AS5x00 Specific Commands and Debugs
| High-density Cisco dial routers include the AS5100, AS5200, AS5300, AS5400, and AS5800 series routers. These devices were all developed for an ISP to provide dial-in services for a wide variety of customers. All these devices are modular so that if a modem or a group of modems is faulty, a feature card can be replaced instead of the entire router. The AS5100 series router is no longer in production, but was solely a router with a lot of external modems on line cards connected to it, all in one chassis; not modular. In fact, phone lines were connected to each of the individual modem line cards on the router. Because the AS5100 is no longer in production and was essentially the same as the router used for the examples on Basic PPP Dial-In Service, it is not covered in detail in this chapter. The AS5200 series was the first Cisco product in this line to introduce 56 k modems. The router used Microcom modems that were software upgradeable using a digital signal processor (DSP) and firmware files available from the Cisco Systems web site. This server was also the first Cisco dial router to use channelized T1s or PRIs to handle incoming calls. This router has since reached the end of the production cycle. The AS5300 opened the door to out-of-band signaling. Although the AS5200 had limited out-of-band signaling, the AS5300 (with the MICA modems) allows for polling all kinds of data from the modem that was not previously available. This includes real-time band -width measurements, line shape measurements, serial-to-noise ratio, as well as many other parameters that are key to troubleshooting real-time. Most, if not all competitor dial servers do not provide for this real-time data, and it must be extracted from the modems via the AT command ati11 after the call is completed. The AS5300 can handle a total of 8 PRIs worth of calls in its 2U chassis. The AS5400 provides the same out of band signaling, but it has taken port density to a new level. At the time this book was written, the AS5400 can receive a CT3 worth of calls (552 calls if split into 24 PRIs with 23 available channels each) in a router that only consumes 2U worth of rack space. This is possible because of the new NextPort modems included in the AS5400. The AS5350 shares these modems in a 1U chassis that can handle 16 PRIs worth of calls. The AS5800 was developed with the AS5300 and provided the same functionality as the AS5300, but in a higher density package. It is a large 48VDC unit that was designed for the service provider environment. As well as the use of the MICA modems, all configuration commands are the same as the AS5300. The AS5850 shares the new NextPort modems with the AS5400 and AS5350, but in a larger chassis developed for sizeable deployments. The AS5850 is a 14U rack mount unit that can handle up to 3360 calls (5xCT3s), 96 T1s or 86 E1s. While not as dense as the AS5400 in terms of ports per unit of rack space, the AS5850 was developed to handle six times its current density. One of the most commonly used maintenance procedures for all earlier platforms is to upgrade the modem firmware. Although it is relatively straightforward, the procedure requires some steps that are included in the following example. To upgrade modem software on the routers, you must first know what version of IOS is running on the router. There are two different scenarios for upgrading modem firmware, depending on the IOS version. Each step is covered here. The first step in upgrading modem firmware is to get the latest version from Cisco.com and put it on your TFTP server. Next , copy it to the flash on the router that requires the update. Be sure not to erase the original contents of the flash memory when copying the upgrade to flash. Example 7-29 shows how to copy an image file to flash. Example 7-29. Output from the copy tftp flash Command5300-dialin# copy tftp flash Address or name of remote host []? 192.168.1.17 ! Enter the image file name you want to copy: Source filename []? mica-modem-pw.2.7.3.0.bin Destination filename [mica-modem-pw.2.7.3.0.bin]? Accessing tftp://www-emp/ mica-modem-pw.2.7.3.0.bin... Erase flash: before copying? [confirm] n Loading mica-modem-pw.2.7.3.0.bin from 192.168.1.17 (via FastEthernet0): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!! [OK - 474939/949248 bytes] Verifying checksum... OK (0xCB52) The image must reside in flash because the modems load this software each time the router is restarted. For IOS versions earlier than 12.0(5), the modem upgrade is done through the copy flash modem command, at an enabled prompt, but not in configuration mode. The following is an illustration of that process: 5300-dialin# copy flash modem Modem Numbers (/[-/] group all)? all Name of file to copy? mica-modem-pw.2.7.3.0.bin Type of service [busyout/reboot] reboot NOTE Using reboot as the type of service does not upgrade the modems until the next time the router is reloaded. This is handy if there are prescheduled maintenance windows . You can then use the reload at command to schedule the