Path Builder S330/S310 Module And Application Overview; Management Cpu; Ctx Switch - 3Com SuperStack II PathBuilder S330 Reference Manual

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Management CPU

CTX Switch

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ATH UILDER
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AND PPLICATION
This chapter describes the operation and data flow for each of the SuperStack
®
PathBuilder S330 and S310 WAN access switch (PathBuilder S330/S310) modules
and supported applications. It contains the following sections:
Management CPU
n
CTX Switch
n
T1/E1 UNI Interface
n
OC3/STM-1 Port
n
DS3/E3 UNI Modules
n
DS3/E3 UNI Modules
n
Ethernet Interface
n
CBR Module
n
Voice Compression Module
n
The management CPU provides an intelligent user interface in addition to the
other built-in interfaces available on the PathBuilder S330/S310. It also monitors
and controls the activity on the shelf. These functions include:
Providing a user interface through a VT100 terminal or Ethernet (Telnet).
n
Programming configurations.
n
Generating and filtering alarms and transmitting them to the NMS.
n
Gathering performance-monitoring data.
n
Checking and assigning an appropriate clock source.
n
Communicating with other nodes via the management VC channel.
n
The CTX switch interfaces to all ATM busses in the system. It handles address
translation and switching among seven ATM ports. Up to four ports come from
the T1/E1 UNIs. The other three ports come from the onboard OC3/STM-1, the
SAR, and expansion slots 7, 8, and/or 9 (the optional CBR module, Voice
Compression module, and DS3/E3 UNI module).
Address translation is done via two lookups. The first lookup is a VP lookup (all 8
bits included). If a VP circuit is set up, then a VP translation is done; otherwise, a
second lookup consisting of 2 VPI bits and 8 VCI bits, is done. For VC connections,
any four VPs in the range 0-255 are allowed. Once the VC is found, the CTX
performs the address translation.
If a cell carries data, then the switch tries to place it in the proper output FIFO
(First-In, First Out) order. If the queue is congested and early packet discard is
S330/S310 M
O
VERVIEW
ODULE
® II