Essential Tools for the OSI Internet Network Working Group IETF-NOOP Working Group INTERNET DRAFT S. Hares, C. Wittbrodt 1. Status This document is an Internet Draft. Internet Drafts are working documents of the Internet Engineering Task Force (IETF), its Areas, and its Working Groups. Note that other groups may also distribute working documents as Internet Drafts. Internet Drafts are draft documents valid for a maximum of six months. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a "working draft" or "work in progress." Please check the I-D abstract listing contained in each Internet Draft directory to learn the current status of this or any other Internet Draft. This Internet Draft specifies tools which are necessary to debug problems in the deployment and maintenance of networks using ISO 8473[1], the connectionless network layer protocol (CLNP). This document will be submitted to the RFC editor as a proposed standard for the OSI Internet. To support some of the needed tools (ping and traceroute) this draft specifies the mechanism specified in RFC1139 [3]. 2. Abstract This document specifies the following three necessary tools to debug problems in the deployment and maintenance of net- works using ISO 8473 (CLNP): - ping or ISO Echo function - traceroute function which uses the ISO Echo function - routing table dump function These CLNS tools are the basics required for hosts and routers for CLNS network support. It is intended that this document specify the most basic support level required for CLNS hosts and routers. This document should progress along the IETF track for host and router requirements. March 23, 1993 Expires September 23, 1993 Page 1 Essential Tools for the OSI Internet 3. Table of Contents Section 1 Status ...................................... 1 Section 2 Abstract .................................... 1 Section 3 Table of Contents ........................... 2 Section 4 Conventions ................................. 2 Section 5 Introduction ................................ 2 Section 6 Specification ............................... 3 Section 6.1 Ping ...................................... 3 Section 6.1.1 Protocol Support ........................ 3 Section 6.1.2 Functions supported by the ping utili- ty ............................................... 4 Section 6.2 Traceroute ................................ 4 Section 6.2.1 Basic Traceroute ........................ 4 Section 6.2.2 Use of Partial Source route in tra- ceroute .......................................... 6 Section 6.2.3 Information needed from a Traceroute utility .......................................... 7 Section 6.3 OSI routing table dump .................... 7 Section 6.4 MIB variables available via SNMP .......... 8 Section 6.4.1 Summary of MIB Variables ................ 8 Section 6.4.2 ASN.1 Syntax for these MIB variables .... 8 Section 7 ISO HOST.txt format ......................... 11 Section 8 Acknowledgements ............................ 12 Section 9 Author's Addresses .......................... 12 Section 10 References ................................. 14 4. Conventions The following language conventions are used in the items of specification in this document: o MUST, SHALL, or MANDATORY -- the item is an absolute requirement of the specification. o SHOULD or RECOMMENDED -- the item should generally be followed for all but exceptional circumstances. o MAY or OPTIONAL -- the item is truly optional and may be followed or ignored according to the needs of the implementor. 5. Introduction Currently in the Internet, OSI protocols are being used more and more. As the network managers of an Internet once predominantly a TCP/IP network began deploying parts of the emerging OSI Internet, it became apparent that network layer ISO network debugging tools were almost nonexistent. When such tools existed, different implementations didn't work together. March 23, 1993 Expires September 23, 1993 Page 2 Essential Tools for the OSI Internet As stated in RFC 1139 a simple network layer mechanism is necessary to allow systems to be probed to test network layer integrity. For the purposes of running OSI networks the authors of this document believe that other tools are necessary too. Other tools described below are an echo function, a traceroute function, and a routing table dump. What this document defines is the minimum subset of tools that are necessary to allow for the debugging of network problems. 