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Router Products Configuration Guide
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About This Manual
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Router Product Overview
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Understanding the User Interface
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Loading System Images, Microcode Images, and Configuration File
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Configuring Terminal Lines and Modem Support
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Managing the System
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Configuring ATM
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Configuring DDR
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Configuring SMDS
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Configuring X.25
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Configuring Apollo Domain
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Configuring AppleTalk
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Configuring Banyan VINES
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Configuring DECnet
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Configuring ISO-CLNS
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Configuring XNS
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Configuring Transparent Bridging
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Configuring Source-Route Bridging
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Configuring Remote Source-Route Bridging
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Configuring DLSw+
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Configuring STUN and BSTUN
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Configuring LLC2 and SDLC Parameters
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Configuring DSPU and SNA Service Point
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Configuring APPN
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Table Of Contents
ATM Access over a Serial Interface
ATM Serial Access Configuration Task List
Map Protocol Addresses to the ATM-DXI PVC
Monitor and Maintain the ATM-DXI Serial Interface
Cisco 7000 AIP Configuration Task List
Enable the AIP on the Cisco 7000
Configure PVCs on the Cisco 7000
Map a Protocol Address to a PVC (Cisco 7000)
Configure Communication with the ILMI (Cisco 7000)
Configure Transmission of Loopback Cells to Verify Connectivity (Cisco 7000)
Configure SVCs on the Cisco 7000
Configure the PVC That Performs SVC Call Setup (Cisco 7000)
Configure the NSAP Address (Cisco 7000)
Configure the Complete NSAP Address Manually
Configure the ESI and Selector Fields
Configure the Idle Timeout Interval (Cisco 7000)
Configure Point-to-Multipoint Signaling (Cisco 7000)
Change Traffic Values (Cisco 7000)
Set the Poll Timer (Cisco 7000)
Set the Keepalive Timer (Cisco 7000)
Set the Connection Control Timer (Cisco 7000)
Set the Transmit and Receive Windows (Cisco 7000)
Configure Classical IP and ARP over ATM on the Cisco 7000
Configure Classical IP and ARP in an SVC Environment (Cisco 7000)
Configure as an ATM ARP Client (Cisco 7000)
Configure as an ATM ARP Server (Cisco 7000)
Configure Classical IP and Inverse ARP in a PVC Environment (Cisco 7000)
Configure Traffic Shaping for ATM SVCs on the Cisco 7000
Customize the AIP on the Cisco 7000
Configure the Rate Queue (Cisco 7000)
Use Dynamic Rate Queues (Cisco 7000)
Configure a Permanent Rate Queue (Cisco 7000)
Configure MTU Size (Cisco 7000)
Set the SONET PLIM (Cisco 7000)
Set Loopback Mode (Cisco 7000)
Set the Exception-Queue Length (Cisco 7000)
Limit the Number of Virtual Circuits (Cisco 7000)
Limit the Message Identifiers Allowed on Virtual Circuits (Cisco 7000)
Set the Raw-Queue Size (Cisco 7000)
Configure Buffer Sizes (Cisco 7000)
Set the VCI-to-VPI Ratio (Cisco 7000)
Set the VP Filter Register (Cisco 7000)
Set the Source of the Transmit Clock (Cisco 7000)
Configure ATM Subinterfaces for SMDS Networks on the Cisco 7000
Configure Transparent Bridging for ATM on the Cisco 7000
Enable Process-Switched Transparent Bridging for SMDS Subinterfaces
Enable Fast-Switched Transparent Bridging for SNAP PVCs
Cisco 4500 ATM Configuration Task List
Enable the ATM Interface on the Cisco 4500
Configure PVCs on the Cisco 4500
Map a Protocol Address to a PVC (Cisco 4500)
Configure Communication with the ILMI (Cisco 4500)
Configure Transmission of Loopback Cells to Verify Connectivity (Cisco 4500)
Configure SVCs on the Cisco 4500
Configure the PVC That Performs SVC Call Setup (Cisco 4500)
Configure the NSAP Address (Cisco 4500)
Configure the Complete NSAP Address Manually
Configure the ESI and Selector Fields
Configure the Idle Timeout Interval (Cisco 4500)
Configure Point-to-Multipoint Signaling (Cisco 4500)
Change Traffic Values (Cisco 4500)
Set the Poll Timer (Cisco 4500)
Set the Keepalive Timer (Cisco 4500)
Set the Connection Control Timer (Cisco 4500)
Set the Transmit and Receive Windows (Cisco 4500)
Configure Classical IP and ARP over ATM on the Cisco 4500
Configure Classical IP and ARP in an SVC Environment (Cisco 4500)
Configure as an ATM ARP Client (Cisco 4500)
Configure as an ATM ARP Server (Cisco 4500)
Configure Classical IP and Inverse ARP in a PVC Environment (Cisco 4500)
Configure Traffic Shaping for ATM SVCs on the Cisco 4500
Customize the NPM on the Cisco 4500
Configure the Rate Queue (Cisco 4500)
Use Dynamic Rate Queues (Cisco 4500)
Configure a Permanent Rate Queue (Cisco 4500)
