VLAN loopbacks. In addition to checking connectivity, the VLAN loopback checks (in the portion of the network between the test set and the loopback) bandwidth availability, packet processing (for example, priority), and data dependencies. Any and all traffic with the appropriate outer VLAN tag is looped back. Only one VLAN in a Alcatel-Lucent 1850 TSS-5 can have an active loopback.
The loopback is initiated out-of-band, via management interface (CLI) rather than by OAMPDUs. The loopback does not require 802.3ah or 802.1ag OAM messages. Traffic received on the network side is looped, and it is sent back out the network side. Customer traffic (coming in from the access side) is not blocked when a loopback is active. The node doing the loopback does not check or process QoS, MTU, throughput, bandwidth, etc The Source and Destination MAC addresses (SA and DA) are swapped during the loopback. The entire packet is sent back to the source. When this loopback is active, there is no other OAM traffic on the specified VLAN.
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