reload for a specific time, in advance. As a precaution, only use busyout if call volume on the router is low. The router upgrades the modems by busying out all modems and upgrading the groups that have no calls on them. These groups contain either six or 12 modems, depending on type. If calls currently connected prevent modems from upgrading, inbound calls can be rejected with a fast-busy signal because no modems are available. To confirm the upgrade, use the command show modem version to verify that the modems have the new version. For IOS releases later than 12.0(5), the upgrade is done in Software Port Entry (SPE) configuration mode. Use the command show spe version to see what firmware versions are stored in flash on the router and determine which ones require an upgrade. The following lines show the configuration commands required to upgrade spe software: 5300-dialin# configure terminal 5300-dialin(config)# spe 1/0 2/9 5300-dialin(config-spe)# firmware upgrade reboot 5300-dialin(config-spe)# firmware location flash:mica-modem-pw.2.7.3.0.bin If you want to use reboot as the type of upgrade service, specify this before specifying the location of the firmware. After the location of the firmware is specified, the router begins the upgrade. Because the default is busyout , you can easily busy out every modem on a busy access server if you do not specify this beforehand. To confirm the upgrade, use the command show spe modem to verify that the modems have the new version. AS5200 Specific Commands and DebugsThere are numerous additional commands for modems in the AS5200 series. Although this product has reached the end of life (EOL), it is still in widespread use so these commands are still worth covering. Only the most useful and most commonly used commands are covered. The first of these commands is show modem , which shows a list of all modems along with the number of successful and failed incoming call attempts, outgoing call attempts, and a percentage of successful calls. In addition, it displays the current status of every modem: active, busied out, bad, downloading firmware, or pending download. If you prefer to only see the summary of this information, use the command show modem summary . You can almost immediately tell if there is a problem by looking at the success percentage. Most dial-in pools have a 90 percent or higher success rate. Using the same show modem slot/port command (including a specific modem) shows you much more detail about the specified modem, along with all the connection speeds reached with that modem. The show modem call-stats command displays the statistics for all modems and includes reasons for disconnect, compression, number of retrains, and a summary of all the information. Another useful command is show modem connect-speeds , which shows the total number of connections at each speed throughout the range for both receive and transmit. A summary along with percentages is also provided later in the section. This is useful to get a quick glimpse of what your clients are experiencing. A command that you use often when reporting problems to the Technical Assistance Center (TAC) is show modem csm slot/port , which provides the TAC a view of exactly what is occurring with a call switching module (CSM) at that precise point in time. Another command that the TAC often uses to help debug problems is show modem log slot/port . It provides all information about what the modem has done previously. The data is purged on a first in first out basis, so use this show command immediately after the problem occurs. The command shows all RS232 events, modem state events, modem analog signal events, and connection events. It also contains information on train-up speeds, modulation, and serial-to-noise ratio. The last of the show commands created for the AS5200 is show modem version , which shows what version of software is on the modems. Always keep this software up to date to obtain the best possible connection for remote users. A separate procedure exists for each kind of modem (see www.cisco.com for further details). The AS5200s also have several added debugging modes. The first is debug modem oob , which shows information about a modem's out-of-band port that polls modem events. The debug modem csm command displays information about the CSM that connects calls. It shows all information about calls coming in from the PRI and what modem it lands on. Perhaps one of the most useful debug commands in dial routers is debug modem trace . With this debug, you can select normal, abnormal, or all reasons for call termination. To gather all abnormal call terminations on the entire router, use the command debug modem trace abnormal . If you want to gather all terminations from a specific modem, in the event that you think a particular modem is malfunctioning, use the command debug modem trace all slot/port . When disconnecting a call that matched the debug, a trace is sent to the screen including everything that took place with the call, down to the finest detail. Finally, there is one other