IEEE Resilient Packet Ring Feature Guide

Transcription

1 IEEE Resilient Packet Ring Feature Guide This feature guide describes how to configure the Cisco implementation of the IEEE Resilient Packet Ring (RPR) protocol on supported Cisco routers and includes information about the benefits of the feature, supported platforms, related publications, and so on. RPR is similar but not identical to the Spatial Reuse Protocol (SRP), the underlying technology used in the Cisco Dynamic Packet Transfer (DPT) family of products. Throughout this document, this feature is referred to as RPR. This document covers the use of the RPR feature. It does not include hardware installation and initial configuration information. Refer to the appropriate router installation and configuration note for information on how to configure the hardware and prepare it for use with RPR. Feature History for RPR Release 12.0(29)S 12.0(30)S Modification This feature was introduced on the Cisco Router. The following commands were introduced on the Cisco Router: ping rpr-ieee oam-echo rpr-ieee fairness active-weights-detect rpr-ieee fairness mode rpr-ieee fairness weight rpr-ieee protection pref jumbo rpr-ieee protection pref wrap rpr-ieee tx-traffic strict The following options were introduced on the Cisco Router: transceiver keyword on the show controllers rpr-ieee command history keyword on the show rpr-ieee fairness command Finding Support Information for Platforms and Cisco IOS Software Images Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear. Corporate Headquarters: Cisco Systems, Inc., 170 West Tasman Drive, San Jose, CA USA Copyright 2004 Cisco Systems, Inc. All rights reserved.

2 Contents IEEE Resilient Packet Ring Feature Guide Contents Information About RPR, page 2 How to Configure RPR, page 5 How to Configure RPR Fairness, page 15 How to Configure RPR Protection, page 20 How to Use Modular QoS CLI to Configure RPR Service Classes, page 28 How to Verify RPR Configuration and Operation, page 32 Configuration Example for RPR, page 39 Additional References, page 40 Command Reference, page 41 Glossary, page 107 Information About RPR Resilient Packet Ring (RPR), as described in IEEE , is a metropolitan area network (MAN) technology supporting data transfer among stations interconnected in a dual-ring configuration. This protocol is very similar to Spatial Reuse Protocol (SRP), which was designed by Cisco and implemented in Dynamic Packet Transport (DPT) products. New DPT interfaces have been designed to include the RPR protocol and are available for multiple Cisco router platforms. This guide describes the RPR interface and how to use RPR on compliant Cisco equipment. RPR is a high-speed MAC-layer protocol that is optimized for packet transmission in resilient ring topologies. RPR employs a ring structure using unidirectional, counter-rotating ringlets. Each ringlet is made up of links with data flow in the same direction. The ringlets are identified as ringlet 0 and ringlet 1, as shown in Figure 1. The use of dual fiber-optic rings provides a high level of packet survivability. If a station fails or fiber is cut, data is transmitted over the alternate ring. 2

3 IEEE Resilient Packet Ring Feature Guide Information About RPR Figure 1 Dual-Ring Structure Ringlet 0 1 Station Station Station Ringlet 1 Station East RX 5 Ringlet 0 data (downstream) 2 West TX 6 Ringlet 0 control (upstream) 3 West RX 7 Ringlet 1 data (downstream) 4 East TX 8 Ringlet 1 control (upstream) As shown in Figure 1, the east interface of Station 1 (S1) transmits to and receives from the west interface of Station 2 (S2). Ringlet 0 always transverses from east to west and ringlet 1 from west to east. The west span is the span on which RPR transmits on ringlet 1 and the east span is the span on which RPR transmits on ringlet 0. RPR stations dynamically share the ring bandwidth and permit many simultaneous conversations. Spatial bandwidth reuse is possible due to the packet destination-stripping property of RPR. RPR provides efficient use of available bandwidth by allowing the destination station to remove unicast packets after they are read, thereby providing bandwidth reuse for the other stations on the RPR ring. Figure 2 illustrates the end-to-end MAC architecture of RPR. 3

4 Information About RPR IEEE Resilient Packet Ring Feature Guide Figure 2 End-to-End View of MAC Architecture RX Queue TX Queue Low priority Medium priority High priority L3 Low priority Medium priority High priority CAM 1 Transit Primary priority Secondary priority 2 Ring Ring 3 Primary priority Secondary priority 4 RPR MAC CAM 1 East RX 2 West TX 3 East TX 4 West RX While DPT and SRP uses SONET/SDH as the physical medium, IEEE RPR has been defined to use both SONET/SDH and the layer used for Gigabit and 10 Gigabit Ethernet. Comparison of RPR with SRP and DPT Technologies IEEE RPR is very similar to the Cisco-developed SRP technology, which is used in the Cisco DPT product line. Besides their different frame formats, other differences and similarities between IEEE RPR and SRP can be summarized as follows: Fairness IEEE RPR has a fairness algorithm that is used in the dynamic SRP-like mode suitable for routing and switching applications. A third priority has been added for traffic that requires guaranteed bandwidth, but that is not sensitive to latency and jitter. Protection SRP supports wrapping. IEEE RPR supports systems that are capable of steering only protection. Cisco-implemented RPR supports both wrapping and steering for protection. Wrapping requires two stations to perform protection and suffers the least packet loss. 4

