Cisco 12000 Series Router SIP and SPA Software Configuration Guide, 12.0(33)S

Configuring the POS SPAs

This chapter provides information about configuring the Packet over SONET (POS) shared port adapters (SPAs) on the Cisco 12000 series router. This chapter includes the following sections:

•Configuration Tasks

•Verifying the Interface Configuration

•Configuration Examples

For information about managing your system images and configuration files, refer to the Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.0 and Cisco IOS Configuration Fundamentals Command Reference, Release 12.0 publications.

For more information about the commands used in this chapter, first see Chapter 19, "SIP and SPA Command Reference" in this book, which documents new and modified commands. Also refer to the related Cisco IOS Release 12.0 software command reference and master index publications. For more information about accessing these publications, see the "Related Documentation" section.

Configuration Tasks

This section describes how to configure POS SPAs and includes information about verifying the configuration.

It includes the following topics:

•Required Configuration Tasks

•Specifying the Interface Address on a SPA

•Modifying the Interface MTU Size

•Modifying the POS Framing

•Modifying the Keepalive Interval

•Modifying the CRC Size

•Modifying the Clock Source

•Modifying SONET Payload Scrambling

•Configuring the Encapsulation Type

•Configuring APS

•Configuring POS Alarm Trigger Delays

•Configuring SDCC

•Configuring Dynamic Packet Transport Features

•Saving the Configuration

•Shutting Down and Restarting an Interface on a SPA

Required Configuration Tasks

This section lists the required configuration steps to configure the POS SPAs. Some of the required configuration commands implement default values that might be appropriate for your network. If the default value is correct for your network, then you do not need to configure the command. These commands are indicated by "(As Required)" in the Purpose column.

To configure the POS SPAs, complete the following steps:

Specifying the Interface Address on a SPA

SPA interface ports begin numbering with "0" from left to right. Single-port SPAs use only the port number 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 Cisco 12000 series router where the SIP is installed.

•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 subslot of a SIP (0) installed in chassis slot 3:

Router(config)# interface serial 3/0/0

This command shows a serial SPA as a representative example, however the same slot/subslot/port format is similarly used for other SPAs (such as ATM and POS) and other non-channelized SPAs.

Modifying the Interface MTU Size

The 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 interface types support different interface MTU sizes and defaults. The interface MTU defines the maximum packet size allowable (in bytes) for an interface before drops occur. If the frame is smaller than the interface MTU size, but is not smaller than three bytes of payload size, then the frame continues to process.

•IP MTU—Can be configured on a subinterface and is used by the Cisco IOS software to determine whether fragmentation of a packet takes place. If an IP packet exceeds the IP MTU size, then the packet is fragmented.

•Tag or Multiprotocol Label Switching (MPLS) MTU—Can be configured on a subinterface and allows up to six different labels, or tag headers, to be attached to a packet. The maximum number of labels is dependent on your Cisco IOS software release.

Different encapsulation methods and the number of MPLS MTU labels add additional overhead to a packet. For example, for an Ethernet packet, SNAP encapsulation adds an 8-byte header, dot1q encapsulation adds a 2-byte header, and each MPLS label adds a 4-byte header (n labels x 4 bytes).

Interface MTU Configuration Guidelines

When 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 than or equal to the interface MTU.

•If you change the interface MTU size, the giant counter increments when the interface receives a packet that exceeds the MTU size that you configured, plus an additional 88 bytes for overhead, and an 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).

•The Frame Relay Local Management Interface (LMI) protocol requires that all permanent virtual circuit (PVC) status reports fit into a single packet. Using the default MTU of 4470 bytes, this limits the number of data-link connection identifiers (DLCIs) to 890. The following formula demonstrates how 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 interface

Interface MTU Configuration Task

To modify the MTU size on an interface, use the following command in interface configuration mode:

To return to the default MTU size, use the no form of the command.

Verifying the MTU Size

To verify the MTU size for an interface, use the show interfaces pos privileged EXEC command and observe 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 SPA installed in subslot 1 of the SIP that is located in slot 2 of the Cisco 12000 series router:

Router# show interfaces pos 2/1/0 

POS2/1/0 is up, line protocol is up (APS working - active)

  Hardware is Packet over Sonet

  Internet address is 10.1.1.1/24

  MTU 4470 bytes, BW 155000 Kbit, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255.

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Modifying the POS Framing

POS framing can be specified as SONET (Synchronous Optical Network) or SDH (Synchronous Digital Hierarchy). SONET and SDH are a set of related standards for synchronous data transmission over fiber- optic networks. SONET is the United States version of the standard published by the American National Standards Institute (ANSI). SDH is the international version of the standard published by the International Telecommunications Union (ITU).

To modify the POS framing, use the following command in interface configuration mode:

To return to the default, use the no form of the command.