6. Specification This document's purpose is to specify a standard ping, tra- ceroute, and OSI routing table dumping mechanisms for use for the ISO 8473 (CLNP) protocol in the OSI Internet. A detailed description of the specified mechanisms is below. These mechanism MUST be available on every router (inter- mediate system) or host (end system) that provides OSI ser- vice for the Internet. These three functions are the basic tool set for the OSI network layer for the Internet. 6.1. Ping 6.1.1. Protocol Support The long term echo mechanism, as described in RFC1139, requires the use of two new type values in the packet header of the ISO 8473 Network Protocol Data Units(NPDUs), or preferably packets. The two values are: 1E(hex) - for the Echo Request Selector and, 1F(hex) - for the Echo Reply Selector. Nodes which support ISO8473 but do not support these two new values (for the type code option field in the header of an ISO 8473 packet) MUST send back an error packet IF the ERROR report flag is set in the packet. To support a ping function for ISO 8473, all end systems (hosts) and intermediate systems (routers) MUST support the "long term" echo function as defined by RFC 1139-Revised AND also set the ERROR report flag in the 8473 header. The setting of the ERROR report flag is required because this allows a way for a compliant host or router to ping a non-compliant host or router. When a non-complaint host or router receives a "ping" packet with the new type function (Echo Request Selector), it MUST attempt to return an ISO 8473 error packet to the originating host, thus showing March 23, 1993 Expires September 23, 1993 Page 3 Essential Tools for the OSI Internet reachability. 6.1.2. Functions supported by the ping utility A ping utility MUST be able to provide the Round trip time of each packet, plus the average minimum and maximum RTT over several ping packets. When an error packet is received by the node, the ping utility MUST report the error code to the user. 6.2. Traceroute The CLNP trace is similar to the ping utility except that it utilizes the "Lifetime" field in the ISO 8473 packet. Hosts and routers that support OSI MUST also support CLNP trace. The "Lifetime" field serves the same function as the Time To Live (TTL) field does in an IP packet. A node (router or host) cannot forward ISO 8473 packet with a value for the Lifetime of zero. If the ERROR REPORT flag is set in the ISO 8473 packet, an error packet, will be returned to the originator of the packet. 6.2.1. Basic Traceroute If a ISO 8473 echo-request packet is sent with "Lifetime" field value of 1, the first hop node (router or end system) will return an error packet to the originator the packet. If the first hop node supports the echo-request type field the error code will be either: A0 (hex) - Lifetime Expired while Data Unit in Transit A1 (hex) - Lifetime Expired during Re-assembly If the first hop node does not support echo-request type field, the error code will be: B0 (hex) - Unsupported Option not Specified. When trying to trace a route to a remote node, the destina- tion address in the echo-request packet sent should be this remote destination. By using increasing values in the "Lifetime" field a route can be traced through the network to the remote node. This traceroute function should be implemented on each system (host or router) to allow a user to trace a network path to a remote host or router. March 23, 1993 Expires September 23, 1993 Page 4 Essential Tools for the OSI Internet The error message is used as evidence of the reachability and identity of the first hop. The originator then sends a packet with a "lifetime" field value of 2. The first hop decrements the "Lifetime" and because the "Lifetime" is still greater than 0, it forwards it on. The second hop decrements the "Lifetime" field value and sends an error packet (ER NPDU) with one of the two "Lifetime Expired" error codes listed above to the originator. This sequence is repeated until either: - the remote host is reached an either an echo-reply packet is sent back or (for nodes that do not have the required Echo support) an error packet is sent back, or - the an error packet is received with error code (B0) indicating that a node will not pass the Echo-Reply packet, or - an error packet is received with one of the following errors: 80(hex) - Destination Address Unreachable 81(hex) - Destination Address