Video over ATM Switched Virtual Circuits on the Cisco MC3810
Available Languages
Table Of Contents
Video over ATM Switched Virtual Circuits on the Cisco MC3810
Related Features and Technologies
Supported Standards, MIBs, and RFCs
Configuring Network Clocks and Controllers
Verifying Network Clock and Controller Configuration
Verifying Serial Interface Configuration
Verifying ATM Interface Configuration
Verifying Video Dial-Peer Configuration
Troubleshooting Video over ATM SVCs and PVCs
Monitoring and Maintaining Video over ATM SVCs and PVCs
show call history video record
Video over ATM Switched Virtual Circuits on the Cisco MC3810
This document describes Cisco IOS configuration for video over Asynchronous Transfer Mode (ATM) switched virtual circuits (SVCs), introduced with the plug-in video dialing module for the Cisco MC3810 multiservice access concentrator. It includes the following sections:
•
Supported Standards, MIBs, and RFCs
•
•
Feature Overview
Video over ATM SVCs expands the capabilities of the Cisco MC3810 multiservice access concentrator to provide cost-effective, dynamic, and flexible videoconferencing system support. Using a plug-in video dialing module (VDM) to provide an RS-366 dialing interface to an H.320 video codec, the Cisco MC3810 automatically accepts dial-out requests from the video system. The codec connects to one of the Cisco MC3810 serial ports and also to the Cisco MC3810 RS-366 dial-up port.
The current feature also improves PVC support by permitting PVC connections with automatic connection through a serial port. Each codec must place a call to the other videoconferencing system prior to the expiration of the video codec time-out period (set on the codec, usually one minute). Using a video dial map, each system reconciles the dialed number with a PVC that has already been configured, allowing fast connectivity.
Service providers, educational organizations, and enterprises can concentrate streams for video with packet data on a single high-speed ATM link without a separate ATM access multiplexer. Here are some features of the Cisco's ATM SVC implementation:
•
•
•
•
Figure 1 Sample ATM Video Application
Figure 2 shows how the physical interfaces interact with software, the codec, and video data to handle connectivity and video functionality. The VDM's Automatic Calling Equipment (ACE) provides the RS-366 interface to the video codec while one of the Cisco MC3810 serial interfaces connects to the video codec data terminal equipment (DTE) interface. The Video Call Manager (ViCM) software manages video calls that travel over a T1 or E1 facility through the Cisco MC3810 Multiflex Trunk (MFT) interface.
Figure 2 Physical Interfaces and Their Functions
Benefits
The primary benefit of this feature is its support of video SVCs, which provide an easy-to-use method of video communications:
•
•
•
•
SVCs offer the following benefits:
•
•
•
•
•
The Cisco MC3810 multiservice access concentrator formerly supported nondial PVCs for ATM traffic with explicit connection through a serial port. With this release, the Cisco MC3810 supports dial PVCs, where each party dials the other in order to make a video connection.
Restrictions
The following restrictions apply to video over ATM using SVCs:
•
•
•
The following features are not supported:
•
•
•
•
•
•
•
•
Related Features and Technologies
The Cisco MC3810, in addition to supporting video and voice over ATM SVCs and PVCs, also supports data over ATM SVCs. Wide-Area Networking Configuration Guide and Wide-Area Networking Command Reference provide more information about the commands and configuration steps required for this capability.
Related Documents
For information about Cisco IOS configuration for video applications, see the following Cisco IOS Release 12.0 documents:
•
•
For information about ATM IOS configuration, see the following Cisco IOS Release 12.0 documents:
•
•
For information about hardware installation as well as video and ATM IOS configuration uniquely for the Cisco MC3810, see the following Cisco documents:
•
•
•
Supported Platforms
This feature is supported on the Cisco MC3810 multiservice access concentrator.
Supported Standards, MIBs, and RFCs
No MIBs are supported by this feature.
No RFCs are supported by this feature.
Other Standards
•
•
•
•
•
•
•
•
•
•
•
•
Prerequisites
This feature requires specific hardware and software:
•
•
•
•
•
•
For additional information about installation and other hardware considerations, see Cisco MC3810 Multiservice Concentrator Hardware Installation.
Configuration Tasks
To configure video over ATM SVCs, perform the following tasks:
•
•
•
•
These tasks do not represent all the configuration tasks required to set up your ATM network. For more information, see the Cisco MC3810 Multiservice Access Concentrator Software Configuration Guide and to the examples shown in the "Configuration Examples" section.
Configuring Network Clocks and Controllers
Because real-time video communications require a continuous and tightly meshed data stream to avoid loss of information, you must synchronize source and destination devices to a single master clock. In the example below, the clock source is derived from a device attached to T1 controller 0; then it is distributed to the devices attached to the local Cisco MC3810 serial ports and to T1 controller 1. Clock source decisions should be based on the network configuration, and a hierarchy of clock sources can be set up, so that backup clock sources are available. For details, see Chapter 4, "Configuring Synchronized Clocking," in Cisco MC3810 Multiservice Access Concentrator Software Configuration Guide.
This configuration task also includes the basic steps required for ATM support over T1/E1 controller 0.
1
Router# configure terminalEnter global configuration mode.
2
Enter controller configuration mode for controller T1/E1 0. ATM traffic is supported on controller T1/E1 0 only.
3
Router(config-controller)# clock source lineConfigure controller T1/E1 0 to obtain the Cisco MC3810 clock source from an attached network device. This is the default setting.
4
Router(config-controller)# no shutdownActivate the controller.
5
(config)#controller {T1 | E1} 1Enter controller configuration mode for controller T1/E1 1.
6
Router(config-controller)# clock source internalConfigure controller T1/E1 1 to obtain its clocking from the internal network clock Phase-Lock-Loop (PLL). Controller T1/E1 1 obtains clocking from the T1/E1 0 controller source, so that both controllers use the same clock source.
7
Router(config-controller)# no shutdownActivate the controller.
8
Router(config-controller)# exitExit controller configuration mode.
9
(config-controller)#framing esfor
Router(config-controller)#framing crc4Set the framing to Extended SuperFrame (ESF) format, which is required for ATM on T1. This setting is automatic for T1 when ATM mode is set.
Set the framing to CRC4, which is required for ATM on E1. This setting is automatic for E1 when the ATM mode is set.
10
(config-controller)#linecode b8zsor
Router(config-controller)#linecode hdb3Set the line coding to binary zero 0 substitution (B8ZS), which is required for ATM on T1. This setting is automatic for T1 when the ATM mode is set.
Set the line coding to HDB3, which is required for ATM on E1. This setting is automatic for E1 when the ATM mode is set.
