Cisco NM-1A-T3 - 1port Ds3 Atm Network Module User manual

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Configuring the Cisco NM-1A-T3/E3 Network
Module
OL-10215-01
First Published: June 28, 2007
The Cisco NM-1A-T3/E3 (or ATM T3/E3) network module provides Asynchronous Transfer Mode
(ATM) services on a T3 or E3 connection. This feature module explains how to configure the ATM
T3/E3 network module for each connection. The ATM T3/E3 network module is supported on
Cisco 2800 and Cisco 3800 routers and includes the following features:
•ATM traffic management features including constant bit rate (CBR), variable bit rate (VBR),
available bit rate (ABR), unspecified bit rate (UBR), and UBR+
•Classic IP over ATM encapsulation (RFC 1577)
•Multiprotocol encapsulation over ATM adaptive layer 5 (AAL5) segmentation (RFC 1483)
•Point-to-Point Protocol (PPP) over ATM
•LAN Emulation (LANE)
Finding Feature Information in This Module
Your Cisco IOS software release may not support all the features documented in this module. To reach
links to specific feature documentation in this module and to see a list of the releases in which each feature is
supported, see the “Feature Information for the Cisco ATM T3/E3 Network Module” section on page 26.
Finding Support Information for Platforms and Cisco IOS and Catalyst OS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS
software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. You do
not need an account on Cisco.com.
Contents
•Restrictions for the Cisco ATM T3/E3 Network Module, page 2
•Information About the Cisco ATM T3/E3 Network Module, page 2
•How to Configure the ATM T3/E3 Network Module, page 4

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•SVCs, page 11
•Customizing the ATM T3/E3 Network Module, page 15
•Configuration Example, page 16
•Recommendations for Watermark Settings, page 16
•Additional References, page 19
•Command Reference, page 21
•Feature Information for the Cisco ATM T3/E3 Network Module, page 26
•Obtaining Documentation, Obtaining Support, and Security Guidelines, page 6
Restrictions for the Cisco ATM T3/E3 Network Module
The following restrictions apply to the Cisco ATM T3/E3 network module:
•There is no default card type configuration on the ATM T3/E3 network module. You must configure
the ATM T3/E3 network module for T3 or E3 before it will work.
•The atm vc-per-vp command is not supported on the ATM T3/E3 network module.
Information About the Cisco ATM T3/E3 Network Module
To configure the Cisco ATM T3/E3 network module, you should understand the following:
•ATM, page 2
•Permanent Virtual Circuits, page 3
•Switched Virtual Circuits, page 3
•Classes of Service, page 4
ATM
ATM is an International Telecommunication Union-Telecommunications Standards Section (ITU-T)
standard for cell relay wherein information for multiple service types (such as voice, video, and data),
is conveyed in small, fixed-size (53-byte) cells via connection-oriented virtual circuits (VCs).
Virtual Circuits
A virtual circuit (VC) is a point-to-point connection between remote hosts and routers. A VC is
established for each ATM end node with which the router communicates. The characteristics of the VC
are established when the VC is created and include the following:
•Classes of Service
•ATM adaptation layer 5 (AAL5)
•Encapsulation type:
– Logical link control Subnetwork Address Protocol (AAL5SNAP)
– Multiplexer (AAL5MUX)

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– Network Layer Protocol ID (AAL5NLPID)
– Integrated Local Management Interface (ILMI)
– Switched Multimegabit Data Service (SMDS)
– ITU/Q.2931 Signaling ATM Adaptation Layer (QSAAL)
– Cisco AUTO PPP over AAL5 (aal5autoppp)
– Cisco PPP over AAL5 (aal5ciscoppp)
Each VC supports the following router functions:
•Multiprotocol switching
•Fast switching of IP packets
•Flow, and Cisco Express Forwarding (CEF) switching of IP packets
•Pseudo-broadcast support for multicast packets
By default, CEF switching is enabled on all ATM T3/E3 module interfaces. These switching features can
be turned off by using interface configuration commands. Flow must be explicitly enabled for each
interface.
Permanent Virtual Circuits
To use a permanent virtual circuit (PVC), configure the PVC in both the router and the ATM switch.
PVCs remain active until the circuit is removed from either configuration. When a PVC is configured,
all the configuration options are passed on to the OC-3 module. You can write these PVCs into NVRAM;
they are used when the system image is reloaded.
Some ATM switches might have point-to-multipoint PVCs that do the equivalent of broadcasting. A
point-to-multipoint PVC can be used as the sole broadcast PVC for all multicast requests.These
switching features can be turned off by using interface configuration commands. Flow must be explicitly
enabled for each interface.
Switched Virtual Circuits
ATM switched virtual circuit (SVC) service operates much like X.25 SVC service, although ATM allows
much higher throughput. Virtual circuits are created and released dynamically, providing user bandwidth
on demand. This service requires a signaling protocol between the router and the switch.
The ATM signaling software provides a method of dynamically establishing, maintaining, and clearing
ATM connections at the user-network interface (UNI). The ATM signaling software conforms to ATM
Forum UNI 3.0 or ATM Forum UNI 3.1, depending on what version is selected by interim local
management interface (ILMI) or configuration.
In UNI mode, the user is the router and the network is an ATM switch. This is an important distinction.
The Cisco router does not perform ATM-level call routing. Instead, the ATM switch does the ATM call
routing, and the router routes packets through the resulting circuit. The router performs as the user and
the LAN interconnection device at the end of the circuit, and the ATM switch performs as the network.

