Cisco Systems 8600 Series manual Configuring Connections ATM over ASI Example

ASI-1, ATM Service Interface Card

Some of the functions performed by the PLPP in the ASI-1 include:

PLPP—Receiver Side

•Provides frame sync for the C-bit parity frame format.

1Provides alarm detection and accumulates B3ZS code violations framing errors, parity errors, C-bit parity errors, and far end bit error (FEBE) events.

•Detects far end alarm channel codes, yellow alarm, and loss of frame.

•Provides optional cell descrambling, header check sequence (HCS) error detection, and cell filtering.

•Small receive FIFO buffer for incoming cells.

Connections are routed using the VPI and VCI address fields in the UNI header. The allowable range for VPI is from 0 to 255 (UNI) and 0 to 1023 (NNI), while VCI can range from 1 to 65535. A total of 1000 combinations of these can be used per ASI card at any one time.

A total of 1000 logical connections (ungrouped) may be configured for the node at any one time. On the BPX switch, 5000 grouped connections can be configured. The ASI-1 supports 1000 connections per card.

Two connection addressing modes are supported. The user may enter a unique VPI/VCI address in which case the BPX switch functions as a virtual circuit switch. Or the user may enter only a VPI address in which case all circuits are switched to the same destination port and the BPX switch functions as a virtual path switch in this case.

There are sixteen egress queues per line (port), including CBR, VBR, and ABR. When a connection is added, the user selects either constant bit rate (CBR), variable bit rate (VBR), or available bit rate (ABR, which uses ForeSight). The CBR queue has higher priority. Queue depth is specified when configuring a line. Maximum depth that can be specified for any one queue is 11,000 cells. Total queue depth cannot exceed 22,000 cells.

Configuring Connections (ATM over ASI Example)

Connections are routed between CPE connected to ASI ports (see Figure 5-3). Before adding connections, an ASI line is upped with the upln command and configured with the cnfln command. Then the associated port is configured with the cnfport command and upped with the upport command. Following this, the ATM connections are added via the addcon command with the syntax: slot.port.vpi.vci. The example shows a connection between alpha 4.1.1.1 and gamma 6.1.1.1.

The slot number is the ASI card slot on the BPX switch. The port number is one of two ports on the ASI, the VPI is the virtual path identifier, and the VCI is the virtual circuit identifier. (The top two ports on the LM-2T3 card are used, the bottom one is not.)

The VPI and VCI fields have significance only to the local BPX switch, and are translated by tables in the BPX switch to route the connection. Connections are automatically routed by the AutoRoute feature once the connection endpoints are specified.

Connections can be either Virtual Path Connections (VPC) or Virtual Circuit Connections (VCC). Virtual Path Connections are identified by an * in the VCI field. Virtual Circuit Connections specify both the VPI and VCI fields. Refer to the Cisco WAN Switching Command Reference for further information.

5-4Cisco BPX 8600 Series Reference