Cisco ACIP-SM User Manual
Customer Order Number:
Documentation Part Number:
ATM Cable Interface Processor (ACIP)
Installation and Configuration
Product Numbers: ACIP-SM(=)
This publication contains instructions for installing and performing a basic configuration of the
Asynchronous Transfer Mode (ATM) Cable Interface Processor (ACIP). This publication contains
basic configuration steps and examples.
Sections in this publication include the following:
• ATM Terms and Acronyms, page 2
• Asynchronous Transfer Mode Overview, page 3
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• ACIP Description, page 4
• ACIP Installation Prerequisites, page 9
• Installing and Removing an ACIP, page 16
• Attaching Network Interface Cables to the ACIP, page 17
• Using LEDs to Check ACIP Status, page 17
• Using show Commands to Verify Interface Status, page 19
• Configuring the ACIP, page 21
• Checking the Configuration, page 26
• Using the Debug ATM Commands, page 27
• Examples of ATM Error Messages, page 28
• Cisco Connection Online, page 32
1
ATM Terms and Acronyms
ATM Terms and Acronyms
The following are common ATM terms and acronyms for your reference:
AAL—ATM Adaptation Layer. An AAL defines the conversion of user information into cells.
AAL1 and AAL2 handle isochronous traffic, such as voice and video; AAL3/4 and AAL5 pertain to
data communications through the segmentation and reassembly of packets.
ATM—Asynchronous transfer mode. A cell-switching and multiplexing technology combining the
benefits of circuit switching (constant transmission delay,guaranteed capacity) with those of packet
switching (flexibility, efficiency for intermittent traffic). ATM is defined by ITU-T standards.
Average-rate—The average rate, in kbps, at which a given virtual circuit (VC) will transmit data.
BISDN—Broadband Integrated Services Digital Network. A set of standards under development by
the ITU-T for services based on ATM switching and SONET/SDH transmission.
CCITT—ConsultativeCommittee for International Telegraphand Telephone(Although commonly
referred to as the CCITT, this international standards body recently adopted the name International
Telecommunication Union/Telecommunication Standardization Sector (ITU-T).
CLP—Cell loss priority.
DXI—Data exchange interface.
ILMI—Interim Local Management Interface. Described in the ATM Forum’s UNI specification,
ILMI allows end users to retrieve a basic set of information, such as status and configuration about
virtual connections and addresses, for a particular UNI.
MIB—Management Information Base.
MIC—Media interface connector.
MID—Message identifier. In AAL3/4 encapsulation, the 2-byte MID field allows multiplexing of
streams of cells on one virtual channel.
NSAP—Network Service Access Point.
OAM—Operation Administration and Maintenance (cells).
PDU—Protocol data unit. An OSI term for a packet.
Peak-rate—The maximum rate, in kbps, at which a given VC can transmit data.
PMD—Physical medium dependent. The lower half of BISDN Layer 1.
PLIM—Physical layer interface module. The PLIM contains the interface to the ATM cable. (See
the section “ACIP Interface” on page 5.)
PVC—Permanent virtual circuit.
QOS—Quality of service.
Rate queues—Rate queues define the speed at which individual VCs will transmit data to the remote
end. Every VC must be associated with one rate queue. After attachment to this rate queue, the VC
is assumed to have its peak rate set to that of the rate queue. Each rate queue can be configured
independently to a portion of the overall bandwidth available on the ATM link. The combined
bandwidths of all rate queues should not exceed the total bandwidth available.
SAR—Segmentation and reassembly.
SDH—Synchronous Digital Hierarchy. International standard for optical digital transmission at
hierarchical rates from 155 Mbps to 2.5 Gbps and greater.
SDU—Service data unit.
2 ATM Cable Interface Processor (ACIP) Installation and Configuration
Asynchronous Transfer Mode Overview
SONET—Synchronous Optical Network. An ATM UNI specification and American National
Standards Institute (ANSI) standard (T1.105-1988) for optical digital transmission at hierarchical
rates from 51.840 Mbps (STS-N) to 2.5 Gbps and greater.
SONET OC3—Optical Carrier-3 specification.
SSCOP—Service Specific Connection Oriented Protocol. SSCOP Resides in the service specific
convergence sublayer of the ATM adaptation layer. SSCOP is used to transfer variable-length
service data units between users of SSCOP, and provides for the recovery of lost or corrupted SDUs.
SSCS—Service specific convergence sublayer.
SVC—Switched virtual circuit.
UNI—User-to-Network Interface. An ATM interface defined by the ATM Forum for public and
private ATM network access.
