TXC-06101AILQ Transwitch Corporation, TXC-06101AILQ Datasheet - Page 10

• Manufacturer Part Number: TXC-06101AILQ
• Manufacturer: Transwitch Corporation

Specifications of TXC-06101AILQ

• Operating Temperature (min): -40C
• Operating Temperature Classification: Industrial
• Operating Temperature (max): 85C
• Package Type: PQFP
• Rad Hardened: No
• Lead Free Status / Rohs Status: Not Compliant

OVERHEAD
The overhead and transport functions in SONET have been broken into layers to promote understanding and
structure. In order of increasing complexity the layers are: Physical Medium, Section, Line and Path. When
viewed with a bottom-up approach, each layer builds upon the services provided by the lower layer. The Physi-
cal Medium Layer provides transmission at a standard bit rate. The Section layer provides framing, scrambling,
and Section maintenance for the bits being transmitted. The Line layer provides Line maintenance and protec-
tion as well as multiplexing of the STS SPEs. The Path layer provides the payload mapping function and Path
maintenance. Note than all layers can be implemented in a single piece of equipment or they can be broken
into multiple pieces of equipment.
Physical Medium Layer
The Physical Medium Layer deals with transport of the bits across the transmission medium. No overhead is
associated with this layer. Its main function is the conversion between signals internal to a Network Element
(NE) and signals suitable for transmission. Issues dealt with at this layer include pulse shape, power levels, and
(for optical equipment) wavelength. Electro-optical units communicate at this level.
Section Layer
The Section Layer deals with the reliable transport of an STS-N frame across the physical medium. Functions
within this layer include framing, scrambling, error monitoring, data communications, and a local orderwire.
Section and Physical Medium Layers can be utilized in some equipment without any higher order layers. A
regenerator would operate in this manner.
Line Layer
The Line Layer deals with the reliable transport of Path Layer payload and its overhead across the Section and
Physical Medium Layers. Overhead added here is accessed at points where SPEs are multiplexed together.
The functions of this layer are to provide synchronization and multiplexing for the Path Layer, as well as error
monitoring, data communications, orderwire, and protection signaling for Line protection switching. An example
of equipment that communicates at this level is an OC-M to OC-N multiplexer where : M < N.
Proprietary TranSwitch Corporation Information for use Solely by its Customers
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XXXXXX01
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H4 Value
t = 125 S
t = 250 S
t = 375 S
t = 500 S
t = 0
Figure 6. VT Superframe
V1
V2
V3
V4
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DATA SHEET
VT1.5
104
26
26
26
26
VT SPE Capacity
VT2
140
35
35
35
35
VT3
212
53
53
53
53
VT6
107
107
107
107
428
Total Bytes
V1 = VT Pointer 1
V2 = VT Pointer 2
V3 = Pointer Action
V4 = Reserved
= VT SPE
Legend
TXC-06101
Ed. 3, April 2001
TXC-06101-MB
PHAST-1