Voice over ATM Switched Virtual
Circuits on the Cisco MC3810
This document describes voice over Asynchronous Transfer Mode (VoATM) switched virtual
circuits (SVCs) for the Cisco MC3810 multiservice access concentrator.
This document includes the following sections:
• Feature Overview, page 1
• Supported Platforms, page 4
• Supported Standards, MIBs, and RFCs, page 4
• Prerequisites, page 4
• Configuration Tasks, page 5
• Troubleshooting Voice over ATM SVCs, page 16
• Monitoring and Main taining Voice over ATM SVCs, page 19
• Configuration Examples, page 20
• Command Reference, page 22
• Glossary, page 30
Feature Overview
VoATM SVCs allow the Cisco MC3810 to transfer voice data dynamically and as needed—without
tying up the resources required for static, manually provisioned permanent virtual circuits (PVCs).
An SVC connection is initiated for each call, and each request includes bandwidth and
quality-of-service (QoS) information required for the connection. SVCs are ideal for networks that
are highly interconnected, where scalability is essential, and in situations where traffic is sporadic.
In addition, service providers often offer more advantageous, usage-based pricing options for SVCs.
VoATM using SVCs on the Cisco MC3810 includes all of the voice features that the Cisco MC3810
supports for PVCs and for Frame Relay transport. Like other Cisco voice implementations, VoATM
using SVCs is based on dial peers and uses ATM Adaptation Layer 5 (AAL5).
ATM SVC service operates much like X.25 SVC service, although ATM allows much higher
throughput. It requires a signaling protocol between a router or a multiservice access concentrator
and an ATM switch. The ATM signaling software provides a method of dynamically establishing,
maintaining, and clearing A TM connections at the User -Network Interface (UNI). In UNI, the router
serves as the user and the AT M switch is considered the network. The router does not perform
call-level routing. Instead, the ATM switch does the A TM call routing, and the router directs pack ets
through the resulting circuit.
Voice over ATM Switched Virtual Circuits on the Cisco MC3810 1
Feature Overview
Local office 1
VoATM SVCs include the following features:
• User-to-Network Interface (UNI) 3.1 signaling procedures, including support for the following
types of information elements:
— Traffic descriptor
— Broadband bearer capability
— ATM addressing information
• The implementation adheres to the required features of ATM Forum User-Network Interface
(UNI) signaling specification, version 4.0, simultaneously supporting permanent virtual circuits
(PVCs) and SVCs.
• Network Service Access Point (NSAP) addressing for private networks
• Interim Local Management Interface (ILMI)
• 24 simultaneous voice calls per Cisco MC3810 system
• Support for tandem switching
Note The Cisco MC3810, in addition to supporting video and voice over A TM SVCs, 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.
Figure 1 Application for Voice over ATM Using SVCs
FXS FXS FXS
FXO
Local office 2
FXS FXS FXS
Cisco
MC3810
MC3810
T1 or E1
Cisco
T1 or E1
ATM PVC
& SVCs
PSTN
T1 or E1
Regional office
PBX
T1 or E1
Cisco
MC3810
22885
Cisco IOS Release 12.0(7)T
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Benefits
Benefits
The Cisco MC3810 multiservice access concentrator formerly supported only non-dial permanent
virtual circuits (PVCs) for ATM traffic.
SVCs offer the following benefits:
• Dynamic resource allocation is more efficient and flexible than in nailed-up PVC connections.
• Many service providers offer favorable pricing for ATM SVC service.
• Interface requirements are determin ed by total bandwidth needs rather than by the number of
different remote connections.
• SVCs support flat network topologies where each endpoint is separated by one hop only , offering
the following advantages:
— Simplifies design and management challenges.
— Impro ves voice quality because there is only one compression cycle—in contrast to sc hemes
where voice is compressed, decompressed, and compressed again.
— Reduces delays over designs with multiple hops.
Restrictions
The following features are not supported.
• Direct E.164 ATM addressing
• Available Bit Rate (ABR) service
• Leaf-initiated joins (LIJs)
• ATM an ycast, communication between one sender and the nearest of se veral recei v ers in a group
• Generic Identifier Transport (GIT), which uses an information element to carry identifiers
between two users
• Switched Virtual Path service, which is the grouping of SVCs to define a path (usually within a
single application) where the switch directs calls as appropriate
• Proxy signaling, where, for example, IP traffic is identified by class or precedence and an IP
router rather than the source host signals an ATM layer
Related Features and Technologies
The Cisco MC3810 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.