command that is neither a show command nor a debug command. This command is test modem back-to-back slot/port slot/port . It performs a test from one modem to the other to ensure that it can train up and pass data. This test is only done at V.34 speeds. AS5300 Specific Commands and DebugsThe commands for the AS5200 also work with the AS5300. The AS5300 added MICA modems along with some unique out-of-band functionality. This allowed for a few more commands to provide real-time information that was not possible before. Most of these commands provide little information, but assist the TAC in quickly determining a problem. The first of these new commands is show modem configuration , which shows the setup of the modem. Any changes you make to the modem through a modemcap, appears in the output of this command. Another command for the AS5300 is show modem mica slot/port . This is another command that the TAC reviews to help determine a problem. The show modem operational-status slot/port command assists you in determining some problems, without the help of TAC engineers . The following is sample output from this command with additional comments provided to assist with troubleshooting: 5300-dial# show modem operational-status 1/13 Modem(1/13) Operational-Status: Parameter #0 Disconnect Reason Info: (0x0) Type (=0 ): <unknown> Class (=0 ): Other Reason (=0 ): no disconnect has yet occurred The parameter #0 of the output shows a disconnect reason that identifies the type of disconnect, the class of disconnect, and the reason that the disconnect took place. If there is an issue with a user frequently getting disconnected, determine what modem the user was last connected on, and perform this command to obtain information about the disconnection. Parameters #1 and #2 cover the connection protocol and compression: Parameter #1 Connect Protocol: LAP-M Parameter #2 Compression: V.42bis both Parameter #3 displays the error correction (EC) retransmission count, or the number of times that the modem has gone into error recovery in the transmit direction for a particular connection. Compare this parameter against the count produced by Parameter #36 (EC packets transmitted, received) to determine if a problem really exists. Parameter #3 EC Retransmission Count: 193 Parameter #4 shows the error count received during a back-to-back modem test. During any normal active call, this number is 0: Parameter #4 Self Test Error Count: 0 Parameter #5 shows how long the call is connected in seconds. This client is connected for just over 3 hours and 44 minutes: Parameter #5 Call Timer: 13491 secs Parameter #6 shows the number of retrains done by the modems. A high number of retrains identifies that the connection made by the client is not stable. This can happen from a dirty phone line, low signal-to-noise ratio (SNR), or even from someone picking up the phone and setting it back down while a modem call is in place over that line: Parameter #6 Total Retrains: 4 Parameter #7 displays the measure of the receive signal quality (SQ) bit error rate for the current modulation, as estimated by the DSP. A value of 0 has the highest number of errors and 7 has the lowest . This value is used in conjunction with some S values configured on the modem to determine when to speed shift or retrain. If the SQ value reported in this parameter drops to the value of S32 (SQ Threshold) for longer than the value of S35 in seconds, the DSP attempts a downward speed shift or retrain. Similarly, if the SQ value goes above the threshold for longer than the value of S34 in seconds, an upward speed shift or retrain occurs. Parameters #8 and #9 show the connection standard and current connection speed of the modem. This real-time data and might not be the same for the connecting client. The client uses a modem that does not have out-of-band signaling and only knows the initial connection speed: Parameter #7 Sq Value: 3 Parameter #8 Connected Standard: V.90 Parameter #9 TX,RX Bit Rate: 50666, 28800 Parameter #11 displays the transmit symbol rate that transmits samples to the line and the receive symbol rate that receives samples from the line: Parameter #11 TX,RX Symbol Rate: 8000, 3200 Parameter #13 displays the transmit carrier frequency in Hertz that the local DCE uses and the receive carrier frequency that the remote DCE uses: Parameter #13 TX,RX Carrier Frequency: 0, 1829 Parameter #15 shows trellis coding. Trellis coding adds dependency between symbols to make the detection in noise more robust (forward error correction [FEC]). Trellis coding is displayed in values. The value of 0 correlates to a connection standard V.22, V.22 bis , V.21, Bell212, Bell103, V.29, or V.27. The value of 8 correlates to a connection standard of V.32, V.32 bis , or V.17. The value of 16, 32, or 64 correlates to a connection standard of V.34, V.34+, V.90, or K56Flex: Parameter #15 TX,RX Trellis Coding: 0, 16 Parameter #16 shows the preemphasis index, which involves shaping the raw transmit spectrum to deal with spectrum roll-offs. A zero denotes no reshaping. This index is