Verifying the POS Framing

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 chassis slot 3:

Router# show controllers pos 3/2/0

POS3/2/0 

SECTION 

LOF = 0 LOS = 0 BIP(B1) = 0 

LINE 

AIS = 0 RDI = 0 FEBE = 0 BIP(B2) = 0 

PATH 

AIS = 0 RDI = 0 FEBE = 0 BIP(B3) = 0 

PLM = 0 UNEQ = 0 TIM = 0 TIU = 0 

LOP = 0 NEWPTR = 0 PSE = 0 NSE = 0 

Active Defects: None 

Active Alarms: None 

Alarm reporting enabled for: SF SLOS SLOF B1-TCA B2-TCA PLOP B3-TCA 

Framing: SONET 

APS 

COAPS = 0 PSBF = 0 

State: PSBF_state = False 

Rx(K1/K2): 00/00 Tx(K1/K2): 00/00 

Rx Synchronization Status S1 = 00 

S1S0 = 00, C2 = CF 

Remote aps status (none); Reflected local aps status (none) 

CLOCK RECOVERY 

RDOOL = 0 

State: RDOOL_state = False 

PATH TRACE BUFFER: STABLE 

Remote hostname : sip-sw-7600-2 

Remote interface: POS3/2/1 

Remote IP addr : 0.0.0.0 

Remote Rx(K1/K2): 00/00 Tx(K1/K2): 00/00 

BER thresholds: SF = 10e-3 SD = 10e-6 

TCA thresholds: B1 = 10e-6 B2 = 10e-6 B3 = 10e-6 

Clock source: internal 

Modifying the Keepalive Interval

When the keepalive feature is enabled, a keepalive packet is sent at the specified time interval to keep the interface active. The keepalive interval must be configured to be the same on both ends of the POS link.

To modify the keepalive interval, use the following command in interface configuration mode:

To disable keepalive packets, use the no form of this command.

Verifying the Keepalive Interval

To verify the keepalive interval, use the show interfaces pos privileged EXEC command and observe the value shown in the "Keepalive" field.

The following example shows that keepalive is enabled for interface port 0 on the POS SPA installed in the SIP that is located in slot 2 of the Cisco 12000 series router:

Router# show interfaces pos 2/0/0

Hardware is Packet over Sonet 
Internet address is 10.1.1.1.2 
MTU 9216 bytes, BW 622000 Kbit, DLY 100 usec, reliability 255/255, txload 1/255, 
rxload 1/255

      Keepalive set (10 sec)

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Modifying the CRC Size

CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. 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.

To modify the CRC size, use the following command in interface configuration mode:

To return to the default CRC size, use the no form of the command.

Verifying the CRC Size

To verify the CRC size, use the show interfaces pos privileged EXEC command and observe the value shown in the "CRC" field.

The following example shows that the CRC size is 16 for interface port 0 on the POS SPA installed in the SIP that is located in slot 2 of the Cisco 12000 series router:

Router# show interfaces pos 2/0/0

Hardware is Packet over Sonet 
Internet address is 10.1.1.2.1 
MTU 9216 bytes, BW 622000 Kbit, DLY 100 usec reliability 255/255, txload 1/255, rxload 
1/255

Encapsulation HDLC, crc 16, loopback not set

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Modifying the Clock Source

A 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 from the line's receive data stream.

For information about the recommended clock source settings for POS router interfaces, refer to Configuring Clock Settings on POS Router Interfaces at the following URL:

http://www.cisco.com/en/US/tech/tk482/tk607/technologies_tech_note09186a0080094bb9.shtml

To modify the clock source, use the following command in interface configuration mode:

To return to the default clock source, use the no form of this command.

Verifying the Clock Source

To verify the clock source, use the show controllers pos privileged EXEC command and observe the value shown in the "Clock source" field.

The following example shows that the clock source is internal for interface port 0 on the POS SPA installed in subslot 0 of the SIP that is located in slot 2 of the Cisco 12000 series router:

Router# show controllers pos 2/0/0 
POS2/0/0 
SECTION 
LOF = 0 LOS = 1 BIP(B1) = 7 
LINE 
AIS = 0 RDI = 1 FEBE = 20 BIP(B2) = 9 
PATH 
AIS = 0 RDI = 0 FEBE = 0 BIP(B3) = 5 
PLM = 0 UNEQ = 0 TIM = 0 TIU = 0 
LOP = 0 NEWPTR = 0 PSE = 0 NSE = 0 
 
 
Active Defects: None 
Active Alarms: None 

Alarm reporting enabled for: SF SLOS SLOF B1-TCA LAIS LRDI B2-TCA PAIS PLOP PRDI PUNEQ 
B3-TCA RDOOL  
 
APS 
 
COAPS = 2 PSBF = 0  
State: PSBF_state = False 
Rx(K1/K2): 00/00 Tx(K1/K2): 00/00 
Rx Synchronization Status S1 = 00 
S1S0 = 02, C2 = CF 
CLOCK RECOVERY 
RDOOL = 0  
State: RDOOL_state = False 
PATH TRACE BUFFER: STABLE 
Remote hostname : RouterTester. Port 102/1  
Remote interface:  
Remote IP addr :  
Remote Rx(K1/K2): / Tx(K1/K2): /  
 
BER thresholds: SF = 10e-5 SD = 10e-6 
TCA thresholds: B1 = 10e-6 B2 = 10e-6 B3 = 10e-6 
 
Clock source: internal

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Modifying SONET Payload Scrambling

SONET payload scrambling applies a self-synchronous scrambler (x43+1) to the Synchronous Payload Envelope (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.

