STD: 59 May 2000 Obsoletes: 1757 Category: Standards Track. Remote Network Monitoring Management Information Base

Transcription

1 Network Working Group S. Waldbusser Request for Comments: 2819 Lucent Technologies STD: 59 May 2000 Obsoletes: 1757 Category: Standards Track Remote Network Monitoring Management Information Base Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2000). All Rights Reserved. Abstract This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in TCP/IP-based internets. In particular, it defines objects for managing remote network monitoring devices. This memo obsoletes RFC This memo extends that specification by documenting the RMON MIB in SMIv2 format while remaining semantically identical to the existing SMIv1-based MIB. Waldbusser Standards Track [Page 1]

2 Table of Contents 1 The SNMP Management Framework Overview Remote Network Management Goals Textual Conventions Structure of MIB The Ethernet Statistics Group The History Control Group The Ethernet History Group The Alarm Group The Host Group The HostTopN Group The Matrix Group The Filter Group The Packet Capture Group The Event Group Control of Remote Network Monitoring Devices Resource Sharing Among Multiple Management Stations Row Addition Among Multiple Management Stations Conventions Definitions Security Considerations Acknowledgments Author s Address References Intellectual Property Full Copyright Statement The SNMP Management Framework The SNMP Management Framework presently consists of five major components: o An overall architecture, described in RFC 2571 [1]. o Mechanisms for describing and naming objects and events for the purpose of management. The first version of this Structure of Management Information (SMI) is called SMIv1 and described in STD 16, RFC 1155 [2], STD 16, RFC 1212 [3] and RFC 1215 [4]. The second version, called SMIv2, is described in STD 58, RFC 2578 [5], RFC 2579 [6] and RFC 2580 [7]. o Message protocols for transferring management information. The first version of the SNMP message protocol is called SNMPv1 and described in STD 15, RFC 1157 [8]. A second version of the SNMP message protocol, which is not an Internet standards track protocol, is called SNMPv2c and described in RFC 1901 [9] and RFC Waldbusser Standards Track [Page 2]

3 1906 [10]. The third version of the message protocol is called SNMPv3 and described in RFC 1906 [10], RFC 2572 [11] and RFC 2574 [12]. o Protocol operations for accessing management information. The first set of protocol operations and associated PDU formats is described in STD 15, RFC 1157 [8]. A second set of protocol operations and associated PDU formats is described in RFC 1905 [13]. o A set of fundamental applications described in RFC 2573 [14] and the view-based access control mechanism described in RFC 2575 [15]. A more detailed introduction to the current SNMP Management Framework can be found in RFC 2570 [22]. Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. Objects in the MIB are defined using the mechanisms defined in the SMI. This memo specifies a MIB module that is compliant to the SMIv2. A MIB conforming to the SMIv1 can be produced through the appropriate translations. The resulting translated MIB must be semantically equivalent, except where objects or events are omitted because no translation is possible (use of Counter64). Some machine readable information in SMIv2 will be converted into textual descriptions in SMIv1 during the translation process. However, this loss of machine readable information is not considered to change the semantics of the MIB. 2. Overview Remote network monitoring devices, often called monitors or probes, are instruments that exist for the purpose of managing a network. Often these remote probes are stand-alone devices and devote significant internal resources for the sole purpose of managing a network. An organization may employ many of these devices, one per network segment, to manage its internet. In addition, these devices may be used for a network management service provider to access a client network, often geographically remote. The objects defined in this document are intended as an interface between an RMON agent and an RMON management application and are not intended for direct manipulation by humans. While some users may tolerate the direct display of some of these objects, few will Waldbusser Standards Track [Page 3]

4 tolerate the complexity of manually manipulating objects to accomplish row creation. These functions should be handled by the management application. While most of the objects in this document are suitable for the management of any type of network, there are some which are specific to managing Ethernet networks. These are the objects in the etherstatstable, the etherhistorytable, and some attributes of the filterpktstatus and capturbufferpacketstatus objects. The design of this MIB allows similar objects to be defined for other network types. It is intended that future versions of this document and additional documents will define extensions for other network types. There are a number of companion documents to the RMON MIB. The Token Ring RMON MIB [19] provides objects specific to managing Token Ring networks. The RMON-2 MIB [20] extends RMON by providing RMON analysis up to the application layer. The SMON MIB [21] extends RMON by providing RMON analysis for switched networks Remote Network Management Goals o Offline Operation There are sometimes conditions when a management station will not be in constant contact with its remote monitoring devices. This is sometimes by design in an attempt to lower communications costs (especially when communicating over a WAN or dialup link), or by accident as network failures affect the communications between the management station and the probe. For this reason, this MIB allows a probe to be configured to perform diagnostics and to collect statistics continuously, even when communication with the management station may not be possible or efficient. The probe may then attempt to notify the management station when an exceptional condition occurs. Thus, even in circumstances where communication between management station and probe is not continuous, fault, performance, and configuration information may be continuously accumulated and communicated to the management station conveniently and efficiently. o Proactive Monitoring Given the resources available on the monitor, it is potentially helpful for it continuously to run diagnostics and to log network performance. The monitor is always available at the onset of any failure. It can notify the management station of the failure and can store historical statistical information Waldbusser Standards Track [Page 4]