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Classes of Service
ATM resources can be specified dynamically on a per-connection basis (per SVC). The ATM T3/E3
network module supports four classes of service:
•Constant Bit Rate (CBR): This class emulates circuit switching. CBR has the highest transport
priority, which is 0. CBR can be used for connections such as voice and video. This bandwidth is
characterized by peak cell rate (PCR).
•Variable Bit Rate (VBR): VBR is available in non-real-time (VBR-nrt) and real-time (VBR-rt). VBR
has the second highest transport priority, which is 1. VBR sends traffic at a rate that varies with time,
depending on the availability of user information.
•Available Bit Rate (ABR): ABR has the transport priority of 2. ABR provides rate-based flow
control and is aimed at data traffic.
•Unspecified Bit Rate (UBR): UBR has the transport priority of 3. UBR is a “best effort” class of
service that uses the unutilized bandwidth for a connection. Traffic categorized as UBR+ is
guaranteed a minimum line rate through the minimum cell rate (MCR) traffic parameter.
How to Configure the ATM T3/E3 Network Module
To configure the ATM T3/E3 network module, complete the following procedures:
•Configuring the Card Type, page 4
•Changing the Card Type, page 5
•Enabling the ATM Interface, page 7
•Configuring PVCs, page 7
Configuring the Card Type
To configure the ATM T3/E3 network module for T3 or E3 operation, perform the following tasks.
Note The ATM T3/E3 network module will not be operational until a card type is configured.
SUMMARY STEPS
1. enable
2. configure terminal
3. card type {t3 | e3} slot

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DETAILED STEPS
Changing the Card Type
To change the ATM T3/E3 network module for T3 or E3 operation, perform the following tasks:
SUMMARY STEPS
1. enable
2. configure terminal
3. no card type {t3 | e3}
4. card type {t3 | e3} slot
5. reload
Command or Action Purpose
Step 1 enable
Example:
Router> enable
Enables privileged EXEC mode.
•Enter your password if prompted.
Step 2 configure terminal
Example:
Router# configure terminal
Enters global configuration mode.
Step 3 card type {t3|e3} slot
Example:
Router(config)# card type t3 1
Specifies T3 or E3 connectivity for the ATM T3/E3 network
module.

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DETAILED STEPS
Note When changing from T3 card type to E3 card type make sure that the interface is configured for 34 Mbps
or less. This is the maximum bandwidth for an E3 connection.
Troubleshooting Tip
T3 interfaces support a maximum bandwidth of 44,209 kbps in ATM and 40,700 kbps in physical layer
convergence procedures (PLCP) mode. E3 interfaces support a maximum bandwidth of 33,920 kbps in
ATM and 30,528 kbps in PLCP mode.
If the total bandwidth used by an interface is greater than 34 Mbps and the card type is changed from T3
to E3, the traffic shaping characteristics of the VCs will be changed. The Cisco IOS software will
reconfigure the VCs so that the total allocated guaranteed bandwidth does not exceed the maximum
allowable E3 bandwidth.
Command or Action Purpose
Step 1 enable
Example:
Router> enable
Enables privileged EXEC mode.
•Enter your password if prompted.
Step 2 configure terminal
Example:
Router# configure terminal
Enters global configuration mode.
Step 3 no card type {t3 | e3}
Example:
Router(config)# no card type t3
Optional. Removes any previously configured card type.
Step 4 card type {t3 | e3} slot
Example:
Router(config)# card type t3 1
Specifies T3 or E3 connectivity for the ATM T3/E3 network
module.
Step 5 reload
Example:
Router(config)# reload
Reloads the router so that changes can take affect.

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Enabling the ATM Interface
To enable the ATM T3/E3 interface, perform the following tasks, starting in global configuration mode.
SUMMARY STEPS
1. interface ATM slot
2. atm clock internal
3. no shut down
DETAILED STEPS
Configuring PVCs
To use a PVC, you must configure the PVC into both the router and the ATM switch. PVCs remain active
until the circuit is removed from either configuration.
To configure a PVC, perform these tasks:
•Creating a PVC
•Mapping a Protocol Address to a PVC
•Configuring the AAL and Encapsulation Type
•Configuring PVC Traffic Parameters
•Setting PVC Watermarks, page 10
Command or Action Purpose
Step 1 interface ATM slot
Example:
Router(config)# interface ATM 1
Enters interface configuration mode.
Step 2 atm clock internal
Example:
Router(config-if)# atm clock internal
Mandatory if the ATM port the network module is
connected to is configured line. Optional otherwise.
Specifies ATM clock source. Default source is line.
Step 3 no shutdown
Example:
Router(config)# no shutdown
(Optional) Enables the ATM interface, thereby beginning
the segmentation and reassembly (SAR) operation on the
interface. The ATM interface is enabled by default.