Configure MTU Size (Cisco 4500)
Set the PLIM Framing (Cisco 4500)
Set Loopback Mode (Cisco 4500)
Set the VCI-to-VPI Ratio (Cisco 4500)
Set the Source of the Transmit Clock (Cisco 4500)
Configure ATM Subinterfaces for SMDS Networks on the Cisco 4500
Configure Transparent Bridging for ATM on the Cisco 4500
Monitor and Maintain the ATM Interface
ATM Access over a Serial Interface Example
Cisco 7000 ATM Configuration Examples
PVC with AAL5 and LLC/SNAP Encapsulation Examples (Cisco 7000)
PVCs in a Fully Meshed Network Example (Cisco 7000)
SVCs in a Fully Meshed Network Example (Cisco 7000)
SVCs with Multipoint Signaling Example (Cisco 7000)
Classical IP and ARP Examples (Cisco 7000)
ATM ARP Client Configuration in an SVC Environment Example (Cisco 7000)
ATM ARP Server Configuration in an SVC Environment Example (Cisco 7000)
ATM Inverse ARP Configuration in a PVC Environment Example (Cisco 7000)
PVC with AAL3/4 and SMDS Encapsulation Examples (Cisco 7000)
Dynamic Rate Queue Examples (Cisco 7000)
Transparent Bridging on an AAL5-SNAP PVC Example (Cisco 7000)
Transparent Bridging on an SMDS Subinterface Example (Cisco 7000)
Traffic Parameters Example (Cisco 7000)
Cisco 4500 ATM Configuration Examples
PVC with AAL5 and LLC/SNAP Encapsulation Examples (Cisco 4500)
PVCs in a Fully Meshed Network Example (Cisco 4500)
SVCs in a Fully Meshed Network Example (Cisco 4500)
Classical IP and ARP Examples (Cisco 4500)
ATM ARP Client Configuration in an SVC Environment Example (Cisco 4500)
ATM ARP Server Configuration in an SVC Environment Example (Cisco 4500)
ATM Inverse ARP Configuration in a PVC Environment Example (Cisco 4500)
Dynamic Rate Queue Examples (Cisco 4500)
PVC with AAL3/4 and SMDS Encapsulation Examples (Cisco 4500)
Transparent Bridging on an AAL5-SNAP PVC Example (Cisco 4500)
Traffic Parameters Example (Cisco 4500)
Configuring ATM
This chapter describes how to configure an Asynchronous Transfer Mode (ATM) interface in the Cisco 7000 series , Cisco 4500, and Cisco 4700 routers, and how to configure a serial interface for ATM access in other routers.
For routers that will use a serial interface for ATM access through an ATM data service unit (ADSU), the chapter explains the steps necessary to enable Asynchronous Transfer Mode-Data Exchange Interface (ATM-DXI) encapsulation, select a multiprotocol encapsulation method using ATM-DXI, and set up a permanent virtual circuit (PVC) for the selected encapsulation.
For Cisco 7000 routers that have an ATM Interface Processor (AIP), the chapter explains the steps necessary to configure the AIP, PVCs, switched virtual circuits (SVCs), and Classical IP over ATM.
For Cisco 4500 and Cisco 4700 routers that have an ATM network processor module (NPM), this chapter explains the steps necessary to configure the ATM, PVCs, and SVCs.
For a complete description of the commands in this chapter, refer to the "ATM Commands" chapter of the Router Products Command Reference publication.
For information about configuring LAN Emulation for ATM, refer to the "Configuring LAN Emulation (LANE)" chapter of this manual. For information about LAN Emulation commands, refer to the "LAN Emulation Commands" chapter of the Router Products Command Reference publication.
Cisco's Implementation of ATM
ATM is a cell-switching and multiplexing technology designed to combine the benefits of circuit switching (constant transmission delay and guaranteed capacity) with those of packet switching (flexibility and efficiency for intermittent traffic).
Cisco provides ATM access in several ways, depending on the hardware available in the router:
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Serial interface, in routers that lack an AIP or NPM
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In routers other than the Cisco 4500, Cisco 4700, and the Cisco 7000 series, a serial interface can be configured for multiprotocol encapsulation over ATM-DXI, as specified by RFC 1483. This standard describes two methods of transporting multiprotocol connectionless network interconnect traffic over an ATM network. One method allows multiplexing of multiple protocols over a single PVC. The other method uses different virtual circuits to carry different protocols. Our implementation supports transport of AppleTalk, Banyan VINES, IP, and Novell IPX traffic.
In routers other than the Cisco 4500, Cisco 4700, and the Cisco 7000 series, an ATM data service unit (ADSU) is required to provide the ATM interface to the network, to compute the DXI Frame Address (DFA) from the virtual path identifier (VPI) and virtual channel identifier (VCI) values defined for the protocol or protocols carried on the PVC, to convert outgoing packets into ATM cells, and to reassemble incoming ATM cells into packets.
On the Cisco 7000 series routers, network interfaces reside on modular interface processors, which provide a direct connection between the high-speed Cisco Extended Bus (CxBus) and the external networks. Each AIP provides a single ATM network interface; the maximum number of AIPs that the Cisco 7000 supports depends on the bandwidth configured. The total bandwidth through all the AIPs in the system should be limited to 200 Mbps full duplex (two TAXI interfaces, or one SONET and one E3, or one SONET and one lightly used SONET, five E3s, or four T3s).
Cisco 4500 and Cisco 4700 routers support one OC-3c network processor module (NPM) or up to two slower E3/DS3 NPMs. PLIMs that support SONET/SDH 155 mbps are available for both single-mode and multimode fiber.
