Beijing Paradise BBS Backup

home *** CD-ROM | disk | FTP | other *** search

/ Beijing Paradise BBS Backup / PARADISE.ISO / bbs / RA / STGEN / REPORT.DOC < prev next >

Wrap

Text File | 1976-11-24 | 22.0 KB | 417 lines

┬┬ ┬ ┌┬──┐ ┬┬──┐ ┌┬──┐ ┌─┬┬─┐ ┌┬──┐ ┌─┬┬─┐ ┌┬──┐ ││ │ ││ ││ │ ││ ││ ││ │ ││ ││ Version 4.13 ││ │ └┴─┬┐ │├─┬┘ └┴─┬┐ ││ │├──┤ ││ └┴─┬┐ ││ │ ││ ││ │ ││ ││ ││ │ ││ ││ 12/30/95 └┴──┘ └──┴┘ ┴┴ ┴─ └──┴┘ ┴┴ ┴┴ ┴ ┴┴ └──┴┘ Interpreting the USRSTATS Report ─────────────────────────────────────────────────────────────────────── Public posting of this document in its unmodified form is permitted. ─────────────────────────────────────────────────────────────────────── The USRSTATS report is divided into several sections, like this: ┌─────────────────────────────────┐ │ Info │ ├───────────────┬─────────────────┤ │ │ │ │ Error Control │ Data Pump stats │ │ and DTE stats │ │ │ │ │ └───────────────┴─────────────────┘ ┌─────────────────────────────┐ │ │ │ Channel Probe │ │ (V.34 and V.FC modes) │ │ │ └─────────────────────────────┘ ┌─────────────────────────────┐ │ │ │ Current settings │ │ (optional) │ │ │ └─────────────────────────────┘ Error Control and DTE stats - This section contains information about the Error Control and Data Compression protocols currently active. This includes MNP, LAPM, V.42, and V.42bis. It also displays the number of characters sent and received by the attached terminal. Data Pump stats - This section contains information on the operation of the Data Pump. Specifically, it provides details of the modulation protocol that was negotiated, the impairments that are affecting the connection, and how the modem has responded to those impairments. Channel Probe - This section is applicable only to connections made under V.34 and VFC modulation. It shows details of the frequency response and bandwidth characteristics of the physical link. (Phone line.) Info - This field contains the USRSTATS banner, and information used for record-keeping purposes, such as the date and time, or the name of the system being called. ─────────────────────────────────────────────────────────────────────── Here's a sample of a V.34 connection report: ┌───────────────────────┬─────────────────┬──────────────────────────┐ │ USRSTATS Version 4.13 │ 12-30-95 11:35 │ Caller 0 │ ├───────────────────────┴─────────┬───────┴──────────────────────────┤ │ Elapsed Time 00:00:18 │ Modulation V.34+ │ │ Blocks Received 15 │ Speed 31200/28800 │ │ Blers 0 │ Symbol Rate 3429/3429 │ │ Blocks sent 5 │ Carrier Frequency 1959/1959 │ │ Link Naks 0 │ Trellis Code 64S-4D/64S-4D │ │ Blocks resent 0 │ Nonlinear Encoding ON/ON │ │ Link Timeouts 0 │ Precoding OFF/ON │ │ Chars sent 0 │ Shaping ON/ON │ │ Octets sent 10 │ Preemphasis 4/6 │ │ Chars lost 0 │ Rx Lev/TX Lev/SNR 25.2/12.0/36.8 │ │ Chars Received 0 │ Echo Loss Near 17.0 Far 40.0 │ │ Octets Received 239 │ Roundtrip Delay 4 │ │ Protocol LAPM SREJ │ Retrains Request/Grant 0/0 │ │ Block Size 244 │ Fallback Enabled │ │ Window Size 15 │ HST Line Reversals 0 │ │ Compression V42BIS │ HST Equalization Long │ │ Dictionary Size 2048 │ SV: 11/01/95 DSP: 11/15/95 │ │ String Length 32 │ Reason: Online │ └─────────────────────────────────┴──────────────────────────────────┘ ┌───────────────────────────────────────────────────────────────┐ │ -22 │ ∙ ∙ ∙ ∙ ∙ ∙ ▄ ▄ ▄ ∙ ∙ ∙ ∙ ∙ ∙ ∙ ∙ ∙ ∙ ∙ ∙ ∙ ∙ ∙ ∙ │ 0 │ │ -24 │ ∙ ∙ ∙ ▄ █ █ █ █ █ █ █ █ █ █ ▄ ▄ ▄ ∙ ∙ ∙ ∙ ∙ ∙ ∙ ∙ │ 2 │ │ -26 │ ∙ ∙ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ ▄ ▄ ∙ ∙ ∙ ∙ │ 4 │ │ -28 │ ∙ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ ▄ ∙ ∙ │ 6 │ │ -30 │ ∙ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ ∙ ∙ │ 8 │ │ -32 │ ∙ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ ▄ ∙ │ 10 │ │ -34 │ ∙ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ ∙ │ 12 │ │ -36 │ ∙ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ ∙ │ 14 │ │ -38 │ ▄ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ ∙ │ 16 │ │ -40 │ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ ∙ │ 18 │ │ -42 │ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ █ │ 20 │ │Level└───────────────────────────────────────────────────┘Atten│ │ 0 0 0 0 0 0 1 1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 3 │ │ 1 3 4 6 7 9 0 2 3 5 6 8 9 1 2 4 5 7 8 0 1 3 4 6 7 │ │ 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 │ │ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 │ └───────────────────────────────────────────────────────────────┘ ─────────────────────────────────────────────────────────────────────── Error Control Group: Blocks Sent/Received - The number of Blocks sent and received by the Error Control protocol. Blers - (Block Errors) This field is a count of errors in received Error Control Protocol or Data blocks. These errors are caused by noise or other impairments in the channel, and small numbers of them are to be expected. On severely impaired lines, values in the hundreds or thousands may be seen. This field is one of the key