VC—Virtual circuit. Point-to-point connections to remote hosts/routers. Each ATM VC has the
following characteristics associated with the VC: peak rate, average rate, cell quota, quality of
service (QOS), AAL mode (AAL3/4 or AAL5), encapsulation type (LLC/SNAP, NLPID, SMDS,
MUX, QSAAL). The VC characteristics are defined when the VC is created.
VCD—Virtual circuit descriptor.
VPI/VCI—Virtualpath identifier/virtual channel identifier. ATM virtual connection information. A
virtual path is a generic term for a bundle of virtual channels that have the same end point.
Asynchronous Transfer Mode Overview
Asynchronous Transfer Mode (ATM) uses cell-switching and multiplexing technology that
combines the benefits of circuit switching (constant transmission delay and guaranteed capacity)
with those of packet switching (flexibility and efficiency for intermittent traffic). 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 (VC). Each VC is a privateconnectionto another node on the ATMnetwork.EachVC
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
networkthatitmustcommunicatewith.AllsuchconnectionsareestablishedusingaPVCoran SVC
with an ATM signaling mechanism. This signaling is based on the ATM Forum UNI Specification
V3.0.
Note The ACIP uses PVC connections with AAL5. There is one PVC for each active subscriber
modem. PVCs are created automatically; there is no need for user intervention.
Each VC is considered a complete and separate link to a destination node. Users can encapsulate
data as they see fit across the connection. The ATM network disregards the contents of the data. The
only requirement is that data be sent to the ACIP card in the specific ATM adaptation layer (AAL)
format.
An AAL defines the conversion of user information into cells. The AAL segments upper-layer
information into cells at the transmitter and reassembles them at the receiver. AAL3/4 and AAL5
support data communications. AAL3/4 is supported as of Cisco IOS Release 10.2 and later.
ATM Cable Interface Processor (ACIP) Installation and Configuration 3
ACIP Description
An ATM connection transfers 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. 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.
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 wanting 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 a particular VC as a broadcast VC. When
the protocol passes a packet with a broadcast address to the ATM driver,the packet is duplicated and
sent to each VC marked as a broadcast VC. This method is known as pseudobroadcasting.
ACIP Description
The ATM Cable Interface Processor (ACIP) (see Figure 1) provides a single ATM network interface
for a Cisco 7500 series router by providing a direct connection between the router’s high-speed
Cisco Extended Bus (CyBus) and external equipment. The ACIP can be connected directly to a
TeraLink 1000 cable headend, or through a Cisco Lightstream 1010 ATM switch or other external
ATM network equipment. The physical layer interface module (PLIM) on the ACIP provides a
SONET/SDH (STS-3C) interface connection.
ACIP Features
Figure 1 ACIP with the UNI 155-Mbps Interface
U111, microcode ROM
UNI 155
TX RX
RX Cells
RX Carrier
ENABLED
The ACIP supports the following features:
• Multiple rate queues.
• Reassembly of up to 512 buffers simultaneously. Each buffer represents a packet.
• Up to 2,048 virtual circuits.
• Transfer rates per VPI limited to fixed values provided by the cable headend.
H2337
• Exception queue, which is used for event reporting. Events such as CRC errors are reported to
the exception queue.
• Raw queue, which is used for all raw traffic over the ATM network. Raw traffic includes
Operation Administration and Maintenance (OAM) cells and Interim Local Management
Interface (ILMI) cells. (ATM signaling cells are not considered raw.)
4 ATM Cable Interface Processor (ACIP) Installation and Configuration
ACIP Interface
The ACIP’s ATM interface is full duplex. You must use the appropriate ATM interface cable to
connect the ACIP with external ATM equipment. (Refer to the section “ACIP Cables, PLIM, and
Connections,” on page 7, for descriptions of ATM cables and connectors.) The ACIP 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 PLIM. The ACIP supports a PLIM that connects
to the following physical layer: SONET/SDH 155 Mbps, multimode fiber optic—STS-3C (or
STM-1).
SONET Distance Limitations
The SONET specification for fiber-optic transmission defines two types of fiber: single mode and
multimode; however,the ACIP supports multimode fiber only.Modes can be thought of as bundles
of light rays entering the fiber at a particular angle. Multimode fiber allows multiple modes of light
to propagate through the fiber. Because multiple modes of light propagating through the fiber travel
different distances depending on the entry angles, causing them to arrive at the destination at
different times (a phenomenon called modal dispersion), single-mode fiber is capable of higher
bandwidth and greater cable run distances than multimode fiber.
The typical maximum distances for multimode transmissions, as defined by SONET,are in Table 1.
If the distance between two connected stations is greater than these maximum distances, significant
signal loss can result, making transmission unreliable.