For a complete description of the Cisco 7000 and AIP, refer to the Cisco 7000 Hardware Installation and Maintenance publication. The AIP is compatible with any Cisco 7000 that is running Cisco Internetwork Operating System (Cisco IOS) Release 10 or later. For a complete description of the Cisco 4500 and the NPM, refer to the Cisco 4000 Series Hardware Installation and Maintenance manual and the Installing NPMs in the Cisco 4000 Series manual.
ATM is a connection-oriented environment. All traffic to or from an ATM network is prefaced with a virtual path identifier (VPI) and virtual channel identifier (VCI). A VPI/VCI pair is considered a single virtual circuit. Each virtual circuit is a private connection to another node on the ATM network. Each virtual circuit is treated as a point-to-point mechanism to another router or host and is capable of supporting bidirectional traffic.
Each ATM node is required to establish a separate connection to every other node in the ATM network that it needs to communicate with. All such connections are established using a PVC or an SVC with an ATM signaling mechanism. This signaling is based on the ATM Forum UNI Specification V3.0.
Each virtual circuit is considered a complete and separate link to a destination node. Users can encapsulate data as needed across the connection. The ATM network disregards the contents of the data. The only requirement is that data be sent to the router's ATM processor card in a manner that follows the specific ATM adaptation layer (AAL) format.
An AAL defines the conversion of user information into cells. An AAL segments upper-layer information into cells at the transmitter and reassembles the cells at the receiver. AAL1 and AAL2 handle isochronous traffic, such as voice and video, and are not relevant to the router. AAL3/4 and AAL5 support data communications; that is, they segment and reassemble packets. Starting with software Release 10.2, Cisco supports both AAL3/4 and AAL5 on the Cisco 7000 series. Starting with Release 10.3(4), Cisco supports AAL5 and starting with release 11.0(5), Cisco supports AAL3/4 on the Cisco 4500. However, on the Cisco 4500, AAL3/4 is not supported at OC-3c rates, and if configured on an OC-3c interface, it should be limited to E3 or DS3 rates by configuring a rate queue. See the "Configure the Rate Queue (Cisco 4500)" section for more information.
An ATM connection is simply used to transfer raw bits of information to a destination router/host. The ATM router takes the common part convergence sublayer (CPCS) frame, carves it up into 53-byte cells and sends these cells to the destination router or host for reassembly. When using AAL5, forty-eight bytes of each cell are used for the CPCS data; the remaining 5 bytes are used for cell routing. The 5-byte cell header contains the destination VPI/VCI, payload type, cell loss priority (CLP), and header error control.
The ATM network is considered a local-area network (LAN) with high bandwidth availability. Each end node in the ATM network is a host on a specific subnet. All end nodes needing to communicate with each other must be within the same subnet in the network.
Unlike a LAN, which is connectionless, ATM requires certain features to provide a LAN environment to the users. One such feature is broadcast capability. Protocols wishing to broadcast packets to all stations in a subnet must be allowed to do so with a single call to Layer 2. In order to support broadcasting, the router allows the user to specify particular virtual circuits as broadcast virtual circuits. When the protocol passes a packet with a broadcast address to the drivers, the packet is duplicated and sent to each virtual circuit marked as a broadcast virtual circuit. This method is known as pseudobroadcasting. Effective with Release 11.0, point-to-multipoint signaling allows pseudobroadcasting to be eliminated. On routers with point-to-multipoint signaling, the router can set up calls between itself and multiple destinations; drivers no longer need to duplicate broadcast packets. A single packet can be sent to the ATM switch which replicates it to multiple ATM hosts.
Classical IP and ARP
Cisco implements classical IP and ARP over ATM as described in RFC 1577. RFC 1577 defines an application of classical IP and ARP in an ATM environment configured as a logical IP subnetwork (LIS). It also describes the functions of an ATM ARP server and ATM ARP clients in requesting and providing destination IP addresses and ATM addresses in situations when one or both are unknown. Our routers can be configured to act as an ARP client, or to act as a combined ARP client and ARP server.
The ATM ARP server functionality allows classical IP networks to be constructed with ATM as the connection medium. Without this functionality, you must configure both the IP network address and the ATM address of each end device with which the router needs to communicate. This static configuration task takes administrative time and makes moves and changes more difficult.
Cisco's implementation of the ATM ARP server functionality provides a robust environment in which network changes can be made more easily and more quickly than in a pure ATM environment. Cisco's ATM ARP client works with any ARP server that is fully compliant with RFC 1577.
Cisco 7000 AIP
This section provides an overview of the ATM features, interfaces, microcode, and virtual circuits available on the Cisco 7000.
AIP Features
The AIP supports the following features:
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Process-switched bridging over ATM supports AAL3/4-SMDS encapsulated packets only. All frames that originate at or are forwarded by the router are sent as 802.3 bridge frames without frame check sequence (FCS) (RFC 1483 bridge frame formats with 0x0007 in the PID field of the SNAP header). You can enable process-switched bridging for Switched Multimegabit Data Service (SMDS) as described later in this chapter.
Fast-switched transparent bridging over ATM supports AAL5-SNAP encapsulated packets only. All bridged AAL5-SNAP encapsulated packets are fast switched. Fast-switched transparent bridging supports Ethernet, FDDI, and Token Ring packets sent in AAL5-SNAP encapsulation over ATM. You can enable fast-switched bridging for AAL5-SNAP as described later in this chapter.
