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CH A P T E R13Configuring the POS SPAsThis chapter provides information about configuring the Packet over SONET (POS) shared port adapters(SPAs) on the Catalyst 6500 Series switch. This chapter includes the following sections: Configuration Tasks, page 13-1 Verifying the Interface Configuration, page 13-18 Configuration Examples, page 13-18For information about managing your system images and configuration files, refer to the Cisco IOSConfiguration Fundamentals Configuration Guide, Release 12.2 and Cisco IOS ConfigurationFundamentals Command Reference, Release 12.2 publications.For more information about the commands used in this chapter, see the Catalyst 6500 Series Cisco IOSCommand Reference, 12.2SX publication. Also refer to the related Cisco IOS Release 12.2 softwarecommand reference and master index publications. For more information about accessing thesepublications, see the “Related Documentation” section on page xliv.Configuration TasksThis section describes how to configure POS SPAs and includes information about verifying theconfiguration.It includes the following topics: Required Configuration Tasks, page 13-2 Specifying the Interface Address on a SPA, page 13-3 Modifying the Interface MTU Size, page 13-4 Modifying the POS Framing, page 13-5 Modifying the Keepalive Interval, page 13-7 Modifying the CRC Size, page 13-7 Modifying the Clock Source, page 13-8 Modifying SONET Payload Scrambling, page 13-9 Configuring the Encapsulation Type, page 13-10 Configuring APS, page 13-11 Configuring POS Alarm Trigger Delays, page 13-12 Configuring SDCC, page 13-15Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration GuideOL-8655-0413-1

Chapter 13Configuring the POS SPAsConfiguration Tasks Configuring Layer 2 Internetworking Features on POS SPAs, page 13-16 Saving the Configuration, page 13-17 Shutting Down and Restarting an Interface on a SPA, page 13-18Required Configuration TasksThis section lists the required configuration steps to configure the POS SPAs. Some of the requiredconfiguration commands implement default values that might be appropriate for your network. If thedefault value is correct for your network, then you do not need to configure the command. Thesecommands are indicated by “(As Required)” in the Purpose column.To configure the POS SPAs, perform this task:CommandPurposeStep 1Router# configure terminalEnters global configuration mode.Step 2Router(config)# interface posslot/subslot/portSpecifies the POS interface to configure and enters interface configuration mode, where: Step 3Step 4Router(config-if)# ip addressip-address mask [secondary]Router(config-if)# posframing {sonet sdh}slot/subslot/port—Specifies the location of the interface. Seethe “Specifying the Interface Address on a SPA” section onpage 13-3.Sets a primary or secondary IP address for an interface, where: ip-address—Specifies the IP address for the interface. mask—Specifies the mask for the associated IP subnet. secondary—(Optional) Specifies that the configured addressis a secondary IP address. If this keyword is omitted, the configured address is the primary IP address.(As Required) Specifies the POS framing type, where: sonet—Enables Synchronous Optical Network Framing foroptical carrier (OC) rates. This is the default. sdh—Enables Synchronous Digital Hierarchy framing forsynchronous transfer mode (STM) rates.The POS framing type must be configured to be the same on bothends of the POS link.Step 5Router(config-if)# mtu bytes(As Required) Configures the maximum transmission unit (orpacket size) for an interface, where: bytes—Specifies the maximum number of bytes for a packet.The default is 4470 bytes.Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration Guide13-2OL-8655-04

