SCTP Administrator's Guide

Transcription

1 SCTP Administrator's Guide HP-UX 11i v2, HP-UX 11i v3 HP Part Number: Published: April 2008 Edition: 1

2 Copyright Hewlett-Packard Development Company, L.P. Confidential computer software. Valid license from HP required for possession, use or copying. Consistent with FAR and , Commercial Computer Software, Computer Software Documentation, and Technical Data for Commercial Items are licensed to the U.S. Government under vendor's standard commercial license. The information contained herein is subject to change without notice. The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein. UNIX is a registered trademark of The Open Group.

3 Table of Contents About This Document...11 Intended Audience...11 Document Organization...11 Typographic Conventions...11 Related Information...13 HP Encourages Your Comments Introduction...15 SCTP Overview...15 SCTP Architecture...15 The ndd Command...18 SCTP Parameters Supported by the ndd Command...18 The netstat Command...23 SCTP Support for the netstat Command...23 The nettl Command...24 The sctpd Application...24 SCTP Support for sctpd...24 Start and Stop Script Troubleshooting and Monitoring the SCTP Product...27 Using the ndd Command...27 Getting the Value of an SCTP Parameter...27 Setting the Value of an SCTP Parameter...27 Displaying the SCTP Parameter Information...28 Using the /etc/rc.config.d/nddconf File to Set the ndd Tunable Parameters...30 Using the netstat Command...30 Displaying the Protocol Statistics...30 Displaying the Routing Table Information...34 Displaying Network Interface Status...35 Displaying the Status of Sockets...36 Using the nettl Command to Control Network Tracing and Logging...37 Using the /etc/rc.conf/sctprcconf File...38 Using the Start and Stop Script...39 Starting the sctpd Application...39 Stopping the sctpd Application...39 Glossary...41 Table of Contents 3

4 Index Table of Contents

5 List of Figures 1-1 SCTP Product Architecture

6 6

7 List of Tables 1-1 SCTP Parameters Supported by the ndd Command Minimum, Maximum, and Default Values of SCTP Parameters Supported by the ndd Command

8 8

9 List of Examples 2-1 Command to Get the Value of an SCTP Parameter Command to Set the Value of an SCTP Parameter Sample output of ndd -h grep sctp and ndd h sctp_rto_max command Configuring an SCTP Parameter in the /etc/rc.config.d/nddconf file Sample Output of netstat s and netstat p SCTP command Sample Output of the netstat rn and the netstat vrn commands Sample Output of the netstat -in command Sample Output of netstat -an and netstat -anv command Sample Tracing and Logging Commands Setting the SCTP_ARGS Variable

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11 About This Document This document describes how to administer the various utilities for troubleshooting and monitoring the Stream Control Transmission Protocol (SCTP) product on systems running HP-UX 11i v2 and HP-UX 11i v3. It also describes the SCTP product architecture. The document printing date and part number indicate the document s current edition. The printing date will change when a new edition is printed. Minor changes may be made at reprint without changing the printing date. The document part number will change when extensive changes are made. The latest version of the document will be available at: Document updates can be issued between editions to correct errors or document product changes. To ensure that you receive the updated or new edition, subscribe to the appropriate support service. Contact your HP sales representative for details. Intended Audience This manual is intended for system administrators who monitor the network traffic and modify network parameters. Administrators are expected to have a thorough knowledge of network monitoring tools and commands, TCP, UDP, UNIX, and networking concepts. Document Organization The SCTP Administrator's Guide is organized as follows: Chapter 1 Chapter 1 (page 15) Introduces the Stream Control Transmission Protocol (SCTP). It also discusses the SCTP product architecture and the utilities you can use to monitor and troubleshoot the SCTP product. Chapter 2 Chapter 2 (page 27) Describes how to use the various SCTP utilities for troubleshooting and monitoring the SCTP product. Typographic Conventions This document uses the following typographical conventions: %, $, or # A percent sign represents the C shell system prompt. A dollar sign represents the system prompt for the Bourne, Korn, and POSIX shells. A number sign represents the superuser prompt. audit(5) A manpage. The manpage name is audit, and it is located in Section 5. Command A command name or qualified command phrase. Intended Audience 11

12 Computer output Text displayed by the computer. Ctrl+x A key sequence. A sequence such as Ctrl+x indicates that you must hold down the key labeled Ctrl while you press another key or mouse button. ENVIRONMENT VARIABLE The name of an environment variable, for example, PATH. [ERROR NAME] The name of an error, usually returned in the errno variable. Key The name of a keyboard key. Return and Enter both refer to the same key. Term The defined use of an important word or phrase. User input Commands and other text that you type. Variable The name of a placeholder in a command, function, or other syntax display that you replace with an actual value. [] The contents are optional in syntax. If the contents are a list separated by, you must choose one of the items. {} The contents are required in syntax. If the contents are a list separated by, you must choose one of the items.... The preceding element can be repeated an arbitrary number of times. Indicates the continuation of a code example. Separates items in a list of choices. WARNING A warning calls attention to important information that if not understood or followed will result in personal injury or nonrecoverable system problems. CAUTION A caution calls attention to important information that if not understood or followed will result in data loss, data corruption, or damage to hardware or software. IMPORTANT This alert provides essential information to explain a concept or to complete a task NOTE A note contains additional information to emphasize or supplement important points of the main text. 12