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AIP Interface Types
All ATM interfaces are full duplex. You must use the appropriate ATM interface cable to connect the AIP with an external ATM network. Refer to the Asynchronous Transfer Mode Interface Processor (AIP) Installation and Configuration publication for descriptions of ATM connectors.
The AIP provides an interface to ATM switching fabrics for transmitting and receiving data at rates of up to 155 Mbps bidirectionally; the actual rate is determined by the physical layer interface module (PLIM). The PLIM contains the interface to the ATM cable. The AIP can support PLIMs that connect to the following physical layers:
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For wide-area networking, ATM is currently being standardized for use in Broadband Integrated Services Digital Networks (BISDNs) by the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) and the American National Standards Institute (ANSI). BISDN supports rates from E3 (34 Mbps) to multiple gigabits per second (gbps).
Microcode
The AIP microcode is a software image that provides card-specific software instructions. An onboard ROM component contains the default AIP microcode. The Cisco 7000 supports downloadable microcode, which enables you to upgrade microcode versions by loading new microcode images onto the Route Processor (RP), storing them in Flash memory, and instructing the AIP to load an image from Flash memory instead of the default ROM image. You can store multiple images for an interface type and instruct the system to load any one of them or the default ROM image with a configuration command. All processor modules of the same type will load the same microcode image from either the default ROM image or from a single image stored in Flash memory.
Although multiple microcode versions for a specific interface type can be stored concurrently in Flash memory, only one image can load at startup. The show controller cxbus command displays the currently loaded and running microcode version for the switch processor (SP) and for each IP. The show running-config command shows the current system instructions for loading microcode at startup.
For a complete description of microcode and downloading procedures, refer to the Asynchronous Transfer Mode Interface Processor (AIP) Installation and Configuration publication.
Virtual Circuits
A virtual circuit is a connection between remote hosts and routers. A virtual circuit is established for each ATM end node with which the router communicates. The characteristics of the virtual circuit are established when the virtual circuit is created and include the following:
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Each virtual circuit supports the following router functions:
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By default, fast switching is enabled on all AIP interfaces. These switching features can be turned off with interface configuration commands. Autonomous switching must be explicitly enabled per interface.
Cisco 4500 NPM
This section provides an overview of the ATM features, interfaces, and virtual circuits available on the Cisco 4500.
NPM Features
The NPM supports the following features:
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An ATM adaptation layer (AAL) defines the conversion of user information into cells. That is, it segments upper-layer information into cells at the transmitter and reassembles them at the receiver. AAL1 and AAL2 handle isochronous traffic, such as voice and video, and are not relevant to the router. AAL3/4 and AAL5 support data communications; that is, they segment and reassemble packets. Starting with Cisco IOS Release 11.0, Cisco supports AAL5, and starting with Release 10.3(4), Cisco supports AAL3/4 on the Cisco 4500.
NPM ATM Interface Types
All ATM interfaces are full duplex. You must use the appropriate ATM interface cable to connect the NPM with an external ATM network. Refer to the Cisco 4000 Series Hardware Installation and Maintenance manual and the Installing NPMs in the Cisco 4000 Series manual for descriptions of ATM connectors.
The NPM provides an interface to ATM switching fabrics for transmitting and receiving data at rates of up to 155 Mbps bidirectionally; the actual rate is determined by the physical layer interface module (PLIM). The PLIM contains the interface to the ATM cable. The NPM can support PLIMs that connect to the following physical layers:
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Virtual Circuits
A virtual circuit is a point-to-point connection between remote hosts and routers. A virtual circuit is established for each ATM end node with which the router communicates. The characteristics of the virtual circuit are established when the virtual circuit is created and include the following:
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Each virtual circuit supports the following router functions:
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ATM Access over a Serial Interface
Our routers provide ATM access in three ways, depending on the hardware available in the router:
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In routers other than the Cisco 7000 series and the Cisco 4500, a serial interface can be configured for multiprotocol encapsulation over ATM-DXI, as specified by RFC 1483. ATM-DXI encapsulation allows a DCE and a DTE to cooperate to provide a User-Network Interface (UNI) for ATM networks. At the ADSU, the DXI header is stripped off, and the protocol data is segmented into cells for transport over the ATM network.
RFC 1483 describes two methods of transporting multiprotocol connectionless network interconnect traffic over an ATM network. One method allows multiplexing of multiple protocols over a single PVC. The other method uses different virtual circuits to carry different protocols. Our implementation of RFC 1483 supports both methods and supports transport of Apollo Domain, AppleTalk, Banyan VINES, DECnet, IP, Novell IPX, ISO CLNS, and XNS traffic.
In routers other than the Cisco 7000 series and the Cisco 4500, an ADSU is required to provide the ATM interface to the network, convert outgoing packets into ATM cells, and reassemble incoming ATM cells into packets.
ATM Serial Access Configuration Task List
To configure ATM access over a serial interface on routers outside the Cisco 7000 series, complete the tasks in the following sections. The first four tasks are required.
