AAL1gator
Encyclopedia
The AAL1gator is a semiconductor device that implements the Circuit Emulation Service
. It was developed between 1994 and 1998 and became a run-away success. It also played a role in the acquisition of four companies. The name was based on the fact that the AAL1gator implements the ATM
AAL-1
standard.
(IgT). It was the first semiconductor solution to implement the Circuit Emulation Service
standard from the ATM Forum
. It implemented 8 DS1
/E1 lines worth of CES and had 256 channels. It flexibly converted the PDH
DS1 signal into Asynchronous Transfer Mode
cells.
The AAL1gator was principally designed by the Network Synthesis CEO, Brian Holden and a consultant, Ed Lennox. Brian Holden was also involved in the ATM Forum
standardization effort for the Circuit Emulation Service
. Additional design efforts came from Andy Annudurai, Ravi Sajwan, and Imran Chaudhri (who also came up with the name). Chee Hu did most of the work on getting the "C" version to work at speed and to be manufacturable. Denis Smetana did most of the work on the "D" version and on the later 32 DS1 version. Jim Jacobson of OnStream Networks
was the Beta Customer.
The AAL1gator has been used in several applications that were completely different than the application it was designed for. The designers knew they had a hit product when reports of these uses came in. One use was to provide fractional T1 service over microwave radio. Another use was to move DS1's around within a box.
The IgT acquisition happened after the development was showing signs of success. The PMC-Sierra acquisition happened after IgT's AAL1gator began to drive the sales of T1/E1 framers from PMC-Sierra. The Onstream and Sentient acquisitions happened after successful Circuit Emulation Service
(CES) product developments based on the AAL1gator.
An anecdote from the AAL1gator's development is that Brian Holden and Ed Lennox made a quick, off-handed decision in a hallway to add the "PMC Mode" to the "B" version of the device in mid-1996 to provide a glueless interface to PMC-Sierra's TQUAD and EQUAD T1 and E1 framers. Little did they know then that this off-handed decision would be a key enabler of PMC-Sierra
's acquisition of the company two years later.
developed a 32 line version of the AAL1gator known as the AAL1gator32.
Circuit Emulation Service
Circuit Emulation Service is an emerging telecommunication technology used to transmit time-division multiplexed services such as the traditional Digital Signal and the E-carrier circuits over Asynchronous Transfer Mode networks...
. It was developed between 1994 and 1998 and became a run-away success. It also played a role in the acquisition of four companies. The name was based on the fact that the AAL1gator implements the ATM
Asynchronous Transfer Mode
Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...
AAL-1
ATM Adaptation Layers
The use of Asynchronous Transfer Mode technology and services creates the need for an adaptation layer in order to support information transfer protocols, which are not based on ATM...
standard.
Development of the AAL1gator
The AAL1gator was developed by Network Synthesis, Inc. under contract from Integrated Telecom TechnologyIntegrated Telecom Technology
Integrated Telecom Technology, Inc., known as "IgT" was a fabless semiconductor company founded in 1991 by Ken Lee, Greg Werth, Imran Chaudhri, Jerry Tall, and Chi Wai in Gaithersburg, Maryland. IgT was one of the first companies to focus on semiconductors for the communications marketplace...
(IgT). It was the first semiconductor solution to implement the Circuit Emulation Service
Circuit Emulation Service
Circuit Emulation Service is an emerging telecommunication technology used to transmit time-division multiplexed services such as the traditional Digital Signal and the E-carrier circuits over Asynchronous Transfer Mode networks...
standard from the ATM Forum
ATM Forum
The ATM Forum was founded in 1991 to be the industry consortium to promote Asynchronous Transfer Mode technology used in telecommunication networks. It was a non-profit international organization. The ATM Forum created over 200 implementation agreements....
. It implemented 8 DS1
Digital Signal 1
Digital signal 1 is a T-carrier signaling scheme devised by Bell Labs. DS1 is a widely used standard in telecommunications in North America and Japan to transmit voice and data between devices. E1 is used in place of T1 outside North America, Japan, and South Korea...
/E1 lines worth of CES and had 256 channels. It flexibly converted the PDH
Plesiochronous Digital Hierarchy
The Plesiochronous Digital Hierarchy is a technology used in telecommunications networks to transport large quantities of data over digital transport equipment such as fibre optic and microwave radio systems...
DS1 signal into Asynchronous Transfer Mode
Asynchronous Transfer Mode
Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...
cells.
The AAL1gator was principally designed by the Network Synthesis CEO, Brian Holden and a consultant, Ed Lennox. Brian Holden was also involved in the ATM Forum
ATM Forum
The ATM Forum was founded in 1991 to be the industry consortium to promote Asynchronous Transfer Mode technology used in telecommunication networks. It was a non-profit international organization. The ATM Forum created over 200 implementation agreements....
standardization effort for the Circuit Emulation Service
Circuit Emulation Service
Circuit Emulation Service is an emerging telecommunication technology used to transmit time-division multiplexed services such as the traditional Digital Signal and the E-carrier circuits over Asynchronous Transfer Mode networks...
