Cisco Systems 8600 Series manual Ingress, Simplified BNI-T3, BNI-E3 Block Diagram

Broadband Network Interface Cards (BNI-T3 and BNI-E3)

Ingress

In the receive direction (from the transmission facility towards the BPX switching matrix, sometimes referred to as ingress), the BNI performs the following functions:

•Receives incoming ATM cells from the DS3 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 (VPI)/Virtual Circuit Identifier (VCI) in the cell header.

•Queues the cells for transmission through the switch matrix.

•Extracts receive timing from the input framing and makes it available for node timing. Line can operate in looped timing mode.

•Recovers clock and data from the bipolar B3ZS (T3) or HDB3 (E3) line signal and converts data to unipolar.

Figure 4-2 Simplified BNI-T3, BNI-E3 Block Diagram

BNI-3E3 only

StrataBus backplane

Comm.

bus

interface

Serial

interface

module

(SIM)

Control

&admin. processor

Network address table

Queue service

engine #1

Queue service

engine #2

Queue service

engine #3

G.832 framer

E3 xmtr/rcvr

G.832 framer

E3 xmtr/rcvr

G.832 framer

E3 xmtr/rcvr

BNI-3T3 only

DS3 function block (PLPP)

DS3 function block (PLPP)

DS3 function block (PLPP)

E3 #1

E3 #2

E3 #3

DS3 #1

DS3 #2

DS3 #3 H8153

4-4Cisco BPX 8600 Series Reference