13 Related Information The following related documents are available for the SCTP product: SCTP Programmer's Guide at: SCTP Release Notes at: Request for Comments (RFC) documents: RFC 2960 (Stream Control Transmission Protocol) at: RFC 3286 (An Introduction to the Stream Control Transmission Protocol (SCTP)) at: RFC 3873 (Stream Control Transmission Protocol (SCTP) Management Information Base (MIB)) at: RFC 3309 (Stream Control Transmission Protocol (SCTP) Checksum Change) at: RFC 3758 (Stream Control Transmission Protocol (SCTP) Partial Reliability Extension) at: RFC 4460 (Stream Control Transmission Protocol (SCTP) Specification Errata and Issues) at Draft RFC's:: draft-ietf-tsvwg-sctpsocket-10.txt at: draft-ietf-tsvwg-sctpsocket-10.txt draft-ietf-tsvwg-addip-sctp-10.txt (Stream Control Transmission Protocol (SCTP) Dynamic Address Reconfiguration) at: draft-ietf-tsvwg-addip-sctp-10.txt Related Information 13

14 draft-stewart-sctp-pktdrprep-02.txt (Stream Control Transmission Protocol (SCTP) Packet Drop Reporting) at: draft-ladha-sctp-nonce-01.txt (ECN Nonces for Stream Control Transmission Protocol (SCTP)) at: HP Encourages Your Comments HP encourages your comments concerning this document. We are committed to providing documentation that meets your needs. Send any errors found, suggestions for improvement, or compliments to: Include the document title, manufacturing part number, and any comment, error found, or suggestion for improvement you have concerning this document. 14

15 1 Introduction This chapter introduces the Stream Control Transmission Protocol (SCTP). It also discusses the SCTP architecture and the utilities you can use to troubleshoot and monitor and the SCTP product. This chapter addresses the following topics: SCTP Overview (page 15) SCTP Architecture (page 15) The ndd Command (page 18) The netstat Command (page 23) The nettl Command (page 24) The sctpd Application (page 24) Start and Stop Script (page 25) SCTP Overview SCTP is a transport protocol that facilitates reliable transmission of data between two endpoints of an association in an Internet Protocol (IP)-based network. In an IP stack, it exists at a level equivalent to that of Transmission Control Protocol (TCP) and User Datagram Protocol ( UDP). SCTP supports multihoming, delivery of data in multiple streams, and preservation of message boundaries. It also supports acknowledged, error-free, non-duplicated transfer of data; fragmentation of data to conform to maximum transmission unit (MTU) size; and optional bundling of user messages into an SCTP packet. SCTP also includes mechanisms such as, checksums, sequence numbers, and selective retransmission of data. In addition, it supports congestion control algorithms, SYN flood protection, and error handling. NOTE: In SCTP, the term stream refers to a sequence of user messages that are delivered in sequence, with respect to other messages within the same stream. In TCP "stream" refers to a sequence of bytes. SCTP Architecture This section discusses the SCTP architecture. It also discusses the various SCTP utilities and describes how these utilities work. SCTP is located between the SCTP user application (SCTP user for short) and a connectionless packet network service, such as IP. During association startup, SCTP enables each endpoint of an association to provide the other endpoint with a list of multiple IP addresses in combination with SCTP ports SCTP Overview 15

16 The endpoints of an association communicate with each other using these addresses. These addresses also serve as the point of origination for the SCTP packets. The association spans across all possible source or destination combinations, which may be generated from each endpoint's lists. For more information on the SCTP architecture, see the SCTP Programmer s Guide available at: Figure 1-1 illustrates the SCTP product architecture. Figure 1-1 SCTP Product Architecture NOTE: Figure 1-1 illustrates the positioning of components specific to SCTP product in a typical IP stack. The SCTP product includes the following components: The SCTP module The Socket API SCTP-based application SCTP Utilities 16 Introduction

17 The netstat command The ndd command The nettl command Start and Stop script The sctpd application The SCTP module: The SCTP module is a multiplexing driver that interacts with the application and the IPv4 or IPv6 layer. It handles the messages received from and sent to the applications, and the messages received from and sent to the IPv4 or IPv6 layer. It contains a pair of upper (read and write) queues per application, and a pair of lower queues each for IPv4 and IPv6. The Multiprocessor (MP) system uses the queue-pair parallelism. The Socket API: Socket API refers to a set of routines and definitions, which provide access to network services. The draft-ieft-tsvwg-sctpsocket-10.txt defines the APIs for the SCTP protocol. SCTP socket API defines two styles of socket APIs: one-to-one and one-to-many. The one-to-one style API is similar to the existing socket APIs for a connection-oriented protocol, such as TCP. The one-to-many style API facilitates simultaneous associations with multiple peers using one end point (that is, it associates with multiple peers using one socket file descriptor simultaneously). The two socket API styles are mutually exclusive; that is, a socket endpoint can either use one-to-one style API or one-to-many style API, but not both. For more information about socket APIs, see the SCTP Programmer s Guide available at: SCTP-based application: The SCTP-based application is a user level program that uses the services of SCTP. The SCTP-based application interacts with the SCTP module through the socket API to perform various operations. The ndd command: The ndd command enables you to examine and modify the tunable parameters that affect networking behavior and operations. The ndd command interacts with the SCTP module through the command library, to manage and monitor network operations. For more information about the ndd command, see The ndd Command (page 18). The netstat command: The netstat command enables you to obtain statistical information about network interfaces and protocols. The netstat command interacts with the SCTP module through the command library, to manage and monitor the network operations. For more information about the netstat command, see The netstat Command (page 23). The nettl command: The nettl command is a tool used to capture network events or packets. It is also used to control the network tracing and logging. The nettl command interacts with the SCTP module through the tracing and logging library to SCTP Architecture 17