5 IEEE Resilient Packet Ring Feature Guide How to Configure RPR Steering requires that every station determines the location of the failure and avoids that particular span. Steering is slower to converge in large topologies versus wrapping. RPR Features RPR offers the following main features: Addressing. Unicast, multicast, and simple broadcast data transfers are supported. Services. Multiple service qualities are supported. Per-service-quality flow-control protocols regulate traffic introduced by clients. Class A. The allocated or guaranteed bandwidth has low circumference-independent jitter. Class B. The allocated or guaranteed bandwidth has bounded circumference-dependent jitter. This class allows for transmissions of excess information rate (EIR) bandwidths (with class C properties). Class C. This class provides best-effort services. Efficiency. Design strategies increase effective bandwidths beyond those of a broadcast ring. Concurrent transmission. Clockwise and counterclockwise transmissions can be concurrent. Bandwidth reallocation. Bandwidths can be reallocated on nonoverlapping segments. Bandwidth reclamation. Unused bandwidths can be reclaimed by opportunistic services. Spatial bandwidth reuse. Opportunistic bandwidths are reused on nonoverlapping segments. Temporal bandwidth reuse. Unused opportunistic bandwidth can be consumed by others. Fairness. Fairness ensures proper partitioning of opportunistic traffic. Weighted. Weighted fairness allows a weighted fair access to available ring capacity. Simple. Simple fairness provides point-of-congestion flow control. Detailed. The (optional) multichoke fairness allows the client to selectively throttle its transmissions based on multiple congestion point indications. Plug-and-play. Automatic topology discovery and advertisement of station capabilities allow systems to become operational without manual intervention. Robustness. Multiple features support robust frame transmissions. Responsive. Service restoration time is less than 50 milliseconds after a station or link failure. Lossless. Queue and shaper specifications avoid frame loss in normal operation. Tolerant. Fully distributed control architecture eliminates single points of failure. OAM. Operations, administration, and maintenance support service provider environments. How to Configure RPR General configuration tasks for the RPR feature are presented in the following sections. Configuring the Attribute Discovery Timer, page 6 Configuring the Clock Source, page 7 Configuring Source Address Tracking, page 8 Configuring the SONET/SDH Overhead, page 8 5

6 How to Configure RPR IEEE Resilient Packet Ring Feature Guide Configuring the SONET Framing, page 9 Configuring Loopback Mode, page 10 Configuring the Reporting of SONET Alarms, page 11 Configuring BER Threshold Values, page 12 Configuring Traffic Rates for Transmission, page 12 For information on configuring RPR fairness, protection, and service classes, see the following additional sections: How to Configure RPR Fairness, page 15 How to Configure RPR Protection, page 20 How to Use Modular QoS CLI to Configure RPR Service Classes, page 28 Configuring the Attribute Discovery Timer Restrictions SUMMARY STEPS DETAILED STEPS Because station attributes are communicated separately from topology and protection packets, there is a separate timer to control the frequency at which these packets are sent. Attribute propagation is therefore determined by the attribute discovery (ATD) timer. The default rate is 1 packet for each ringlet per second. To configure the ATD timer, perform the following steps. Both ringlets are configured with the same value. 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee atd-timer seconds Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Router# configure terminal 6

7 IEEE Resilient Packet Ring Feature Guide How to Configure RPR Step 3 Step 4 Command or Action interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee atd-timer seconds Router(config-if)# rpr-ieee atd-timer 2 Purpose Enters interface configuration mode for a specific RPR interface. Specifies the time, in seconds, within which one station attributes packet is sent for each ringlet. The default is one packet for each ringlet per second. Configuring the Clock Source To configure the clock source for the interface, perform the following steps. SUMMARY STEPS 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee clock-source {internal line} [east west] DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 Step 4 rpr-ieee clock-source {internal line} [east west] Enters interface configuration mode for a specific RPR interface. Specifies the clock source as either line or internal. The default is internal. Router(config-if)# rpr-ieee clock-source line east 7

8 How to Configure RPR IEEE Resilient Packet Ring Feature Guide Configuring Source Address Tracking To count packets from a specified source on the ringlet, perform the following steps. SUMMARY STEPS 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee count src-address DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee count src-address Router(config-if)# rpr-ieee count Enters interface configuration mode for a specific RPR interface. Counts the number of packets from the specified 48-bit source address (src-address) on the ringlet. Troubleshooting Tips Use the show rpr-ieee source-counters command to view the source address counters. Router# show rpr-ieee source-counters Source Address Information for Interface RPR-IEEE1/ , index 0, pkt. count 0, byte count , index 1, pkt. count 0, byte count 0 Configuring the SONET/SDH Overhead To configure the SONET/SDH overhead values for the frame header, perform the following steps. 8