Voice over ATM Switched Virtual Circuits on the Cisco MC3810 3
Related Documents
Related Documents
For information about Cisco IOS configuration for voice applications, consult the following Cisco
IOS Release 12.0 documents:
• Voice, Video, and Home Applications Configuration Guide
• Voice, Video, and Home Applications Command Reference
For information about Cisco IOS configuration for ATM, consult the following Cisco IOS Release
12.0 documents:
• Wide-Area Networking Configuration Guide
• Wide-Area Networking Command Reference
For information about IOS configuration that is unique to the Cisco MC3810, consult the following
Cisco documents:
• Cisco MC3810 Multiservice Access Concentrator Softwar e Configuration Guide
• Cisco MC3810 Multiservice Access Concentrator Software Command Reference
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.
Other Standards
• ATM Forum document af-uni-0010.002, ATM User-Network Interface Specification V3.1
(1994), including support for the following types of information elements:
— Traffic Descriptor
— Broadband Bearer Capability
— ATM Addressing Information
• ATM F orum document af-sig-0061.000, A TM UNI Signaling Specif ication V4.0 (1996) with the
exceptions noted in “Restrictions” on page 3
• ITU recommendation Q.2931
• ITU-T X.213 and OSI Network Service Access Point (NSAP) addressing
• ATM Forum document af-ilmi-0065.0 00, Integrated Local Management Interface (1996)
Prerequisites
• Cisco IOS Software Release 12.0(5)XK or 12.0(7)T or a later release
• A configured ATM network
Cisco IOS Release 12.0(7)T
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Configuring Network Clocks and Controller Settings
Configuration Tasks
Perform the following tasks to configure VoATM SVCs service:
• Set up clock sources, T1/E1 controller settings, and serial interfaces.
• Configure the ATM interface, including signaling and management PVCs.
• Set up voice POTS and ATM dial peers.
These tasks do not represent all of the configuration tasks required to set up your A TM network. F or
more information, refer to the Cisco MC3810 Multiservice Access Concentrator Software
Configuration Guide and to the examples shown in the “Configuration Examples” section on
page 20.
Configuring Network Clocks and Controller Settings
Because voice communications require a continuous and tightly meshed data stream to avoid loss of
information, and PSTNs provide a variety of clocks, you must synchronize source and destination
devices to a single master clock. In the example that follows, the clock source is derived from a
device attached to T1 controller 0; then the clock source is distributed to the de vices attached to the
local Cisco MC3810 serial ports and to T1 controller 1. Base clock source decisions on the network
configuration, and set up a hierarchy of clock sources, so that backup clock sources are available.
For details, see Chapter 4, “Configuring Synchronized Clocking,” in Cisco MC3810 Multiservice
Access Concentrator Software Conf iguration Guide.
This configuration task also includes the basic steps required for ATM support over T1/E1
controller 0.
Step Command Purpose
Router# configure terminal
1
Router(config)# controller {T1 | E1} 0
2
Router(config-controller)# clock source line
3
Router(config-controller)# no shutdown
4
Router(config)# controller {T1 | E1} 1
5
Router(config-controller)# clock source internal
6
Router(config-controller)# no shutdown
7
Router(config-controller)# exit
8
Router(config)# framing esf
9
or
Router(config)# framing crc4
Enter global configuration mode.
Enter controller configuration mode for controller
T1/E1 0. ATM traffic is supported on controller T1/E1 0
only.
Configure controller T1/E1 0 to obtain the Cisco MC3810
clock source from an attached network device. This is the
default setting.
Activate the controller.
Enter controller configuration mode for controller
T1/E1 1.
Configure controller T1/E1 1 to obtain its clocking from
the internal network clock Phase-Lock-Loop (PLL). In
this way, controller T1/E1 1 obtains clocking from the
T1/E1 0 controller source—the switch.
Activate the controller.
Exit controller configuration mode.
Set the framing to Extended Superframe (ESF) format,
required for ATM on T1. This setting is automatic for T1
when the ATM mode is set.
Set the framing to CRC4, required for ATM on E1. This
setting is automatic for E1 when the ATM mode is set.
Voice over ATM Switched Virtual Circuits on the Cisco MC3810 5
Verifying Network Clocks and Controller Settings
Step Command Purpose
Router(config)# linecode b8zs
10
or
Set the line coding to binary zero 0 substitution (B8ZS),
required for ATM on T1. This setting is automatic for T1
when the ATM mode is set.
Router(config)# linecode hdb3
Set the line coding to HDB3, required for ATM on E1.
This setting is automatic for E1 when the ATM mode is
set.
Router(config)# mode atm
11
Configure 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 super frame (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, channel-associated signaling (CAS)
groups, common channel signaling (CCS) groups or clear
channels are not allowed on the trunk because ATM traffic
occupies all the DS0s.
Router(config)# network-clock base rate {56k | 64k}
12
Set the network clock base-rate for the serial ports. The
default is 56 kbps.