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Creating a PVC
To create a PVC on the ATM interface and enter interface-ATM-VC configuration mode, use the
following command, beginning in interface configuration mode:
The range of values for vpi isfrom 0 to 255. The range of values for vci is from 1 to 65535.
Once you specify a name for a PVC, you can reenter the interface-ATM-VC configuration mode by
simply entering pvc name.
Mapping a Protocol Address to a PVC
The ATM interface supports a static mapping scheme that identifies the network addresses of remote
hosts or routers. This section describes how to map a PVC to an address, which is a required task for
configuring a PVC.
To map a protocol address to a PVC, use the following command in interface-ATM-VC configuration
mode:
Note If you enable or disable broadcasting directly on a PVC by using the protocol command, this
broadcasting configuration will take precedence over any direct configuration made using the broadcast
command.
Command Purpose
Router(config-if)# pvc [name] vpi/vci [ilmi | qsaal]
Example:
Router(config-if)# pvc cisco 0/16 ilmi
Configures a new ATM PVC by assigning a name (optional)
and VPI/VCI values. Enters interface-ATM-VC
configuration mode. Optionally configures ILMI or QSAAL
encapsulation.
Command Purpose
Router(config-if-atm-vc)# protocol protocol
protocol-address [ [no] broadcast]
Example:
Router(config)# protocol ip 10.68.34.237 broadcast
Maps a protocol address to a PVC.

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Configuring the AAL and Encapsulation Type
To configure the ATM adaptation layer (AAL) and encapsulation type on a VC, use the following
command, beginning in interface-ATM-VC configuration mode:
For a description of AAL types, see the encapsulation aal5 command in the “ATM Commands” chapter
of the Cisco IOS Wide-Area Networking Command Reference.
Configuring PVC Traffic Parameters
The supported traffic parameters (or classes of service) for the ATM T3/E3 network module are CBR,
real-time and non-real-time VBR, UBR, UBR+, and ABR.
To configure PVC traffic parameters on a VC, use one of the following commands, beginning in
interface-ATM-VC configuration mode:
Command Purpose
Router(config-if-atm-vc)# encapsulation {aal2 |
aal5auto | aal5autoppp virtual-template number
[group group-name] | aal5ciscoppp virtual-template
number | aal5mux protocol | aal5nlpid | aal5snap}
Example:
Router(config-if-atm-vc)# encapsulation aal5auto
Configures the ATM adaptation layer (AAL) and
encapsulation type on the VC.
Command Purpose
Router(config-if-atm-vc)# abr output-pcr output-mcr
Example:
Router(config-if-atm-vc)# abr 10000 3000
Configures ABR.
Router(config-if-atm-vc)# ubr output-pcr
Example:
Router(config-if-atm-vc)# ubr 10000
Configures UBR.
Router(config-if-atm-vc)# ubr+ output-pcr output-mcr
Example:
Router(config-if-atm-vc)# ubr+ 10000 3000
Configures UBR+.
Router(config-if-atm-vc)# vbr-nrt output-pcr
output-scr output-mbs
Example:
Router(config-if-atm-vc)# vbr-nrt 10000 5000 64
Configures non-real-time VBR.

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The -pcr, -scr, and -mcr arguments are peak cell rate, sustainable cell rate, and guaranteed minimum cell
rate, respectively, in kbps. The -mbs argument is maximum burst size in number of cells.
The peak rate, average rate, and rate arguments are in kbps. The burst argument is in number of cells.
For ABR VCs, you can optionally configure the factor by which the cell transmission rate increases or
decreases in response to flow control information from the network or destination. To configure this
option, use the following command in interface-ATM-VC configuration mode:
Setting PVC Watermarks
The SAR, which is used by the ATM T3/E3 module, uses queues inside the SAR hardware. One queue
is used for each created PVC. To manage the latency, shaping, and throughput on the PVCs, use the
following command in interface-ATM-VC configuration mode:
Router(config-if-atm-vc)# vbr-rt peak-rate
average-rate burst
Example:
Router(config-if-atm-vc)# vbr-rt 10000 3000 64
Configures real-time VBR.
Router(config-if-atm-vc)# cbr rate
Example:
Router(config-if-atm-vc)# cbr 10000
Configures CBR.
Command Purpose
Command Purpose
Router(config-if-atm-vc)# atm abr rate-factor
[rate-increase-factor] [rate-decrease-factor]
Example:
Router(config-if-atm-vc)# atm abr rate-factor 32 32
Specifies the ABR rate factors. The default rate increase
factor is 16. The default rate decrease factor is 16.
Command Purpose
Router(config-if-atm-vc)# queue-depth <hwm> <lwm>
Example:
Router(config-if-atm-vc)# queue-depth 10 5
Sets the high watermark (hwm) and low watermark (lwm)
level for each created PVC.
When the number of ATM cells in the SAR queues reach the
high watermark level, the SAR stops processing the ATM
cells on that particular PVC. After the ATM cells drain to the
low watermark level, the SAR starts processing the ATM
cells again.