5 about the failure. This historical information can be played back by the management station in an attempt to perform further diagnosis into the cause of the problem. o Problem Detection and Reporting The monitor can be configured to recognize conditions, most notably error conditions, and continuously to check for them. When one of these conditions occurs, the event may be logged, and management stations may be notified in a number of ways. o Value Added Data Because a remote monitoring device represents a network resource dedicated exclusively to network management functions, and because it is located directly on the monitored portion of the network, the remote network monitoring device has the opportunity to add significant value to the data it collects. For instance, by highlighting those hosts on the network that generate the most traffic or errors, the probe can give the management station precisely the information it needs to solve a class of problems. o Multiple Managers An organization may have multiple management stations for different units of the organization, for different functions (e.g. engineering and operations), and in an attempt to provide disaster recovery. Because environments with multiple management stations are common, the remote network monitoring device has to deal with more than own management station, potentially using its resources concurrently Textual Conventions Two new data types are introduced as a textual convention in this MIB document, OwnerString and EntryStatus Structure of MIB The objects are arranged into the following groups: - ethernet statistics - history control - ethernet history - alarm - host Waldbusser Standards Track [Page 5]

6 - hosttopn - matrix - filter - packet capture - event These groups are the basic unit of conformance. If a remote monitoring device implements a group, then it must implement all objects in that group. For example, a managed agent that implements the host group must implement the hostcontroltable, the hosttable and the hosttimetable. While this section provides an overview of grouping and conformance information for this MIB, the authoritative reference for such information is contained in the MODULE-COMPLIANCE and OBJECT-GROUP macros later in this MIB. All groups in this MIB are optional. Implementations of this MIB must also implement the system group of MIB-II [16] and the IF-MIB [17]. MIB-II may also mandate the implementation of additional groups. These groups are defined to provide a means of assigning object identifiers, and to provide a method for implementors of managed agents to know which objects they must implement The Ethernet Statistics Group The ethernet statistics group contains statistics measured by the probe for each monitored Ethernet interface on this device. This group consists of the etherstatstable The History Control Group The history control group controls the periodic statistical sampling of data from various types of networks. This group consists of the historycontroltable The Ethernet History Group The ethernet history group records periodic statistical samples from an ethernet network and stores them for later retrieval. This group consists of the etherhistorytable. Waldbusser Standards Track [Page 6]

7 The Alarm Group The alarm group periodically takes statistical samples from variables in the probe and compares them to previously configured thresholds. If the monitored variable crosses a threshold, an event is generated. A hysteresis mechanism is implemented to limit the generation of alarms. This group consists of the alarmtable and requires the implementation of the event group The Host Group The host group contains statistics associated with each host discovered on the network. This group discovers hosts on the network by keeping a list of source and destination MAC Addresses seen in good packets promiscuously received from the network. This group consists of the hostcontroltable, the hosttable, and the hosttimetable The HostTopN Group The hosttopn group is used to prepare reports that describe the hosts that top a list ordered by one of their statistics. The available statistics are samples of one of their base statistics over an interval specified by the management station. Thus, these statistics are rate based. The management station also selects how many such hosts are reported. This group consists of the hosttopncontroltable and the hosttopntable, and requires the implementation of the host group The Matrix Group The matrix group stores statistics for conversations between sets of two addresses. As the device detects a new conversation, it creates a new entry in its tables. This group consists of the matrixcontroltable, the matrixsdtable and the matrixdstable The Filter Group The filter group allows packets to be matched by a filter equation. These matched packets form a data stream that may be captured or may generate events. This group consists of the filtertable and the channeltable. Waldbusser Standards Track [Page 7]