Chapter 13Configuring the POS SPAsConfiguration TasksStep 6CommandPurposeRouter(config-if)# keepalive[period [retries]](As Required) Specifies the frequency at which the Cisco IOSsoftware sends messages to the other end of the link, to ensure thata network interface is alive, where: period—Specifies the time interval in seconds for sendingkeepalive packets. The default is 10 seconds. retries—Specifies the number of times that the device willcontinue to send keepalive packets without response beforebringing the interface down. The default is 5 retries.The keepalive must be configured to be the same on both ends ofthe POS link.Step 7Router(config-if)# crc [16 32](As Required) Specifies the length of the cyclic redundancy check(CRC), where: 16—Specifies a 16-bit length CRC. This is the default. 32—Specifies a 32-bit length CRC.The CRC size must be configured to be the same on both ends ofthe POS link.Step 8Step 9(As Required) Specifies the clock source for the POS link, where:Router(config-if)# clocksource {line internal}Router(config-if)# encapsulation encapsulation-type line—The link uses the recovered clock from the line. This isthe default. internal—The link uses the internal clock source.(As Required) Specifies the encapsulation method used by theinterface, where: encapsulation-type—Can be HDLC, PPP, or Frame Relay.The default encapsulation is HDLC.The encapsulation must be configured to be the same on both endsof the POS link.Note: The POS SPAs on the Cisco 7600 SIP-600 do not supportFrame Relay.Step 10Router(config-if)# posscramble-atm(As Required) Enables SONET payload scrambling.The default configuration is SONET payload scrambling disabled.The SONET payload scrambling must be configured to be thesame on both ends of the POS link.Step 11Router(config-if)# noshutdownEnables the interface.Specifying the Interface Address on a SPASPA interface ports begin numbering with “0” from left to right. Single-port SPAs use only the portnumber 0. To configure or monitor SPA interfaces, you need to specify the physical location of the SIP,SPA, and interface in the CLI. The interface address format is slot/subslot/port, where: slot—Specifies the chassis slot number in the Catalyst 6500 Series switch where the SIP is installed.Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration GuideOL-8655-0413-3

Chapter 13Configuring the POS SPAsConfiguration Tasks subslot—Specifies the secondary slot of the SIP where the SPA is installed. port—Specifies the number of the individual interface port on a SPA.The following example shows how to specify the first interface (0) on a SPA installed in the first subslotof a SIP (0) installed in chassis slot 3:Router(config)# interface serial 3/0/0This command shows a serial SPA as a representative example, however the same slot/subslot/portformat is similarly used for other SPAs (such as ATM and POS) and other non-channelized SPAs.For more information about identifying slots and subslots, see the “Identifying Slots and Subslots forSIPs, SSCs, and SPAs” section on page 4-2.Modifying the Interface MTU SizeThe Cisco IOS software supports three different types of configurable maximum transmission unit(MTU) options at different levels of the protocol stack: Interface MTU—Checked by the SPA on traffic coming in from the network. Different interfacetypes support different interface MTU sizes and defaults. The interface MTU defines the maximumpacket size allowable (in bytes) for an interface before drops occur. If the frame is smaller than theinterface MTU size, but is not smaller than three bytes of payload size, then the frame continues toprocess. IP MTU—Can be configured on a subinterface and is used by the Cisco IOS software to determinewhether fragmentation of a packet takes place. If an IP packet exceeds the IP MTU size, then thepacket is fragmented. Tag or Multiprotocol Label Switching (MPLS) MTU—Can be configured on a subinterface andallows up to six different labels, or tag headers, to be attached to a packet. The maximum numberof labels is dependent on your Cisco IOS software release.Different encapsulation methods and the number of MPLS MTU labels add additional overhead to apacket. For example, for an Ethernet packet, SNAP encapsulation adds an 8-byte header, dot1qencapsulation adds a 2-byte header, and each MPLS label adds a 4-byte header (n labels x 4 bytes).Interface MTU Configuration GuidelinesWhen configuring the interface MTU size on the POS SPAs, consider the following guidelines: If you are also using MPLS, be sure that the mpls mtu command is configured for a value less thanor equal to the interface MTU. If you change the interface MTU size, the giant counter increments when the interface receives apacket that exceeds the MTU size that you configured, plus an additional 88 bytes for overhead, andan additional 2 or 4 bytes for the configured cyclic redundancy check (CRC).For example, with a maximum MTU size of 9216 bytes, the giant counter increments:– For a 16-bit CRC (or FCS), when receiving packets larger than 9306 bytes (9216 88 2).– For a 32-bit CRC, when receiving packets larger than 9308 bytes (9216 88 4).Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration Guide13-4OL-8655-04