indicators of the receive channel quality. This number is a count of 50 millisecond time units during which one or more errors occurred, and is therefore related to the elapsed time of the connection as well as the number of blocks received. Link Naks - This field indicates the number of times the remote modem requested the re-send of one or more blocks of data. Since it is possible for the request to encompass more than 1 block, this number does not necessarily indicate the actual block count. The remote modem requests a re-send when a data block is corrupted by impairments in the channel. Blocks resent - This field is a count of transmitted Error Control protocol blocks that were re-sent at the request of the remote receiver. The Link Naks field counts these requests, and is related to the number of blocks resent. Link Timeouts - This field indicates the number of times the Error Control protocol did not receive a response from the remote modem within the expected time frame. This is normally caused by channel impairments, and also occurs when the remote receiver is being flow controlled by its terminal. Chars Sent/Received - These fields count the number of characters sent and received through the modem's DTE interface. These fields are only updated periodically when in the on-line state. After the modem goes off-line, the true value is shown. Octets sent/Received - Octets are compressed data units. The compression ratio can be determined by dividing Characters by Octets. Chars lost - This field indicates the number of characters lost in the Transmit Buffer, due to buffer over-runs. This field should always be zero. Non-zero values indicate a problem with Transmit Data flow control in the terminal. Protocol - This field indicates the Error Control protocol in use. Possible values include NONE, HST, MNP, and LAPM. (LAPM is sometimes referred to as V.42, although it is actually only one part of the V.42 spec.) USR modems will prefer LAPM over MNP, although they can be forced into MNP mode. HST Error Control is only used in conjunction with the proprietary HST modulation mode. Block Size - The data frame size used in LAPM and MNP modes. Larger block sizes result in less protocol overhead, and faster throughput. This is a negotiated parameter, and will vary depending on the remote modems capabilities. Window Size - The number of LAPM or MNP data frames that may be in transit without being accounted for at any moment in time. Larger window sizes can improve performance under conditions of high round- trip delay. This is a negotiated parameter, and will vary depending on the remote modems capabilities. Compression - This field indicates the Data Compression protocol in use. Possible values are NONE, MNP5, or V42BIS. Dictionary Size - The number of entries in the V42bis compression table. Larger numbers indicate greater potential compression performance with certain data types. This number may vary when connecting to modems from different manufacturers. USR modems default to a Dictionary Size of 2048 entries. String Length - The length of each string in the V42bis compression table. Larger numbers indicate greater potential compression performance with certain data types. This number may vary when connecting to modems from different manufacturers. USR modems default to a String Length of 32 characters. ─────────────────────────────────────────────────────────────────────── Data Pump Group: Modulation - This field indicates the modulation protocol negotiated for this connection. Possible values are V.34, VFC, V.32/bis/terbo, HST, V.22bis, and several others. Note that the USR Courier modems will report V.32/bis/terbo for ANY of the V.32-type modulation schemes. HST is USR's proprietary High-Speed protocol. Speed - This field indicates the current bit rate of the connection, in Bits Per Second (BPS). For normal V.32/bis/terbo AND VFC modulation, a single speed will be displayed since those protocols require the receive and transmit channels to always run at the same speed. This is an important point, because it means that both channels are limited to the speed of the LOWER of the two directions. USR's ASL feature enhances the V.32/bis/terbo protocols by allowing the transmit and receive channel speeds to be adjusted independently, maintaining maximum throughput in each channel regardless of the "direction" of the channel impairments. In this case, two speeds will be displayed, which are the Receiver and Transmitter speeds, respectively. Other fields in the Data Pump Group which display 2 values follow the same convention of Receiver/Transmitter. ─────────────────────────────────────────────────────────────────────── This concept of independent channel speed is an integral part of the V.34 protocol, and is one of the key improvements over VFC. ─────────────────────────────────────────────────────────────────────── Symbol Rate - This field indicates the Symbol Rate of the receiver and transmitter, respectively. A