To modify SONET payload scrambling, use the following command in interface configuration mode:

To disable SONET payload scrambling, use the no form of this command.

Verifying SONET Payload Scrambling

To verify SONET payload scrambling, use the show interfaces pos privileged EXEC command and observe the value shown in the "Scramble" field.

The following example shows that SONET payload scrambling is disabled for interface port 0 on the POS SPA installed in subslot 0 of the SIP that is located in slot 2 of the Cisco 12000 series router:

Router# show interfaces pos 2/0/0 
	Hardware is Packet over Sonet 
	Internet address is 10.0.0.1/24 
	MTU 9216 bytes, BW 622000 Kbit, DLY 100 usec,  
		reliability 255/255, txload 1/255, rxload 1/255 
		Encapsulation HDLC, crc 16, loopback not set 
	Keepalive not set 
	Scramble disabled 
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Configuring the Encapsulation Type

By default, the POS interfaces support High-Level Data Link Control (HDLC) encapsulation. The encapsulation method can be specified as HDLC, Point-to-Point Protocol (PPP) or Frame Relay. The encapsulation type must be configured to be the same on both ends of the POS link.

Note In Cisco IOS Release 12.0(31)S, the POS SPAs do not support Frame Relay.

To modify the encapsulation method, use the following command in interface configuration mode:

Verifying the Encapsulation Type

To verify the encapsulation type, use the show interfaces pos privileged EXEC command and observe the value shown in the "Encapsulation" field.

The following example shows the encapsulation type is HDLC for port 0 on the POS SPA installed in subslot 0 of the SIP that is located in slot 2 of the Cisco 12000 series router:

Router# show interfaces pos 2/0/0

  Hardware is Packet over Sonet 
  Internet address is 10.0.0.1/24 
  MTU 9216 bytes, BW 622000 Kbit, DLY 100 usec,  
  reliability 255/255, txload 1/255, rxload 1/255 
  Encapsulation HDLC, crc 16, loopback not set 
	Keepalive not set 
	Scramble disabled 
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Configuring APS

Automatic protection switching (APS) allows switchover of POS circuits in the event of circuit failure and is often required when connecting SONET equipment to telco equipment. APS refers to the mechanism of using a "protect" POS interface in the SONET network as the backup for a "working" POS interface. When the working interface fails, the protect interface quickly assumes its traffic load. Depending on the configuration, the two circuits may be terminated in the same router, or in different routers.

For more information about APS, refer to A Brief Overview of Packet Over SONET APS at the following URL:

http://www.cisco.com/en/US/tech/tk482/tk607/technologies_tech_note09186a0080093eb5.shtml

To configure the working POS interface, use the following command in interface configuration mode:

To remove the POS interface as a working interface, use the no form of this command.

To configure the protect POS interface, use the following command in interface configuration mode:

To remove the POS interface as a protect interface, use the no form of this command.

Verifying the APS Configuration

To verify the APS configuration or to determine if a switchover has occurred, use the show aps command.

The following is an example of a router configured with a working interface. In this example, POS interface 0/0/0 is configured as a working interface in group 1, and the interface is selected (that is, active).

Router# show aps 
POS0/0/0 working group 1 channel 1 Enabled Selected 

The following is an example of a router configured with a protect interface. In this example, POS interface 2/1/1 is configured as a protect interface in group 1. The output also shows that the working channel is located on the router with the IP address 10.0.0.1 and that the interface currently selected is enabled.

Router# show aps

POS2/1/1 APS Group 1: protect channel 0 (inactive)

Working channel 1 at 10.0.0.1 (Enabled)

  SONET framing; SONET APS signalling by default

  Remote APS configuration: (null)

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Configuring POS Alarm Trigger Delays

A trigger is an alarm that, when activated, causes the line protocol to go down. The POS alarm trigger delay helps to ensure uptime of a POS interface by preventing intermittent problems from disabling the line protocol. The POS alarm trigger delay feature delays the setting of the line protocol to down when trigger alarms are received. If the trigger alarm was sent because of an intermittent problem, the POS alarm trigger delay can prevent the line protocol from going down when the line protocol is functional.

Line-Level and Section-Level Triggers

The pos delay triggers line command is used for POS router interfaces connected to internally-protected Dense Wavelength Division Multiplexing (DWDM) systems. This command is invalid for interfaces that are configured as working or protect APS. Normally a few microseconds of line- or section-level alarms brings down the link until the alarm has been clear for ten seconds. If you configure holdoff, the link-down trigger is delayed for 100 milliseconds. If the alarm stays up for more than 100 milliseconds, 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 issue the pos delay triggers line command to delay a down trigger of the line protocol on the interface. You can set the delay from 50 to 10000 milliseconds. The default delay is 100 milliseconds.

To configure POS line- or section-level triggers, use the following commands beginning in interface configuration mode:

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 the show controllers pos command.