used only with V.34 and V.34+ connection standards: Parameter #16 TX,RX Preemphasis Index: 22, 0 Parameter #17 shows if constellation shaping is used. Constellation shaping is a technique for improving noise immunity by using a probability distribution for transmitted signal points. The signal states predict the sensitivity to certain transmission impairments. Constellation shaping is used only with the V.34 and V.34+ connection standards. Values displayed by this parameter are either Off or On: Parameter #17 TX,RX Constellation Shaping: Off, Off Parameter #18 shows if nonlinear encoding is used. Nonlinear encoding occurs during the training phase and moves the outer points of the constellation away to deal with nonlinear distortion. Nonlinear distortion tends to affect the higher- powered signals. Moving the outer constellation points out reduces the chance of error. Nonlinear encoding is used only with the V.34 and V.34+ connection standards. Values displayed by this parameter are either Off or On: Parameter #18 TX,RX Nonlinear Encoding: Off, Off Parameter #19 shows if precoding is used. Precoding serves the same purpose as the preemphasis index, but instead manages the bits and not the raw transmit signals. This management is done only when asked for and therefore occurs only in the receive mode. Precoding is used only with the V.34 and V.34+ connection standards. Values displayed by this parameter are either Off or On: Parameter #19 TX,RX Precoding: Off, Off Parameter #20 shows the transmit level reduction. The transmit level affects the transmit signal by reducing it in a range of 0 to 15 dBm. If nonlinear distortion is detected on either end, the modem detecting this distortion requests a lower-powered transmit signal. Transmit level reduction is used with the V.34 and V.34+ connection standards: Parameter #20 TX,RX Xmit Level Reduction: 0, 0 dBm Parameter #21 shows the SNR. This is the ratio on the server side and should not change. The SNR on the client side is determined by issuing the command ati11 on the modem after disconnect. The higher the number, the better: Parameter #21 Signal Noise Ratio: 36 dB Parameter #22 shows that the power of the received signal ranges from 0 to -128. The optimum range for the receive level displayed by this parameter is from -12 dBm to -24 dBm: Parameter #22 Receive Level: -23 dBm Parameter #23 shows the frequency offset, which is a shift in the receive spectrum between the expected carrier frequency and the actual carrier frequency. The typical value is 0 Hz: Parameter #23 Frequency Offset: 0 Hz Parameters #24 and #25 deal with phase jitter. This is found only in analog trunk circuits. Typical frequencies are power generation frequencies and their harmonics (that is, 60 and 120 Hz within the U.S; 50 and 100 Hz international). MICA modems cancel all frequencies of phase jitter: Parameter #24 Phase Jitter Frequency: 0 Hz Parameter #25 Phase Jitter Level: 0 degrees Parameter #26 displays the far-end echo level (the portion of the transmitted analog signal that has bounced off of the analog front end of the remote modem), which can range from 0 to -90 dBm. A MICA modem cannot handle near-end echo if far-end echo is present and the round-trip delay is greater than ten microseconds. This constraint comes from the number of taps in the echo canceller of MICA modems. The reported far-end echo level must be less than -55 dBm to achieve a V.34+ connection. A greater echo level indicates a digital-to-analog conversion in the path between the MICA modem and the switch: Parameter #26 Far End Echo Level: -47 dBm A form of this signal/constellation pattern echoes off equipment at the central office and is sent back to the MICA modem. However, the constellation shape might be rotated from its original position. This rotation is called the phase roll. It is shown in degrees of rotation in Parameter #27. The echoed signal consists of a frequency component and a phase component. If the frequency component changes at all, a correction is needed for echo cancellation to work correctly. The typical value is 0 or close to 0: Parameter #27 Phase Roll: 0 degrees Parameter #28 shows round-trip delay, which is the total round-trip from modem to modem in microseconds. This delay is important for proper echo cancellation: Parameter #28 Round Trip Delay: 7 msecs Parameter #30 displays the total count of characters sent and received before any modem compression takes place: Parameter #30 Characters transmitted, received: 11116387, 2693386 Parameter #32 is included but not used. Other parameters, such as 10, 12, 14, 34, and 37 do not even show up in the output: Parameter #32 General Portware Information: 22 Parameters #33 and #35 show the number of packets transmitted and received by the dial server from the client modem. This is useful in determining whether or not the modems are passing traffic to each other: Parameter #33 PPP/SLIP packets transmitted, received: 24080, 23583 Parameter #35 PPP/SLIP packets received (BAD/ABORTED): 0 Parameter #36 displays the number of EC packets transmitted