Cisco Systems 8600 Series Broadband Network Interface Cards, BNI-155, Overview, Egress, Ingress

Broadband Network Interface Cards, BNI-155

Broadband Network Interface Cards, BNI-155

The BNI-155 interfaces the BPX switch with ATM OC3/STM-1 broadband trunks. The ATM trunk may connect to either another BPX switch or customer CPE equipped with an ATM OC3/STM-1 interface.

There are three BNI-155 back cards, the LM-2OC3-SMF for single-mode fiber intermediate range, the LM-2OC3-SMFLR for single-mode fiber long range, and the LM-2OC3-MMF for multi-mode fiber. Any of the 12 general purpose slots can be used to hold these cards. These backcards may also be used with the ASI-155.

Features

A summary of features for the BNI-155 cards include:

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LM-OC3-SMF and LM-OC3-MMF cards provide two ports, each operating at 155.52 Mbps.

Up to 353,208 cells per second.

Up to 12 class-based queues for each port.

8 K cell ingress (receive) VBR buffer.

32 K cell egress (transmit) buffers.

800 Mbps backplane speed.

Two-stage priority scheme for serving cells.

Accumulates trunk statistics for OC3/STM-1.

Optional 1:1 card redundancy using Y-cable configuration for BNI-155.

Overview

Egress

In the transmit direction (from the BPX switching matrix towards the transmission facility, referred to as egress), the BNI performs the following functions (see Figure 4-6):

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Receives incoming cells from the switch matrix on the BCC.

Serves the cells based on the class-of-service algorithm.

Sets congestion indication (EFCN) in cell header when necessary.

Ingress

In the receive direction (from the transmission facility towards the BPX switching matrix, referred to as ingress), the BNI performs the following functions (see Figure 4-6):

•Receives incoming ATM cells from the OC3 transmission facility, stripping the framing and overhead from the received bit stream.

•Determines the address of the incoming cells by scanning the Virtual Path Identifier/Virtual Circuit Identifier (VPI/VCI) in the cell header.

Network Interface (Trunk) Cards 4-11