Description

The PM8620-BI is a monolithic CMOS integrated circuit that performs DS0 and above granularity space switching on 32 SBI336 streams carried as serial SBI336S in 8B/10B coding over LVDS at 777.6 Mbit/s. It also performs VT1.5/VT2 and above granularity switching on 32 STS-12/STM-4 SONET/SDH streams carried as Serial TelecomBus signals in 8B/10B coding over LVDS at 777.6 Mbit/s.

Specifications and features

The PM8620-BI, also known as the Narrowband Switch Element 20G (NSE-20G), has the following features:

• Implements a Scaleable Bandwidth Interconnect (SBI™) DS0 granularity space switch.
• Implements a SONET/SDH VT1.5/VT2/TU11/TU12 granularity space switch for the serial 777.6 MHz LVDS TelecomBus.
• With the allied SBS or SBS-lite device, implements a DS0 granularity Memory-Space Memory switch.
• Supports 32 STS-12 equivalent serial ports via 777.6 MHz, 8B/10B encoded LVDS links.
• When configured for SBI mode, switches DS0 or N*DS0 for all T1 and E1 tributaries and aggregate columns for switching T1, E1, TVT1.5, TVT2, DS3, and E3 tributaries.
• When configured for the serial 777.6 MHz TelecomBus interface, switches any SONET/SDH virtual tributary or tributary unit up to STS-1.
• Supports switching of arbitrary non-standard octet aggregates.
• Supports unicast, multicast, and broadcast for all switching modes.
• Provides 20 Gbit/s (258,048 DS0s, 10,752 T1s/VT1.5s, 8,064 E1s/VT2s, 384 DS3s/E3s) switching.
• Works with SBS devices that support up to four 19.44 MHz SBI buses or one 77.76 MHz SBI336 bus that communicates with PMC-Sierra’s SBI device family.
• Alternatively, the SBS and SBS-lite devices support up to four 19.44 MHz STS-3 TelecomBuses or one 77.76 MHz STS-12 TelecomBus for connection with PMC-Sierra’s SPECTRA™ family of devices.
• Can be combined in applications with PMC-Sierra’s CHESS™ Set devices (PM5374 TSE and PM5307 TBS).
• Supports a microprocessor interface which is used to configure/control the NSE, to make DS0-granularity switch settings.
• Supports clean error checked 8 Mbit/s full-duplex, in-band communications channels from the NSE’s attached microprocessor to the attached microprocessors of each of the 32 attached SBS336S devices.
• Supports JTAG for all non-LVDS signals.
• Requires dual power supplies at 1.8 V and 3.3 V.
• Packaged as a 480 ball UBGA.
• In conjunction with the SBS or SBS-lite, supports “1+1” and “1:N” fabric redundancy.

Application Scenarios

The PM8620-BI NSE supports a variety of flexible Layer 1 and Layer 2 architectures in combination with PMC-Sierra devices such as PM8610 SBS and PM8611 SBS-lite (SBI Serializer and Memory switching stage), SBI bus devices (PM8315 TEMUX™/PM5365 TEMAP, FREEDM™ devices, S/UNI®-IMA devices, AAL1gator™ devices, and other future devices), and CHESS chip set devices (PM5374 TSE, PM5307 TBS, PM5315 SPECTRA™-2488, and PM7390 S/UNI®-MACH48). These architectures include T1/E1 SONET Add/Drop Multiplexers (ADMs), TDM ASAP applications, PHY cards with DS0 (and above) level switching, PSTN replacement switching cores as part of any-service-any-port applications, and Voice Gateways.

Comparison

The advantages of the PM8620-BI include:

• Supports DS0 and above granularity space switching.
• Supports VT1.5/VT2 and above granularity switching.
• Supports switching of arbitrary non-standard octet aggregates.
• Provides 20 Gbit/s switching.
• Supports various SBI and TelecomBus interfaces.
• Supports redundant fabric configurations.

However, the PM8620-BI also has some disadvantages:

• Requires dual power supplies at 1.8 V and 3.3 V.
• Requires additional PMC-Sierra devices for certain functionalities.
• Only supports specific PMC-Sierra chip sets and devices.