ACIP Description
Power Budget
Table 1 SONET Maximum Fiber-Optic Transmission Distances
Transceiver Type Maximum Distance between Stations
Multimode Up to 1.5 miles (3 kilometers)
1. Table 1 gives typical results. You should use the power budget calculations to
determine the actual distances.
To design an efficient optical data link, evaluate the power budget. The power budget is the amount
of light available to overcome attenuation in the optical link and to exceed the minimum power that
the receiver requires to operate within its specifications. Proper operation of an optical data link
depends on modulated light reaching the receiver with enough power to be correctly demodulated.
Attenuation, caused by the passive media components (cables, cable splices, and connectors), is
common to both multimode and single-mode transmission.
The following variables reduce the power of the signal (light) transmitted to the receiver in
multimode transmission:
1
• Chromatic dispersion (spreading of the signal in time because of the different speeds of light
wavelengths)
• Modal dispersion (spreading of the signal in time because of the different propagation modes in
the fiber)
Attenuation is significantly lowerfor optical fiber than for other media. Formultimode transmission,
chromatic and modal dispersion reduce the available power of the system by the combined
dispersion penalty (dB). The power lost over the data link is the sum of the component, dispersion,
and modal losses.
Table 2 lists the factors of attenuation and dispersion limit for typical fiber-optic cable.
ATM Cable Interface Processor (ACIP) Installation and Configuration 5
ACIP Description
Table 2 Typical Fiber-Optic Link Attenuation and Dispersion Limits
Limits Multimode
Attenuation 1.0 dB/km
Dispersion 500 MHzkm
1. The product of bandwidth and
distance must be less than 500
MHzkm.
Approximating the ACIP Power Margin
The LED used for a multimode transmission light source creates multiple propagation paths of light,
each with a different path length and time requirement to cross the optical fiber, causing signal
dispersion (smear). Higher order mode loss (HOL)resultsfromlightfrom the LED entering the fiber
and being radiated into the fiber cladding. A worst case estimate of power margin (PM) for
multimode transmissions assumes minimum transmitter power (PT), maximum link loss (LL), and
minimum receiver sensitivity (PR). The worst case analysis provides a margin of error, although not
all of the parts of an actual system will operate at the worst case levels.
The power budget (PB) is the maximum possible amount of power transmitted. The following
equation lists the calculation of the power budget:
1
PB = PT – PR
PB = –18.5 dBm – (–30 dBm)
PB = 11.5 dB
The power margin calculation is derived from the power budget minus the link loss, as follows:
PM = PB – LL
If the power margin is positive, as a rule, the link will work.
Table 3 lists the factors that contribute to link loss and the estimate of the link loss value attributable
to those factors.
Table 3 Estimating Link Loss
Link Loss Factor Estimate of Link Loss Value
Higher order mode losses 0.5 dB
Clock recovery module 1 dB
Modal and chromatic dispersion Dependent on fiber and wavelength used
Connector 0.5 dB
Splice 0.5 dB
Fiber attenuation 1 dB/km
After calculating the power budget minus the data link loss, the result should be greater than zero.
Results less than zero may have insufficient power to operate the receiver.
6 ATM Cable Interface Processor (ACIP) Installation and Configuration
For the ACIP, the signal must meet the worst case parameters listed in Table 4.
Table 4 ACIP SONET Signal Requirements
Parameter Multimode
PT –15
PR –28
PB –13
Multimode Power Budget Example with Sufficient Power for Transmission
The following is an example multimode power budget calculated based on the following variables:
• Length of multimode link = 3 kilometers (km)
• 4 connectors
• 3 splices
• Higher order loss (HOL)
ACIP Description
• Clock recovery module (CRM)
Estimate the power budget as follows:
PB = 11.5 dB – 3 km (1.0 dB/km) – 4 (0.5 dB) – 3 (0.5 dB) – 0.5 dB (HOL) – 1 dB (CRM)
PB = 11.5 dB – 3 dB – 2 dB – 1.5 dB – 0.5 dB – 1 dB
PB = 3.5 dB
The value of 3.5 dB indicates that this link would have sufficient power for transmission.
Multimode Power Budget Example of Dispersion Limit
Following is an example with the same parameters as the previous example, but with a multimode
link distance of 4 km:
PB = 11.5 dB – 4 km (1.0 dB/km) – 4 (0.5 dB) – 3 (0.5 dB) – 0.5 dB (HOL) – 1 dB (CRM)
PB = 11.5 dB – 4 dB – 2 dB – 1.5 dB – 0.5 dB – 1 dB
PB = 2.5 dB
The value of 2.5 dB indicates that this link would have sufficient power for transmission. But,
because the dispersion limit on the link (4 km x 155.52 MHz > 500 MHzkm), this link would not
work with multimode fiber. In this case, single-mode fiber would be the better choice.