9 IEEE Resilient Packet Ring Feature Guide How to Configure RPR SUMMARY STEPS 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee flag {c2 j0} value [east west] DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee flag {c2 j0} value [east west] Router(config-if)# rpr-ieee flag c2 22 east Enters interface configuration mode for a specific RPR interface. Specifies the decimal value for the path signal label (c2) or section trace (j0) SONET/SDH overhead bytes. The default for c2 is 0x16, and the default for j0 is 0x01. Configuring the SONET Framing SUMMARY STEPS To configure the framing for the packet header and trailer to ensure synchronization and error control, perform the following steps. 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee framing {sdh sonet} [east west] 9

10 How to Configure RPR IEEE Resilient Packet Ring Feature Guide DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee framing {sdh sonet} [east west] Router(config-if)# rpr-ieee framing sdh east Enters interface configuration mode for a specific RPR interface. Specifies the framing as either SDH or SONET. The default is sonet. Configuring Loopback Mode SUMMARY STEPS DETAILED STEPS To configure the framer into loopback mode, perform the following steps. This task is for diagnostics only and affects ring operation. 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee loopback {internal line} {east west} Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Router# configure terminal 10

11 IEEE Resilient Packet Ring Feature Guide How to Configure RPR Step 3 Command or Action interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 Step 4 rpr-ieee loopback {internal line} {east west} Purpose Enters interface configuration mode for a specific RPR interface. Configures the interface in either internal or line loopback mode. Router(config-if)# rpr-ieee loopback internal west Configuring the Reporting of SONET Alarms SUMMARY STEPS DETAILED STEPS To enable the reporting of information regarding various SONET alarms, perform the following steps. 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee report {b1-tca b2-tca b3-tca lais lrdi pais plop prdi sd-ber sf-ber slof slos} [east west] Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 Step 4 rpr-ieee report {b1-tca b2-tca b3-tca lais lrdi pais plop prdi sd-ber sf-ber slof slos} [east west] Enters interface configuration mode for a specific RPR interface. Enables reporting on the specified alarm. Router(config-if)# rpr-ieee report pais west 11

12 How to Configure RPR IEEE Resilient Packet Ring Feature Guide Configuring BER Threshold Values To configure BER threshold values for various alarms on an RPR interface, perform the following steps. SUMMARY STEPS 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee threshold {b1-tca b2-tca b3-tca sd-ber sf-ber} rate [east west] DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 Step 4 rpr-ieee threshold {b1-tca b2-tca b3-tca sd-ber sf-ber} rate [east west] Router(config-if)# rpr-ieee threshold sf-ber 4 Enters interface configuration mode for a specific RPR interface. Specifies the BER threshold value of the specified alarm. The rate value ranges from 3 to 9, thereby representing the bit error rate in the format 10e-n, where n is the rate value. The default is 6 (10e-6) for all thresholds except for sf-ber, where the default is 3 (10e-3). Configuring Traffic Rates for Transmission The different priorities of traffic can be configured with rate limiters and prescribed specific bandwidths. This configuration may differ on the east and west spans, or can be configured equally on both. Also, transmitted idle packets can be configured to partake in rate synchronization. The highest-priority traffic, known as service class A0, can reserve a portion of total ringlet bandwidth using the reserved keyword. This reservation is propagated throughout the ringlet, and all stations recognize the bandwidth allocation cumulatively. Reserved A0 bandwidth can be used only by the station that reserves it. The default allocation is 0 megabits per second. Service class A1 is configured as high-priority traffic in excess of the A0 bandwidth reservation, and can be rate-limited using the high tx-traffic rate limiter. The default allocation is 10 megabits per second. 12

13 IEEE Resilient Packet Ring Feature Guide How to Configure RPR The medium transmit traffic rate limiter allows a certain amount of traffic to be added to the ringlet that is not subject to fairness eligibility, but must compete for the unreserved bandwidth with other traffic of the same service class. This traffic is committed information rate (B-CIR) traffic. Some interfaces may not support this class of traffic, so this command may not be available on all RPR interfaces. The default allocation is 10 megabits per second. The low transmit traffic rate limiter restricts the amount of bandwidth that service classes B-EIR and C may use on the ringlet. This traffic class is fairness eligible and thus this value impacts the effectiveness of the fairness algorithm. The default allocation is full bandwidth. The idle packet transmitter approximately synchronizes rates between stations by padding traffic with idle packets transmitted at a certain rate. Idle packets are transmitted only to the neighbor, and therefore do not take up transit queue space. If the transit queue vacancy of the local station falls below the configurable idle threshold, fewer idle packets are transmitted by the local station to give more transmit time to drain the queue. This rate synchronization is used in the extreme congestion case to prevent packet drops in the transit queue. Traffic can be specified to be in strict or relaxed mode. Relaxed mode does not flush (drop) traffic in case of a protection event, such as a fiber failure. As a result, there is less traffic loss but a slight possibility of re-ordering packets during a node recovery. Relaxed mode is the default traffic mode. Strict mode flushes traffic after a topology change, such as a protection event, until the topology stabilizes. To configure transmit traffic rates, perform the following steps. SUMMARY STEPS 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee tx-traffic rate-limit {high low medium reserved} rate [east west] 5. rpr-ieee tx-traffic idle {enable threshold threshold} [east west] 6. rpr-ieee tx-traffic strict DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 Enters interface configuration mode for a specific RPR interface. 13