Symbol is a waveform transmitted by the modem, which contains a certain number of encoded bits of data to be moved across the link. The receiving modem decodes this waveform, recovers the package of bits, and re-assembles it. (The noise levels in the channel determine how many bits are encoded in each symbol. Lower noise levels allow a greater number of bits per symbol.) The design of the telephone system limits how many of these symbols may be sent across a phone line each second. Symbols cannot be sent faster than the *bandwidth* available through the phone line. V.34 and VFC modulation allow adjusting this symbol rate to any of six possible values, to obtain the best match with the available bandwidth. Other protocols only allow a single, fixed value for the symbol rate, regardless of the bandwidth of the link. This field has a very direct link to the overall connection speed, and under V.34 and VFC modulation, it is directly related to the available bandwidth as determined by the line probe. ─────────────────────────────────────────────────────────────────────── The V.34 protocol allows independent adjustment of the Symbol Rate in the receive and transmit channels, while VFC requires both channels to run at the same Symbol Rate, the LOWER of the two. ─────────────────────────────────────────────────────────────────────── Carrier Freq - This field indicates the Carrier Frequency (in Hz) of the receiver and transmitter, respectively. Under V.34 and VFC modulation, the Carrier Frequency can be one of several values, determined during the handshake and line probe processes. Under other modulation types, the Carrier Frequency is a single fixed value. Trellis Code - This field indicates the type of Trellis Code in use by the receiver and transmitter, respectively. Trellis coding improves the system's noise immunity. The type of coding may vary when connecting modems from different manufacturers. Nonlinear Encoding - This field applies only under V.34 and VFC modulation, and shows the state of the received signal and transmitted signal, respectively. Nonlinear Encoding is an operation performed on the transmitted signal to improve the operation of the receiver in the presence of nonlinear distortion. The modem will automatically negotiate this option during the handshake. Precoding - This field applies only under V.34 and VFC modulation, and shows the state of the received signal and transmitted signal, respectively. Precoding is an operation performed on the transmitted signal to reduce the effects of noise multiplication in the adaptive equalization process. The modem will automatically negotiate this option during the handshake. Shaping - This field applies only under V.34 and VFC modulation, and shows the state of the received signal and transmitted signal, respectively. Shaping is an operation performed on the transmitted signal to improve the operation of the receiver in the presence of certain types of noise. The modem will automatically negotiate this option during the handshake. Preemphasis Index - This field applies only under V.34 and VFC modulation, and shows the Index value for the receiver and transmitter, respectively. Preemphasis is a way of compensating for poor phone line bandwidth. If the line has poor bandwidth, the upper frequencies of the transmitted signal can be boosted to compensate for the roll-off. The modem will select 1 of 10 possible values, based on the actual roll-off rate of the phone line. This field indicates which value has been chosen, larger numbers mean that more preemphasis is being applied to compensate for the line. The modem will automatically negotiate this option during the handshake. Rx/Tx Level - This field indicates the level (in -dB) of the receive and transmit signals, respectively. Standard transmit level for US/Canada modems is approximately -10 dB, although under V.34 and VFC modulation, the levels are negotiated and adjusted by the modem during the handshake. Receive level can vary widely, depending on the conditions on your local phone line, the line at the remote modem, and any long-distance or inter-office carrier facilities. *Typical* values will range from -40 dB at the low end, to -15 dB at the high end, with figures in the -20 to -35 range being most common. Extreme values in either direction probably indicate a problem in your local loop, which the phone company may be able to adjust. SNR (Signal to Noise Ratio) - The number displayed is the ratio of the Receive Level to the Noise Level. The Absolute Noise Level (in dBm) can be computed from the SNR and Receive Level. In a "noiseless" channel, the Absolute Noise Level is approximately -60 dBm. SNR is one of the most important factors in modem performance. Lower SNR values generally result in lower connect speeds. Note that a poor SNR does not necessarily mean that the Noise Level is too high; it can also mean that the RX Level is too low. Typical SNR values range from 15 to 35 dB. Larger values