255-700-025
3-63
PacketStar
™
Access Concentrator 60 User Guide
, Issue 1
Release 6.3.0
Chapter 3 System Features
Multi-Serial Module
•
HDLC passthrough mode (N x 56 and N x 64)
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Frame relay UNI and NNI (FRF.1, FRF.2, FRF.5, and FRF.8)
•
ITU-T I.370 (Frame relay policing)
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Congestion management
•
Traffic policing
Hardware Features
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Number of ports: 12
•
Connector type: One Mini-Champ connector that mates with the AMP
cable # 1324936-1
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Line rate: 1.544 Mbps
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Framing mode: cyclic redundancy check multi-frequency (CRC-mf)
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Interfaces: ITU-T G.703, ITU G.704
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Line encoding mode: B8ZS
Multi-Serial Module
The Multi-Serial module provides six serial ports for several types of serial
data interfaces, with a maximum line rate of 2.048 Mbps, and a maximum
aggregate rate of 4 Mbps.
Bit Stuffing and CES
Conversion
The module also supports bit stuffing and 56K–64K circuit emulation service
(CES) conversion, available as standard features in the R6.3 software.
The framing for SS7's Message Transfer Part (MTP) Level 2 is a modified
version of HDLC. The difference between SS7 MTP framing and standard
HDLC is in the opening and closing 1-byte flag. SS7 MTP messages use only
the closing flag. In order to support external SS7 transport requirements, it is
necessary to exchange information via T-1 circuits where each 64 kbps DS-0
of the T-1 is filled with 56 kbps of SS7 data and 8 kbps of overhead (stuffing)
data.
The SS7 circuits originating from the Multiserial interface can be mapped
using AAL1 to an individual ATM constant bit rate (CBR) class of service
exiting on a DS3 ATM cell-bearing interface. At the far-end, the ATM circuit
is adapted (based on AAL-1 adaptation) to a native Multiserial (TDM) or CES
(TDM) circuit. SS7 traffic can originate from the Multiserial interface and
terminate on the Enhanced DS1 interface.
Interfaces
The interfaces support RS-232 (synchronous and asynchronous), RS-449,
RS-530, and V.35. For synchronous interfaces, each port can be
independently configured as either data terminating equipment (DTE) or
data communications equipment (DCE). Each port can be independently
configured for frame relay, circuit emulation, terminal emulation and