14 How to Configure RPR IEEE Resilient Packet Ring Feature Guide Step 4 rpr-ieee tx-traffic rate-limit {high low medium reserved} rate [east west] Step 5 Command or Action Router(config-if)# rpr-ieee tx-traffic rate-limit high 20 west Router(config-if)# rpr-ieee tx-traffic rate-limit reserved 10 east rpr-ieee tx-traffic idle {enable threshold threshold} Router(config-if)# rpr-ieee tx-traffic idle threshold Purpose Specifies a rate limit on a traffic queue. The allowable rate depends on the speed of the interface. reserved Reserves bandwidth for the highest priority traffic, known as service class A0. The default allocation is 0 Mbps. high Limits the rate of service class A1. The default allocation is 10 Mbps. medium Limits the rate of service class B-CIR. The default allocation is 10 Mbps. low Limits the rate of service classes B-EIR and C. The default allocation is full bandwidth. Specifies the behavior of the idle packet transmission. enable Determines whether any idle packets are sent at all. The default operation is enabled. threshold Specifies the transit queue vacancy under which fewer idle packets are transmitted, allowing for the transit queue to drain faster. A higher threshold allows the idle packet transmit behavior to change sooner. The default vacancy threshold is one MTU. Troubleshooting Tips Use the show rpr-ieee rate-limit command to view the configured values for the rate manipulators on the various classes of traffic. There are rate limiters for classes A0 (or reserved), A1, B-CIR, and B-EIR and C. Some interfaces don't support class B on transmit, so only the other three are displayed. Following is sample output from the show rpr-ieee rate-limit command: Router# show rpr-ieee rate-limit Rate Limit Information for Interface RPR-IEEE1/1 West Span: Reserved Bandwidth (Class A0): 0 Mbps Rate Limiter High (Class A1): 10 Mbps Rate Limiter Medium (Class B-CIR): 10 Mbps Rate Limiter Low (Class B-EIR, C): 2488 Mbps East Span: Reserved Bandwidth (Class A0): 0 Mbps Rate Limiter High (Class A1): 10 Mbps Rate Limiter Medium (Class B-CIR): 10 Mbps Rate Limiter Low (Class B-EIR, C): 2488 Mbps Following is sample output from the show rpr-ieee rate-limit command when no low rate limit is configured. In this instance, full is shown. This is equivalent to having a rate limit of 2488 Mbps configured on an OC48 link. Router# show rpr-ieee rate-limit West Span: Reserved Bandwidth (Class A0): 0 Mbps Rate Limiter High (Class A1): 10 Mbps Rate Limiter Medium (Class B-CIR): 10 Mbps Rate Limiter Low (Class B-EIR, C): full 14

15 IEEE Resilient Packet Ring Feature Guide How to Configure RPR Fairness Use the details keyword to display the idle packet transmission configuration, as shown in the following example: router# show rpr-ieee rate-limit details Rate Limit Information for Interface RPR-IEEE1/1 West Span: Reserved Bandwidth (Class A0): 0 Mbps Rate Limiter High (Class A1): 10 Mbps Rate Limiter Medium (Class B-CIR): 10 Mbps Rate Limiter Low (Class B-EIR, C): 2488 Mbps East Span: Reserved Bandwidth (Class A0): 0 Mbps Rate Limiter High (Class A1): 10 Mbps Rate Limiter Medium (Class B-CIR): 10 Mbps Rate Limiter Low (Class B-EIR, C): 2488 Mbps Service Type: Relaxed Idle Shaper is Enabled Transmit at 500 packets per million when PTQ vacancy above bytes Transmit at 250 packets per million when PTQ vacancy below bytes How to Configure RPR Fairness A larger enhancement of RPR over DPT is its configurable fairness system, used to control congestion on each ringlet. This feature moderates bandwidth utilization of the ringlet to minimize and potentially eliminate starvation of any station. Each station has two instances of the fairness machine, to control traffic that is being transmitted and transited out of each span of the interface. Each fairness machine is devoted to a particular ringlet, and controls the traffic that is destined to that ringlet. Fairness is configured in the west and east directions independently. Each ringlet in an unwrapped ring is independent, and thus the fairness configuration can differ for each direction. To configure RPR fairness, perform the following tasks: Configuring Active Weights, page 15 Configuring Fairness Rate Adjustments, page 16 Configuring Multichoke Fairness, page 17 Configuring Fairness Weights, page 18 Troubleshooting Tips, page 19 Configuring Active Weights IEEE fairness is a weighted process for negotiating fair rates. By default, all weights are set to the lowest possible value (1), and this results in equal-weight fairness. If any station is configured with a higher weight, then weighted fairness is activated. In aggressive fairness mode, this happens automatically and a station uses its own weight to determine the fair transmission rate. In conservative fairness mode, the station uses its own weight and weights detected from upstream stations to determine its fair transmission rate. If you do not want conservative fairness mode to use detected weights in the fair-rate calculation, you can disable the active-weight detection (which is enabled by default). Active-weight detection affects only conservative fairness mode when weights are not set to their lowest value. 15