Chapter 13Configuring the POS SPAsConfiguration Tasks The Frame Relay Local Management Interface (LMI) protocol requires that all permanent virtualcircuit (PVC) status reports fit into a single packet. Using the default MTU of 4470 bytes, this limitsthe number of data-link connection identifiers (DLCIs) to 890. The following formula demonstrateshow to determine the maximum DLCIs for a configured interface MTU:– Maximum DLCIs (MTU bytes – 20)/(5 bytes per DLCI)– Maximum DLCIs for the default MTU (4470 – 20)/5 890 DLCIs per interfaceInterface MTU Configuration TaskTo modify the MTU size on an interface, perform this task in interface configuration mode:CommandPurposeRouter(config-if)# mtu bytesConfigures the maximum packet size for an interface,where: bytes—Specifies the maximum number of bytes fora packet. The default is 4470 bytes.To return to the default MTU size, use the no form of the command.Verifying the MTU SizeTo verify the MTU size for an interface, use the show interfaces pos privileged EXEC command andobserve the value shown in the MTU field.The following example shows an MTU size of 4470 bytes for interface port 0 (the first port) on the SPAinstalled in subslot 1 of the SIP that is located in slot 2 of the Catalyst 6500 Series switch:Router# show interfaces pos 2/1/0POS2/1/0 is up, line protocol is up (APS working - active)Hardware is Packet over SonetInternet address is 10.1.1.1/24MTU 4470 bytes, BW 155000 Kbit, DLY 100 usec,reliability 255/255, txload 1/255, rxload 1/255.Modifying the POS FramingPOS framing can be specified as SONET (Synchronous Optical Network) or SDH (Synchronous DigitalHierarchy). SONET and SDH are a set of related standards for synchronous data transmission over fiberoptic networks. SONET is the United States version of the standard published by the American NationalStandards Institute (ANSI). SDH is the international version of the standard published by theInternational Telecommunications Union (ITU).Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration GuideOL-8655-0413-5

Chapter 13Configuring the POS SPAsConfiguration TasksTo modify the POS framing, perform this task in interface configuration mode:CommandPurposeRouter(config-if)# pos framing {sonet sdh}Specifies the POS framing type, where: sonet—Enables Synchronous Optical Networkframing for optical carrier (OC) rates. This is thedefault. sdh—Enables Synchronous Digital Hierarchyframing for synchronous transfer mode (STM)rates.The POS framing type must be configured to be thesame on both ends of the POS link.To return to the default, use the no form of the command.Verifying the POS FramingTo verify the POS framing, use the show controllers pos privileged EXEC command and observe thevalue shown in the Framing field. The following example shows that POS framing mode is set to SONETfor the first interface (0) on the POS SPA installed in subslot 2 of a SIP installed in chassis slot 3:Router# show controllers pos 3/2/0POS3/2/0SECTIONLOF 0 LOS 0 BIP(B1) 0LINEAIS 0 RDI 0 FEBE 0 BIP(B2) 0PATHAIS 0 RDI 0 FEBE 0 BIP(B3) 0PLM 0 UNEQ 0 TIM 0 TIU 0LOP 0 NEWPTR 0 PSE 0 NSE 0Active Defects: NoneActive Alarms: NoneAlarm reporting enabled for: SF SLOS SLOF B1-TCA B2-TCA PLOP B3-TCAFraming: SONETAPSCOAPS 0 PSBF 0State: PSBF state FalseRx(K1/K2): 00/00 Tx(K1/K2): 00/00Rx Synchronization Status S1 00S1S0 00, C2 CFRemote aps status (none); Reflected local aps status (none)CLOCK RECOVERYRDOOL 0State: RDOOL state FalsePATH TRACE BUFFER: STABLERemote hostname : sip-sw-7600-2Remote interface: POS3/2/1Remote IP addr : 0.0.0.0Remote Rx(K1/K2): 00/00 Tx(K1/K2): 00/00BER thresholds: SF 10e-3 SD 10e-6TCA thresholds: B1 10e-6 B2 10e-6 B3 10e-6Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration Guide13-6OL-8655-04