ACIP Cables, PLIM, and Connections
An ACIP interface cable is used to connect your router to an ATM network. For SONET/SDH
(STS-3C) multimode connections, use one multimode duplex SC-type connector (see Figure 2) or
two single SC-type connectors. (See Figure 3.)
ATM Cable Interface Processor (ACIP) Installation and Configuration 7
ACIP Description
Figure 2 Duplex SC-Type Connector
H2214
Figure 3 Simplex SC-Type Connector
H2399
The multimode cable connects to the SC connector on the PLIM. (See Figure 4.)
Figure 4 SONET Multimode SC Duplex PLIM
H2210
The SONET multimode SC-type duplex connector is shipped with a dust plug. (See Figure 5.)
Remove the plug by pulling on the plug as you squeeze its sides.
Figure 5 SONET ATM Multimode Fiber-Optic Transceiver and Dust Plug
H1983
8 ATM Cable Interface Processor (ACIP) Installation and Configuration
ACIP Installation Prerequisites
Before you begin the ACIP installation, review the guidelines in this section to ensure a successful
installation, to avoid injuring yourself, or to avoid damaging the equipment. This section also
provides a list of parts and tools you will need to perform the installation.
ACIP Software Prerequisites
To ensure correct operation of the ACIP, Cisco IOS Release 11.2(7)P or later is required.
Hardware and Host Router Prerequisites
The following list describes specific hardware and host router prerequisites:
• Note that the ACIP is not supported in Cisco 7500 series routers with an RSP4 installed. Only
RSP1s and RSP2s can be used with the ACIP.
• Note that the ACIPis not supported in the Cisco 7000 series routers: Cisco 7000 and Cisco 7010.
• You must use the ACIP in the following Cisco 7500 series routers:
— Cisco 7505 (see Figure 6)
ACIP Installation Prerequisites
— Cisco 7507 (see Figure 7)
— Cisco 7513 (see Figure 8)
The Cisco 7500 series routers provide high reliability,availability, serviceability,and performance,
and supports multiprotocol, multimedia routing, and bridging with a wide variety of protocols and
any combination of available electrical interfaces and media. Network interfaces reside on modular
interface processors (such as the ACIP), which provide a direct connection between the high-speed,
1.067-gigabits-per-second (Gbps) Cisco Extended Bus (CyBus) and external networks. The
Cisco 7507 and Cisco 7513 each have two CyBuses for an aggregate bandwidth of 2.134 Gbps.
Figure 6 shows the rear of the 5-slot Cisco 7505 router. In the Cisco 7505, one slot (4) is reserved
for the Route Switch Processor (RSP1), which contains the main system processor and performs
packet switching functions. Slots 0 through 3 are for interface processors, including the ACIP.
(There are no restrictions on slot locations or sequence; you can install an ACIP in any available
interface processor slot.)
Figure 6 Cisco 7505, Interface Processor End
Power switch
Chassis
grounding
receptacles
NORMAL
EJECT
SLOT 1
SLOT 0
ENABLE
CPU HALT
ENABLE
RESET
AUX.
ROUTE SWITCH PROCESSOR
CONSOLE
RSP slot
Interface processor slot 3
Interface processor slot 2
Interface processor slot 1
Interface processor slot 0
DC OK LED
H2761
Power receptacle AC-input power supply
ATM Cable Interface Processor (ACIP) Installation and Configuration 9
ACIP Installation Prerequisites
Figure 7 shows the rear of the 7-slot Cisco 7507 router. In the Cisco 7507, up to two slots (2 and 3)
are reserved for the Route Switch Processor (RSP2), which contains the system processor and
performs packet switching functions. Slots 0 and 1, and 4 through 6 are for interface processors,
including the ACIP. (There are no restrictions on slot locations or sequence; you can install an ACIP
in any available interface processor slot.)
Figure 7 Cisco 7507, Interface Processor End
Captive
installation screw
Upper
power supply
DC FAIL
AC POWER
NORMAL
ENABLE
Chassis
grounding
receptacles
Captive
installation screw
Lower
power supply
DC FAIL
AC POWER
EJECT
SLOT 1
I
O
I
O
Slot 0
SLOT 0
MASTER
SLAVE
SLAVE/MASTER
CPU HALT
RESET
AUX.
ROUTE SWITCH PROCESSOR 2
CONSOLE
2
1
34 5 6
ENABLE
H3888
RSP slots
10 ATM Cable Interface Processor (ACIP) Installation and Configuration
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