16 How to Configure RPR Fairness IEEE Resilient Packet Ring Feature Guide SUMMARY STEPS 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee fairness active-weights-detect [east west] DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 Step 4 rpr-ieee fairness active-weights-detect [east west] Router(config-if)# rpr-ieee fairness active-weight-detect east Enters interface configuration mode for a specific RPR interface. Enables the calculation of ringlet weights from stations that have recently contributed traffic over a configurable interval from the specified direction. Use the no form of this command to disable active-weights. Configuring Fairness Rate Adjustments SUMMARY STEPS The fairness rate adjustment method can be changed to one of two modes. Only one mode is selectable at a time on an interface. Switching between modes can be disruptive to traffic because it requires that the fairness machine completely restart with new initial values. Aggressive and conservative stations can be configured on the same ringlet, but more consistent operation results from using one or the other on every station. Aggressive rate adjustment is the default setting. 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee fairness mode {aggressive conservative} 16

17 IEEE Resilient Packet Ring Feature Guide How to Configure RPR Fairness DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 Step 4 rpr-ieee fairness mode {aggressive conservative} Enters interface configuration mode for a specific RPR interface. Specifies the fairness rate adjustment method. The default is aggressive. Router(config-if)# rpr-ieee fairness mode conservative Configuring Multichoke Fairness SUMMARY STEPS Multichoke fairness enables enhanced fairness beyond a single congestion point. This feature may not be supported on all platforms and is optional in the standard. It is disabled by default. 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee fairness multi-choke 17

18 How to Configure RPR Fairness IEEE Resilient Packet Ring Feature Guide DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee fairness multi-choke Router(config-if)# rpr-ieee fairness multi-choke east Enters interface configuration mode for a specific RPR interface. Enables multichoke fairness. It is disabled by default. Use the no form of this command to disable multichoke fairness. Configuring Fairness Weights SUMMARY STEPS The local station weight impacts how congested the station appears with respect to other stations in the ringlet. It also affects how much more bandwidth a station may use over other stations in the ring. A higher weight tends to result in giving the local station more than its fair share of ringlet bandwidth compared with its neighbors. Lower weights tend to result in less bandwidth demand from the local station. The default value is 0 configured as an exponent of 2, which yields an effective weight of enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee fairness weight weight [east west] 18

19 IEEE Resilient Packet Ring Feature Guide How to Configure RPR Fairness DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee fairness weight weight [east west] Router(config-if)# rpr-ieee fairness weight 6 east Enters interface configuration mode for a specific RPR interface. Specifies the weight for a station on the ringlet. Values can range from 0 to 7, which are configured as an exponent of 2, thereby yielding weights ranging from 1 to 128. Troubleshooting Tips To view the fairness information, use the show rpr-ieee fairness command. The fairness system uses a large quantity of input to determine its behavior. This input and some results of the fairness algorithm can be displayed. Information for both directions is always shown. The following example shows what would be seen on an OC-48 interface employing aggressive rate adjustment, with no multichoke fairness. Router# show rpr-ieee fairness IEEE Fairness on RPR-IEEE1/1: Bandwidth: kilobits per second Station using aggressive rate adjustment. Westbound Tx (Ringlet 1) Weighted Fairness: Local Weight: 0 (1) Single-Choke Fairness Status: Local Congestion: Congested? No Head? No Downstream Congestion: Congested? No Tail? No Received Source Address: Reserved Rate: 0 Kbps Unreserved Rate: Kbps Eastbound Tx (Ringlet 0) Weighted Fairness: Local Weight: 0 (1) Single-Choke Fairness Status: 19