Note
11
(config-controller)#mode atmConfigure the controller for ATM traffic. This allows the controller to support ATM encapsulation and create virtual ATM interface 0 for SVCs and PVCs. Controller framing is automatically set to extended superframe (ESF) on T1 and to CRC4 on E1. The line coding is automatically set to B8ZS on T1 and to HDB3 on E1. Channel groups, CAS groups, Common Channel Signaling (CCS) groups or clear channels are not allowed on the trunk because ATM traffic occupies all the DS0s.
12
(config-controller)#exitExit controller configuration mode.
13
Set the network clock base rate for the serial ports. For video stream rates of 384, 768, 1.152, or 1.28 kbps (see Step 3), set the rate to 64 kbps. The default is 56 kbps.
Note
Verifying Network Clock and Controller Configuration
To verify the configuration of network clock sources and controller settings, follow the steps below:
Step 1
Router# show network-clocksPriority 1 clock source(inactive config): T1 0Priority 1 clock source(active config) : T1 0Clock switch delay: 10Clock restore delay: 10T1 0 is clocking system bus for 9319 seconds.Run Priority Queue: controller0Step 2
router# show controller t1 1T1 1 is up.Applique type is Channelized T1Cablelength is long gain36 0dbNo alarms detected.Slot 4 CSU Serial #07789650 Model TEB HWVersion 4.70 RX level = 0DBFraming is ESF, Line Code is B8ZS, Clock Source is Internal.Data in current interval (819 seconds elapsed):0 Line Code Violations, 0 Path Code Violations0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail SecsData in Interval 1:0 Line Code Violations, 0 Path Code Violations0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail SecsData in Interval 2:0 Line Code Violations, 0 Path Code Violations0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs...Data in Interval 96:0 Line Code Violations, 0 Path Code Violations0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail SecsTotal Data (last 24 hours)0 Line Code Violations, 0 Path Code Violations,0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs!Router# show controllers E1 1E1 1 is up.Applique type is Channelized E1 - balancedNo alarms detected.Slot 4 Serial #06868949 Model TEB HWVersion 3.80Framing is CRC4, Line Code is HDB3, Clock Source is Internal.Data in current interval (292 seconds elapsed):0 Line Code Violations, 0 Path Code Violations0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs...Total Data (last 66 15 minute intervals):9 Line Code Violations, 0 Path Code Violations,1 Slip Secs, 0 Fr Loss Secs, 4 Line Err Secs, 0 Degraded Mins,5 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail SecsConfiguring Serial Interfaces
This configuration task includes the basic steps required for setting up a serial port for the video codec.
1
Router# configure terminalEnter global configuration mode.
2
interface serial {0 | 1}Enter interface configuration mode either for Serial 0 or Serial 1, depending on where the video codec is connected.
3
clock rate network rateConfigure the network clock speed for DCE mode, in bits per second, corresponding to the video stream rate you are using. The rate must be a multiple of the value set with the network-clock base-rate command in Step 13 of "Configuring Network Clocks and Controllers" on page 10. Make sure this setting is 384000, 768000, or 1152000. 768000 is a common setting.
4
encapsulation atm-cesConfigure the interface for ATM encapsulation circuit emulation service (CES), which is required for video codec support.
5
serial restart-delay countThe serial restart-delay command allows you to set the amount of time that the router waits before trying to bring up a serial interface when the interface goes down. The router resets the hardware each time the restart timer expires. This command is often used with dial backup and with the pulse-time command, which sets the amount of time to wait before redealing when a DTR dialed device fails to connect.
count is a value from 0 to 900 in seconds. This is the frequency at which the hardware is reset. A value of 0 means that the hardware is not reset when down. In this way, if the interface is used to answer a call, it does not cause DTR to drop, which can cause the modem to disconnect.
Verifying Serial Interface Configuration
Enter the privileged EXEC command show interfaces serial command to see the status of all serial interfaces or of a specific serial interface, as shown in the example below. You can use this command to check the encapsulation, scrambling, and serial restart delay settings:
Router# show interface serial0Serial0 is down, line protocol is downHardware is PQUICC Serial TransMTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,reliability 255/255, txload 65/255, rxload 1/255Encapsulation CES-ATM, loopback not setKeepalive not setScramble enabledRestart-Delay is 0 secsLast input never, output never, output hang neverLast clearing of "show interface" counters 5d13hQueueing strategy: fifoOutput queue 0/100, 101 drops; input queue 0/75, 0 drops5 minute input rate 0 bits/sec, 0 packets/sec5 minute output rate 0 bits/sec, 0 packets/sec13452224 packets input, 1526136219 bytes, 0 no bufferReceived 0 broadcasts, 0 runts, 0 giants, 0 throttles0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort215189699 packets output, 1654453088 bytes, 0 underruns0 output errors, 0 collisions, 1 interface resets0 output buffer failures, 0 output buffers swapped out0 carrier transitionsCable attached: V.35 (DCE)Hardware config: V.35; DCE; PLL nx64K;DSR = UP DTR = DOWN RTS = DOWN CTS = DOWN DCD = DOWNConfiguring ATM Interfaces
In this section, the ATM interface is set up, including PVCs to carry signaling for SVCs. The video NSAP addressing commands specify session target information for SVC video communications.
In addition, the following steps include procedures for configuring a dial PVC for videoconferencing.
1
Router# configure terminalEnter global configuration mode.
2
Router(config)#interface atm0Enter interface configuration mode for ATM 0—the only interface that supports video over ATM.
3
For IP protocol communications, assign the IP address and subnet mask to the interface.
4
Router(config-if)# atm scramble-enable(E1 configuration only) Helping to ensure reliability, scrambling randomizes the ATM cell payload frames to avoid continuous non-variable bit patterns and improve the efficiency of ATM's cell delineation algorithms.
5
(config-if)#atm video aesa {default |esi-address}This command sets the unique ATM end-station address (AESA) for an ATM video interface that is using SVC mode.
The default keyword automatically creates an NSAP address for the interface, based on a prefix from the ATM switch (26 hexadecimal characters), the MAC address (12 hexadecimal characters) as the ESI (end station identifier), and a selector byte (two hexadecimal characters).
The esi-address option requires that you enter 12 hexadecimal characters as the ESI. The ATM switch provides the prefix, and the video selector byte provides the remaining characters.
You can view the assigned address by using the show atm video-voice address command.
6
(config-if)#pvc [name] vpi/vci ilmiCreate an ATM PVC for ILMI management purposes and enter PVC configuration mode.
The optional name is a unique label that can be up to 16 characters long. It identifies to the processor the virtual path identifier-virtual channel identifier (VPI-VCI) pair to use for a particular packet.