Path-Level Triggers

You can issue the pos delay triggers path command to configure various path alarms as triggers and to specify an activation delay between 50 and 10000 milliseconds. The default delay value is 100 milliseconds. The following path alarms are not triggers by default. You can configure these path alarms as triggers and also specify a delay:

•Path alarm indication signal (PAIS)

•Path remote defect indication (PRDI)

•Path loss of pointer (PLOP)

•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 B2 and B3 error rates is compared with the signal failure (SF) threshold. If the SF threshold is crossed, the line protocol of the interface goes down.

To configure POS path-level triggers, use the following command in interface configuration mode:

To disable path-level triggers, use the no form of this command.

Verifying POS Alarm Trigger Delays

To verify POS alarm trigger delays, use the show controllers pos privileged EXEC command and observe 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 installed in the SIP that is located in slot 2 of the Cisco 12000 series router:

Router# show controllers pos 2/0/0 details  
POS2/0/0 
SECTION 
LOF = 0 LOS = 1 BIP(B1) = 5 
LINE 
AIS = 0 RDI = 1 FEBE = 5790 BIP(B2) = 945 
PATH 
AIS = 0 RDI = 0 FEBE = 0 BIP(B3) = 5 
PLM = 0 UNEQ = 0 TIM = 0 TIU = 0 
LOP = 1 NEWPTR = 0 PSE = 0 NSE = 0 
 
Active Defects: None 
Active Alarms: None 
Alarm reporting enabled for: SF SLOS SLOF B1-TCA B2-TCA PLOP B3-TCA  
 
Line alarm trigger delay = 100 ms 
Path alarm trigger delay = 100 ms 
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Configuring SDCC

Before any management traffic can traverse the section data communication channel (SDCC) links embedded in the POS SPA overhead, the SDCC interfaces must be configured and activated.

Note SDCC is not supported by the 4-Port and 8-Port OC-3c/STM-1 POS SPA or 2-Port, 4-Port, and 8-Port OC-3c/STM-1 and OC-12c/STM-4 POS SPAs.

SDCC Configuration Guidelines

When configuring SDCC on a POS SPA, consider the following guidelines:

•SDCC must be enabled on the main POS interfaces.

•SDCC supports only HDLC and PPP encapsulation, not Frame Relay.

SDCC Configuration Task

To configure the POS SPAs for SDCC, complete the following steps:

Verifying the SDCC Interface Configuration

To verify the SDCC interface, use the show interfaces sdcc privileged EXEC command and observe the value shown in the "Hardware is" field.

The following example shows the SDCC interface port 1 on the POS SPA installed in subslot 0 of the SIP that is located in slot 5 of the Cisco 12000 series router:

Router# show interfaces sdcc 5/0/1

SDCC5/0/1 is up, line protocol is up 

  Hardware is SDCC

  Internet address is 10.14.14.14/8

  MTU 1500 bytes, BW 155000 Kbit, DLY 20000 usec, 

     reliability 5/255, txload 1/255, rxload 1/255

  Encapsulation HDLC, crc 16, loopback not set

  Keepalive not set

  Last input 00:01:24, output never, output hang never

  Last clearing of ''show interface'' counters 00:01:30

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: fifo

  Output queue: 0/40 (size/max)

  5 minute input rate 0 bits/sec, 0 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

  5 packets input, 520 bytes, 0 no buffer

     Received 0 broadcasts (0 IP multicast)

     0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

  5 packets output, 520 bytes, 0 underruns

     0 output errors, 0 collisions, 0 interface resets

     0 output buffer failures, 0 output buffers swapped out

     0 carrier transitions

Configuring Dynamic Packet Transport Features

This section provides information about the Dynamic Packet Transport (DPT) features supported by the SIPs and SPAs on the Cisco 12000 series router. It includes SIP- and SPA-specific configuration guidelines and restrictions for these features. Many of the features supported by the SIPs and SPAs work the same way as for other DPT products on the Cisco 12000 series router. However, be sure to apply the product-specific configuration guidelines in this document prior to using the documentation links referenced for additional configuration information about these features on the Cisco 12000 series router.

Configuring the Spatial Reuse Protocol

Spatial Reuse Protocol (SRP) is a Cisco-developed MAC-layer protocol, used in conjunction with Cisco's Dynamic Packet Transport (DPT) product family. SRP is implemented using fiber media on bidirectional, dual counter-rotating ring topologies in which multiple nodes can transmit simultaneously without any tokens required for access to the network.

Spatial reuse is a concept used in rings to increase the overall aggregate bandwidth of the ring. The bandwidth gain is possible because unicast traffic is only passed along ring spans between source and destination nodes, rather than across the entire ring, as in earlier ring-based protocols such as Token Ring and FDDI. SRP uses destination stripping of packets, while older technologies use source stripping. With source stripping, packets must cross the entire ring until they are removed by the source. In older technologies, even if the source and destination nodes are next to each other on the ring, packets continue to travel through the entire ring until they return to the source to be removed, which uses unnecessary bandwidth. SRP provides more efficient use of available bandwidth by having the destination node remove the packet after it is read.