and the number of EC packets received: Parameter #36 EC packets transmitted, received OK: 53258, 48144 Parameter #38 shows the moving average of EC packets. One way to determine if the connection has gotten better or worse with speedshifts and retrains is to check the moving average several times over the duration of a call. If the value decreases, the connection has become more stable: Parameter #38 Moving Average of EC packets (Received BAD/ABORTED): 88 Parameter #39 shows what robbed bit signaling pattern is used. If robbed bit signaling is detected, the dial server must run a pattern so that the missing bit does not affect data transfer. As long as this is a 0, there is no RBS line between the server and the client: Parameter #39 Robbed Bit Signalling (RBS) pattern: 0 Chapter 5, "Dial Technology Background," provided an explanation of the digital pad. Cisco dial servers try to avoid the problems incurred by the use of digital pads on a link. Parameter #40 shows if the dial server detected a digital pad and the compensation status: Parameter #40 Digital Pad: 6.0 dB, Digital Pad Compensation: Enabled Parameters 41 through 44 deal with V.110 calls. These parameters show frames received bad, frames received good, frames transmitted, and number of times synchronization has been lost. Because this is a V.90 call, the values are always 0: Parameter #41 V110/PIAFS frames received bad: 0 Parameter #42 V110/PIAFS frames received good: 0 Parameter #43 V110/PIAFS frames transmitted: 0 Parameter #44 V110/PIAFS sync lost: 0 The last piece of information to specifically review from the show modem operational-status output is the line shape. The MICA modems use the V.90 Digital Impairment Learning (DIL) sequence to determine the quality of the line and how much of the line is usable for data. Even if the DIL shows that V.90 is not feasible for the client modem connecting, it does store this information and trains up in V.34 mode. When reviewing the line shape, you want the vertical line created by the asterisks to be as straight as possible. As the line is more curved at the beginning and the end, the maximum attainable connection speed drops. Example 7-30 shows the line shape output. Example 7-30. Line Shape.........................* ................................* .................................* .................................* ................................* ................................* ................................* ................................* ................................* ................................* ................................* ................................* ................................* ................................* ................................* ................................* ................................* ................................* ................................* ................................* ................................* ................................* ...............................* .............................* .........................* In this case, the line is mostly straight. Also, if you noticed the speed from parameter 9, the connection speed attained in the example is 50,666 baud, which is almost as good as you can get with a 56 k modem. The only debugs added for the AS5300s are MICA modem debugs. The command debug modem mica displays the status of software downloads to the modems. AS5400 Specific Commands and DebugsWith the introduction of the AS5400, most of the modem commands changed. The following is a list of the commands from the AS5200 and AS5300 that exist in the AS5400 under a different command:
The first of the two newly added show commands is show spe modem active slot/spe . It is not really a new command, but because modem types changed from MICA to NextPort modems, this command replaces the show modem operational-status from the AS5300s. Unfortunately, this command only works when the modem is active. To view the disconnect reason for a specific disconnected modem, refer to the command show spe log slot / spe . The other helpful command is show spe modem disconnect-reason [ slot / port summary ]. This command reveals the allocation of disconnect reasons that the particular slot and/or port on that specific modem has encountered . When reviewing the summary, it displays the total number of disconnects for each disconnect reason. This provides a quick indication of how many modem train-up failures took place. Show commands are not the only thing that changed between the AS5300 and the AS5400. Most of the debug commands changed or are no longer available. The debug modem csm changed to debug csm modem and the debug modem trace command changed to debug spe modem trace . Many specialized debugs added for the AS5400 deal with the NextPort engine and modules. The details of each are more than this book can cover. If you are experiencing a problem where these debugs are required for troubleshooting, the TAC can instruct you on which debugs to run and provide the required output. |
EAN: 2147483647
Pages: 235