The ATM network VPI of this PVC is an 8-bit field in the header of the ATM cell. The vpi value is unique only on a single link, not throughout the ATM network, because it has local significance only. The vpi value must match that of the switch. Valid values are from 0 to 255, but the value is usually 0 for ILMI communications. If a value is not specified, the vpi value is set to 0.
You cannot set both vpi and vci to 0; if one is 0, the other cannot be 0.
For ILMI communications, this value is typically 16. The VCI is a 16-bit field in the header of the ATM cell. The VCI value is unique only on a single link, not throughout the ATM network, because it has only local significance.
To set up communication with the ILMI, enter the ilmi keyword for ATM adaptation layer encapsulation; the associated vpi and vci values are ordinarily 0 and 16, respectively.
Note
7
(config-if-atm-pvc)#pvc [name] vpi/vci qsaalSee the explanations in Step 6 for the name, vpi, and vci values.
To enable the signaling for setup and tear-down of SVCs, specify the Q.SAAL (Signaling ATM Adaptation Layer) encapsulation; the associated vpi and vci values are ordinarily 0 and 5, respectively. You cannot create this PVC on a subinterface.
8
(config-if-atm-pvc)#pvc [name] vpi/vciThis command sets up a PVC for communications.
The optional name is a unique label that can be up to 16 characters long.
The ATM network VPI of this PVC is an 8-bit field in the header of the ATM cell. Valid values are from 0 to 255, but the values from 0 to 31 are usually reserved for particular services (such as ILMI).
You cannot set both vpi and vci to 0; if one is 0, the other cannot be 0.
The VCI is a 16-bit field in the header of the ATM cell.
9
(config-if-atm-pvc)#protocol protocol
protocol-address [[no] broadcast]Use this command to map a protocol address to the PVC.
10
(config-if-atm-pvc)#cbr rateUse this command to configure the constant bit rate (CBR) for the ATM for an ATM PVC. Real-time video requires CBR.
The valid range for the rate value is from 56 to 10,000 kbps. To set the rate that corresponds to the desired video speed, use a value that is 17 percent higher than the rate set on the serial DCE interface (see Step 3 in "Configuring Network Clocks and Controllers" on page 10). For example, if you specify a DCE clock rate of 768 kbps, the result is 899 kbps:
768 x 1.17 = 899 kbps
11
(config-if-atm-pvc)#encapsulation aal1AAL1 encapsulation is necessary for videoconferencing using PVCs.
12
(config-if-atm-pvc)#exitReturn to interface configuration mode.
13
(config-if)#interface atm 0 [.subinterface-number
{multipoint | point-to-point}]Optionally, you can create and configure a subinterface. This is useful when you wish to configure an extra parameter on the ATM interface. For example, you can specify one IP address on the main interface, as shown in Step 3; then, configure a second IP address on a subinterface.
subinterface-number is a value in the range from 1 to 4294967293.
Use the multipoint keyword when your network is fully meshed and you wish to communicate with multiple routers. The point-to-point keyword configures the subinterface for communication with one router, as in a hard-wired connection. There is no default for this parameter.
Verifying ATM Interface Configuration
To verify ATM interface configuration, follow the steps below:
Step 1
Router# show atm pvc 0/5ATM0: VCD: 2, VPI: 0, VCI: 5, Connection Name: SAALUBR, PeakRate: 56AAL5-SAAL, etype:0x4, Flags: 0x26, VCmode: 0x0OAM frequency: 0 second(s), OAM retry frequency: 1 second(s), OAM retry frequency: 1 second(s)OAM up retry count: 3, OAM down retry count: 5OAM Loopback status: OAM DisabledOAM VC state: Not ManagedILMI VC state: Not ManagedInARP DISABLEDInPkts: 2044, OutPkts: 2064, InBytes: 20412, OutBytes: 20580InPRoc: 2044, OutPRoc: 2064, Broadcasts: 0InFast: 0, OutFast: 0, InAS: 0, OutAS: 0OAM cells received: 0F5 InEndloop: 0, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI: 0OAM cells sent: 0F5 OutEndloop: 0, F5 OutSegloop: 0, F5 OutRDI: 0F4 OutEndloop: 0, F4 OutSegloop: 0, F4 OutRDI: 0OAM cell drops: 0Compress: DisabledStatus: INACTIVE, State: NOT_IN_SERVICE!Router# show atm pvc 0/16ATM0: VCD: 1, VPI: 0, VCI: 16, Connection Name: ILMIUBR, PeakRate: 56AAL5-ILMI, etype:0x0, Flags: 0x27, VCmode: 0x0OAM frequency: 0 second(s), OAM retry frequency: 1 second(s), OAM retry frequency: 1 second(s)OAM up retry count: 3, OAM down retry count: 5OAM Loopback status: OAM DisabledOAM VC state: Not ManagedILMI VC state: Not ManagedInARP DISABLEDInPkts: 398, OutPkts: 421, InBytes: 30493, OutBytes: 27227InPRoc: 398, OutPRoc: 421, Broadcasts: 0InFast: 0, OutFast: 0, InAS: 0, OutAS: 0OAM cells received: 0F5 InEndloop: 0, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI: 0OAM cells sent: 0F5 OutEndloop: 0, F5 OutSegloop: 0, F5 OutRDI: 0F4 OutEndloop: 0, F4 OutSegloop: 0, F4 OutRDI: 0OAM cell drops: 0Compress: DisabledStatus: INACTIVE, State: NOT_IN_SERVICEStep 2
Router# show interface atm 0ATM0 is up, line protocol is upHardware is PQUICC Atom1Internet address is 9.1.1.6/8MTU 1500 bytes, sub MTU 1500, BW 1536 Kbit, DLY 20000 usec,reliability 255/255, txload 22/255, rxload 11/255NSAP address: 47.0091810000000002F26D4901.000011116666.06Encapsulation ATM292553397 packets input, -386762809 bytes164906758 packets output, 1937663833 bytes0 OAM cells input, 0 OAM cells output, loopback not setKeepalive not supportedEncapsulation(s):, PVC mode1024 maximum active VCs, 28 current VCCsVC idle disconnect time: 300 secondsSignalling vc = 1, vpi = 0, vci = 5UNI Version = 4.0, Link Side = userLast input 00:00:00, output 2d05h, output hang neverLast clearing of "show interface" counters neverInput queue: -1902/75/0 (size/max/drops); Total output drops: 205Queueing strategy: weighted fairOutput queue: 0/1000/64/0 (size/max total/threshold/drops)Conversations 0/0/256 (active/max active/max total)Reserved Conversations 0/0 (allocated/max allocated)5 minute input rate 67000 bits/sec, 273 packets/sec5 minute output rate 136000 bits/sec, 548 packets/sec76766014 packets input, 936995443 bytes, 0 no bufferReceived 0 broadcasts, 0 runts, 0 giants, 0 throttles0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort367264676 packets output, 3261882795 bytes, 0 underruns0 output errors, 0 collisions, 2 interface resets0 output buffer failures, 0 output buffers swapped outStep 3
Router# show atm vcVCD / Peak Avg/Min BurstInterface Name VPI VCI Type Encaps SC Kbps Kbps Cells Sts0 1 0 5 PVC SAAL UBR 56 UP0 2 0 16 PVC ILMI UBR 56 UP0 3 34 35 PVC AAL1 CBR 768 768 UP0 4 38 39 SVC CES CBR 768 768 UPStep 4
Router# show atm video-voice addressnsap address type ilmi status47.0091810000000002F26D4901.00107B4832E1.FE VOICE_AAL5 Confirmed47.0091810000000002F26D4901.00107B4832E1.C8 VIDEO_AAL1 ConfirmedConfiguring Video Dial Peers
In this section, the video dial peers are set up to support the local codec and the remote video system.
