STM-4 - Hardware

System Hardware

Chassis
The VCL100 STM-1/4 is a 19” wide, 10.5” high 14 slot chassis, in a half-depth rack allowing back-to-back arrangement for VCL100 STM-1/4s. This chassis can be installed in both 19” and 23” rack with suitable adapters.

Of the 14 slots above, 2 are reserved for aggregate cards, 2 for cross-connect cards, 5 for tributary cards, 2 for processor sub-system, 2 for power supply units and 1 for management interface.

A line sketch of the VCL100 STM-1/4 chassis is shown below:

VCL100 STM-1/4 card structure (front view)

A sample faceplate layout is shown below:

Hardware components

STM-1 Aggregate/Tributary Card

The aggregate/tributary card has 1 or 2 STM-1 interfaces. Terminal multiplexer configuration can utilize a single 1 STM-1 card. Add-Drop Multiplexer configuration can utilize either two 1 STM-1 card or a single 2 STM-1 card. To provide aggregate card redundancy, additional card be inserted in the second aggregate card slot.

STM-4 Aggregate Card

The aggregate card has 1 STM-4 interface for terminal multiplexer or add-drop multiplexer applications respectively. To provide aggregate card redundancy for Terminal Multiplexer configuration, additional card be inserted in the second aggregate card slot.

Optionally, ITU-T G.691 V4.2 optics interface can be incorporated to achieve very long spans.

21E1 Tributary Card
Up to 5, 21E1 tributary cards are supported in a single VCL100 STM-1/4 chassis.

1E3 Tributary Card
Up to 5 1xE3 tributary cards are supported in a VCL100 STM-1/4 chassis.

1DS3 Tributary Card
Multiple 1DS3 tributary cards are supported, up to a maximum of 5 in a single VCL100 STM-1/4 chassis.

8-Port 10/100 Mbps Ethernet Tributary Card (ETC)

The 8-port ETC card maps 10/100 Mbps Ethernet data on to VC-12’s with a rate adaptation granularity of 2 Mbps. Each port’s bandwidth is configurable in increments of 2Mbps, based on per port user demand. The aggregate bandwidth from each ETC card is STM-1 line rate (63 VC-12 worth of traffic), or lower. It also supports auto-negotiation and auto-sensing with full rate 10/100 Mbps Ethernet service. Ingress Ethernet traffic is shaped using flow control as per the standard IEEE 802.3x by using PAUSE frames. The ETC is compliant to ITU-T X.86 and supports Virtual Concatenation.

Management Interface Card (MIC)

The MIC card would contain all the management interfaces to the VCL100 STM-1/4 . This card has a 10/100 Mbps NMS (Ethernet) port apart from a usual RS232C craft port for managing the VCL100 STM-1/4 through the command line interface (CLI). This card also supports the engineering order-wire interface through the analog 2-wire interface. The EOW bytes are software selectable to E1 or E2. The MIC also supports the “Potential free contacts” for extending the alarms and also taking in certain environmental alarms like “Power or Air-conditioning failure” , “equipment room door open” etc.

Processor Sub-System Card (PSS1)

The PSS card would contain the processor, memory and hard disk required to operate the VCL100 STM-1/4. The embedded software residing in this card controls the overall management of the VCL100 STM-1/4. PSS1 card can be configured as redundant.

Power Supply Card (PSU1)

The power to entire chassis is distributed from this card. This is a hot-insertible, hot stand-by current sharing power supply, running off a –36V to –60V DC supply. This would supply power to all the cards. PSU1 can be configured to be redundant.

4x4 STM-1 Cross connect Card

This card contains the cross-connect fabric for 4x4 STM-1 with granularity of VC-12 (ie. 252x252) and VC-3 (ie. 12x12) This card also has the system timing generation as well as synchronization timing modules.

4x4 STM-4 Cross connect Card

This card contains the cross-connect fabric for 4x4 STM-4 with granularity of VC-12 (ie. 1008x1008), VC-3 (ie. 48x48) and VC-4 (ie. 16x16). This card will also have the system timing generation as well as synchronization timing modules.

Synchronization

VCL100 STM-1/4 can derive its clock from a variety of sources. VCL100 STM-1/4 could be line-timed, externally timed or could derive its clock from its own internal Stratum-3 source. In a line-timed mode, it derives its clock from any one of the E1/E3 tributaries or STM-1 signal. In an externally timed mode, an external 2048 KHz or 2 Mbps signal could be used as the clock source. If none of these sources are available, VCL100 STM-1/4 goes into a holdover mode when it uses the stored timing data to control the output frequency for a short duration (of around 24 hrs). Beyond this it uses its own internal oscillator in a free running mode.

VCL100 STM-1/4 also supports Synchronization Status Messaging (SSM) as per ITU-T standards. This is a messaging technique, which enables a SDH equipment to determine the derivation of a timing source. It uses overhead bytes contained within the SDH overhead (S1) for transmitting these messages. Thus when a failure occurs, elements communicate timing reconfiguration information across the network.

A 2.048 M BITS clock output is available from the system, which can be set to either a 2.048 MHz clock or a framed E1 data at 2.048 Mbps.

Related Links

Aries Telecom
10842, N 127th Place
Scottsdale, AZ 85259, U.S.A.
Phone: 1-480-816-8672 Fax: 1-480-451-6693
E-mail: info@ariestelecom.com
Website: http://www.ariestelecom.com

All brandnames and trademarks are the property of their respective owners.