Unknown. If any of the following Error codes are received in an error packet, a second packet should be sent by the originating node: CodeReason from 8473 ----------------------------- 00(hex) - Reason not specified 01(hex) - Protocol procedure error 02(hex) - Incorrect checksum 03(hex) - Packet Discarded due to Congestion 04(hex) - Header Syntax Error (cannot be parsed) 05(hex) - Segmentation needed but not permitted 06(hex) - Incomplete packet received 07(hex) - Duplicate Option B1(hex) - Unsupported Protocol Version B2(hex) - Unsupported Security Option B3(hex) - Unsupported Source Routeing Option B4(hex) - Unsupported Recording of Route Option C0(hex) - Reassembly Interface If one of these error is detected, an error value should be returned to the user. More than one echo packet, may be sent at a "Lifetime" value. The number of additional echo packets is left up to the implementation of this traceroute function. March 23, 1993 Expires September 23, 1993 Page 5 Essential Tools for the OSI Internet If one of the following errors is received, AND "partial source route" is not specified in the echo-request packets, send a second echo-request packet to the destination at a "Lifetime" value: Code Reason from 8473 -------------------------------- 90(hex) Unspecified Source Routeing Error 91(hex) Syntax Error in Source Routeing Field 92(hex) Unknown Address in Source Routeing Field 93(hex) Path not Acceptable (The echo-request packet may have been damaged while traversing through the network.) 6.2.2. Use of Partial Source route in traceroute The current IP traceroute has a 3rd party or "loose source route" function. The ISO 8473 protocol also supports a "partial source routeing" function. However, if a node (router or host) does not support the "partial source route- ing" function an ISO 8473 packet gets passed along the path "exactly as though the function has not been selected. The packet shall not be discarded for this reason."[2] In order utilize the partial source route function in the ISO traceroute, a node must set the "source routeing" option and "partial source routeing" parameter within that option. A 3rd party, or "loose source route" traceroute function requires that a node send an echo-request packet with the "loose source routeing" field set. The functioning of the 3rd party/"loose source route" traceroute is the same except the following errors cause the traceroute to be terminated: Code Reason from ISO 8473 -------------------------------------------------- 92 Unknown Address in Source Routeing Field 93 Path not Acceptable These errors may indicate a problem with the "loose source route" listed in the echo-request packet for this destina- tion. Additional packets with the same lifetime will only repeat this error. These errors should be reported to the user of the traceroute function. March 23, 1993 Expires September 23, 1993 Page 6 Essential Tools for the OSI Internet 6.2.3. Information needed from a Traceroute utility A traceroute utility should provide the following informa- tion to the user: - the identity of systems that comprise the path or route to the destination (the identifiers are called Network Entity Titles or NETs in OSI and ISO 8473) - ping times (in Round trip times) for each hop in the path, - error codes from error packet received as a response to the an echo-request packet, and - any other error conditions encountered by traceroute. 6.3. OSI routing table dump Each OSI host (end system) or router (intermediate system) MUST be able to dump any of its routing tables. Routing tables may come from the: a.) the ES-IS information b.) static c.) IS-IS d.) IDRP or any other source. Each system MUST be able to dump the routing table entries via some out of band mechanism. A method MUST exist to pro- vide these. A show osi routes command SHOULD be created with the following options: - a for all routes - esis for es-is routes - isis for is-is routes - idrp for idrp routes - static for static routes - other for routes from other sources. In addition, routing tables SHOULD be available via either SNMP or CMIP. The specification of CMIP variables are out- side the scope of this specification. Section 6.4 specifies March 23, 1993 Expires September 23, 1993 Page 7 Essential Tools for the OSI Internet the RFC 1238 MIB variables which MUST be available via SNMP. These two variables simply allow the user to get some basic CLNS routing information. Please note that not all the information requested is avail- able via the CLNS MIB. Due to this fact, it is anticipated that additional work on a CLNS MIB will be done in the future. When a new MIB is written, it is anticipated that this document will be updated to include the additional MIB variables to collect such things as the ES-IS cache. 