18 perform tracing and logging operations. For more information about the nettl command, see The nettl Command (page 24). Start and Stop script: The Start and Stop script enables you to start and stop the sctpd application. For more information about the Start and Stop script, see Start and Stop Script (page 25). The sctpd application: The sctpd application enables you to manage domain name resolution requests, to support the SCTP hostname parameter. It automatically configures the interfaces into SCTP, whenever an interface is configured. The sctpd application interacts with the SCTP module through the command library, to manage and monitor network operations. For more information about the sctpd application, see The sctpd Application (page 24). The following sections discuss the SCTP utilities in detail. The ndd Command This section discusses the ndd command. It also describes the SCTP tunable parameters that the ndd command supports. The ndd command enables you to examine and modify the tunable parameters that affect networking behavior and operations. You can change the value of a tunable using the /etc/rc.config.d/nddconf file. Configuring an SCTP variable is similar to configuring a TCP or a UDP variable. This command enables you to enter arguments for TCP,UDP, or SCTP parameters on the command line. SCTP Parameters Supported by the ndd Command This section lists the SCTP parameters supported by ndd. It also lists the maximum, minimum, and default value for each of the supported SCTP parameters. Table 1-1 lists the SCTP parameters supported by the ndd command. Table 1-1 SCTP Parameters Supported by the ndd Command Parameter sctp_status sctp_max_init_retr sctp_max_assoc_retr Description Queries the SCTP module for global statistical information and displays the retrieved data. Specifies the default number of times an INIT message is retransmitted, before SCTP considers a peer unreachable. The maximum number of INIT messages sent is one value greater than the specified sctp_max_init_retr value. (The first message is not treated as a retransmission.) Specifies the default number of times DATA, SHUTDOWN, or HEARTBEAT message is retransmitted, before SCTP considers the peer unreachable, and treats the association as aborted. 18 Introduction

19 Table 1-1 SCTP Parameters Supported by the ndd Command (continued) Parameter sctp_max_path_retr sctp_a_rwnd sctp_max_out_streams sctp_default_out_streams sctp_max_in_streams sctp_rto_min sctp_rto_max sctp_rto_initial Description Specifies the default number of times a DATA, SHUTDOWN, or HEARTBEAT message is retransmitted to a particular address of an association, before SCTP considers that address inactive. If an address is inactive, SCTP sends packets to an alternate active address, if the peer has more than one address. If there are no alternate active addresses, then the primary address is used for n number of retries, where n is the value specified in sctp_max_assoc_retr. After that, the association is treated as aborted. Specifies the default value to advertise to the peer at the receive window size (in bytes). This amount of data can be either in-flight or waiting to send to a user before the peer is flow-controlled. Specifies the maximum number of 'out' streams that can be used by an association. The SCTP user cannot use a higher value, even if the per-association option is used. Specifies the default number of 'out' streams that are requested for an association. The actual number allocated depends on the number of in streams allowed by the peer. The SCTP user can override this value using the per-association option. Specifies the maximum number of 'in' streams that can be used by an association. If a peer specifies a number that is greater than sctp_max_in_strms, then the value specified in sctp_max_in_strms is used instead. However, the SCTP user can override this value using the per-association option. Specifies the default minimum time (in milliseconds) for the retransmission timer. Specifies the default maximum time (in milliseconds) for the retransmission timer. Specifies the default initial time (in milliseconds) for the retransmission timer. The ndd Command 19

20 Table 1-1 SCTP Parameters Supported by the ndd Command (continued) Parameter sctp_hb_interval sctp_max_burst sctp_ack_delay sctp_bundle_timer sctp_val_cookie_life sctp_max_cookie_pres Description Specifies the default average time (in milliseconds) between the two consecutive heartbeat requests. If this is set to 0, then heartbeats are disabled by default. However, the heartbeats are still used for address confirmation. NOTE: The time between two consecutive heartbeats is jittered at random. As a result, heartbeats will not occur at the exact time. Moreover, the interval spans across all addresses in an association. If there are several addresses, it will take long time before a heartbeat is sent to the same address again. Specifies the maximum number of 'Path MTUs' of new data that can be sent at a time. Specifies the time to wait (in milliseconds) before sending a SACK packet, to acknowledge the received data. The SACK timer may not have to prompt for sending a SACK, because SACK is sent very frequently (for every two packets) Specifies the time to wait (in milliseconds) for other data chunks to bundle in the same packet. The data is sent without waiting for this time-out if the amount outstanding is more than the threshold, or if bundling is disabled ('no delay' option). This parameter can be configured by an SCTP user using the per-association option. Specifies the duration (in milliseconds) for which a COOKIE parameter sent in an INIT ACK is valid for. The COOKIE must be returned in a COOKIE ECHO message before this period ends, or it is considered stale. Specifies the maximum value (in milliseconds) that is added to the default life of a COOKIE (see sctp_val_cookie_life) sent (in an INIT ACK) as a response to an INIT, which has a Cookie Preservative parameter. If the time specified in the Cookie Preservative parameter is more than this value, then sctp_max_cookie_pres is used instead. If the value is 0, the Cookie Preservative Parameter in an incoming INIT is ignored. 20 Introduction