1
Router# configure terminalEnter global configuration mode.
2
Specify the slot where the VDM is located and the port for the RS-366 interface. The slot value is either 1 or 2. The Cisco MC3810 VDM has only one video port, so the port value is 0.
3
(config)# dial-peer video tag videoatmDefine a video ATM dial peer for the remote system and enter dial-peer configuration mode. Video dial peers are persistent and exist until they are specifically removed with the no form of the dial-peer video command.
The tag value identifies the dial peer and must be unique on the Cisco MC3810. Do not duplicate a specific tag number. Valid values are from 1 to 10000.
4
(config-dialpeer)#destination-pattern string [T]Configure the dial peer's destination pattern so that the system can reconcile dialed digits with the peer's NSAP address. The string is a series of digits that specify the E.164 or private dialing plan telephone number. Valid entries are the digits 0 through 9 and the letters A through D. The plus symbol (+) is not valid. You can enter the following special characters:
•
•
•
•
5
(config-dialpeer)#session target ATM0 {svc nsap
address | pvc [name | vpi/vci}Configure the ATM session target for the dial peer. Make sure that you specify ATM 0 as the interface.
Through SVCs and a video map, dialed digits are reconciled with the remote ATM interface's video NSAP address.
If you are using PVCs to send video data, you can also specify a PVC defined on the ATM interface as a session target by using a name or a VPI/VCI combination. For additional information, see the Voice, Video, and Home Applications Configuration Guide for Cisco IOS Release 12.0.
6
(config-dialpeer)# exitComplete the configuration of this dial peer.
7
(config)# dial-peer video tag videcodecDefine a video ATM dial peer for the local video codec.
The tag value identifies the dial peer and must be unique on the Cisco MC3810. Do not duplicate a specific tag number. Valid values are from 1 to 10000.
8
(config-dialpeer)#destination-pattern stringConfigure the dial peer's destination pattern. See Step 4 for more information.
9
(config-dialpeer)#port signal slot/portSpecify the slot where the VDM is located and the port for the RS-366 interface. The slot value is either 1 or 2. The Cisco MC3810 has only one video port, so the port value is 0.
10
(config-dialpeer)#port media interfaceSpecify the serial interface by using the name Serial and a port of either 0 or 1, depending on where the local codec is connected.
11
(config-dialpeer)#nsap nsap-addressThis command specifies the NSAP address for the codec. nsap-address is a unique 40-digit hexadecimal number.
Verifying Video Dial-Peer Configuration
To verify the dial-peer configuration, enter the privileged EXEC show dial-peer video command. In the following example, note that the third dial peer uses a PVC specified with a VPI/VCI value while the second uses an SVC. The first dial peer is for the local codec.
Router# show dial-peer videoVideo Dial-Peer 1type = videocodec, destination-pattern = 111port signal = 1/0, port media = Serial1nsap = 47.0091810000000050E201B101.00107B09C6F2.C8Video Dial-Peer 2type = videoatm, destination-pattern = 222session-target = ATM0 svc nsap 47.0091810000000050E201B101.00E01E92ADC2.C8Video Dial-Peer 3type = videoatm, destination-pattern = 333session-target = ATM0 pvc 70/70Troubleshooting Video over ATM SVCs and PVCs
When problems occur with video over PVCs or SVCs, follow the steps below to look first for common problems before progressing to more complex possible issues.
Note
Step 1
Step 2
Step 3
(a)
(b)
DSR = UP DTR = UP RTS = UP CTS = UP DCD = UPStep 4
Router# show atm pvcVCD / Peak Avg/Min BurstInterface Name VPI VCI Type Encaps SC Kbps Kbps Cells Sts0 1 0 5 PVC SAAL UBR 56 UP0 2 0 16 PVC ILMI UBR 56 UPStep 5
Router# show atm vcVCD / Peak Avg/Min BurstInterface Name VPI VCI Type Encaps SC Kbps Kbps Cells Sts0 3 38 35 PVC AAL1 CBR 384 384 UPStep 6
router# show atm video-voice addressnsap address type ilmi status47.0091810000000002F26D4901.00107B4832E1.FE VOICE_AAL5 Confirmed47.0091810000000002F26D4901.00107B4832E1.C8 VIDEO_AAL1 Confirmedrouter# show atm ilmi-statusInterface : ATM0 Interface Type : Private UNI (User-side)ILMI VCC : (0, 16) ILMI Keepalive : Enabled (5 Sec 4 Retries)ILMI State: UpAndNormalPeer IP Addr: 10.1.1.11 Peer IF Name: ATM1/0/0Peer MaxVPIbits: 8 Peer MaxVCIbits: 14Active Prefix(s) :47.0091.8100.0000.0002.f26d.4901End-System Registered Address(s) :47.0091.8100.0000.0002.f26d.4901.0000.1111.5555.05(Confirmed)47.0091.8100.0000.0002.f26d.4901.0010.7b48.32e1.fe(Confirmed)47.0091.8100.0000.0002.f26d.4901.0010.7b48.32e1.c8(Confirmed)Step 7
...Data in current interval (819 seconds elapsed):0 Line Code Violations, 0 Path Code Violations0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail SecsData in Interval 1:0 Line Code Violations, 0 Path Code Violations0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail SecsData in Interval 2:0 Line Code Violations, 0 Path Code Violations0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail SecsData in Interval 3:0 Line Code Violations, 0 Path Code Violations0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs...A few slip errors may not indicate a problem with clocking. However, if there are numerous errors, especially incrementing numbers of errors, check the following possibilities:
–
–
Step 8
router# show sscopSSCOP details for interface ATM0Current State = Data Transfer ReadyInterpretation of the command output requires familiarity with SSCOP, so unless you are familiar with the protocol, just use the command to ensure that the protocol is in a state of readiness. If you need to make changes, see the Cisco IOS Release 12.0 documents, Wide-Area Networking Configuration Guide and Wide-Area Networking Command Reference.