SRP provides some of the following services:

•Topology discovery—Updates network topology maps for each SRP node. Each node performs topology discovery by sending out topology discovery packets, periodically or as needed, on both rings. The topology packet received on the outer ring is usually processed. This packet is a point-to-point packet which hops around the ring from node to node. Each node appends its MAC address, updates the length field and sends it to the next hop on the ring. When the node that generated the topology discovery packet receives it back, it reads the information in the packet and updates its topology map accordingly.

•Intelligent Protection Switching (IPS)—Detects and recovers from fiber or equipment failures and signal degradation. When a failure is detected, traffic going to and from the failure direction is wrapped, or looped back, to go in the opposite direction on the other ring. The wrap takes place on nodes adjacent to the failure, under control of the IPS protocol.

•Single Ring Recovery (SRR)—Provides detection of multiple faults on the same ring and corrective action by removal of all wraps use of the error-free ring for packet transmission.

•Destination stripping of unicast packets

•Broadcast and multicast packet transmission

•SRP Fairness Algorithm for flow control

SRP Configuration Guidelines

When configuring SRP for SIPs and SPAs on the Cisco 12000 series router, consider the following guidelines:

•For information about SIPs and SPAs that support SRP, refer to the "POS Feature Compatibility and Restrictions by SIP and SPA Combination" table in Chapter 14, "Overview of the POS SPAs."

•The SRP mate either can be on the same SIP or on an adjacent SIP according to certain installation guidelines for each SIP and SPA. For more information, refer to the "SRP Mate Configuration Guidelines" section.

•The default mode for all SPA interfaces is POS. To change between POS and SRP modes, you must shut down the SPA interface.

•Whenever you change modes on a POS SPA, the SPA automatically reloads.

•To change the SRP mate configuration, you must shut down the SPA interfaces.

•You cannot configure subinterfaces on an SRP interface.

•To distinguish between the two rings, one is referred to as the "inner" ring and the other as the "outer" ring. SRP operates by sending data packets in one direction (downstream) and sending the corresponding control packets in the opposite direction (upstream) on the other fiber. An SRP node uses SRP side A to receive (RX) outer ring data and transmit (TX) inner ring data. The node uses SRP side B to receive (RX) inner ring data and transmit (TX) outer ring data. Side A on one node connects to Side B on an adjacent SRP node.

For configuration of SRP on POS SPAs in multiple slots on the same SIP, the lower-numbered slot and subslot combination hosts the SRP interface and becomes "Side A" of the SRP interface. The slot number of the side-A interface must be lower than the slot location of the SRP mate (side B) interface.

•To configure SRP options, you must specify the slot and subslot location of the side-A interface, in addition to a port number.

SRP Mate Configuration Guidelines

The following mating rules apply for SRP on the SIPs and SPAs on the Cisco 12000 series router:

•For the 2-Port OC-48c/STM-16 POS SPA, the following guidelines apply:

–You cannot mate multiple 2-Port OC-48c/STM-16 POS SPAs.

–For a single 2-Port OC-48c/STM-16 POS SPA, mating is done internally between the two SONET ports, and no mate cabling is required.

•The Cisco 12000 SIP-600 and Cisco 12000 SIP-601 can support a maximum of two 1-Port OC-192c/STM-64 POS/RPR XFP SPAs.

•When mating two 1-Port OC-192c/STM-64 POS/RPR XFP SPAs for SRP within the same Cisco 12000 SIP-600 or Cisco 12000 SIP-601, the SPAs can only be installed in subslot 0 and subslot 1.

•If you configure SRP mating between two SPAs that are inserted into adjacent SIPs, each SPA must be inserted into the same subslot on both SIPs.

For example, if the 1-Port OC-192c/STM-64 POS/RPR SPA or 1-Port OC-192c/STM-64 POS/RPR VSR Optics SPA is installed in subslot 1 on the first SIP, then the 1-Port OC-192c/STM-64 POS/RPR SPA or 1-Port OC-192c/STM-64 POS/RPR VSR Optics SPA mate also must be installed in subslot 1 on the adjacent SIP.

SRP Configuration Tasks

The following tasks describe how to configure SRP:

•Enabling SRP Mode (required)

•Configuring SRP Options (optional)

•Changing from SRP Mode to POS Mode (optional)

Enabling SRP Mode

When you install a POS/RPR SPA, POS mode is automatically enabled on all of the SPA interfaces. Therefore, you must explicitly enable SRP on the SPA.

SRP Mode Configuration Guidelines

When enabling SRP mode, consider the following guidelines:

•For proper configuration of SRP for SPAs installed in the same SIP, you should enable SRP using the hw-module subslot srp command on the POS SPA that is installed in the lower-numbered slot and subslot combination. This SPA is considered the host SRP interface.

•You only need to configure the hw-module subslot srp command on the host SRP interface—not on the mate SRP interface.

•The host SRP interface becomes "Side A" of the SRP interface. When configuring SPAs that are installed in different slots on the same SIP for SRP, the slot number of the side-A interface must be lower than the slot location of the SRP mate (side B) interface. Also, you must specify the side-A interface location for configuration of any SRP options.

•The SIP reads the information it receives from the hardware cable mating to validate the mate cable connectivity with your software configuration.

•You must shut down the POS interface before enabling SRP.

•When you change the SPA mode, the SPA automatically reloads.