6.4. MIB variables available via SNMP The Simple Network Management Protocol [cf] plays an impor- tant role in monitoring of multi-protocol, managed resources in the Internet. By convention, SNMP is mapped onto User Datagram Protocol (UDP, cf); however, in those situations where it is not possible to communicate with an ISO 8473 managed resource using SNMP over UDP, or where communication with an ISO 8473 managed resource using SNMP/UDP is not possible/appropriate, SNMP messages should be mapped onto an OSI transport (cf) The following Managed Objects for the SNMP must/should/may be supported to facilitate remote moni- toring using the SNMP: The Simple Network Management Protocol (SNMP) plays an important role in monitoring of multi-protocol, managed resources in the Internet. By convention, SNMP is mapped onto User Datagram Protocol (UDP); however in those situa- tions where it is not possible to communicate with an ISO 8473 managed resource using SNMP over UDP, or where communi- cation with an ISO 8473 managed resource using SNMP/UDP is not possible/appropriate, SNMP should be mapped onto an OSI tranport (TP4 reference). It is RECOMMENDED that the fol- lowing Managed Objects be supported for remoted monitoring using SNMP: 6.4.1. Summary of MIB Variables RFC 1238 CLNS MIB[5] 1) clnpAddrTable - Addresses for Interfaces 2) clnpRoutingTable - ISO routes in system routing table. 6.4.2. ASN.1 Syntax for these MIB variables The ASN.1 sytnax for the two variables the MIB in CLNS MIB (RFC 1238) is included below for easy reference. Both these RFCs remain the authoritative source for the MIB March 23, 1993 Expires September 23, 1993 Page 8 Essential Tools for the OSI Internet definitions. 1) clnpAddrTable clnpAddrTable OBJECT-TYPE object.id = .... {clnp 21 } (Dave what do I put here??) clnpAddrTable = SEQUENCE OF ClnpAddrEntry CLNPAddrEntry ::= SEQUENCE { clnpAdEntAddr CLNPAddres, clnpAdEntIfIndex, INTEGER, clnpAdEntReasmMaxSize INTEGER (0...65535); } clnpAdEntAddr = ClnpAddress clnpAddress = OCTET string (Size (1...20); clnpAdEntIfIndex = INTEGER; clnpAdEntReasmMaxSize = INTEGER (0...65535); # Descriptions of Table entry values: clnpAdEntAddr - CLNP address for this interface value clnpAdEntIfIndex - Interface Index value corresponding to IfIndex value. clnpAdEntReasmMaxSize = Maximum size of a pdu that can be reassembled from incoming PDUs received on this interface. March 23, 1993 Expires September 23, 1993 Page 9 Essential Tools for the OSI Internet 2) clnpRoutingTable object id =....{clnp 22} clnpRoutingTable = SEQUENCE OF ClnpRouteEntry; ClnpRouteEntry = SEQUENCE OF { clnpRouteDest, clnpRouteIfIndex, clnpRouteMetric1, clnpRouteMetric2, clnpRouteMetric3, clnpRouteNextHop, clnpRouteType, clnpRouteProto, clnpRouteAge, clnpRouteInfo} clnpRoutDest ::= ClnpAddress; # Address in Route table (prefix or # full address clnpRouteIfIndex ::= Integer; # IfIndex value for interface # next hop can be reached through. clnpRouteMetric1 ::= Integer; # primary routing metric for this # protocol. Specific meaning # depends on clnpRouteProto value # -1 if not used clnpRouteMetric2 ::= Integer; # alternate routing metric for this # protocol. Specific meaning # depends on clnpRouteProto value # -1 if not used clnpRouteMetric3 ::= Integer; # alternate routing metric for this # protocol. Specific meaning # depends on clnpRouteProto value # -1 if not used clnpRouteMetric4::= Integer; # alternate routing metric for this # protocol. Specific meaning # depends on clnpRouteProto value # -1 if not used clnpRouteNextHop::= ClnpAddress; # Address of Next Hop in Routing # Table clnpRouteType::=INTEGER { other (1), # none of following invalid (2), # an invalid route direct(3), # a direct route remote(4)} # a remote route clnprouteProto::= INTEGER { other (1), # none of the following # (manually configured # falls in this category) local(2), # configured entries netmngt(3), # set via Network management is-is(9), # ISO 10589 ciscoIgrp(11), # Ciscos OSI IGRP ospf(13), # OSPF set March 23, 1993 Expires September 23, 1993 Page 10 Essential Tools for the OSI Internet