Chapter 13Configuring the POS SPAsConfiguration TasksClock source: internalModifying the Keepalive IntervalWhen the keepalive feature is enabled, a keepalive packet is sent at the specified time interval to keepthe interface active. The keepalive interval must be configured to be the same on both ends of the POSlink.To modify the keepalive interval, perform this task in interface configuration mode:CommandPurposeRouter(config-if)# keepalive [period[retries]]Specifies the frequency at which the Cisco IOSsoftware sends messages to the other end of the link,to ensure that a network interface is alive, where: period—Specifies the time interval in seconds forsending keepalive packets. The default is 10seconds. retries—Specifies the number of times that thedevice will continue to send keepalive packetswithout response before bringing the interfacedown. The default is 5 retries.To disable keepalive packets, use the no form of this command.Verifying the Keepalive IntervalTo verify the keepalive interval, use the show interfaces pos privileged EXEC command and observethe value shown in the Keepalive field.The following example shows that keepalive is enabled for interface port 0 on the POS SPA installed inthe SIP that is located in slot 2 of the Catalyst 6500 Series switch:Router# show interfaces pos 2/0/0Hardware is Packet over SonetInternet address is 10.1.1.1.2MTU 9216 bytes, BW 622000 Kbit, DLY 100 usec, reliability 255/255, txload 1/255,rxload 1/255Keepalive set (10 sec).Modifying the CRC SizeCRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitteddata. The CRC size indicates the length in bits of the FCS.The CRC size must be configured to be the same on both ends of the POS link.Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration GuideOL-8655-0413-7

Chapter 13Configuring the POS SPAsConfiguration TasksTo modify the CRC size, perform this task in interface configuration mode:CommandPurposeRouter(config-if)# crc [16 32](As Required) Specifies the length of the cyclicredundancy check (CRC), where: 16—Specifies a 16-bit length CRC. This is thedefault. 32—Specifies a 32-bit length CRC.The CRC size must be configured to be the same onboth ends of the POS link.To return to the default CRC size, use the no form of the command.Verifying the CRC SizeTo verify the CRC size, use the show interfaces pos privileged EXEC command and observe the valueshown in the CRC field.The following example shows that the CRC size is 16 for interface port 0 on the POS SPA installed inthe SIP that is located in slot 2 of the Catalyst 6500 Series switch:Router# show interfaces pos 2/0/0Hardware is Packet over SonetInternet address is 10.1.1.2.1MTU 9216 bytes, BW 622000 Kbit, DLY 100 usec reliability 255/255, txload 1/255, rxload1/255Encapsulation HDLC, crc 16, loopback not set.Modifying the Clock SourceA clock source of internal specifies that the interface clocks its transmitted data from its internal clock.A clock source of line specifies that the interface clocks its transmitted data from a clock recovered fromthe line’s receive data stream.For information about the recommended clock source settings for POS switch interfaces, refer toConfiguring Clock Settings on POS Router Interfaces at the following chnologies tech note09186a0080094bb9.shtmlTo modify the clock source, perform this task in interface configuration mode:CommandPurposeRouter(config-if)# clock source {line internal}Specifies the clock source for the POS link, where: line—The link uses the recovered clock fromthe line. This is the default. internal—The link uses the internal clocksource.Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration Guide13-8OL-8655-04