Note
Step 9
Router1# show dial-peer videodial-peer video 111 videocodecnsap 47.0091810000000002F26D4901.00107B4832E1.C8port signal 1/0port media Serial0destination-pattern 121!dial-peer video 221 videoatmdestination-pattern 221session target ATM0 svc nsap 47.0091810000000002F26D4901.00107B09C645.C8Router2# show dial-peer videodial-peer video 111 videocodecnsap 47.0091810000000002F26D4901.00107B09C645.C8port signal 1/0port media Serial0destination-pattern 221!dial-peer video 121 videoatmdestination-pattern 121session target ATM0 svc nsap 47.0091810000000002F26D4901.00107B4832E1.C8Step 10
When no call is in progress, the output looks like this:
Router# show video call summarySerial0:ViCM = Idle, Codec ReadyWhen a call is starting, the output looks like this:
Router# show video call summarySerial0:ViCM = Call ConnectedWhen a call is disconnecting, the output looks like this:
Router# show video call summarySerial0:ViCM = IdleStep 11
router# show call history video recordCallId = 4CalledNumber = 221CallDuration = n/a - call is in progressDisconnectText = n/a - call is in progressSVC: call ID = 8598630Remote NSAP = 47.0091810000000002F26D4901.00107B09C645.C8Local NSAP = 47.0091810000000002F26D4901.00107B4832E1.C8vcd = 414, vpi = 0, vci = 158SerialPort = Serial0VideoSlot = 1, VideoPort = 0CallId = 3CalledNumber = 221CallDuration = 557 secondsDisconnectText = local hangupSVC: call ID = 8598581Remote NSAP = 47.0091810000000002F26D4901.00107B09C645.C8Local NSAP = 47.0091810000000002F26D4901.00107B4832E1.C8vcd = 364, vpi = 0, vci = 108SerialPort = Serial0VideoSlot = 1, VideoPort = 0CallId = 2CalledNumber = n/a - incoming callCallDuration = 125 secondsDisconnectText = local hangupSVC: call ID = 8598484Remote NSAP = n/aLocal NSAP = 47.0091810000000002F26D4901.00107B4832E1.C8vcd = 264, vpi = 0, vci = 273SerialPort = Serial0VideoSlot = 1, VideoPort = 0CallId = 1CalledNumber = n/a - incoming callCallDuration = 171651 secondsDisconnectText = remote hangupSVC: call ID = 8594356Remote NSAP = n/aLocal NSAP = 47.0091810000000002F26D4901.00107B4832E1.C8vcd = 7, vpi = 0, vci = 39SerialPort = Serial0VideoSlot = 1, VideoPort = 0Step 12
router# debug video vicmVideo ViCM FSM debugging is on***** Starting Video call *****router# SVC HANDLE in rcvd:0x80001B:00:42:55:ViCM - current state = Idle, Codec Ready00:42:55:ViCM - current event = SVC Setup00:42:55:ViCM - new state = Call Connected00:42:55:ViCM - current state = Call Connected00:42:55:ViCM - current event = SVC Connect Ack00:42:55:ViCM - new state = Call Connected*****Video Call Disconnecting*****router#00:43:54:ViCM - current state = Call Connected00:43:54:ViCM - current event = SVC Release00:43:54:ViCM - new state = Remote Hangup00:43:54:ViCM - current state = Remote Hangup00:43:54:ViCM - current event = SVC Release Complete00:43:54:ViCM - new state = Remote Hangupmc3810_video_lw_periodic:Codec is not readymc3810_video_lw_periodic:sending message00:43:55:ViCM - current state = Remote Hangup00:43:55:ViCM - current event = DTR Deasserted00:43:55:ViCM - new state = Idlemc3810_video_lw_periodic:Codec is readymc3810_video_lw_periodic:sending message00:43:55:ViCM - current state = Idle00:43:55:ViCM - current event = DTR Asserted00:43:55:ViCM - new state = Idle, Codec ReadyMonitoring and Maintaining Video over ATM SVCs and PVCs
Configuration Examples
This configuration excerpts in this section illustrate how two Cisco MC3810 multiservice access concentrators communicate back to back as shown in Figure 3.
These examples do not show complete configurations but focus on the specific requirements of ATM video SVCs and PVCs, not on complete ATM setup.
Figure 3 Sample Configuration: Two Cisco MC3810s using ATM SVCs and/or PVCs for Videoconferencing
Initially, the network clocks are set up on each router so that video codecs can operate at a multiple of 64 Kbps.
The following commands show the configuration of the T1 0 controller, which is for ATM service. ESF framing and B8ZS are required for ATM. The default clock source is line, and the default for the T1 1 controller automatically becomes internal.
Serial interface 0 connects to the local video codec. The restart delay is set to 0 minutes so that the hardware is not reset when it goes down. The clock rate of 384 kbps is the speed at which the video images are transmitted.
The following commands show how to configure the ATM interface and set up PVCs to supply Q.SAAL signaling and ILMI management for SVC communications. Note that you can also specify the NSAP address by using the atm video aesa command with an ESI value.
The following examples show dial PVCs for video communications. Constant Bit Rate (CBR) is required for reliable video. The CBR speed is set at 117 percent of the video data rate of 384 kbps, which is configured on serial interface 0.
The following examples show dial peers set up for SVC video. Specify local peers through the port signal command, which indicates the slot location of the VDM and the port location of the RS-366 interface. Enter the port media command to specify the serial interface for the codec connection. The two configurations are shown one after the other rather than side by side.
The commands are as follows for MC3810A:
dial-peer video 111 videocodecnsap 47.0091810000000002F26D4901.00107B4832E1.C8port signal 1/0port media Serial0destination-pattern 121!dial-peer video 221 videoatmdestination-pattern 221session target ATM0 svc nsap 47.0091810000000002F26D4901.00107B09C645.C8The commands are as follows for MC3810B:
dial-peer video 111 videocodecnsap 47.0091810000000002F26D4901.00107B09C645.C8port signal 1/0port media Serial0destination-pattern 221!dial-peer video 121 videoatmdestination-pattern 121session target ATM0 svc nsap 47.0091810000000002F26D4901.00107B4832E1.C8Command Reference
This section documents new or modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command reference publications.