Note At this point, you can also configure network
protocol settings such as IP hosts. For more information,
see the Cisco IOS Release 12.0 network protocol
configuration and command reference guides.
Verifying Network Clocks and Controller Settings
T o v erify the configuration of network clock sources and controller settings, follow the steps below.
Step 1 Enter the privileged EXEC show network-clocks command to see the status of clock
source settings.
Router# show network-clocks
Priority 1 clock source(inactive config): T1 0
Priority 1 clock source(active config) : T1 0
Step 2 Enter the privileged EXEC show controllers t1 or sho w controllers e1 command to s ee
the status of T1/E1 controllers.
router# show controller t1 1
T1 1 is up.
Applique type is Channelized T1
Cablelength is long gain36 0db
No alarms detected.
Slot 4 CSU Serial #07789650 Model TEB HWVersion 4.70 RX level = 0DB
Framing is ESF, Line Code is B8ZS, Clock Source is Internal.
Data in current interval (819 seconds elapsed):
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
Data in Interval 1:
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
Data in Interval 2:
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
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Configuring ATM Interfaces
.
.
.
Data in Interval 96:
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
Total 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 1
E1 1 is up.
Applique type is Channelized E1 - balanced
No alarms detected.
Slot 4 Serial #06868949 Model TEB HWVersion 3.80
Framing is CRC4, Line Code is HDB3, Clock Source is Internal.
Data in current interval (292 seconds elapsed):
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
.
.
.
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 Se
Configuring ATM Interfaces
In this section, the ATM interface is set up, including PVCs to carry signaling for SVCs. In addition,
an NSAP address for an ATM SVC is specified. For additional information, see Cisco MC3810
Multiservice Access Concentrator Software Configuration Guide and Cisco MC3810 Multiservice
Access Concentrator Software Command Reference.
You can also configure PVCs for voice communications. Wide-Area Networking Configuration
Guide and Wide-Area Networking Command Reference provide additional information about this
and other aspects of ATM configuration.
Step Command Purpose
Router# configure terminal
1
Router(config)# interface atm0
2
Router(config-if)# ip address ip-address mask
3
Enter global configuration mode.
Enter interface configuration mode for ATM 0—the only
ATM interface that supports voice over SVCs.
Assign the IP address and subnet mask to the interface.
Voice over ATM Switched Virtual Circuits on the Cisco MC3810 7
Configuring ATM Interfaces
Step Command Purpose
Router(config-if)# atm voice aesa {default |
4
esi-address}
This command sets the unique ATM end-station address
(AESA) for an ATM interface that is using SVC mode for
voice.
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 id entifier),
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 v o ic e selector byte provides
the remaining characters.
You can view the assigned address using the show atm
video-voice address command.
Router(config-if)# pvc [name] vpi/vci ilmi
5
Create an ATM permanent virtual circuit (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. name 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 v alue 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 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 local significance only.
To set up communication with the ILMI, enter a value of
ilmi for ATM adaptation layer encapsulation; the
associated vpi and vci values are ordinarily 0 and 16,
respectively.
Note Typically, the lo w values 0 to 31 are reserved for
specific traffic (for example, F4 OAM, SVC signaling,
ILMI, and so on) and you should not use them for other
PVCs.
Router(config-if-atm-pvc)# pvc [name] vpi/vci qsaal
6
See the explanations in Step 5 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.
#Router(config-if-atm-pvc)# exit
7
Exit PVC interface configuration mode.
Cisco IOS Release 12.0(7)T
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Step Command Purpose
Router(config-if)# interface atm 0 [.subinterface-number
8
{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 you can configure a second IP address on a
subinterface.
subinterface-number is a value in the range from 1 to
4294967293.