Chapter 13Configuring the POS SPAsConfiguration TasksTo return to the default clock source, use the no form of this command.Verifying the Clock SourceTo verify the clock source, use the show controllers pos privileged EXEC command and observe thevalue shown in the Clock source field.The following example shows that the clock source is internal for interface port 0 on the POS SPAinstalled in subslot 0 of the SIP that is located in slot 2 of the Catalyst 6500 Series switch:Router# show controllers pos 2/0/0POS2/0/0SECTIONLOF 0 LOS 1 BIP(B1) 7LINEAIS 0 RDI 1 FEBE 20 BIP(B2) 9PATHAIS 0 RDI 0 FEBE 0 BIP(B3) 5PLM 0 UNEQ 0 TIM 0 TIU 0LOP 0 NEWPTR 0 PSE 0 NSE 0Active Defects: NoneActive Alarms: NoneAlarm reporting enabled for: SF SLOS SLOF B1-TCA LAIS LRDI B2-TCA PAIS PLOP PRDI PUNEQB3-TCA RDOOLAPSCOAPS 2 PSBF 0State: PSBF state FalseRx(K1/K2): 00/00 Tx(K1/K2): 00/00Rx Synchronization Status S1 00S1S0 02, C2 CFCLOCK RECOVERYRDOOL 0State: RDOOL state FalsePATH TRACE BUFFER: STABLERemote hostname : RouterTester. Port 102/1Remote interface:Remote IP addr :Remote Rx(K1/K2): / Tx(K1/K2): /BER thresholds: SF 10e-5 SD 10e-6TCA thresholds: B1 10e-6 B2 10e-6 B3 10e-6Clock source: internal.Modifying SONET Payload ScramblingSONET payload scrambling applies a self-synchronous scrambler (x43 1) to the Synchronous PayloadEnvelope (SPE) of the interface to ensure sufficient bit transition density.The default configuration is SONET payload scrambling disabled.SONET payload scrambling must be configured to be the same on both ends of the POS link.Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration GuideOL-8655-0413-9

Chapter 13Configuring the POS SPAsConfiguration TasksTo modify SONET payload scrambling, perform this task in interface configuration mode:CommandPurposeRouter(config-if)# pos scramble-atmEnables SONET payload scrambling.To disable SONET payload scrambling, use the no form of this command.Verifying SONET Payload ScramblingTo verify SONET payload scrambling, use the show interfaces pos privileged EXEC command andobserve the value shown in the Scramble field.The following example shows that SONET payload scrambling is disabled for interface port 0 on thePOS SPA installed in subslot 0 of the SIP that is located in slot 2 of the Catalyst 6500 Series switch:Router# show interfaces pos 2/0/0Hardware is Packet over SonetInternet address is 10.0.0.1/24MTU 9216 bytes, BW 622000 Kbit, DLY 100 usec,reliability 255/255, txload 1/255, rxload 1/255Encapsulation HDLC, crc 16, loopback not setKeepalive not setScramble disabled.Configuring the Encapsulation TypeBy default, the POS interfaces support High-Level Data Link Control (HDLC) encapsulation. Theencapsulation method can be specified as HDLC, Point-to-Point Protocol (PPP) or Frame Relay. Theencapsulation type must be configured to be the same on both ends of the POS link.To modify the encapsulation method, perform this task in interface configuration mode:CommandPurposeRouter(config-if)# encapsulationencapsulation-typeSpecifies the encapsulation method used by theinterface, where: encapsulation-type—Can be HDLC, PPP, orFrame Relay. The default is HDLC.Verifying the Encapsulation TypeTo verify the encapsulation type, use the show interfaces pos privileged EXEC command and observethe value shown in the Encapsulation field.The following example shows the encapsulation type is HDLC for port 0 on the POS SPA installed insubslot 0 of the SIP that is located in slot 2 of the Catalyst 6500 Series switch:Router# show interfaces pos 2/0/0Hardware is Packet over SonetInternet address is 10.0.0.1/24MTU 9216 bytes, BW 622000 Kbit, DLY 100 usec,Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration Guide13-10OL-8655-04

Chapter 13Configuring the POS SPAsConfiguration Tasksreliability 255/255, txload 1/255, rxload 1/255Encapsulation HDLC, crc 16, loopback not setKeepalive not setScramble disabled.Configuring APSAutomatic protection switching (APS) allows switchover of POS circuits in the event of circuit failureand is often required when connecting SONET equipment to telco equipment. APS refers to the methodof using a protect POS interface in the SONET network as the backup for a working POS interface. Whenthe working interface fails, the protect interface quickly assumes its traffic load. Depending on theconfiguration, the two circuits may be terminated in the same switch, or in different switches.For more information about APS, refer to A Brief Overview of Packet Over SONET APS at the /tk607/technologies tech note09186a0080093eb5.shtmlTo configure the working POS interface, perform this task in interface configuration mode:CommandPurposeRouter(config-if)# aps workingcircuit-numberConfigures a POS interface as a working APSinterface, where: circuit-number—Specifies the circuit numberassociated with this working interface.To remove the POS interface as a working interface, use the no form of this command.To configure the protect POS interface, perform this task in interface configuration mode:CommandPurposeRouter(config-if)# aps protectcircuit-number ip-addressConfigures a POS interface as a protect APSinterface, where: circuit-number—Specifies the number of thecircuit to enable as a protect interface. ip-address—Specifies the IP address of theswitch that has the working POS interface.To remove the POS interface as a protect interface, use the no form of this command.Verifying the APS ConfigurationTo verify the APS configuration or to determine if a switchover has occurred, use the show apscommand.Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration GuideOL-8655-0413-11