•
•
In Cisco IOS Release 12.0(1)T or later releases, you can search and filter the output for show and more commands. This functionality is useful when you need to sort through large amounts of output, or if you want to exclude output that you do not need to see.
To use this functionality, enter a show or more command followed by the "pipe" character (|), one of the keywords begin, include, or exclude, and an expression that you want to search or filter on:
command | {begin | include | exclude} regular-expression
In the following example of the show atm vc command, you want the command output to begin with the first line where the expression "PeakRate" appears:
show atm vc | begin PeakRate
For more information on the search and filter functionality, refer to the Cisco IOS Release 12.0(1)T feature module titled CLI String Search.
atm scramble-enable
Scrambling improves data reliability on E1 links by randomizing the ATM cell payload frames to avoid continuous non-variable bit patterns and improve the efficiency of ATM's cell delineation algorithms. The no form disables scrambling.
atm scramble-enable
no atm scramble-enable
Syntax Description
This command has no arguments or keywords.
Defaults
By default, payload scrambling is off.
Command Mode
Interface configuration
Command History
12.0(5)XK and 12.0(7)T
This command was introduced for ATM interface configuration on the Cisco MC3810.
Usage Guidelines
Enable scrambling on E1 links only. On T1 links, the default B8ZS line encoding normally ensures sufficient reliability.
The scrambling setting must match that of the far end.
Example
On a Cisco MC3810, the following example shows how to set the ATM0 E1 link to scramble payload:
interface atm0atm scramble-enableatm video aesa
The atm video aesa ATM interface configuration command sets the unique ATM end-station address (AESA) for an ATM video interface that is using SVC mode. The no form of this command removes any configured address for the interface.
atm video aesa [default | esi-address]
no atm video aesa
Syntax Description
Default
The default keyword is the default.
Command Mode
Interface configuration
Command History
12.0(5)XK and 12.0(7)T
This command was introduced for ATM interface configuration on the Cisco MC3810.
Usage Guidelines
You cannot specify the ATM interface NSAP address in its entirety. The system creates either all of the address or part of it, depending on how you use this command.
Example
On a Cisco MC3810, the following example shows the ATM interface NSAP address set automatically:
interface atm0atm video aesa defaultOn a Cisco MC3810, the following example shows the ATM interface NSAP address set to a specific ESI value:
interface atm0/1atm video aesa 444444444444Related Command
show atm video-voice address
Allows you to review the address assigned to an ATM interface.
dial-peer video
To define a video ATM dial peer for a local or remote video codec, specify video-related encapsulation, and enter dial-peer configuration mode, enter the dial-peer video global configuration command. The video dial peer is persistent and remains until you use the no form of the command to remove it.
dial-peer video tag {videocodec | videoatm}
no dial-peer video tag {videocodec | videoatm}
Syntax Description
Default
No video dial peer is configured.
Command Mode
Global configuration
Command History
12.0(5)XK and 12.0(7)T
This command was introduced for ATM interface configuration on the Cisco MC3810.
Usage Guidelines
The tag value that you assign must be unique to the device.
Video dial peers are persistent and remain until explicitly removed using the no form of the command.
Example
On a Cisco MC3810, the following example shows the setup of a local video dial peer designated as 10:
dial-peer video 10 videocodecRelated Command
show dial-peer video
Displays details about all video dial peers or a specified video dial peer, or provides summary information about all video dial peers.
nsap
To specify the network service access point (NSAP) address for a local video dial peer, enter the nsap dial-peer configuration command. The no form of the command removes any configured NSAP address from the dial peer.
nsap nsap-address
no nsap
Syntax Description
Default
No video dial peer NSAP address is configured.
Command Mode
Dial-peer configuration
Command History
12.0(5)XK and 12.0(7)T
This command was introduced for ATM video dial-peer configuration on the Cisco MC3810.
Usage Guidelines
The address must be unique on the router.
Example
On a Cisco MC3810, the following example sets up an NSAP address for the local video dial peer designated as 10:
dial-peer video 10 videocodecnsap 47.0091810000000002F26D4901.333333333332.02Related Commands
port media
For a local video dial peer, enter the port media video dial-peer configuration command to specify the serial interface where the local video codec is connected. The no form of the command removes any configured locations from the dial peer.
port media interface
no port media
Syntax Description
Default
No interface is specified.
Command Mode
Dial-peer configuration
Command History
12.0(5)XK and 12.0(7)T
This command was introduced for ATM video dial-peer configuration on the Cisco MC3810.
Example
On a Cisco MC3810 local video dial peer designated as 10, the following example shows serial interface 0 as the specified interface for the codec:
dial-peer video 10 videocodecport media Serial0Related Commands
port signal
For a local video dial peer, enter the port signal video dial-peer configuration command to specify the slot location of the video dialing module (VDM) and the port location of the RS-366 interface for signaling. The no form of the command removes any configured locations from the dial peer.
port signal slot/port
no port signal
Syntax Description
slot
Enter either 1 or 2 as the slot location of the VDM.
port
Enter the port location of the RS-366 interface. The Cisco MC3810 VDM has only one port, so the port value is always 0.
Default
No locations are specified.
Command Mode
Dial-peer configuration
Command History
12.0(5)XK and 12.0(7)T
This command was introduced for ATM video dial-peer configuration on the Cisco MC3810.
Example
On a Cisco MC3810, the following example shows how to set up the VDM and RS-366 interface locations for the local video dial peer designated as 10:
dial-peer video 10 videocodecport signal 1/0Related Commands
serial restart-delay
To set the amount of time that the router waits before trying to bring up a serial interface when it goes down, use the serial restart-delay interface configuration command. The no form of the command sets the delay to the default.
serial restart-delay count
no serial restart-delay
Syntax Description
count
count is a value from 0 to 900 in seconds. This is the frequency at which the hardware is reset.
Default
0 is the default value.
Command Mode
Interface configuration
Command History
12.0(5)XK and 12.0(7)T
This command was introduced for serial interface configuration on the Cisco MC3810.
Usage Guidelines
The router resets the hardware each time the serial restart timer expires. This command is often used with the dial backup feature and with the pulse-time command, which sets the amount of time to wait before redialing when a DTR dialed device fails to connect.
When the count value is set to the default of 0, the hardware is not reset when it goes down. In this way, if the interface is used to answer a call, it does not cause DTR to drop, which can cause a communications device to disconnect.
