BPX Switch Common Core Components

The BCC-4V provides a 16 x 32 crosspoint switch architecture to extend the BPX peak switching capability from 9.6 up to 19.2 Gbps peak. The BCC-4V also provides 4 MBytes of BRAM and 128 MBytes of DRAM.

The functions of the common core components include:

• For non-redundant nodes, a single BCC is used in front slot number 7 with its appropriate backcard.

• For redundant nodes, a pair of BCCs of matching type, are used in front slot numbers 7 and 8.

  ---

  Note   The three types of BCCs with their proper backcards may be operated together temporarily for maintenance purposes, for example, replacing a failed controller card. Throughout a network, individual BPX switches may have either a single BCC-4V controller card or a pair of the identical type of BCC.

  ---

The term BCC is used in this manual to refer to the functional operation of the Broadband Controller Card. When a difference in operation does occur, the specific type of BCC is specified.

The BCC-4V provides a 16 x 32 cross-point architecture that increases the peak switching capacity of the BPX switch to 19.2 Gbps, with a sustained non-blocking throughput of 9.6 Gbps.

Each Broadband Controller Card includes the following:

• 68EC040 processor operating at 33 MHz.

• 32 Mb or 64 MB option for BCC-4.

• 4 Mb of Flash EEPROM for downloading system software.

• 512 Kbytes of BRAM for storing configuration data.

• EPROM for firmware routines.

• 68302 Utility processor.

• SAR engine processor operating at 33 MHz.

• Communication bus interface.

• HDLC processor for the LAN connection interface.

• Two RS-232 serial port interfaces.

Only one connection at a time is allowed to an individual card.

With the BPX switch equipped with two BCCs, the cell switching is completely redundant in that there are always two arbiters, two crosspoint switches, two completely independent data buses, and two independent polling buses.

The BCC incorporates non-volatile flash EEPROM which permits new software releases to be downloaded over the network and battery-backup RAM (BRAM) for storing user system configuration data. These memory features maintain system software and configuration data even during power failures, eliminating the need to download software or reconfigure after the power returns.

The BPX switch cell switching is not synchronized to any external clocks; it runs at its own rate. No switch fabric clocks are used to derive synchronization nor are these signals synchronized to any external sources.

Node clocking is generated by the BCC. Because the BPX switch resides as an element in a telecommunications network, it is capable of synchronizing to higher-stratum clocking devices in the network and providing synchronization to lower stratum devices. The BCC can be synchronized to any one of three different sources under software control:

• An internal, high-stability oscillator.

• Derived clock from a BNI module.

• An external clock source connected directly to the BPX.

The BCC clock circuits provide clocking signals to every other card slot. If a function card needs to synchronize its physical interface to the BPX switch clock, it can use this timing signal to derive the proper reference frequency. These reference frequencies include DS1, E1, DS3, and E3.

The BCC-4V provides important features such as support for up to 19.2 Mbps peak operation with BXM cards. Both BCCs in a node should be of the same type.

The backcard provides these interfaces:

• An 802.3 AIU (Ethernet) interface for connecting the node to a CWM NMS.

• A serial RS-232 Control Port for connecting to a VT100-compatible terminal or modem.

• A serial RS-232 Auxiliary Port for connecting to an external printer.

• External clock inputs at T1 or E1 rates, output at 8 kHz.

The LAN port of the primary Broadband Control Card is active. If the secondary Broadband Control Card becomes primary (active), then its LAN port becomes active. The Cisco WAN Manager workstation will automatically try to restore communications over the LAN and will interface with the newly active Broadband Controller Card.

For small networks, one Cisco WAN Manager workstation is adequate to collect statistics and provide network management. For larger networks additional Cisco WAN Manager workstations may be required. Refer to the Cisco WAN Manager Operations Guide.

The ASM and LM-ASM cards are non-critical cards used for monitoring the operation of the node and not directly involved in system operation. Therefore, there is no provision or requirement for card redundancy.

The LM-ASM backcard must be installed in back slot number 15.

Although the ATM data paths between the switching fabric and the interface modules are individual data connections, there are also a number of system bus paths for controlling the operation of the BPX switch. The StrataBus backplane, in addition to the 15 card connectors, contains these signal paths:

• ATM crosspoint wiring
  Individual paths to carry ATM trunk data between both the network interface and service interface modules and the crosspoint switching fabric.

• Polling bus
  To carry enable signals between the BCC and all network interface modules.

• Communications bus
  For internal communications between the BCC and all other cards in the node.

• Clock bus
  To carry timing signals between the BCC and all other system cards.

• Control bus
  Enables either the A-bus wiring or B-bus wiring.

All StrataBus wiring is completely duplicated and the two sets of bus wiring operate independently to provide complete redundancy. Either the A-side wiring or B-side wiring is enabled at any particular time by signals on the Control bus.