21 Table 1-1 SCTP Parameters Supported by the ndd Command (continued) Parameter sctp_rto_alpha sctp_rto_beta sctp_in_host_supported sctp_hostname sctp_checksum sctp_sws_threshold Description Specifies the value of 'alpha', which is used to calculate the retransmission timeout. The higher the value of 'alpha', the more influence the latest round-trip time has on the current smoothed round-trip time value. The value of 'alpha' is a decimal specified in the range 0 to Specifies the value for 'beta', which is used to calculate the retransmission timeout. The higher the value of 'beta', the more influence the latest round-trip variance has on the current smoothed round-trip variance value. The value of beta is a decimal specified in the range 0 to Provides an option to support the hostname address in the incoming INIT or INIT ACK chunks. If this option is set to YES, then INIT or INIT ACKs received contains the 'hostname' address, and the 'hostname' is resolved to the address. The supported address types option indicates that the hostname address format is supported. If this is set to NO, then SCTP will not support a 'hostname' address in an incoming INIT or INIT ACK. The supported address types option indicates that the 'hostname' address format is not supported. Enables you to append a 'hostname' address to the outgoing INIT or INIT ACK chunks and to specify the name to be appended in the INIT or INIT ACK chunk. To specify that a 'hostname' address parameter must not be appended to the outgoing packets, the name field must be left blank Specifies the checksum type to be used for the messages. This option is not available if SCTP supports either CRC-32c or Adler32 checksum algorithms. Hence, if this option is used, it results in a warning. Specifies the Silly Window Syndrome threshold. It is a percentage and it must be in the range 0 to 100. If the value of sctp_sws_threshold is less than the existing percentage, then the receive window is set to 1. As a result, it stops the peer from using very small windows to send data. The ndd Command 21

22 Table 1-1 SCTP Parameters Supported by the ndd Command (continued) Parameter sctp_pd_threshold sctp_hash_size sctp_pr_sctp sctp_ecn Description Specifies the Partial Delivery threshold. It is a percentage and must be in the range 0 to 100. If the receive window advertised to the peer is less than or equal to this percentage, then partial delivery is enabled and the user receives fragments of messages. Partial delivery enables you to free the buffers, so that the receive window can be opened. This is useful when the reassembled data is larger than the receive window. Specifies the size of the hash tables used for quick-lookup using verification tags and port numbers. If the size of the hash table is large, it is faster and the probability of the different associations using the same hash location is reduced. However, large tables require more memory. If the sctp_hash_size is a prime number, then the probability of different hash locations being used increases. Provides an option to negotiate the Partial Reliability (PR)_SCTP with the peer. The default value is YES. Provides an option to negotiate the Explicit Congestion Notification (ECN) with the peer. It also specifies if ECN NONCES s used (if value is 'nonce'). Table 1-2 lists the minimum, maximum, and default values for each of the SCTP parameters supported by the ndd command. Table 1-2 Minimum, Maximum, and Default Values of SCTP Parameters Supported by the ndd Command Parameter Minimum Maximum Default sctp_max_init_retr sctp_max_assoc_retr sctp_max_path_retr sctp_a_rwnd sctp_max_out_streams sctp_default_out_streams sctp_max_in_streams sctp_rto_min sctp_rto_max Introduction

23 Table 1-2 Minimum, Maximum, and Default Values of SCTP Parameters Supported by the ndd Command (continued) Parameter Minimum Maximum Default sctp_rto_initial sctp_hb_interval sctp_max_burst sctp_ack_delay sctp_bundle_timer sctp_val_cookie_life sctp_max_cookie_pres sctp_rto_alpha sctp_rto_beta sctp_in_host_supported - - NO sctp_checksum - - CRC-32c sctp_sws_threshold sctp_pd_threshold sctp_hash_size sctp_pr_sctp - - YES sctp_ecn - - YES The netstat Command The netstat command enables you to obtain the statistical information for network interfaces and protocols. SCTP Support for the netstat Command The netsat command supports various interfaces through command-line options to display the following information: The statistical information for network interfaces and protocols. The contents of various network-related data structures. The output format varies depending on the options that you specify. For more information about these interfaces, see Using the netstat Command (page 30) The netstat Command 23