Step 1
Step 2
Step 3
Step 4
Step 5
Enable the Serial Interface
To begin configuring the serial interface for ATM access, enable the serial interface by performing the following steps beginning in global configuration mode:
Enable the serial interface.
interface serial number1
For each protocol to be carried, assign a protocol address to the interface. (The commands shown are a partial list for the supported protocols.)
appletalk address network.node2
ip address address mask3
ipx network number4
1 This command is documented in the "Interface Commands" chapter of the Router Products Command Reference publication
2 This command is documented in the "AppleTalk Commands" chapter of the Router Products Command Reference publication.
3 This command is documented in the "IP Commands" chapter of the Router Products Command Reference publication.
4 This command is documented in the "Novell IPX Commands" chapter of the Router Products Command Reference publication.
The supported protocols are Apollo Domain, AppleTalk, Banyan VINES, DECnet, IP, Novell IPX, ISO CLNS, and XNS.
For information about the addressing requirements of a protocol, see the relevant protocol chapter of this publication.
Enable ATM-DXI Encapsulation
To enable ATM-DXI encapsulation on a serial or HSSI interface, perform the following task in interface configuration mode:
Set Up the ATM-DXI PVC
An ATM-DXI PVC can be defined to carry one protocol, multiple protocols as described by RFC 1490, or multiple protocols as described by RFC 1483.
To set up the ATM-DXI PVC, perform the following task in interface configuration mode:
Define the ATM-DXI PVC and the encapsulation method.
dxi pvc vpi vci [snap | nlpid | mux]
The MUX option defines the PVC to carry one protocol only; each protocol must be carried over a different PVC. The NLPID option is multiprotocol encapsulation, compatible with RFC 1490; this option is provided for backward compatibility with default setting in earlier versions of the Cisco IOS software. The SNAP option is LLC/SNAP multiprotocol encapsulation, compatible with RFC 1483; SNAP is the current default option.
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Map Protocol Addresses to the ATM-DXI PVC
This section describes how to map protocol addresses to the VCI and the VPI of a PVC that can carry multiprotocol traffic. The protocol addresses belong to the host at the other end of the link. To map a protocol address to an ATM-DXI PVC, complete the following task in interface configuration mode:
Map a protocol address to the ATM-DXI PVC's VPI and VCI.
dxi map protocol protocol-address vpi vci [broadcast]
Repeat this task for each protocol to be carried on the PVC.
The supported protocols are Apollo Domain, AppleTalk, Banyan VINES, DECnet, IP, Novell IPX, ISO CLNS, and XNS.
For an example of configuring a serial interface for ATM, see the "ATM Access over a Serial Interface Example" section later in this chapter.
Monitor and Maintain the ATM-DXI Serial Interface
After configuring the serial interface for ATM, you can display the status of the interface, the ATM-DXI PVC, or the ATM-DXI map. To display interface, PVC, or map information, complete the following tasks in EXEC mode:
Display the serial ATM interface status.
show interfaces atm [slot/port]1
Display the ATM-DXI PVC information.
show dxi pvc
Display the ATM-DXI map information.
show dxi map
1 This command is documented in the "Interface Commands" chapter of the Router Products Command Reference publication.
Cisco 7000 AIP Configuration Task List
To configure ATM on the AIP in Cisco 7000 series routers, complete the tasks in the following sections. The first task is required, and then you must configure at least one PVC or SVC. The virtual circuit options you configure must match in three places: on the router, on the ATM switch, and at the remote end of the PVC or SVC connection.
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See the "Cisco 7000 ATM Configuration Examples" section for configuration examples.
Enable the AIP on the Cisco 7000
This section describes how to begin configuring the AIP. The Cisco 7000 identifies an interface address by its slot number (slots 0 to 4) and port number in the format slot/port. Because each AIP contains a single ATM interface, the port number is always 0. For example, the slot/port address of an ATM interface on an AIP installed in slot 1 is 1/0.
To begin to configure the AIP, start the following task in privileged EXEC mode:
Step 1
configure1
[terminal] <CR>Step 2
interface atm slot/02
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ip address ip-address mask3
1 This command is documented in the "System Image, Microcode Image, and Configuration File Load Commands" chapter of the Router Products Command Reference publication.
2 This command is documented in the "Interface Commands" chapter of the Router Products Command Reference publication.
3 This command is documented in the "IP Commands" chapter of the Router Products Command Reference publication.
To enable the AIP, perform the following task in interface configuration mode:
Change the shutdown state to up and enable the ATM interface, thereby starting the segmentation and reassembly (SAR) operation on the interface.
no shutdown1
1 This command is documented in the "Interface Commands" chapter of the Router Products Command Reference publication.
The no shutdown command passes an enable command to the AIP, which then begins segmentation and reassembly (SAR) operations. It also causes the AIP to configure itself based on the previous configuration commands sent.
Configure PVCs on the Cisco 7000
If you are going to use a permanent virtual circuit (PVC), the PVC must be configured into both the router and the ATM switch. PVCs remain active until the circuit is removed from either configuration.
All virtual circuit characteristics listed in the section "Virtual Circuits" earlier in this chapter apply to these PVCs. When a PVC is configured, all the configuration options are passed on to the AIP. These PVCs are writable into the nonvolatile RAM (NVRAM) as part of the RP configuration and are used when the RP image is reloaded.
Some ATM switches might have point-to-multipoint PVCs that do the equivalent of broadcasting. If a point-to-multipoint PVC exists, then that PVC can be used as the sole broadcast PVC for all multicast requests.
To configure a PVC, perform the tasks in the following sections. The first two tasks are required; the third is optional.