bgp(14), # BGP sets idrp(15) # addition suggested to rfc 1238 # in processing clnpRouteMetric5::= Integer; # alternate routing metric for this # protocol. Specific meaning # depends on clnpRouteProto value # -1 if not used clnpRouteInfo ::= OBJECT-ID; # protocol id that # installed this route } 7. ISO HOST.txt format The OSI format for addresses allows addresses to be 20 bytes. In the long term, a Directory service (DNS service or OSI Directory service (X.500)), will provide a host name to address mapping. The process of getting OSI capable DNS and Directory service may require OSI pathway to already be set-up. Most host and router system use a fixed table to provide this name to NSAP address mapping in order to get OSI working on their system. The current operational problem is each implementation has a different format. This docu- ment defines a fixed format so that these initial name to NSAP mapping files can be shared through-out the internet. To conform to this document, a host or router supporting CLNS MUST have support a "osi host.txt" file with the format below. The "osi host.txt" file may be used for other OSI applications or TUBA applications. For these other applica- tions, other fields may be defined but the definition of these is outside the scope of this specification. OSI applications may use another file name for osi address information. We strongly RECOMMEND that NSAP addresses in any osi address information use the format below. This host name to NSAP mapping MUST BE available for use by the fol- lowing utilities on CLNS hosts and routers: - ISO Echo (Ping) function, - ISO traceroute function, and - router table look-up for CLNS routing information We RECOMMEND that host and router systems also support a NSAP to name mapping by the Domain Name Service Directory or or the OSI Directory service (X.500). March 23, 1993 Expires September 23, 1993 Page 11 Essential Tools for the OSI Internet Format of osi hosts file: ... The NSAP Address should be in the following format: .<2nd octet 3rd octet>.<4th octet 5 octet>. ..... <18th octet> <19th octet> .<20th octet> comments on the above format: The NSAP octets should be expressed in hexidecimal. The dots are aids to help read the NSAP address, and not required for an NSAP address parsing. However, each NSAP address file MUST be able to have the ability to handle the insertion of dots. An example of this use in the GOSIP format is: 47.0005.80ff.ff00.0000.0001.0001.0a0b.0c0d.0204.00 An example of this format in ANSI format is: 39.480f.8000.0500.0000.0001.0001.0a0b0c0d.0204.00 This value quickly shows the AFI and the NSEL octets on either end. - Indicates a sequence of name associated with this nsap address. 8. Acknowledgements The authors would like to acknowledge the contributions made by Dave Piscitello. He not only kept the document accurate, but also helped us to get rid of the ISO jargon and make the document more readable. Thanks to Paulina Knibbe for her work with the host.txt format. We would also like to thank members of the Network OSI Operations Working Group of the IETF for their comments. 9. Author's Addresses March 23, 1993 Expires September 23, 1993 Page 12 Essential Tools for the OSI Internet Susan K. Hares MERIT/NSFNET Internet Engineering 1075 Beal Avenue Ann Arbor, MI 48109-2112 (313) 936-3000 Cathy J. Wittbrodt Stanford University/BARRNet Networking Systems Pine Hall 115 Stanford, CA 94305 (415) 725-5481 March 23, 1993 Expires September 23, 1993 Page 13 Essential Tools for the OSI Internet 10. References [1] ISO/IEC 8473, Information Processing Systems, "Protocol for Providing the Connectionless-mode Network Service and Provision of Underlying Service". May, 1987. [2] R. Hagens, "An Echo Function for ISO 8473", Request For Comment #1139, January 1990. DDN Network Information Center, SRI International. [3] S.Hares and C.Wittbrodt, "An Echo Function for ISO 8473", Internet Draft, October 1992. DDN Network Infor- mation Center, SRI International. [4] ISO/IEC DIS 10747 Information Processing Sys- tems - Telecommunications and Information Exchange between Systems - Protocol for Exchange of Inter-domain Routeing Information among Intermediate Systems to Support Forwarding of ISO 8473 packets. [5] RFC 1238 CLNS MIB (Greg Satz) - for use with Connec- tionless Network Protocol (ISO 8473) and End system to Intermediate System Protocol (ISO 9452) March 23, 1993 Expires September 23, 1993 Page 14