24 The nettl Command The nettl command is a tool used to capture network events or packets. It is also used to control the network tracing and logging. Logging is a means of capturing network activities, such as state changes, errors, and connection establishment. Tracing is used to capture or obtain a snapshot of inbound and outbound packets that pass through the network, including packet loopback or header information. The sctpd Application The sctpd application enables you to manage domain name resolution requests, to support the SCTP hostname parameter. It automatically configures interfaces into SCTP, whenever an interface is configured. When IP addresses are required for a peer's hostname, the SCTP module sends the request to sctpd. The sctpd application looks up the hostname and sends the IP addresses, or an error if the hostname cannot be resolved to the SCTP module. The sctpd application supports automatic configuration of the interfaces. When an interface is configured, the sctpd application automatically configures the same into SCTP, using a poll. The sctpd application checks and configures all the interfaces at the given interval of time. This interval is configured using the /etc/rc.conf/sctprcconf file. For more information about using the /etc/rc.conf/sctprcconf file, see Using the /etc/rc.conf/sctprcconf File (page 38) The sctpd application is available at the following location: /usr/sbin/sctpd SCTP Support for sctpd The sctpd application supports the following command-line options specific to SCTP: -t <sec> This option enables you to configure the poll timer interval for sctpd. During each of these intervals, sctpd scans the and configures all the interfaces. The timer is used to initiate a SIGALRM, and when this signal is received, sctpd verifies all the interfaces present and configures them. -d This option provides an event driven logging facility. It is event driven, because logging is mostly error-based (failure of malloc() or failure of fork() is treated as an event and is suitably logged). The DEBUG feature is built into the sctpd binary. This option also provides debugging information related to Domain Name System (DNS) and the interface configurations that sctpd handles. The -t and -d options can be configured using the /etc/rc.conf/sctprcconf file. For more information about using the /etc/rc.conf/sctprcconf file, see Using the /etc/rc.conf/sctprcconf File (page 38) 24 Introduction

25 Start and Stop Script SCTP provides the Start and Stop (sctprc) script to start and stop the sctpd application. You must run this script as a superuser. This script is available at the following location: /sbin/init.d/sctprc Start and Stop Script 25

26 26

27 2 Troubleshooting and Monitoring the SCTP Product This chapter describes how to use the various SCTP utilities for troubleshooting and monitoring the SCTP product. This chapter addresses the following topics: Using the ndd Command (page 27) Using the netstat Command (page 30) Using the nettl Command to Control Network Tracing and Logging (page 37) Using the /etc/rc.conf/sctprcconf File (page 38) Using the Start and Stop Script (page 39) Using the ndd Command This section discusses the command-line options that ndd supports. It also provides a sample output for each command-line option. This section addresses the following topics: Getting the Value of an SCTP Parameter (page 27) Setting the Value of an SCTP Parameter (page 27) Displaying the SCTP Parameter Information (page 28) Using the /etc/rc.config.d/nddconf File to Set the ndd Tunable Parameters (page 30) Getting the Value of an SCTP Parameter The following syntax for the ndd command enables you to get the value of an SCTP parameter: ndd -get network_device parameter This command also prints the value of the SCTP parameter to the standard output. Example 2-1 Command to Get the Value of an SCTP Parameter To get the value of an SCTP parameter, enter the following command: ndd get /dev/sctp sctp_rto_max The following output is displayed: Setting the Value of an SCTP Parameter The following syntax for the ndd command enables you to set the value of an SCTP parameter: ndd -set network_device parameter value Using the ndd Command 27

28 Example 2-2 Command to Set the Value of an SCTP Parameter To set the value of an SCTP parameter, enter the following command: ndd set /dev/sctp sctp_rto_max When you run this command, the value of sctp_rto_max is set to To verify whether the value of sctp_rto_max is set to 65001, enter the following command: ndd get /dev/sctp sctp_rto_max The value of sctp_rto_max is displayed as WARNING! Setting a tunable parameter to an inappropriate value can adversely affect the networking operations. Displaying the SCTP Parameter Information The ndd command provides the -h option to display the parameter information. To display a list of all supported parameters for SCTP, enter the following command: ndd -h grep sctp The -h option also displays the minimum, maximum, and default values for the specified parameter. To display information about a specific parameter (that is, sctp_rto_max), enter the following command: ndd -h sctp_rto_max 28 Troubleshooting and Monitoring the SCTP Product

29 Example 2-3 Sample output of ndd -h grep sctp and ndd h sctp_rto_max command Following is a sample output of the ndd -h grep sctp command: node1:>/ndd -h grep sctp sctp_max_init_retr sctp_max_assoc_retr sctp_max_path_retr sctp_a_rwnd sctp_max_out_strms sctp_default_out_streams sctp_max_in_strms sctp_rto_min sctp_rto_max sctp_rto_initial sctp_hb_interval sctp_max_burst sctp_ack_delay sctp_bundle_timer sctp_val_cookie_life sctp_max_cookie_pres sctp_rto_alpha sctp_rto_beta sctp_in_host_supported sctp_hostname sctp_checksum sctp_sws_threshold sctp_pd_threshold sctp_hash_size sctp_pr_sctp sctp_ecn sctp_status - Controls retransmissions of an INIT message before considering the peer unreachable - Controls retransmissions of DATA, SHUTDOWN,or HEARTBEAT before considering the peer unreachable - Controls retransmissions of DATA, SHUTDOWN,or HEARTBEAT before considering an address inactive - Receive window size - Maximum number of out streams - Default number of out streams - Maximum number of in streams - Minimum retransmission time - Maximum retransmission time - Initial retransmission time - Time between heartbeat requests - Max number of 'Path MTUs' - Waiting time before sending a SACK packet - Waiting time for other data chunks to bundle in the same packet - Valid time for a COOKIE parameter sent in an INIT ACK - Time added to the life of a COOKIE. - Retranmission timeout for alpha - Retranmission timeout for beta - INIT/INIT ACKs can/cannot contain hostname - Hostname in outgoing INIT/INIT ACK chunks - Checksum type - Silly Window Syndrome threshold - Partial Delivery threshold - Size of the hash tables - Partial Reliability) should be negotiated or not - Explicit Congestion Notification) should be negotiated or not - Retrieve statistics from the SCTP driver Following is a sample output of the ndd -h sctp_rto_max command: node1:/> ndd -h sctp_rto_max sctp_rto_max: Using the ndd Command 29