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Create a PVC (Cisco 7000)
To create a PVC on the AIP interface, perform the following task in interface configuration mode:
Create a PVC.
atm pvc vcd vpi vci aal-encap [[midlow midhigh] [peak average burst]] [oam seconds]
When you create a PVC, you create a virtual circuit descriptor (VCD) and attach it to the VPI and VCI. A VCD is an AIP-specific mechanism that identifies to the AIP which VPI/VCI to use for a particular packet. The AIP requires this feature to manage the packets, for transmission. The number chosen for the VCD is independent of the VPI/VCI used.
When you create a PVC, you also specify the AAL and encapsulation. A rate queue is used that matches the peak and average rate selections, which are specified in kilobits per second. Omitting a peak and average value causes the PVC to be connected to the highest bandwidth rate queue available. In this case, the peak and average values are equal.
You can also configure the PVC for communication with the Interim Local Management Interface so the router can receive SNMP traps and new network prefixes. Refer to the "Configure Communication with the ILMI (Cisco 7000)" section for details.
You can also optionally configure the PVC to send OAM F5 loopback cells to verify connectivity on the virtual circuit. The remote end must respond by echoing back such cells.
See examples of PVC configurations in the section "Cisco 7000 ATM Configuration Examples" at the end of this chapter.
Map a Protocol Address to a PVC (Cisco 7000)
The ATM interface supports a static mapping scheme that identifies the ATM address of remote hosts or routers. This address is specified as a virtual circuit descriptor (VCD) for a PVC (or an NSAP address for SVC operation). This section describes how to map a PVC to an address, which is a required task if you are configuring a PVC.
You enter mapping commands as groups. You first create a map list and then associate it with an interface. Begin the following tasks in global configuration mode:
Step 1
map-list name
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protocol protocol-address atm-vc vcd [broadcast]
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protocol protocol-address atm-vc vcd [broadcast]
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interface atm slot/port1
Step 5
map-group name
1 This command is documented in the "Interface Commands" chapter of the Router Products Command Reference publication.
A map list can contain multiple map entries, as Steps 2 and 3 in the preceding task table illustrate. The broadcast keyword specifies that this map entry is to be used when the corresponding protocol sends broadcast packets to the interface (for example, any network routing protocol updates). If you do not specify broadcast, the ATM software is prevented from sending routing protocol updates to the remote hosts.
If you do specify broadcast, but do not set up point-to-multipoint signaling, pseudobroadcasting is enabled. To eliminate pseudobroadcasting and set up point-to-multipoint signaling on virtual circuits configured for broadcasting, see the "Configure Point-to-Multipoint Signaling (Cisco 7000)" section.
Step 5 illustrates that when the map list is complete, you associate the map list with an ATM interface by using the same name argument.
You can create multiple map lists, but only one map list can be associated with an interface. Different map lists can be associated with different interfaces. See the examples at the end of this chapter.
Configure Communication with the ILMI (Cisco 7000)
You can configure a PVC for communication with the Interim Local Management Interface (ILMI) so the router can receive SNMP traps and new network prefixes. To configure ILMI communication, complete the following task in interface configuration mode:
Note
Once you have configured an ILMI PVC, you can optionally enable ILMI keepalive function by completing the following task in interface configuration mode:
Optionally, enable ILMI keepalives and set the interval between keepalives.
atm ilmi-keepalives [seconds]
No other configuration steps are required.
ILMI address registration for receipt of SNMP traps and new network prefixes is enabled by default. The ILMI keepalive function is disabled by default; when enabled, the default interval between keepalives is three seconds.
Configure Transmission of Loopback Cells to Verify Connectivity (Cisco 7000)
You can optionally configure the PVC to send OAM F5 loopback cells to verify connectivity on the virtual circuit. The remote end must respond by echoing back such cells. If OAM response cells are missed (indicating the lack of connectivity), the system console displays a debug message indicating the failure of the PVC, provided the debug atm errors command is enabled. If you suspect that a PVC is faulty, enabling OAM cell generation and the debug atm errors command allows you to monitor the status of the PVC.
To configure the transmission of OAM F5 loopback cells, add the oam keyword to the atm pvc command, as shown in the following task:
Configure transmission of OAM F5 cells on the PVC.
atm pvc vcd vpi vci aal-encap [[midlow midhigh] [peak average burst]] [oam seconds]
Configure SVCs on the Cisco 7000
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.
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 is viewed as the user and the LAN interconnection device at the end of the circuit, and the ATM switch is viewed as the network.
illustrates the router position in a basic ATM environment. The router is used primarily to interconnect LANs via an ATM network. The workstation connected directly to the destination ATM switch illustrates that you can connect not only routers to ATM switches, but also any computer with an ATM interface that conforms to ATM Forum UNI specification.
Figure 7-1 Basic ATM Environment
Complete the tasks in the following sections if you are going to use SVCs. The first two tasks are required; the third and fourth are optional:
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The tasks in the following sections are optional SVC tasks for customizing your network. These tasks are considered advanced; the default values are almost always adequate. You should not have to perform these tasks unless you need to customize your particular SVC connection.
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Configure the PVC That Performs SVC Call Setup (Cisco 7000)
Unlike X.25 service, which uses in-band signaling (connection establishment done on the same circuit as data transfer), ATM uses out-of-band signaling. One dedicated PVC exists between the router and the ATM switch, over which all SVC call establishment and call termination requests flow. After the call is established, data transfer occurs over the SVC, from router to router. The signaling that accomplishes the call setup and teardown is called Layer 3 signaling or the Q.2931 protocol.