indicate better SNR. Near Echo Loss - Near End echo occurs when the transmitted signal is reflected from the local modem's hybrid circuit due to impedance mismatch. The number displayed is the ratio of the Transmit Level to the Near End Echo Level, or the amount of attenuation the Near End echo has when compared to the transmitter. Under normal conditions, the Near End echo is approximately 30 dB below the TX signal level. Larger numbers indicate better impedance matching at the local modem. Far Echo Loss - Far End echo occurs when the transmitted signal is reflected from the REMOTE modem's hybrid circuit due to impedance mismatch. This echo experiences both the forward channel and reverse channel losses, and is usually very small in magnitude. The number displayed is the ratio of the Receive Level (which has the reverse channel loss embedded within) to the Far End Echo Level along with the forward channel loss. Typical values of Far Echo Loss are approximately 30 dB. Larger numbers indicate better impedance matching at the remote modem. Roundtrip Delay - This field indicates the amount of time (in milliseconds) it takes for the modem to hear a reflection of it's own transmitter. This is closely related to the physical length and transmission path of the phone link, and it affects the operation of the modem's echo canceller. This delay also affects the timing of the modem's handshaking routines. Retrains Requested - This field is a count of the number of times the modem sent a request for a re-train to the remote end. This happens when the line quality degrades to the point where the modems lose sync with each other. Note that under some modulation types, and with certain configuration settings, the remote modem is NOT required to *honor* this request, it may be simply ignored. This field corresponds with the "Retrains Granted" field of the REMOTE modem, NOT the field in THIS report. Retrains Granted - This field is a count of the number of times the modem responded to a re-train request from the remote end. This field corresponds to the "Retrains Requested" field of the REMOTE modem, NOT the field in THIS report. Fallback - This field indicates whether the modem has performed a speed shift, either up or down, at any point during the connection. "Disabled" means that there has been no speed shift, "Enabled" means there has been a speed shift. HST Line Reversals - This field is only meaningful for connections using HST modulation. It then indicates the number of times the modem switched the directions of the high-speed forward channel and the low- speed back channel. HST Equalization - This field indicates whether the modem is using extra pre-emphasis on the transmitted signal. This field applies only to HST modulation. SV - This field indicates the revision date of the modem Supervisor (Controller) firmware. DSP - This field indicates the revision date of the modem DSP (Data Pump) firmware. Reason - This is the "Disconnect Reason" reported by the modem. ─────────────────────────────────────────────────────────────────────── Line Probe Group: Line Probing only applies to V.34 and VFC modulation. This is a test to determine the actual bandwidth available over the phone line. During the handshake, the modems send a series of tones to each other, at known levels and specific frequency points. The modem calculates the level of the received signal at each point, and therefore can determine the maximum bandwidth available for use. This section of the report shows each of those frequency points, and, on the left side of the graph, the signal level (in -dB) at that point. (Levels are referenced from 0.) The right side of the graph shows the attenuation at each frequency, relative to the HIGHEST level recorded. (This corresponds to the dynamic range of the received signal.) If any of the signal levels fall below -44 dB, the chart will include a line of ==== characters to show that threshold. Generally speaking, values below about -40 dB become difficult for the modem to interpret, depending on other line conditions. The effective bandwidth calculated here directly affects the Symbol Rate, and overall connect rate. The modem will select the fastest Symbol Rate that can be reliably handled by this bandwidth. ─────────────────────────────────────────────────────────────────────── Info Group: This field shows the USRSTATS banner and version number, and the date and time that the report was created. (Not when the data was captured!) It will also optionally show the Caller and Node number (when used with the PCBoard PPE), the last number dialed (in stand- alone mode), the elapsed time of the current call, or other data passed by a "door" program on a BBS. ─────────────────────────────────────────────────────────────────────── Settings Group: This is an optional display of the current modem settings at the time the report data was captured. ─────────────────────────────────────────────────────────────────────── [END]