•The entire SPA operates either in POS mode or SRP mode—you cannot have some interfaces configured for POS mode, and other interfaces configured for SRP mode.

To enable SRP on the host SRP interface, use the following commands beginning in global configuration mode:

Configuring SRP Options

The POS SPAs support all of the SRP options available for other DPT products on the Cisco 12000 series router. You only configure SRP options on the SRP host interface, or side-A interface. For more information about the SRP host interface, see the "SRP Configuration Guidelines" section.

For more information about configuring SRP options, refer to the Spatial Reuse Protocol Feature Guide, located at the following URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120limit/120s/srpapsgs.htm

To enable SRP options on the host SRP interface, use the following commands beginning in global configuration mode:

Changing from SRP Mode to POS Mode

If a POS SPA has been configured for SRP mode using the hw-module subslot srp command, you can return the POS SPA to POS mode using the no form of this command.

Caution When you change modes on a POS SPA, the SPA automatically reloads.

To change from SRP mode to POS mode on a POS SPA, use the following commands beginning in global configuration mode:

Configuring Single Ring Recovery

The Single Ring Recovery (SRR) protocol is an extension to SRP supported by the POS/RPR SPAs on the Cisco 12000 series router. For information about how to configure and use the SRR protocol, refer to the Single Ring Recovery Protocol publication at http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120limit/120s/120s16/srr.htm.

Verifying the SRP Configuration

To display information about the configuration for an SRP interface, use the show interfaces srp command as shown in the following example:

Router# show interfaces srp 1/0

SRP1/0 is up, line protocol is up

  Hardware is SRP over SONET, address is 0012.3456.0001 (bia 0008.200e.5954)

  Internet address is 10.4.4.1/24

  MTU 4470 bytes, BW 2488000 Kbit, DLY 100 usec, rely 255/255, load 1/255

  Encapsulation SRP2,

  Side A: loopback not set

  Side B: loopback not set

     3 nodes on the ring   MAC passthrough not set

     Side A: not wrapped   IPS local: IDLE       IPS remote: IDLE

     Side B: not wrapped   IPS local: IDLE       IPS remote: IDLE

  Last input 00:00:01, output 00:00:00, output hang never

  Last clearing of "show interface" counters 00:00:20

  Queueing strategy: fifo

  Output queue 0/40, 0 drops; input queue 0/75, 0 drops

  Side A: 5 minutes output rate 0 bits/sec, 0 packets/sec

          5 minutes input rate 0 bits/sec, 0 packets/sec

  Side B: 5 minutes output rate 0 bits/sec, 0 packets/sec

          5 minutes input rate 0 bits/sec, 0 packets/sec

     0 packets input, 0 bytes, 0 no buffer

     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

     0 packets output, 0 bytes, 0 underruns

     0 output errors, 0 collisions, 0 interface resets

     0 output buffer failures, 0 output buffers swapped out

     Side A received errors:

        0 input errors, 0 CRC, 0 ignored,

        0 framer runts, 0 framer giants, 0 framer aborts,

        0 mac runts, 0 mac giants, 0 mac aborts

     Side B received errors:

        0 input errors, 0 CRC, 0 ignored,

        0 framer runts, 0 framer giants, 0 framer aborts,

        0 mac runts, 0 mac giants, 0 mac aborts

For more information about monitoring and maintaining your SRP configuration and ring, refer to the Spatial Reuse Protocol Feature Guide, located at the following URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120limit/120s/srpapsgs.htm

Saving the Configuration

To save your running configuration to nonvolatile random-access memory (NVRAM), use the following command in privileged EXEC configuration mode:

For more information about managing configuration files, refer to the Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.2 and Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 publications.

Shutting Down and Restarting an Interface on a SPA

You can shut down and restart any of the interface ports on a SPA independently of each other. Shutting down an interface stops traffic and then enters the interface into an "administratively down" state.

If you are preparing for an OIR of a SPA, it is not necessary to independently shut down each of the interfaces prior to deactivation of the SPA. You do not need to independently restart any interfaces on a SPA after OIR of a SPA or SIP.

To shut down an interface on a SPA, use the following command in interface configuration mode:

To restart an interface on a SPA, use the following command in interface configuration mode:

Verifying the Interface Configuration

Besides using the show running-configuration command to display your Cisco 12000 series router configuration settings, you can use the show interfaces pos and show controllers pos commands to get detailed information on a per-port basis for your POS SPAs.

Verifying Per-Port Interface Status

To find detailed interface information on a per-port basis for the POS SPAs, use the show interfaces pos command.