20 How to Configure RPR Protection IEEE Resilient Packet Ring Feature Guide Local Congestion: Congested? No Head? No Downstream Congestion: Congested? No Tail? No Received Source Address: Reserved Rate: 0 Kbps Unreserved Rate: Kbps This information can also be viewed in a more detailed form by using the details keyword. The additional information includes the coefficients used, more expressions of the configured and detected rates, and transit queue information. How to Configure RPR Protection RPR includes steering and wrapping protection. A number of tasks can be used to configure the protection capabilities: Configuring the Hold-off Timer, page 20 Configuring Protection Preferences, page 21 Configuring Forced or Manual Switching, page 22 Configuring SONET Protection, page 23 Configuring Protection Timers, page 24 Configuring the Wait-to-Restore Timer, page 25 Protection Troubleshooting Tips, page 26 Shutting Down a Span, page 27 Configuring Keepalive Events, page 27 Configuring the Hold-off Timer SUMMARY STEPS A protection response to Layer 1 failure events (such as a signal failure or signal degradation) can be delayed by configuring the hold-off timer. A higher value for this timer causes a protection response to be delayed, avoiding link errors that persist long enough to be detected by protection but short enough to avoid costs of protecting the span. This delay can result in higher traffic loss, however. The default value for this timer is 0 milliseconds. 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee protection sonet holdoff-timer time [east west] 20

21 IEEE Resilient Packet Ring Feature Guide How to Configure RPR Protection DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee protection sonet holdoff-timer time [east west] Router(config-if)# rpr-ieee protection holdoff-timer 5 west Enters interface configuration mode for a specific RPR interface. Specifies the delay before a protection response is sent. Values range from 0 to 20, in units of 10 milliseconds. The default is 0. Configuring Protection Preferences SUMMARY STEPS The interface can be configured to support jumbo frames and wrapping. These commands are not mutually exclusive. The jumbo setting specifies that the station support an MTU of up to 9100 bytes. To be enabled, all stations on the ring must be set to support jumbo frames. The wrap setting specifies that by default the station use wrapping instead of steering. 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee protection pref {jumbo wrap} 21

22 How to Configure RPR Protection IEEE Resilient Packet Ring Feature Guide DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee protection pref {jumbo wrap} Router(config-if)# rpr-ieee protection pref wrap Enters interface configuration mode for a specific RPR interface. Enables jumbo frames or wrap-capability on the interface: jumbo Enables handling of frames in excess of the standard 1500 bytes, up to a maximum size of 9100 bytes. A jumbo-enabled station changes the interface MTU to 9100 bytes only if all stations in the ring are jumbo enabled. This option is disabled by default. A message is generated to indicate that the ring supports jumbo frames when all stations are configured for this preference. wrap Makes stations use wrapping protection instead of steering, as long as conditions permit. Although a station that is wrap capable uses wrapping regardless of the settings of other stations on the ring, it is critical that all stations be configured for the same protection preference (wrapping or steering) for traffic protection to operate correctly. An alarm message is issued if protection preferences differ between stations on the ring. This option is disabled by default to prefer steering. Configuring Forced or Manual Switching SUMMARY STEPS You can request certain protection states to take effect manually on either span of the interface, to avoid link usage or in anticipation of failures. 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee protection request {forced-switch manual-switch} {east west} 22

23 IEEE Resilient Packet Ring Feature Guide How to Configure RPR Protection DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 Step 4 rpr-ieee protection request {forced-switch manual-switch} {east west} Router(config-if)# rpr-ieee protection request forced-switch east Enters interface configuration mode for a specific RPR interface. Specifies that a switch take place on the interface: forced-switch Precedes all other failure events on a ring, for the span on which it is configured. The operation protects the span indicated by the command. In the case of steering, forwarding uses only the topology list for the opposite span. In the case of wrapping, the other span becomes wrapped. A forced switch is saved in the configuration. manual-switch Behaves similarly to a forced switch, in that it coerces a reaction from the protection system. The difference is that this configuration can be usurped by higher-level requests detected on the configured or the opposite span. A manual switch is not saved in the configuration. Configuring SONET Protection SUMMARY STEPS For SONET-based devices, RPR can set the threshold at which a protection event occurs for a signal failure or signal degradation (sf-ber or sd-ber). 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee protection sonet threshold {sd-ber threshold sf-ber threshold} [east west] 23

24 How to Configure RPR Protection IEEE Resilient Packet Ring Feature Guide DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee protection sonet threshold {sd-ber threshold sf-ber threshold} [east west] Router(config-if)# rpr-ieee protection sonet threshold sd-ber 6 Enters interface configuration mode for a specific RPR interface. Specifies the threshold at which a signal degradation or signal failure is triggered. The threshold values represent the bit error rate as 10 to the minus threshold, where threshold ranges from 4 to 9. Configuring Protection Timers SUMMARY STEPS Protection messages are sent based on the intervals of two timers. These timers apply under different circumstances: Fast timer Immediately after a protection event occurs, a fast protection timer is used. This timer is configured between 1 and 20 milliseconds to cause a rapid acknowledgement of the protected state on the ring. A finite number of packets are sent at this frequency after the event. The default for this timer is 10 milliseconds. Slow timer Between protection events, the slow timer communicates the current protection state of the ring. This timer is configured from 1 to 10 in units of 100 milliseconds. The default is 10, which represents 100 milliseconds. The protection timers are configured the same on both spans of an interface. 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee protection timer {fast time slow time} 24