Example
On Cisco MC3810 interface Serial 0, this examples shows the restart delay set to 0:
interface Serial0serial restart-delay 0Related Commands
pulse-time seconds
Enables pulsing DTR signal intervals on the serial interfaces.
show interface serial
Displays details about serial interface configuration.
session target
To configure an ATM network-specific address for a permanent virtual connection (PVC) or switch virtual connection (SVC) dial peer, enter the ATM form of the session target dial-peer configuration command. The no form of the command disables the feature.
session target atm interface {svc nsap nsap-address | pvc {name | vpi/vci | vci}
no session target
Syntax Description
Default
Enabled with no IP address or domain name defined.
Command Mode
Dial-peer configuration
Command History
Usage Guidelines
Enter the ATM-specific version of this command to specify an ATM PVC or SVC for voice or video communications.
Through SVCs and a video map, dialed digits are reconciled with the remote ATM interface's video NSAP address,
Examples
The following example shows an ATM video dial peer configured for SVC communications:
dial-peer video 10 videoatmdestination-pattern 221session target ATM0 svc nsap 47.0091810000000002F26D4901.444444444444.01The following example shows a session target for Voice over ATM that uses PVCs. The session target is for a PVC with VPI-VCI values of 100/100:
dial-peer voice 12 voatmdestination-pattern 13102221111session target atm0 pvc 100/100Related Commands
show atm video-voice address
To display the network service access point (NSAP) address for the ATM interface, enter the show atm video-voice address privileged EXEC command.
show atm video-voice address
Syntax Description
There are no keywords or arguments
Default
No default behavior or values.
Command History
Usage Guidelines
Enter this command to review ATM interface NSAP addresses that have been assigned with the atm video aesa or atm voice aesa command and to ensure that ATM management is confirmed for those addresses.
Example
On a Cisco MC3810, the following example displays information about ATM interface NSAP addresses:
router# show atm video-voice addressnsap address type ilmi status47.0091810000000002F26D4901.00107B4832E1.FE VOICE_AAL5 Confirmed47.0091810000000002F26D4901.00107B4832E1.C8 VIDEO_AAL1 ConfirmedTable 1 describes the fields in the command output.
Table 1
ilmi status
Indicates whether an ILMI PVC is set up and operational to manage SVC communications.
nsap address
ATM interface NSAP address.
type
Interface ATM encapsulation type.
show atm video-voice address Fields
Related Command
show call history video record
To display information about video calls, enter the privileged EXEC show call history video record command.
show call history video recordSyntax Description
There are no keywords or arguments.
Default
No default behavior or values.
Command History
Usage Guidelines
Use this command to review statistics about recent incoming and outgoing video calls.
Example
On a Cisco MC3810, the following example displays information about two video calls:
Router# show call history video recordCallId = 4CalledNumber = 221CallDuration = 39006 secondsDisconnectText = remote hangupSVC: call ID = 8598630Remote NSAP = 47.0091810000000002F26D4901.00107B09C645.C8Local NSAP = 47.0091810000000002F26D4901.00107B4832E1.C8vcd = 414, vpi = 0, vci = 158SerialPort = Serial0VideoSlot = 1, VideoPort = 0CallId = 3CalledNumber = 221CallDuration = 557 secondsDisconnectText = local hangupSVC: call ID = 8598581Remote NSAP = 47.0091810000000002F26D4901.00107B09C645.C8Local NSAP = 47.0091810000000002F26D4901.00107B4832E1.C8vcd = 364, vpi = 0, vci = 108SerialPort = Serial0VideoSlot = 1, VideoPort = 0Table 2 describes the fields in the command output.
Table 2
show call history video record Fields
show controllers rs366
To display information about the RS-366 video interface on the video dialing module (VDM), enter the privileged EXEC show controllers rs366 command.
show controllers rs366 slot port
Syntax Description
Default
No default behavior or values.
Command History
Usage Guidelines
The table below explains the meaning of the fields in the show controllers rs366 command.
Example
On a Cisco MC3810, the following example displays information about the RS-366 controller:
Router# show controller rs366 0 1RS366:driver is initialized in slot 1, port 0:STATUS STATE LSR LCR ICSR EXT T1 T2 T3 T4 T50x02 0x01 0x00 0x50 0xE0 0x00 5000 5000 5000 20000 10000Dial string:121C
show dial-peer video
To display dial-peer configuration, enter the privileged EXEC show dial-peer video command.
show dial-peer video [number] [summary]
Syntax Description
Default
No default behavior or values.
Command History
Usage Guidelines
Use this command to review video dial-peer configuration.
Example
On a Cisco MC3810, the following example displays detailed information about all configured video dial peers:
Router# show dial-peer videoVideo Dial-Peer 1type = videocodec, destination-pattern = 111port signal = 1/0, port media = Serial1nsap = 47.0091810000000050E201B101.00107B09C6F2.C8Video Dial-Peer 2type = videoatm, destination-pattern = 222session-target = ATM0 svc nsap 47.0091810000000050E201B101.00E01E92ADC2.C8Video Dial-Peer 3type = videoatm, destination-pattern = 333session-target = ATM0 pvc 70/70The dial-peer information is specified for each dial peer, which is identified by a unique ID number (in the example above, 1, 2, and 3) that was defined using the dial-peer video command. Table 3 describes the fields in the command output.
show video call summary
To display summary information about video calls and the current status of the Video Call Manager (ViCM), enter the show video call summary privileged EXEC command.
show video call summary
Syntax Description
There are no keywords or arguments.
Default
No default behavior or values
Command History
Usage Guidelines
Use this command to quickly look at the status of current calls. In Cisco IOS Releases 12.0(5)XK and 12.0(7)T, there can be only one video call in progress.
Examples
On a Cisco MC3810, the following example displays information about the ViCM when no call is in progress on the serial interface that connects to the local video codec:
Router# show video call summarySerial0:ViCM = Idle, Codec ReadyWhen a call is starting, the output looks like this:
Router# show video call summarySerial0:ViCM = Call ConnectedWhen a call is disconnecting, the output looks like this:
Router# show video call summarySerial0:ViCM = IdleRelated Command
show call history video record
Provides details about current and recent video calls.
Debug Command
This section documents a new debug command, debug video vicm.
debug video vicm
To display debug messages for the Video Call Manager (ViCM) that handles video calls, enter the privileged EXEC debug video vicm command. The no form of the command disables ViCM debugging.
[no] debug video vicm
Syntax Description
This command has no arguments or keywords.
Default
Debugging for the ViCM is not enabled.