The following example provides sample output for interface port 0 (the first port) on the SPA located in the subslot 0 of the SIP that is installed in slot 3 of the Cisco 12000 series router:

Router# show interfaces pos 3/0/0

POS3/0/0 is up, line protocol is up 

  Hardware is Packet over Sonet

  MTU 4470 bytes, BW 622000 Kbit, DLY 100 usec, 

     reliability 194/255, txload 1/255, rxload 1/255

  Encapsulation FRAME-RELAY, crc 16, loopback not set

  Keepalive set (10 sec)

  Scramble disabled

  LMI enq sent  18, LMI stat recvd 0, LMI upd recvd 0

  LMI enq recvd 1473, LMI stat sent  1473, LMI upd sent  0, DCE LMI up

  LMI DLCI 1023  LMI type is CISCO  frame relay DCE

  FR SVC disabled, LAPF state down

  Broadcast queue 0/256, broadcasts sent/dropped 2223/1, interface

broadcasts 1977

  Last input 00:00:05, output 00:00:05, output hang never

  Last clearing of "show interface" counters 04:46:02

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: fifo

  Output queue: 0/40 (size/max)

  5 minute input rate 0 bits/sec, 0 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

     47019 packets input, 163195100 bytes, 0 no buffer

     Received 0 broadcasts (0 IP multicast)

     14332 runts, 925 giants, 0 throttles

              0 parity

     17820 input errors, 1268 CRC, 0 frame, 0 overrun, 0 ignored, 10 abort

     49252 packets output, 170900767 bytes, 0 underruns

     0 output errors, 0 applique, 2 interface resets

     0 output buffer failures, 0 output buffers swapped out

     3 carrier transitions.

Monitoring Per-Port Interface Statistics

To find detailed alarm and error information on a per-port basis for the POS SPAs, use the show controllers pos command. For a description of the command output, see Chapter 19, "SIP and SPA Command Reference".

The following is sample output from the show controllers pos command on a Cisco 12000 series router for POS interface 4/3/0 (which is the interface for port 0 of the SPA in subslot 3 of the SIP in chassis slot 4):

Router# show controllers pos 4/3/0 

POS4/3/0

SECTION

  LOF = 0          LOS    = 0                            BIP(B1) = 65535

LINE

  AIS = 0          RDI    = 0          FEBE = 65535      BIP(B2) = 16777215

PATH

  AIS = 0          RDI    = 0          FEBE = 65535      BIP(B3) = 65535

  PLM = 0          UNEQ   = 0          TIM  = 0          TIU     = 0

  LOP = 0          NEWPTR = 3          PSE  = 0          NSE     = 0

Active Defects: None

Active Alarms:  None

Alarm reporting enabled for: SF SLOS SLOF B1-TCA B2-TCA PLOP B3-TCA 

Framing: SONET

APS

  COAPS = 1          PSBF = 0         

  State: PSBF_state = False

  Rx(K1/K2): 00/00  Tx(K1/K2): 00/00

  Rx Synchronization Status S1 = 00

  S1S0 = 00, C2 = CF

  Remote aps status (none); Reflected local aps status (none)

CLOCK RECOVERY

  RDOOL = 0         

  State: RDOOL_state = False

PATH TRACE BUFFER: STABLE

  Remote hostname : woodson

  Remote interface: POS3/0/0

  Remote IP addr  : 0.0.0.0

  Remote Rx(K1/K2): 00/00  Tx(K1/K2): 00/00

BER thresholds:  SF = 10e-3  SD = 10e-6

TCA thresholds:  B1 = 10e-6  B2 = 10e-6  B3 = 10e-6

  Clock source:  internal

Configuration Examples

This section includes the following examples for configuring a POS SPA installed in a Cisco 12000 series router:

•Basic Interface Configuration Example

•MTU Configuration Example

•POS Framing Configuration Example

•Keepalive Configuration Example

•CRC Configuration Example

•Clock Source Configuration Example

•SONET Payload Scrambling Configuration Example

•Encapsulation Configuration Example

•APS Configuration Example

•POS Alarm Trigger Delays Configuration Example

•SDCC Configuration Example

•SRP Configuration Example

Basic Interface Configuration Example

The following example shows how to enter global configuration mode to enter global configuration mode to specify the interface that you want to configure, configure an IP address for the interface, enable the interface, and save the configuration. This example configures interface port 0 (the first port) of the SPA located in subslot 0 of the SIP that is installed in slot 2 of the Cisco 12000 series router:

!Enter global configuration mode

!

Router# configure terminal

!

! Specify the interface address

!

Router(config)# interface pos 2/0/0

!

! Configure an IP address

!

Router(config-if)# ip address 192.168.50.1 192.255.255.0

!

! Enable the interface

!

Router(config-if)# no shutdown

!

! Save the configuration to NVRAM

!

Router(config-if)# exit

Router# copy running-config startup-config

MTU Configuration Example

The following example sets the MTU to 4470 bytes on interface port 1 (the second port) of the SPA located in the bottom subslot (1) of the SIP that is installed in slot 2 of the Cisco 12000 series router:

!Enter global configuration mode

!

Router# configure terminal

!

! Specify the interface address

!

Router(config)# interface pos 2/1/1

!

! Configure MTU

!

Router(config-if)# mtu 4470

POS Framing Configuration Example

The following example shows how to change from the default POS framing of SONET to SDH:

!Enter global configuration mode

!

Router# configure terminal

!

! Specify the interface address

!

Router(config)# interface pos 2/1/1

! (The default pos framing is sonet)

!

!Modify the framing type

!

Router(config-if)# pos framing sdh

Keepalive Configuration Example

The following example shows how to change from the default keepalive period of 10 seconds to 20 seconds:

!Enter global configuration mode

!