. Additional design efforts came from Andy Annudurai, Ravi Sajwan, and Imran Chaudhri (who also came up with the name). Chee Hu did most of the work on getting the "C" version to work at speed and to be manufacturable. Denis Smetana did most of the work on the "D" version and on the later 32 DS1 version. Jim Jacobson of OnStream Networks
OnStream Networks
OnStream Networks was a Santa Clara, California-based supplier of Circuit Emulation Service based Asynchronous Transfer Mode solutions. It was formerly T3Plus....
was the Beta Customer.
Patents on the AAL1gator
Two U.S. patents were issued on the AAL1gator's calendar-based transmit scheduler, one on the original product and an even better one on the "D" version enhancements designed by Denis Smetana. The scheduler implemented several intricate methods of minimizing the jitter caused by the scheduling of the 256 channels. The AAL1gator also could have gotten another patent on its method of queuing the SRTS samples, but the designers were too busy to get the application in.Functions of the AAL1gator
The AAL1gator could flexibly map individual DS0s or groups of DS0s into 256 ATM VCs. It also had a high speed mode which mapped a single DS-3 into ATM. Additionally, it had a high performance implementation of the SRTS clock recovery algorithm. The original AAL1gator also was delivered along with the code for an external digital frequency synthesizer. A later version incorporated that synthesizer.The AAL1gator has been used in several applications that were completely different than the application it was designed for. The designers knew they had a hit product when reports of these uses came in. One use was to provide fractional T1 service over microwave radio. Another use was to move DS1's around within a box.
The AAL1gator and acquisitions
The AAL1gator played a significant role in the following four technology acquisitions:- Network Synthesis by Integrated Telecom TechnologyIntegrated Telecom TechnologyIntegrated Telecom Technology, Inc., known as "IgT" was a fabless semiconductor company founded in 1991 by Ken Lee, Greg Werth, Imran Chaudhri, Jerry Tall, and Chi Wai in Gaithersburg, Maryland. IgT was one of the first companies to focus on semiconductors for the communications marketplace...
in June 1996 - Integrated Telecom TechnologyIntegrated Telecom TechnologyIntegrated Telecom Technology, Inc., known as "IgT" was a fabless semiconductor company founded in 1991 by Ken Lee, Greg Werth, Imran Chaudhri, Jerry Tall, and Chi Wai in Gaithersburg, Maryland. IgT was one of the first companies to focus on semiconductors for the communications marketplace...
by PMC-SierraPMC-SierraPMC-Sierra is a fabless semiconductor company which develops and sells devices into the communications, storage, printing, and embedded computing marketplaces.-Corporate history:...
in April 1998 - OnStream NetworksOnStream NetworksOnStream Networks was a Santa Clara, California-based supplier of Circuit Emulation Service based Asynchronous Transfer Mode solutions. It was formerly T3Plus....
by 3Com3Com3Com was a pioneering digital electronics manufacturer best known for its computer network infrastructure products. The company was co-founded in 1979 by Robert Metcalfe, Howard Charney, Bruce Borden, and Greg Shaw...
in 1996 - Sentient NetworksSentient NetworksSentient Networks was a San Jose, California based supplier of Asynchronous Transfer Mode and Frame Relay central office concentrators and switches.-Market space:...
by Cisco SystemsCisco SystemsCisco Systems, Inc. is an American multinational corporation headquartered in San Jose, California, United States, that designs and sells consumer electronics, networking, voice, and communications technology and services. Cisco has more than 70,000 employees and annual revenue of US$...
in 1998
The IgT acquisition happened after the development was showing signs of success. The PMC-Sierra acquisition happened after IgT's AAL1gator began to drive the sales of T1/E1 framers from PMC-Sierra. The Onstream and Sentient acquisitions happened after successful Circuit Emulation Service
Circuit Emulation Service
Circuit Emulation Service is an emerging telecommunication technology used to transmit time-division multiplexed services such as the traditional Digital Signal and the E-carrier circuits over Asynchronous Transfer Mode networks...
(CES) product developments based on the AAL1gator.
An anecdote from the AAL1gator's development is that Brian Holden and Ed Lennox made a quick, off-handed decision in a hallway to add the "PMC Mode" to the "B" version of the device in mid-1996 to provide a glueless interface to PMC-Sierra's TQUAD and EQUAD T1 and E1 framers. Little did they know then that this off-handed decision would be a key enabler of PMC-Sierra
PMC-Sierra
PMC-Sierra is a fabless semiconductor company which develops and sells devices into the communications, storage, printing, and embedded computing marketplaces.-Corporate history:...
's acquisition of the company two years later.
The AAL1gator-32
PMC-SierraPMC-Sierra
PMC-Sierra is a fabless semiconductor company which develops and sells devices into the communications, storage, printing, and embedded computing marketplaces.-Corporate history:...
developed a 32 line version of the AAL1gator known as the AAL1gator32.