Command History
Example
The following example shows output when you use the debug video vicm command. Comments are enclosed in asterisks (*).
router# debug video vicmVideo ViCM FSM debugging is on***** Starting Video call *****router# SVC HANDLE in rcvd:0x80001B:00:42:55:ViCM - current state = Idle, Codec Ready00:42:55:ViCM - current event = SVC Setup00:42:55:ViCM - new state = Call Connected00:42:55:ViCM - current state = Call Connected00:42:55:ViCM - current event = SVC Connect Ack00:42:55:ViCM - new state = Call Connected*****Video Call Disconnecting*****router#00:43:54:ViCM - current state = Call Connected00:43:54:ViCM - current event = SVC Release00:43:54:ViCM - new state = Remote Hangup00:43:54:ViCM - current state = Remote Hangup00:43:54:ViCM - current event = SVC Release Complete00:43:54:ViCM - new state = Remote Hangupmc3810_video_lw_periodic:Codec is not readymc3810_video_lw_periodic:sending message00:43:55:ViCM - current state = Remote Hangup00:43:55:ViCM - current event = DTR Deasserted00:43:55:ViCM - new state = Idlemc3810_video_lw_periodic:Codec is readymc3810_video_lw_periodic:sending message00:43:55:ViCM - current state = Idle00:43:55:ViCM - current event = DTR Asserted00:43:55:ViCM - new state = Idle, Codec Ready
Glossary
AAL—ATM Adaptation Layer. Service-dependent sublayer of the data link layer. The AAL accepts data from different applications and presents it to the ATM layer in the form of 48-byte ATM payload segments. AALs consist of two sublayers: convergence sublayer (CS) and segmentation and reassembly (SAR). AALs differ on the basis of the source-destination timing used, whether they use constant bit rate (CBR) or variable bit rate (VBR), and whether they are used for connection-oriented or connectionless mode data transfer. At present, the four types of AAL recommended by the ITU-T are AAL1, AAL2, AAL3/4, and AAL5.
AAL1—ATM adaptation layer 1. One of four AALs recommended by the ITU-T. AAL1 is used for connection-oriented, delay-sensitive services requiring constant bit rates, such as uncompressed video and other isochronous traffic.
AESA—ATM End System Address
ATM—Asynchronous Transfer Mode. International standard for cell relay in which multiple service types (such as voice, video, or data) are conveyed in fixed-length (53-byte) cells. Fixed-length cells allow cell processing to occur in hardware, thereby reducing transit delays. ATM is designed to take advantage of high-speed transmission media such as E3, SONET, and T3.
B8ZS—binary 8-zero substitution. Line-code type, used on T1 and E1 circuits, in which a special code is substituted whenever 8 consecutive zeros are sent over the link. This code is then interpreted at the remote end of the connection. This technique guarantees ones density independent of the data stream.
CBR—constant bit rate. QoS class defined by the ATM Forum for ATM networks. CBR is used for connections that depend on precise clocking to ensure undistorted delivery.
CES—circuit emulation service. Enables users to multiplex or concentrate multiple circuit emulation streams for voice and video with packet data on a single high-speed ATM link without a separate ATM access multiplexer.
E1—European digital carrier facility used for transmitting data through the telephone hierarchy. The transmission rate for E1 is 2.048 megabits per second (Mbps).
ESF—Extended Superframe. Framing type used on T1 circuits that consists of 24 frames of 192 bits each, with the 193rd bit providing timing and other functions. ESF is an enhanced version of Superframe format.
ESI—end station identifier
ILMI—Interim Local Management Interface. Specification developed by the ATM Forum for incorporating network-management capabilities into the ATM User-Network Interface (UNI).
IMA—Inverse Multiplexing for ATM, a standard protocol defined by the ATM Forum in 1997.
ISDN—Integrated Services Digital Network. Communication protocol, offered by telephone companies, that permits telephone networks to carry data, voice, and other source traffic.
NSAP—network service access point. Network addresses, as specified by ISO. An NSAP is the point at which OSI Network Service is made available to a transport layer (Layer 4) entity.
PVC—permanent virtual circuit. Virtual circuit that is permanently established. PVCs save bandwidth associated with circuit establishment and tear down in situations where certain virtual circuits must exist all the time. In ATM terminology, called a permanent virtual connection.
QoS—quality of service. Measure of performance for a transmission system that reflects its transmission quality and service availability.
SAR—segmentation and reassembly. One of the two sublayers of the AAL CPCS, responsible for dividing (at the source) and reassembling (at the destination) the PDUs passed from the CS. The SAR sublayer takes the PDUs processed by the CS and, after dividing them into 48-byte pieces of payload data, passes them to the ATM layer for further processing.
SONET—Synchronous Optical Network. High-speed (up to 2.5 Gbps) synchronous network specification developed by Bellcore and designed to run on optical fiber. STS-1 is the basic building block of SONET.
SVC—switched virtual circuit. Virtual circuit that is dynamically established on demand and is torn down when transmission is complete. SVCs are used in situations where data transmission is sporadic. Called a switched virtual connection in ATM terminology.
T1—Digital WAN carrier facility. T1 transmits DS-1-formatted data at 1.544 Mbps through the telephone switching network, using alternate mark inversion or B8ZS coding.
UNI—User-Network Interface. ATM Forum specification that defines an interoperability standard for the interface between ATM-based products (a router or an ATM switch) located in a private network and the ATM switches located within the public carrier networks. Also used to describe similar connections in Frame Relay networks.
VBR—variable bit rate. QoS class defined by the ATM Forum for ATM networks. VBR is subdivided into a real time (RT) class and non-real time (NRT) class. VBR (RT) is used for connections in which there is a fixed timing relationship between samples. VBR (NRT) is used for connections in which there is no fixed timing relationship between samples, but that still need a guaranteed QoS.
VC—virtual circuit. Logical circuit created to ensure reliable communication between two network devices. A virtual circuit is defined by a VPI/VCI pair, and can be either permanent (PVC) or switched (SVC). Virtual circuits are used in Frame Relay and X.25. In ATM, a virtual circuit is sometimes called a virtual channel.
VCI—virtual channel identifier. 16-bit field in the header of an ATM cell. The VCI, together with the virtual path identifier (VPI), is used to identify the next destination of a cell as it passes through a series of ATM switches on its way to its destination. ATM switches use the VPI/VCI fields to identify the next network virtual channel link (VCL) that a cell needs to transit on its way to its final destination.
VCL—virtual channel link. Connection between two ATM devices. A VCC is made up of one or more VCLs.
VPI—virtual path identifier. 8-bit field in the header of an ATM cell. The VPI, together with the VCI, is used to identify the next destination of a cell as it passes through a series of ATM switches on its way to its destination. ATM switches use the VPI/VCI fields to identify the next VCL that a cell needs to transit on its way to its final destination.
Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.
© 2007 Cisco Systems, Inc. All rights reserved.
Feedback