Enter the multipoint keyword when your netwo rk is fully
meshed and you want 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 Enter the privileged EXEC show atm vc command to see how SVCs and PVCs are set
up, as in the following example:
Router# show atm vc
VCD / Peak Avg/Min Burst
Interface Name VPI VCI Type Encaps SC Kbps Kbps Cells Sts
0 1 0 5 PVC SAAL UBR 0 UP
0 2 0 16 PVC ILMI UBR 0 UP
0 379 0 60 SVC SNAP UBR 0 UP
0 986 0 84 SVC SNAP UBR 0 UP
0 14 0 133 SVC VOICE VBR 64 16 10 UP
0 15 0 134 SVC VOICE VBR 64 16 10 UP
0 16 0 135 SVC VOICE VBR 64 16 10 UP
0 17 0 136 SVC VOICE VBR 64 16 10 UP
0 18 0 137 SVC VOICE VBR 64 16 10 UP
0 19 0 138 SVC VOICE VBR 64 16 10 UP
0 20 0 139 SVC VOICE VBR 64 16 10 UP
0 21 0 140 SVC VOICE VBR 64 16 10 UP
0 22 0 141 SVC VOICE VBR 64 16 10 UP
0 23 0 142 SVC VOICE VBR 64 16 10 UP
0 24 0 143 SVC VOICE VBR 64 16 10 UP
0 25 0 144 SVC VOICE VBR 64 16 10 UP
0 26 0 145 SVC VOICE VBR 64 16 10 UP
0 27 0 146 SVC VOICE VBR 64 16 10 UP
0 28 0 147 SVC VOICE VBR 64 16 10 UP
Verifying ATM Interface Configuration
Step 2 Enter the show atm svc command with or without the VPI/VCI specified. The following
example shows information for a specific SVC:
Router# show atm svc 0/134
ATM0: VCD: 5, VPI: 0, VCI: 134
VBR, PeakRate: 64000
AAL5, etype: 0x0, Flags 0x440, VCmode: 0xE000
OAM frequency: 0 second(s), OAM retry frequency: 1 second(s)
OAM up retry count: 3, OAM down retry count: 5
OAM Loopback status: OAM Disabled
OAM VC state: Not Managed
ILMI VC state: Not Managed
InARP DISABLED
Voice over ATM Switched Virtual Circuits on the Cisco MC3810 9
Verifying ATM Interface Configuration
InPkts: 4, OutPkts: 4, InBytes: 432, OutBytes: 432
InPRoc: 4, OutPRoc: 4, Broadcasts: 0
InFast: 0, OutFast: 0, InAS: 0, OutAS: 0
OAM cells received: 0
F5 InEndloop: 0, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI:0
F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI:0
OAM cells sent: 0
F5 OutEndloop: 0, F5 OutSegloop: 0, F5 OutRDI: 0
OAM cell drops: 0
Status: UP
TTL: 3
interface = ATM0, call locally initiated, call reference = 5558610
vcnum = 5, vpi = 0, vci = 134, state = Active(U10), point-to-point call
Retry count: Current = 0
timer currently inactive, timer value = 00:00:00
Remote Atm Nsap address:47.00918100000000400B0A2501.0060837B4743.00,
VCowner:Static Map
Step 3 To see the PVCs that are set up for ILMI management and Q.SAAL signaling, enter the
show atm pvc command with the VPI/VCI specified, as in the following example:
Router# show atm pvc 0/5
ATM0: VCD: 2, VPI: 0, VCI: 5, Connection Name: SAAL
UBR, PeakRate: 56
AAL5-SAAL, etype:0x4, Flags: 0x26, VCmode: 0x0
OAM frequency: 0 second(s), OAM retry frequency: 1 second(s), OAM retry frequenc
y: 1 second(s)
OAM up retry count: 3, OAM down retry count: 5
OAM Loopback status: OAM Disabled
OAM VC state: Not Managed
ILMI VC state: Not Managed
InARP DISABLED
InPkts: 2044, OutPkts: 2064, InBytes: 20412, OutBytes: 20580
InPRoc: 2044, OutPRoc: 2064, Broadcasts: 0
InFast: 0, OutFast: 0, InAS: 0, OutAS: 0
OAM cells received: 0
F5 InEndloop: 0, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0
F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI: 0
OAM cells sent: 0
F5 OutEndloop: 0, F5 OutSegloop: 0, F5 OutRDI: 0
F4 OutEndloop: 0, F4 OutSegloop: 0, F4 OutRDI: 0
OAM cell drops: 0
Compress: Disabled
Status: INACTIVE, State: NOT_IN_SERVICE
!
Router# show atm pvc 0/16
ATM0: VCD: 1, VPI: 0, VCI: 16, Connection Name: ILMI
UBR, PeakRate: 56
AAL5-ILMI, etype:0x0, Flags: 0x27, VCmode: 0x0
OAM frequency: 0 second(s), OAM retry frequency: 1 second(s), OAM retry frequenc
y: 1 second(s)
OAM up retry count: 3, OAM down retry count: 5
OAM Loopback status: OAM Disabled
OAM VC state: Not Managed
ILMI VC state: Not Managed
InARP DISABLED
InPkts: 398, OutPkts: 421, InBytes: 30493, OutBytes: 27227
InPRoc: 398, OutPRoc: 421, Broadcasts: 0
InFast: 0, OutFast: 0, InAS: 0, OutAS: 0
OAM cells received: 0
F5 InEndloop: 0, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0
F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI: 0
OAM cells sent: 0
F5 OutEndloop: 0, F5 OutSegloop: 0, F5 OutRDI: 0
F4 OutEndloop: 0, F4 OutSegloop: 0, F4 OutRDI: 0
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