25 IEEE Resilient Packet Ring Feature Guide How to Configure RPR Protection DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee protection timer {fast time slow time} Router(config-if)# rpr-ieee protection timer fast 10 Enters interface configuration mode for a specific RPR interface. Specifies the value of the fast or slow protection timer. fast Ranges from 1 to 20 milliseconds. The default is 10. slow Ranges from 1 to 10 in units of 100 milliseconds. The default is 1 (100 milliseconds). Configuring the Wait-to-Restore Timer SUMMARY STEPS When a failure is de-asserted on a span, a wait-to-restore timer defines how long before the span becomes unprotected. This timer can be used to protect against false negatives in the detection of the failure status, and thus avoid protection-flapping by using larger values. Smaller values result in faster recovery times, however. This timer can be configured between 0 and 1440 seconds, or configured to not recover automatically at all. The default for the timer is 10 seconds. 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee protection wtr-timer {time never} 25

26 How to Configure RPR Protection IEEE Resilient Packet Ring Feature Guide DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee protection wtr-timer {time never} Router(config-if)# rpr-ieee protection wtr-timer 20 Enters interface configuration mode for a specific RPR interface. Specifies the value of the wait-to-restore timer: time Ranges from 0 to 1440 seconds. The default is 10. never Specifies that protection is never restored (nonrevertive mode). Protection Troubleshooting Tips To verify the protection configurations, use the show rpr-ieee protection command. Following is sample output from this command: Router# show rpr-ieee protection Protection Information for Interface RPR-IEEE1/1 MAC Addresses West Span (Ringlet 0 RX) neighbor East Span (Ringlet 1 RX) neighbor Station MAC address TP frame sending timers: fast timer: 10 msec slow timer: 1x100 msec (100 msec) Protection holdoff timers: L1 Holdoff Keepalive Detection West Span 0x10 msec ( 0 msec) West Span 3 msec East Span 0x10 msec ( 0 msec) East Span 3 msec Configured protection mode: STEERING Protection Status Ring is IDLE Protection WTR period is 10 sec. (timer is inactive) Self Detected Requests Remote Requests West Span IDLE West Span IDLE East Span IDLE East Span IDLE Distant Requests East Span IDLE West Span IDLE West Span Failures: none East Span Failures: none 26

27 IEEE Resilient Packet Ring Feature Guide How to Configure RPR Protection Shutting Down a Span SUMMARY STEPS DETAILED STEPS To cause a forced switch on the span of the interface, perform the following steps. The rpr-ieee shutdown command performs the same task as the rpr-ieee protection request forced-switch command. 1. enable 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee shutdown {east west} Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee shutdown {east west} Enters interface configuration mode for a specific RPR interface. Causes a forced switch on a span of the interface. Router(config-if)# rpr-ieee shutdown west Configuring Keepalive Events SUMMARY STEPS A station can determine whether a link is alive if it is receiving fairness messages from it. This feature is independent of the fairness algorithm itself, but is nonetheless a function performed by the fairness machine. The number of milliseconds that pass without receiving a fairness message from the neighboring stations is measured. When this time exceeds a configured timeout, then a keepalive event is triggered, which generates a protection event. The timer may have a different value on either span. The keepalive timer should be configured greater than or equal to the hold-off timer. The default keepalive timer is 3 milliseconds. 1. enable 27

28 How to Use Modular QoS CLI to Configure RPR Service Classes IEEE Resilient Packet Ring Feature Guide 2. configure terminal 3. interface rpr-ieeeslot/port 4. rpr-ieee keepalive-timer time [east west] DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Router# configure terminal interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 rpr-ieee keepalive-timer time [east west] Router(config-if)# rpr-ieee keepalive-timer 5 west Enters interface configuration mode for a specific RPR interface. Specifies the amount of time that can pass before a keepalive event is triggered after not receiving a fairness message from a neighboring station. Values range from 2 to 200 milliseconds. The default is 3. How to Use Modular QoS CLI to Configure RPR Service Classes SUMMARY STEPS Layer 3 prioritized traffic is directed to the three service classes supported by RPR by using the Modular QoS CLI (MQC). MQC is a CLI structure that allows you to create traffic policies and attach these policies to interfaces. A traffic policy contains a traffic class and one or more QoS features. A traffic class classifies traffic, while the QoS features in the traffic policy determine how to treat the classified traffic. 1. enable 2. configure terminal 3. class-map match-any class-name 4. match ip precedence number 5. exit 6. policy-map policy-name 7. class class-name 8. shape rate 28