For out-of-band signaling, a signaling PVC must be configured before any SVCs can be set up. Figure 7-2 illustrates that a signaling PVC from the source router to the ATM switch is used to set up two SVCs. This is a fully meshed network; workstations A, B, and C all can communicate with each other.
Figure 7-2 One or More SVCs Require a Signaling PVC
To configure the signaling PVC for all SVC connections, perform the following task in interface configuration mode:
Configure the signaling PVC for a major interface that uses SVCs.
atm pvc vcd vpi vci qsaal
Note
The VPI and VCI values must be configured consistently with the local switch. The standard value of VPI is 0; the standard value of VCI is 5.
See the section "SVCs in a Fully Meshed Network Example (Cisco 7000)" at the end of this chapter for a sample ATM signaling configuration.
Configure the NSAP Address (Cisco 7000)
Every ATM interface involved with signaling must be configured with an network service access point (NSAP) address. The NSAP address is the ATM address of the interface and must be unique across the network.
You can do one of the following to configure an NSAP address:
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If you choose to configure the ESI and Selector fields, you also must configure a PVC to communicate with the switch via ILMI. The switch then provides the Prefix field of the NSAP address.
Configure the Complete NSAP Address Manually
When you configure the ATM NSAP address manually, you must enter a the entire address in hexadecimal format; that is, each digit entered represents a hexadecimal digit. To represent the complete NSAP address, you must enter 40 hexadecimal digits in the following format:
XX.XXXX.XX.XXXXXX.XXXX.XXXX.XXXX.XXXX.XXXX.XXXX.XX
Note
Because the interface has no default NSAP address, you must configure the NSAP address for SVCs. To set the ATM interface's source NSAP address, perform the following task in interface configuration mode:
The following example assigns NSAP address AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12 to ATM interface 4/0:
interface ATM4/0atm nsap-address AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12You can display the ATM address for the interface by executing the show interface atm command.
Configure the ESI and Selector Fields
To use this method of entering the router's NSAP address, the switch must be capable of delivering the NSAP address prefix to the router via ILMI and the router must be configured with a PVC for communication with the switch via ILMI.
To configure the router to get the NSAP prefix from the switch and use locally entered values for the remaining fields of the address, complete the following tasks in interface configuration mode:
Configure a PVC for communicating with the switch via ILMI.
atm pvc vcd 0 16 ilmi
Enter the ESI and Selector fields of the NSAP address.
atm esi-address esi.selector
In the atm esi-address command, the esi argument is 6 hexadecimal bytes long (12 digits), and the selector argument is one hexadecimal byte long (2 digits).
You can also specify a keepalive interval for the ILMI PVC. See the "Configure Communication with the ILMI (Cisco 7000)" section for more information.
Configure the Idle Timeout Interval (Cisco 7000)
You can specify an interval of inactivity after which any idle SVC on an interface will be disconnected. This might help control costs and free router memory and other resources for other uses.
To change the idle timeout interval, perform the following task in interface configuration mode:
Configure the interval of inactivity after which an idle SVC will be disconnected.
atm idle-timeout seconds
The default idle timeout interval is 300 seconds (5 minutes).
Configure Point-to-Multipoint Signaling (Cisco 7000)
Point-to-multipoint signaling (or multicasting) allows the router to send one packet to the ATM switch and have the switch replicate the packet to the destinations. It replaces pseudobroadcasting on specified virtual circuits for protocols configured for broadcasting (configuration of such virtual circuits is in the previous task table).
You configure multipoint signaling on an ATM interface after you have mapped protocol addresses to NSAPs and configured one or more protocols for broadcasting.
After multipoint signaling is set, the router uses existing static map entries that have the broadcast keyword set to establish multipoint calls. The call is established to the first destination with a Setup message. Additional parties are added to the call with AddParty messages each time a multicast packet is sent. One multipoint call will be established for each logical subnet of each protocol that has the broadcast keyword set.
To configure multipoint signaling on an ATM interface, complete the following tasks beginning in global configuration mode. The first task is required to configure this feature; the others are optional.
If multipoint virtual circuits are closed, they are reopened with the next multicast packet. Once the call is established, additional parties are added to the call when additional multicast packets are sent. If a destination never comes up, the router constantly attempts to add it to the call by means of multipoint signaling.
For an example of configuring multipoint signaling on an interface that is configured for SVCs, see the "SVCs with Multipoint Signaling Example (Cisco 7000)" later in this chapter.
Change Traffic Values (Cisco 7000)
The tasks in this section are optional and advanced. The ATM signaling software can specify to the AIP card and the ATM switch a limit on how much traffic the source router will be sending. It provides this information in the form of traffic parameters. (These parameters have default values.) The ATM switch in turn sends these parameters as requested by the source to the ATM destination node. If the destination cannot provide such capacity levels, the call may fail (for Cisco 7000 series behavior, see the per-interface atm sig-traffic-shaping strict command in the Router Products Command Reference). There is a single attempt to match traffic parameters.
This section describes how to change traffic values to customize your SVC connection. The individual tasks that separately specify peak, sustainable, or burst values for an SVC are analogous to the peak, average, and burst values defined when you create a PVC. Valid values for the peak rate on the AIP are between 130 kbps and the PLIM rate. The valid values for the average rate are fractions of the peak rate—the peak rate divided by a number between 1 and 64. When the average rate is below one-half the peak rate, the average rate defaults to the next available fraction. The valid range for the maximum burst size is between 32 cells and 2016 cells. Values between 32 and 2016 will round up to the next multiple of 32 cells.
