The first pseudowire specifications were the Martini draft for ATM pseudowires, and the TDMoIP draft for transport of E1 / T1 over IP.

Utfors employed the first generation TDMoIP product ( known as Ipmux-4 ) to provide bundled services including TDM private lines, TDM leased lines and a variety of IP and Ethernet services.

For structure-indication and structure-reassembly TDMoIP draws on proven adaptation mechanisms originally developed for ATM.

TDMoIP transport is denoted " structured-agnostic " when the TDM is unframed, or when it is framed or even channelized, but the framing and channelization structure are completely disregarded by the transport mechanisms.

TDMoIP operates by segmenting, adapting and encapsulating the TDM traffic at PSN ingress and performing the inverse operations at PSN egress.

The packetization latency added by TDMoIP depends on the number of cells per packet but is typically in the single millisecond range due to the higher data rate of a complete multiplex as compared to a single VoIP flow.

However, unlike other traffic types that can be carried over pseudowires ( e. g. ATM, Frame Relay, and Ethernet ), TDM is a real-time bit stream, leading to TDMoIP having unique characteristics.

TDMoIP presents a migration path, whereby modern packet switched networks can be used for transport, while the end-user equipment need not be immediately replaced.

In all cases a TDMoIP packet commences with PSN headers.

After the control word comes the TDMoIP payload.

TDMoIP allows concatenation of any number of AAL1 cells into a packet ( note that these are AAL1 cells and not ATM cells, i. e. they do not include the five-byte " cell tax ").

TDMoIP concatenates the minicells from all active time slots into a single packet.

For time slots carrying high-level data link control ( HDLC ) data, such as data for common channel signaling ( CCS ), TDMoIP has a special adaptation that encapsulates stretches of non-idle data.

In contrast, TDMoIP maps TDM octets directly into the payload with no voice compression algorithms and no resultant algorithmic delay.

The problem arises when at most one side of the TDMoIP tunnel has a highly accurate time standard.

The TDMoIP control word described above includes a 16-bit sequence number for detecting and handling lost and mis-ordered packets.

In the case of lost packets, TDMoIP requires insertion of interpolation packets to maintain TDM timing.

The precise effect of packet loss on voice quality and the development of packet loss concealment algorithms have been the subject of detailed study in the VoIP community, but their results are not directly applicable to the TDMoIP case.

This is because VoIP packets typically contain between 80 samples ( 10 ms ) and 240 samples ( 30 ms ) of the speech signal, while TDMoIP packets may contain only a small number of samples.

Since TDMoIP packets are so small, it is acceptable to simply insert a constant value in place of any lost speech samples.

In computer networking and telecommunications, TDM over IP ( TDMoIP ) is the emulation of time-division multiplexing ( TDM ) over a packet switched network ( PSN ).

TDMoIP is a type of pseudowire ( PW ).

Another issue that must be addressed is TDMoIP packet loss concealment ( PLC ).

For statically allocated, constant bit-rate ( CBR ) TDM links, TDMoIP employs ATM adaptation layer 1 ( AAL1 ).

By allowing multiple cells per packet, TDMoIP facilitates flexible tradeoffs of buffering delay ( which decreases with fewer cells per packet ) for bandwidth efficiency ( which increases with more cells per packet, due to the per packet overhead ).

For dynamically allocated TDM links, whether the information rate varies due to activation of time slots or due to voice activity detection, TDMoIP employs ATM adaptation layer 2 ( AAL2 ).

But her prettiness was what he had noticed first, and all the other things had come afterward: cruelty, meanness, self-will.

There was an artificial lake just out of sight in the first stand of trees, fed by a half dozen springs that popped out of the ground above the hillside orchard.

The first part of the road was steep, but it leveled off after the second bend and curled gradually into the valley.

No one was behind it, but in the rear wall of the office I noticed, for the first time, a door which had been left partially open.

The herd was watered and then thrown onto a broad grass flat which was to be the first night's bedground.

Once again, Tom Horn was the first and most likely suspect, and he was brought in for questioning immediately.

For Matilda, it was the first she had known in many a night.

Even the knowledge that she was losing another boy, as a mother always does when a marriage is made, did not prevent her from having the first carefree, dreamless sleep that she had known since they dropped down the canyon and into Bear Valley, way, way back there when they were crossing those other mountains.

Stevens was grunting over the last empty pocket when Russ abruptly rose and lunged toward Carmer's hat, which had tumbled half-a-dozen feet away when he first fell.

The Indian's arm whipped sidewise -- there was a flash of amber and froth, the crash of the bottle shattering against the side of the first car.

It was her first smile.

At first, I thought he was out of his head, talking wildly like this.

Hell, I gave him the first decent job he ever had, six, seven -- how many years ago was it, Rob ''??

Miss Langford ( her first name was Evelyn ) was an attractive girl.

School began in August, the hottest part of the year, and for the first few days Miss Langford was very lenient with the children, letting them play a lot and the new ones sort of get acquainted with one another.

It was just as well that the ignorant Dandy enjoyed himself to the hilt that first evening, for the room was to become his prison cell.

`` Bastards '', he would say, `` all I did was put a beat to that Vivaldi stuff, and the first chair clobbered me ''!!

In 1961 the first important legislative victory of the Kennedy Administration came when the principle of national responsibility for local economic distress won out over a `` state's-responsibility '' proposal -- provision was made for payment for unemployment relief by nation-wide taxation rather than by a levy only on those states afflicted with manpower surplus.

The first systematic thinking about this Pandora's box within Pandora's boxes was done four years ago by Fred Ikle, a frail, meek-mannered Swiss-born sociologist.

The smell at first was more surprising than unpleasant.

His collaboration with Washington, begun when he was the general's aide during the Revolution, was resumed when he entered the first Cabinet as Secretary of the Treasury.