Router# configure terminal

!

! Specify the interface address

!

Router(config)# interface pos 2/1/1

!

! Configure keepalive 20

!

Router(config-if)# keepalive 20

CRC Configuration Example

The following example shows how to change the CRC size from 32 bits to the default 16 bits for POS SPAs:

!Enter global configuration mode

!

Router# configure terminal

!

! Specify the interface address

!

Router(config)# interface pos 2/1/1

!

! Configure crc 16

!

Router(config-if)# crc 16

Clock Source Configuration Example

The following example shows how to change from the default clock source of internal to line:

!Enter global configuration mode

!

Router# configure terminal

!

! Specify the interface address

!

Router(config)# interface pos 2/1/1

!

! Configure the clock source

!

Router(config-if)# clock source line

SONET Payload Scrambling Configuration Example

The following example shows how to change from a default SONET payload scrambling of disabled to enabled:

!Enter global configuration mode

!

Router# configure terminal

!

! Specify the interface address

!

Router(config)# interface pos 2/1/1

!

! Configure the SONET payload scrambling

!

Router(config-if)# pos scramble-atm

Encapsulation Configuration Example

The following example shows how to change from the default encapsulation method of HDLC to PPP:

!Enter global configuration mode

!

Router# configure terminal

! Specify the interface address

Router(config)# interface pos 2/1/1

!

! Configure ppp

!

Router(config-if)# encapsulation ppp

APS Configuration Example

The following example shows the configuration of APS on router A and router B, and how to configure more than one protect or working interface on a router by using the aps group command. See Figure 15-1.

Figure 15-1 Basic APS Configuration

In this example, router A is configured with the working interface and router B is configured with the protect interface. If the working interface on router A becomes unavailable, the connection will automatically switch over to the protect interface on router B. The loopback interface is used as the interconnect. The aps group command is used even when a single protect group is configured.

The following example shows how to configure Router A for this scenario:

!Enter global configuration mode

!

Router# configure terminal

!

! Configure a loopback interface as the protect interconnect path

!

Router(config)# interface loopback 1 

Router(config-if)# ip address 10.10.10.10 255.0.0.0 

! Configure the POS interface address for the APS working interface

!

Router(config)# interface pos 2/0/0

!

! Configure the POS interface IP address and other interface parameters

!

Router(config-if)# ip address 172.16.1.8 255.255.0.0

Router(config-if)# no ip directed-broadcast

Router(config-if)# no keepalive

Router(config-if)# crc 32

!

! Configure the APS group number by which to associate APS interfaces

!

Router(config-if)# aps group 1

!

! Configure a circuit number for the APS working interface

!

Router(config-if)# aps working 1

The following example shows how to configure Router B for this scenario:

!Enter global configuration mode

!

Router# configure terminal

!

! Configure the POS interface address for the APS protect interface

!

Router(config)# interface pos 3/0/0 

!

! Configure the POS interface IP address and other interface parameters

!

Router(config-if)# ip address 172.16.1.9 255.255.0.0

Router(config-if)# no ip directed-broadcast

Router(config-if)# no keepalive

Router(config-if)# crc 32

!

! Configure the APS group number by which to associate APS interfaces

!

Router(config-if)# aps group 1

!

! Configure a circuit number for the protect interface and an IP address for the router

! that has the APS working interface. In this case, the loopback interface address is

! used.

!

Router(config-if)# aps protect 1 10.10.10.10 

POS Alarm Trigger Delays Configuration Example

The following example shows how to change POS line-level and path-level alarm trigger delays from the default of 100 milliseconds to 200 milliseconds:

!Enter global configuration mode

!

Router# configure terminal

!

! Specify the interface address

!

Router(config)# interface pos 2/1/1

!

Router(config-if)# pos delay triggers line 200

Router(config-if)# pos delay triggers path 200

SDCC Configuration Example

The following example shows how to configure an SDCC interface:

!

! Specify the SDCC interface

!

Router(config)# interface sdcc 5/0/0

!

! Specify the IP address

!

Router(config-if)# ip address 10.14.14.14. 255.0.0.0

!

! Enable the interface

!

Router(config-if)# no shutdown

SRP Configuration Example

The following example shows how to enable SRP on a POS/RPR SPA:

! Select the POS interface

!

Router(config)# interface pos 1/0/0

!

! Shut down the POS interface

!

Router(config-if)# shutdown

!

! Enable SRP on the host SRP SPA with optional mate CLI

! Note: When the SRP SPAs are installed in different slots on the same SIP, the SPA in the 
! lower-numbered slot and subslot location is the side-A or host SPA. 

! In this example, the SPA installed in slot 1 and subslot 0 of the SIP is the side-A SPA.

!

Router(config-if)# exit

Router(config))# hw-module subslot 1/0 srp mate 1/1

!

! Configure an SRP interface 

!

Router(config)# interface srp 1/0/0

Router(config-if)# mac-address 0003.0003.0003

Router(config-if)# ip address 10.4.4.1 255.255.255.0

Router(config-if)# no ip directed-broadcast

Router(config-if)# ipv6 address 10:4:4::1/64

Router(config-if)# service-policy output parent