29 IEEE Resilient Packet Ring Feature Guide How to Use Modular QoS CLI to Configure RPR Service Classes 9. set rpr-ieee service-class {a b c} 10. exit 11. exit 12. interface rpr-ieeeslot/port 13. service-policy output policy-name DETAILED STEPS Step 1 Step 2 Command or Action enable Router> enable configure terminal Purpose Enables privileged EXEC mode. Enter your password if prompted. Enters global configuration mode. Step 3 Step 4 Step 5 Router# configure terminal class-map match-any class-name Router(config)# class-map match-any RPR_A match ip precedence number Router(config-cmap)# match ip precedence 6 7 exit Specifies the user-defined name of the traffic class and the logical OR operator for all matching statements under this traffic class. Specifies up to eight IP precedence values (0 to 7) used as match criteria. For RPR, class maps link Layer 3 precedences to MQC classes. For IP version 4, there are eight priority levels that must be mapped. The example shows the configuration of three class maps corresponding to the three RPR service classes. Exits class mode. Step 6 Step 7 Router(config-pmap-c)# exit policy-map policy-name Router(config)# policy-map RPR_class class class-name Router(config-pmap)# class RPR_A Specifies the name of the service policy to configure. Service policies link the configured class maps to Layer 2 traffic priorities, or in this case, the three service classes of RPR. An assignment has to be constructed for each class map. Specifies the name of a predefined class, which was defined with the class-map command, to be included in the service policy. Note Each of the three RPR classes must be configured as described in this procedure. 29

30 How to Use Modular QoS CLI to Configure RPR Service Classes IEEE Resilient Packet Ring Feature Guide Step 8 shape rate Router(config-pmap-c)# shape Step 9 set rpr-ieee service-class {a b c} Step 10 Command or Action Router(config-pmap-c)# set rpr-ieee service-class guaranteed exit Purpose When configuring RPR traffic classes, the shape or bandwidth command must be used. If the shape command is set to full line rate, as in this example, then only RPR queue control (fairness and rate limits) affects the transmission rate. If a lower value for a shape or a bandwidth value is used, the impact of the RPR queue control on transmit is altered. The two applications take effect in series. The rate is in Kbps. Specifies the appropriate RPR service class for the class. The three classes correspond to each of the three RPR service classes. Only one service class can be configured for each MQC class. Exits class mode. Step 11 Router(config-pmap-c)# exit exit Exits policy map mode. Step 12 Step 13 Router(config-pmap)# exit interface rpr-ieeeslot/port Router(config)# interface rpr-ieee2/0 service-policy output policy-name Specifies the RPR interface to which to attach the configured service policy. Attaches the configured service policy to the RPR interface. Router(config-if)# service-policy output RPR_Class Configuration Example Using MQC to Configure RPR Service Classes Following is an example of the entire configuration process for the three RPR service classes: class-map match-any RPR_A match ip precedence 6 7 class-map match-any RPR_B match ip precedence 4 5 class-map match-any RPR_C match ip precedence policy-map RPR_CLASS class RPR_A shape set rpr-ieee service-class a class RPR_B shape

31 IEEE Resilient Packet Ring Feature Guide How to Use Modular QoS CLI to Configure RPR Service Classes set rpr-ieee service-class b class RPR_C shape set rpr-ieee service-class c interface rpr-ieee1/1 service-policy output RPR_CLASS Troubleshooting Tips To verify the service class configurations, use the following commands: Command Router# show policy-map class-name Router# show policy-map interfaces rpr-ieee slot/port Purpose Displays the configuration of the specified class. Displays statistics for the class on a specific interface and the number of packets sent to each service class of the interface. Following is sample output from the show policy-map command: Router# show policy-map RPR_CLASS Policy Map RPR_CLASS Class RPR_A shape set rpr-ieee service-class a Class RPR_B shape set rpr-ieee service-class b Class RPR_C shape set rpr-ieee service-class c Following is sample output from the show policy-map interfaces command: Router# show policy-map interfaces rpr-ieee1/1 Service-policy output: RPR_CLASS (1047) Class-map: RPR_A (match-any) (1083/4) 0 packets, 0 bytes 5 minute offered rate 0 bps, drop rate 0 bps Match: ip precedence 6 7 (1084) shape (VCCI 2->side E): kbps shape (VCCI 3->side W): kbps QoS Set rpr-ieee service-class a Packets marked 0 Class-map: RPR_B (match-any) (1105/5) 0 packets, 0 bytes 5 minute offered rate 0 bps, drop rate 0 bps Match: ip precedence 4 5 (1106) shape (VCCI 2->side E): kbps shape (VCCI 3->side W): kbps QoS Set rpr-ieee service-class b Packets marked 0 31