Chapter 13Configuring the POS SPAsConfiguration TasksThe following is an example of a switch configured with a working interface. In this example, POSinterface 0/0/0 is configured as a working interface in group 1, and the interface is selected (that is,active).Router# show apsPOS0/0/0 working group 1 channel 1 Enabled SelectedThe following is an example of a switch configured with a protect interface. In this example, POSinterface 2/1/1 is configured as a protect interface in group 1. The output also shows that the workingchannel is located on the switch with the IP address 10.0.0.1 and that the interface currently selected isenabled.Router# show apsPOS2/1/1 APS Group 1: protect channel 0 (inactive)Working channel 1 at 10.0.0.1 (Enabled)SONET framing; SONET APS signalling by defaultRemote APS configuration: (null).Configuring POS Alarm Trigger DelaysA trigger is an alarm that when activated causes the line protocol to go down. The POS alarm triggerdelay helps to ensure uptime of a POS interface by preventing intermittent problems from disabling theline protocol. The POS alarm trigger delay feature delays the setting of the line protocol to down whentrigger alarms are received. If the trigger alarm was sent because of an intermittent problem, the POSalarm trigger delay can prevent the line protocol from going down when the line protocol is functional.Line-Level and Section-Level TriggersThe pos delay triggers line command is used for POS switch interfaces connected to internallyprotected Dense Wavelength Division Multiplexing (DWDM) systems. This command is invalid forinterfaces that are configured as working or protect APS. Normally, a few microseconds of line- orsection-level alarms brings down the link until the alarm has been clear for ten seconds. If you configureholdoff, the link-down trigger is delayed for 100 milliseconds. If the alarm stays up for more than 100milliseconds, the link is brought down. If the alarm clears before 100 milliseconds, the link remains up.The following line- and section-level alarms are triggers, by default, for the line protocol to go down: Line alarm indication signal (LAIS) Section loss of signal (SLOS) Section loss of frame (SLOF)You can use the pos delay triggers line command to delay a down trigger of the line protocol on theinterface. You can set the delay from 50 to 10000 milliseconds. The default delay is 100 milliseconds.Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration Guide13-12OL-8655-04

Chapter 13Configuring the POS SPAsConfiguration TasksTo configure POS line- or section-level triggers, perform this task beginning in interface configurationmode:Step 1CommandPurposeRouter(config-if)# pos delaytriggers line msSpecifies a delay for setting the line protocol to down when aline-level trigger alarm is received, where: Step 2Step 3Router(config-if)# posthreshold {b1-tca b2-tca b3-tca sd-ber sf-ber} ratems—Specifies the delay in milliseconds. The default delay is100 milliseconds.Configures the POS bit error rate (BER) threshold values of thespecified alarms, where: b1-tca rate—Specifies the B1 BER threshold crossing alarm.The default is 6. b2-tca rate—Specifies the B2 BER threshold crossing alarm.The default is 6. b3-tca rate—Specifies the B3 BER threshold crossing alarm.The default is 6. sd-ber rate—Specifies the signal degrade BER threshold.The default is 6. sf-ber rate—Specifies the signal failure BER threshold. Thedefault is 3. rate—Specifies the bit error rate from 3 to 9 (10e-n). Thedefault varies by the type of threshold that you configure.Sends a line alarm indication signal (AIS-L) to the other end ofthe link after a shutdown command has been issued to thespecified POS interface. AIS-L is also known as LAIS whenalarm-related output is generated using the show controllers poscommand.Router(config-if)# posais-shutBy default, the AIS-L is not sent to the other end of the link.Stops transmitting the AIS-L by issuing either the no shutdownor the no pos ais-shut commands.To disable alarm trigger delays, use the no form of the pos delay triggers line command.To determine which alarms are reported on the POS interface, and to display the BER thresholds, use theshow controllers pos command.Path-Level TriggersTo configure various path alarms as triggers and to specify an activation delay between 50 and 10000milliseconds, use the pos delay triggers path command. The default delay value is 100 milliseconds.The following path alarms are not triggers by default. You can configure these path alarms as triggersand also specify a delay: Path alarm indication signal (PAIS) Path remote defect indication (PRDI) Path loss of pointer (PLOP)Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration GuideOL-8655-0413-13