Forward commands apply to the flow of cells from the source router to the destination router. Backward commands apply to the flow of cells from the destination router to the source router.
Most of the SVC traffic parameters include the concept of cell loss priority (CLP). CLP defines two levels of cell importance:
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illustrates a source and a destination router implementing traffic settings that correspond end-to-end. The value for the forward command at the source router corresponds to the value for the backward command at the destination router.
Figure 7-3 Source and Destination Routers Have Corresponding Traffic Settings
You can define map lists and map groups to tie specified SVCs to the protocol addresses of remote hosts and to specify whether broadcast protocols are supported. Then you can define map classes and specify the traffic parameters needed for the specified protocol traffic on those SVCs.
You must enter map-class configuration mode before you can change the traffic values from their default values. To enter map-class configuration mode, perform the following task in global configuration mode:
Enter map-class configuration mode, specifying a map-class name.
map-class atm class-name
If a map class with the specified name does not exist, the router creates a new one. All the following commands apply to the named map class.
See the "Traffic Parameters Example (Cisco 7000)" section for an example defining map classes, map groups, map lists and traffic parameters.
To change traffic parameters, perform one or more of the following tasks in map-class configuration mode:
Configure SSCOP (Cisco 7000)
The Service Specific Connection Oriented Protocol (SSCOP) resides in the service-specific convergence sublayer (SSCS) of the ATM adaptation layer (AAL). SSCOP is used to transfer variable-length service data units (SDUs) between users of SSCOP. SSCOP provides for the recovery of lost or corrupted SDUs.
Note
Set the Poll Timer (Cisco 7000)
The poll timer controls the maximum time between transmission of a POLL PDU when SD or SDP PDUs are queued for transmission or are outstanding pending acknowledgments. To change the poll timer from the default value of 10 seconds, perform the following task in interface configuration mode:
Set the Keepalive Timer (Cisco 7000)
The keepalive timer controls the maximum time between transmission of a POLL PDU when no SD or SDP PDUs are queued for transmission or are outstanding pending acknowledgments. To change the keepalive timer from the default value of 30 seconds, perform the following task in interface configuration mode:
Set the Connection Control Timer (Cisco 7000)
The connection control timer determines the time between transmission of BGN, END, or RS PDUs as long as an acknowledgment has not been received. Connection control performs the establishment, release, and resynchronization of an SSCOP connection.
To change the connection control timer from the default value of 10 seconds, perform the following task in interface configuration mode:
To change the retry count of the connection control timer from the default value of 10, perform the following task in interface configuration mode:
Set the number of times that SSCOP will retry to transmit BGN, END, or RS PDUs when they have not been acknowledged.
sscop max-cc retries
Set the Transmit and Receive Windows (Cisco 7000)
A transmit window controls how many packets can be transmitted before an acknowledgment is required. To change the transmitter's window from the default value of 7, perform the following task in interface configuration mode:
A receive window controls how many packets can be received before an acknowledgment is required. To change the receiver's window from the default value of 7, perform the following task in interface configuration mode:
Close an SVC (Cisco 7000)
You can disconnect an idle SVC by completing the following task in EXEC mode:
Configure Classical IP and ARP over ATM on the Cisco 7000
Cisco implements both the ATM ARP server and ATM ARP client functions described in RFC 1577. RFC 1577 models an ATM network as a logical IP subnetwork on a LAN.
The tasks required to configure classical IP and ARP over ATM depend on whether the environment uses SVCs or PVCs.
Configure Classical IP and ARP in an SVC Environment (Cisco 7000)
The ATM ARP mechanism is applicable to networks that use SVCs. It requires a network administrator to configure only the device's own ATM address and that of a single ATM ARP server into each client device. When the client makes a connection to the ATM ARP server, the server sends ATM Inverse ARP requests to learn the IP network address and ATM address of the client on the network. It uses the addresses to resolve future ATM ARP requests from clients. Static configuration of the server is not required or needed.
In Cisco's implementation, the ATM ARP client tries to maintain a connection to the ATM ARP server. The ATM ARP server can tear down the connection, but the client attempts once each minute to bring the connection back up. No error messages are generated for a failed connection, but the client will not route packets until the ATM ARP server is connected and translates IP network addresses.
For each packet with an unknown IP address, the client sends an ATM ARP request to the server. Until that address is resolved, any IP packet routed to the ATM interface will cause the client to send another ATM ARP request. When the ARP server responds, the client opens a connection to the new destination so that any additional packets can be routed to it.
Cisco routers may be configured as ATM ARP Clients to work with any ATM ARP Server conforming to RFC 1577. Alternatively, one of the Cisco routers in a logical IP Subnet (LIS) may be configured to act as the ATM ARP Server itself. In this case, it automatically acts as a client as well. To configure classical IP and ARP in an SVC environment, perform one of the following tasks:
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Configure as an ATM ARP Client (Cisco 7000)
In an SVC environment, configure the ATM ARP mechanism on the interface by performing the following tasks in interface configuration mode:
Step 1
interface atm slot/01
Step 2
atm nsap-address nsap-address
Step 3
ip address address mask
Step 4
atm arp-server nsap nsap-address
Step 5
no shutdown1