30 This specifies the default maximum time (in milliseconds) for the retransmission timer. Using the /etc/rc.config.d/nddconf File to Set the ndd Tunable Parameters The /etc/rc.config.d/nddconf file contains the tunable parameters that are automatically set during system startup. The /etc/rc.config.d/nddconf file contains the following fields: TRANSPORT_NAME NDD_NAME NDD_VALUE Specifies the name of the transport component. Specifies the name of the ndd tunable parameter. Specifies the value for the ndd tunable parameter. To enable ndd to read the input from /etc/rc.config.d/nddconf file and set the value of the tunable parameter during system startup, enter the following command: ndd c Example 2-4 Configuring an SCTP Parameter in the /etc/rc.config.d/nddconf file To set the sctp_rto_max parameter to milliseconds, the /etc/rc.config.d/nddconf fields must be specified, as follows: TRANSPORT_NAME [1] = sctp NDD_NAME [1] = sctp_rto_max NDD_VALUE [1] = Using the netstat Command This section discusses the various command-line options supported by netstat. It also provides a sample output for each option. This section addresses the following topics: Displaying the Protocol Statistics (page 30) Displaying the Routing Table Information (page 34) Displaying Network Interface Status Displaying the Status of Sockets (page 36) The netstat command supports command-line options, to display statistical information for the network interface and the protocol. The output format varies depending on the command-line option. For information on the command-line options supported by netstat, see netstat(1). Displaying the Protocol Statistics To display per protocol statistics for the SCTP, UDP, TCP, ICMP, Internet Group Management Protocol (IGMP) and IP protocols, enter the following command: netstat -s 30 Troubleshooting and Monitoring the SCTP Product

31 To display the statistics for SCTP protocol, enter the following command: netstat -p sctp This command displays areas where the specified protocol contains problems. Using the netstat Command 31

32 Example 2-5 Sample Output of netstat s and netstat p SCTP command Following is a sample output of the netstat -s command: node1:/> netstat -s tcp: 6693 packets sent 5326 data packets ( bytes) 17 data packets (440 bytes) retransmitted 1367 ack-only packets (533 delayed) 20 URG only packets 0 window probe packets 0 window update packets 1512 control packets packets received 5024 acks (for bytes) 0 duplicate acks 0 acks for unsent data 6904 packets ( bytes) received in-sequence 0 completely duplicate packets (0 bytes) 0 packets with some dup, data (0 bytes duped) 0 out of order packets (0 bytes) 0 packets (0 bytes) of data after window 0 window probes 288 window update packets 0 packets received after close 0 segments discarded for bad checksum 0 bad TCP segments dropped due to state change 306 connection requests 291 connection accepts 597 connections established (including accepts) 822 connections closed (including 243 drops) 243 embryonic connections dropped 4676 segments updated rtt (of 4676 attempts) 24 retransmit timeouts 1 connection dropped by rexmit timeout 0 persist timeouts 3 keepalive timeouts 0 keepalive probes sent 0 connections dropped by keepalive 0 connect requests dropped due to full queue 565 connect requests dropped due to no listener 0 suspect connect requests dropped due to aging 0 suspect connect requests dropped due to rate sctp: 0 current established associations 15 active established 15 passive established 0 aborted 30 shutdowns 38 out of the blue packets 0 checksum errors 134 out control chunks 13 out ordered chunks 0 out unordered chunks 126 in control chunks 13 in ordered chunks 0 in unordered chunks 32 Troubleshooting and Monitoring the SCTP Product

33 udp: ip: icmp: igmp: 0 fragmented user messages 0 reassembled user messages 147 out sctp packets 147 in sctp packets 0 discontinuity time 0 incomplete headers 0 bad checksums 0 socket overflows total packets received 0 bad IP headers 0 fragments received 0 fragments dropped (dup or out of space) 0 fragments dropped after timeout 0 packets forwarded 0 packets not forwardable 471 calls to generate an ICMP error message 0 ICMP messages dropped Output histogram: echo reply: 469 destination unreachable: 2 source quench: 0 routing redirect: 0 echo: 0 time exceeded: 0 parameter problem: 0 time stamp: 0 time stamp reply: 0 address mask request: 0 address mask reply: 0 0 bad ICMP messages Input histogram: echo reply: 65 destination unreachable: 4 source quench: 0 routing redirect: 0 echo: 469 time exceeded: 0 parameter problem: 0 time stamp request: 0 time stamp reply: 0 address mask request: 0 address mask reply: responses sent 90 messages received 0 messages received with too few bytes 0 messages received with bad checksum 90 membership queries received 0 membership queries received with incorrect fields(s) 0 membership reports received 0 membership reports received with incorrect field(s) 0 membership reports received for groups to which this host belongs 0 membership reports sent Following is a sample output of the netstat -p sctp command: Using the netstat Command 33