Chapter 13Configuring the POS SPAsConfiguration Tasks sd-ber (signal degrade [SD] bit error rate [BER]) sf-ber (signal failure [SF] BER) b1-tca (B1 BER threshold crossing alarm [TCA]) b2-tca (B2 BER TCA) b3-tca (B3 BER TCA)The pos delay triggers path command can also bring down the line protocol when the higher of the B2and B3 error rates is compared with the signal failure (SF) threshold. If the SF threshold is crossed, theline protocol of the interface goes down.To configure POS path-level triggers, perform this task in interface configuration mode:CommandPurposeRouter(config-if)# pos delay triggerspath msSpecifies that path-level alarms should act as triggersand specifies a delay for setting the line protocol todown when a path-level trigger alarm is received,where: ms—Specifies the delay in milliseconds. Thedefault delay is 100 milliseconds.To disable path-level triggers, use the no form of this command.Verifying POS Alarm Trigger DelaysTo verify POS alarm trigger delays, use the show controllers pos privileged EXEC command andobserve the values shown in the Line alarm trigger delay and Path alarm trigger delay fields.The following example shows the POS alarm trigger delays for interface port 0 on the POS SPA installedin the SIP that is located in slot 2 of the Catalyst 6500 Series switch:Router# show controllers pos 2/0/0 detailsPOS2/0/0SECTIONLOF 0 LOS 1 BIP(B1) 5LINEAIS 0 RDI 1 FEBE 5790 BIP(B2) 945PATHAIS 0 RDI 0 FEBE 0 BIP(B3) 5PLM 0 UNEQ 0 TIM 0 TIU 0LOP 1 NEWPTR 0 PSE 0 NSE 0Active Defects: NoneActive Alarms: NoneAlarm reporting enabled for: SF SLOS SLOF B1-TCA B2-TCA PLOP B3-TCALine alarm trigger delay 100 msPath alarm trigger delay 100 ms.Catalyst 6500 Series Switch SIP, SSC, and SPA Software Configuration Guide13-14OL-8655-04

Chapter 13Configuring the POS SPAsConfiguration TasksConfiguring SDCCBefore any management traffic can traverse the section data communication channel (SDCC) linksembedded in the POS SPA overhead, the SDCC interfaces must be configured and activated.NoteSDCC is not supported by the 1-Port OC-48c/STM-16 POS SPA on the Cisco 7600 SIP-400 and is notsupported by any POS SPAs on the Cisco 7600 SIP-600.SDCC Configuration GuidelinesWhen configuring SDCC on a POS SPA, consider the following guidelines: SDCC must be enabled on the main POS interfaces. SDCC can be configured on up to two interfaces of the 4-Port OC-3c/STM-1 POS SPA. SDCC supports only HDLC and PPP encapsulation, not Frame Relay.SDCC Configuration TaskTo configure the POS SPAs for SDCC, perform this task:CommandPurposeStep 1Router# configure terminalEnters global configuration mode.Step 2Router(config)# interface posslot/subslot/portSpecifies the POS interface to configur

To verify the POS framing, use the show controllers pos privileged EXEC command and observe the value shown in the Framing field. The following example shows that POS framing mode is set to SONET for the first interface (0) on the POS SPA installed in subslot 2 of a SIP installed in chassi