34 inet18:/> netstat -p sctp sctp: 0 current established associations 3 active established 3 passive established 0 aborted 6 shutdowns 6 out of the blue packets 0 checksum errors 24 out control chunks 3 out ordered chunks 0 out unordered chunks 24 in control chunks 3 in ordered chunks 0 in unordered chunks 0 fragmented user messages 0 reassembled user messages 27 out sctp packets 27 in sctp packets 0 discontinuity time NOTE: You can read the protocol statistics for SCTP and identify problems, if any. Displaying the Routing Table Information To display the routing table information, enter the following command: netstat rn To display additional routing information, such as network masks for the route entries, enter the following command: netstat -vrn 34 Troubleshooting and Monitoring the SCTP Product

35 Example 2-6 Sample Output of the netstat rn and the netstat vrn commands Following is the output of the netstat -rn command: inet18:/> netstat -rn Routing tables Destination Gateway Flags Refs Interface Pmtu UH 0 lo UH 0 lan U 2 lan U 0 lo0 0 default UG 0 lan0 0 Following is the output of the netstat -vrn command: inet18:/> netstat -vrn Routing tables Dest/Netmask Gateway Flags Refs Interface Pmtu / UH 0 lo / UH 0 lan / U 2 lan / U 0 lo0 0 default/ UG 0 lan0 0 where: Dest/Netmask Gateway Flags Interface Pmtu Specifies the destination network and the mask to be applied to the destination address of an IP packet, which needs to be forwarded. Specifies the address of the immediate gateway for reaching the destination. It can be the address of the outgoing interface if the destination is on a directly connected network. Shows the status of the route. Following are the different types of flags: U Specifies that the route is up. G Specifies that the route is a gateway. H Specifies that the destination is a host (with or without H). Specifies the network interface used for the route. Displays the path maximum transmission unit (PMTU). Displaying Network Interface Status To display the status of network interfaces, enter the following command: netstat -in Using the netstat Command 35

36 This command displays the interfaces configured with an IP address, or with the plumb option of the ipconfig command. Example 2-7 Sample Output of the netstat -in command Following is a sample output of netstat -in command: inet18:/> netstat -in Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll lan lo This output displays the number of packets transmitted and received over each network. It also provides the network addresses of the interface and MTU. Displaying the Status of Sockets To display the active and passive sockets associated with the SCTP, enter the following command: netstat -an The netstat -an displays only the first local and first remote address. An SCTP socket endpoint contains multiple IP address. To display all the local and remote addresses of an SCTP association, enter the following command: netstat -anv 36 Troubleshooting and Monitoring the SCTP Product

37 Example 2-8 Sample Output of netstat -an and netstat -anv command Following is a sample output of netstat -an command: Proto Recv-Q Send-Q Local Address Foreign Address <state> tcp ESTABLISHED sctp ESTABLISHED tcp ESTABLISHED Following is a sample output of netstat -anv command: Proto Recv-Q Send-Q Local Address Foreign Address <state> tcp ESTABLISHED sctp ESTABLISHED tcp Using the nettl Command to Control Network Tracing and Logging This section describes how to use command-line options supported by nettl, to control network tracing and logging operations. For information on the command-line options supported by nettl, see nettl(1m). Following is the syntax for the nettl command: nettl -option where: option Specifies the tracing and logging options. Consider the following points while using the nettl command: By default, the nettl command sends the log and trace messages to the /var/adm/nettl.log## file or the /var/adm/nettl.trc## file. The nettl command sends disaster messages to the system console. Exercise caution while performing network tracing and logging operations, because these operations affect system performance. Using the nettl Command to Control Network Tracing and Logging 37

38 Example 2-9 Sample Tracing and Logging Commands Following are sample nettl commands used for performing tracing and logging operations: To initialize the tracing and logging facility, enter the following command: nettl -start To check the network logging and tracing status, enter the following command: nettl -status To start the inbound and outbound Protocol Data Unit (PDU) tracing for the SCTP subsystems and to send the binary trace messages to the /var/adm/tracefile file, enter the following command: nettl -traceon pduin pduout-entity ns_ls_sctp -f /var/adm/tracefile To stop tracing for the SCTP subsystem, enter the following command: nettl -entity ns_ls_sctp -traceoff To terminate the tracing and logging facility, enter the following command: nettl -stop To format the SCTP trace file and move the content of the file to the/tmp/traceout file, enter the following command: netfmt -f /tmp/tracefile.trc000 >/tmp/traceout NOTE: By default, the/etc/rc.config.d/nettl is configured with the SCTP subsystem information. You need not modify any of the settings in the /etc/rc.config.d/nettl file to configure the nettl command. Using the /etc/rc.conf/sctprcconf File You can use the /etc/rc.conf/sctprcconf file to perform the following tasks: Configure an autotimer for an interface Enable debugging in an sctpd application The SCTP_ARGS variable in the /etc/rc.conf/sctprcconf file enables you to set these options. Following is the syntax for defining the SCTP_ARGS variable: SCTP_ARGS="[option_name1] [option_name2 <value>]" 38 Troubleshooting and Monitoring the SCTP Product

39 Example 2-10 Setting the SCTP_ARGS Variable To configure the autotimer for an interface and to enable debugging for sctpd application, set the SCTP_ARGS variable in the /etc/rc.conf/sctprcconf file, as follows: SCTP_ARGS="-d t 60" where: -d Enables debugging for the sctpd application. -t 60 Sets the autotimer to 60 seconds to poll for a new interface. NOTE: By default, the t and d options are defined in the SCTP_ARGS variable, and the t option is set to 60 seconds. You can modify the value of the t option to set a different autotimer for an interface. If you modify the /etc/rc.conf/sctprcconf file, HP recommends that the you use the /sbin/init.d/sctprc script to start or stop the stcpd application. By default, the /sbin/init.d/sctprc script is executed while installing the SCTP product and after rebooting the system. Using the Start and Stop Script This section discusses commands to start and stop the sctpd application using the /sbin/init.d/sctprc script. This section addresses the following topics: Starting the sctpd Application (page 39) Stopping the sctpd Application (page 39) Starting the sctpd Application To start the sctpd application, enter the following command: # /sbin/init.d/sctprc start NOTE: When the sctpd application starts, it reads the /etc/rc.conf/sctprcconf file and sets the options defined in thesctp_args variable. Stopping the sctpd Application To stop the sctpd application, enter the following command: # /sbin/init.d/sctprc stop Using the Start and Stop Script 39

40 40

41 Glossary Association Bundling Chunks Cookie Preservative parameter Endpoints HEARTBEAT Hostname parameter INIT ACK Maximum Transmission Unit Message Partial Delivery Partial Reliability (PR)_SCTP Path RAW IP Receive Window A protocol relationship between two SCTP endpoints. The association also contains the protocol state information that includes verification tags and the currently active set of Transmission Sequence Numbers (TSNs). An association can be uniquely identified by the transport addresses used by the endpoints in the association. An optional multiplexing operation, where more than one user message can be carried in the same SCTP packet. Each user message occupies its own DATA chunk. A unit of information within an SCTP packet, consisting of a chunk header and chunk-specific content. The sender of the INIT uses this parameter to suggest to the receiver of the INIT for a longer life-span of the State Cookie. The logical sender or receiver of SCTP packets. On a multi-homed host, an SCTP endpoint is represented to its peers as a combination of a set of eligible destination transport addresses to which SCTP packets can be sent and a set of eligible source transport addresses from which SCTP packets can be received. All transport addresses used by an SCTP endpoint must use the same port number but the endpoint can use multiple IP addresses. A transport address is unique to an SCTP endpoint. Therefore, a transport address used by an SCTP endpoint must not be used by another SCTP endpoint. An endpoint should send this chunk to its peer endpoint to probe the reachability of a particular destination transport address defined in the present association. The sender of INIT uses this parameter to pass its Host Name (in place of its IP addresses) to its peer. The peer is responsible for resolving the name. The INIT ACK chunk is used to acknowledge the initiation of an SCTP association. The Maximum Transmission Unit (MTU) determines the maximum size of the packet that is supported by a communications protocol. Data submitted to SCTP by the Upper Layer Protocol (ULP). Partial Delivery is invoked when a message is large in size and the SCTP stack needs to begin delivery of the message to help free some of the resources held by it during re-assembly of the data. Partial Reliability (PR)_SCTP allows the sender to choose the retransmission behavior on a per message basis. Timed reliability service is one of the partial reliability services provided. Timed reliability means that the user can specify the lifetime of a message: when the lifetime expires and the message is not acknowledged, the sender stops the retransmission and drops the packet. The route taken by the SCTP packets sent by one SCTP endpoint to a specific destination transport address of its peer SCTP endpoint. Sending to different destination transport addresses does not necessarily guarantee getting separate paths. RAW IP is a non-formatted protocol, unlike TCP and UDP. It works at network and transport layers. A socket associated with RAW IP is known as a raw socket. UDP and TCP sockets just receive the payload or the data, whereas RAW Sockets receive the header info of the packet along with the data. An SCTP variable that a sender uses to store the most recently calculated receiver window (in bytes) of its peer. The value of rwnd indicates the space available in the receiver's inbound buffer. 41

42 SACK SCTP packet SHUTDOWN Silly Window Syndrome Stream Supported Address Types Verification Tags This chunk is sent to the peer endpoint to acknowledge the received DATA chunks and to inform the peer endpoint of gaps in the received subsequences of DATA chunks as represented by their Transmission Sequence Numbers. The unit of data delivery across the interface between SCTP and the connectionless packet network (for example, IP). An SCTP packet contains the common SCTP header, possible SCTP control chunks, and user data encapsulated within SCTP DATA chunks. An endpoint in an association must use this chunk to initiate a graceful termination of the association with its peer. Silly Window Syndrome is a condition when only small amounts of data are exchanged across the connection, instead of full-sized segments A uni-directional logical channel established from one to another associated SCTP endpoint, within which all user messages are delivered in sequence except for those submitted to the unordered delivery service. The sender of INIT must include a Supported Address Types parameter in theinit to indicate the types of address that are acceptable. When this parameter is present, the receiver ofinit must either use one of the address types indicated in the Supported Address Types parameter when responding to the INIT, or abort the association with an "Unresolvable Address" error. A 32-bit unsigned integer that is randomly generated. The verification tag provides a key that allows a receiver to verify that the SCTP packet belongs to the current association and is not an old or stale packet from a previous association. 42 Glossary