8 The Packet Capture Group The Packet Capture group allows packets to be captured after they flow through a channel. This group consists of the buffercontroltable and the capturebuffertable, and requires the implementation of the filter group The Event Group The event group controls the generation and notification of events from this device. This group consists of the eventtable and the logtable. 3. Control of Remote Network Monitoring Devices Due to the complex nature of the available functions in these devices, the functions often need user configuration. In many cases, the function requires parameters to be set up for a data collection operation. The operation can proceed only after these parameters are fully set up. Many functional groups in this MIB have one or more tables in which to set up control parameters, and one or more data tables in which to place the results of the operation. The control tables are typically read-write in nature, while the data tables are typically read-only. Because the parameters in the control table often describe resulting data in the data table, many of the parameters can be modified only when the control entry is invalid. Thus, the method for modifying these parameters is to invalidate the control entry, causing its deletion and the deletion of any associated data entries, and then create a new control entry with the proper parameters. Deleting the control entry also gives a convenient method for reclaiming the resources used by the associated data. Some objects in this MIB provide a mechanism to execute an action on the remote monitoring device. These objects may execute an action as a result of a change in the state of the object. For those objects in this MIB, a request to set an object to the same value as it currently holds would thus cause no action to occur. To facilitate control by multiple managers, resources have to be shared among the managers. These resources are typically the memory and computation resources that a function requires. Waldbusser Standards Track [Page 8]

9 3.1. Resource Sharing Among Multiple Management Stations When multiple management stations wish to use functions that compete for a finite amount of resources on a device, a method to facilitate this sharing of resources is required. Potential conflicts include: o Two management stations wish to simultaneously use resources that together would exceed the capability of the device. o A management station uses a significant amount of resources for a long period of time. o A management station uses resources and then crashes, forgetting to free the resources so others may use them. A mechanism is provided for each management station initiated function in this MIB to avoid these conflicts and to help resolve them when they occur. Each function has a label identifying the initiator (owner) of the function. This label is set by the initiator to provide for the following possibilities: o A management station may recognize resources it owns and no longer needs. o A network operator can find the management station that owns the resource and negotiate for it to be freed. o A network operator may decide to unilaterally free resources another network operator has reserved. o Upon initialization, a management station may recognize resources it had reserved in the past. With this information it may free the resources if it no longer needs them. Management stations and probes should support any format of the owner string dictated by the local policy of the organization. It is suggested that this name contain one or more of the following: IP address, management station name, network manager s name, location, or phone number. This information will help users to share the resources more effectively. There is often default functionality that the device or the administrator of the probe (often the network administrator) wishes to set up. The resources associated with this functionality are then owned by the device itself or by the network administrator, and are intended to be long-lived. In this case, the device or the administrator will set the relevant owner object to a string starting with monitor. Indiscriminate modification of the monitor-owned configuration by network management stations is discouraged. In fact, a network management station should only modify these objects under the direction of the administrator of the probe. Waldbusser Standards Track [Page 9]

10 Resources on a probe are scarce and are typically allocated when control rows are created by an application. Since many applications may be using a probe simultaneously, indiscriminate allocation of resources to particular applications is very likely to cause resource shortages in the probe. When a network management station wishes to utilize a function in a monitor, it is encouraged to first scan the control table of that function to find an instance with similar parameters to share. This is especially true for those instances owned by the monitor, which can be assumed to change infrequently. If a management station decides to share an instance owned by another management station, it should understand that the management station that owns the instance may indiscriminately modify or delete it. It should be noted that a management application should have the most trust in a monitor-owned row because it should be changed very infrequently. A row owned by the management application is less long-lived because a network administrator is more likely to reassign resources from a row that is in use by one user than from a monitor-owned row that is potentially in use by many users. A row owned by another application would be even less long-lived because the other application may delete or modify that row completely at its discretion Row Addition Among Multiple Management Stations The addition of new rows is achieved using the method described in RFC 1905 [13]. In this MIB, rows are often added to a table in order to configure a function. This configuration usually involves parameters that control the operation of the function. The agent must check these parameters to make sure they are appropriate given restrictions defined in this MIB as well as any implementation specific restrictions such as lack of resources. The agent implementor may be confused as to when to check these parameters and when to signal to the management station that the parameters are invalid. There are two opportunities: o When the management station sets each parameter object. o When the management station sets the entry status object to valid. If the latter is chosen, it would be unclear to the management station which of the several parameters was invalid and caused the badvalue error to be emitted. Thus, wherever possible, the implementor should choose the former as it will provide more information to the management station. Waldbusser Standards Track [Page 10]

11 A problem can arise when multiple management stations attempt to set configuration information simultaneously using SNMP. When this involves the addition of a new conceptual row in the same control table, the managers may collide, attempting to create the same entry. To guard against these collisions, each such control entry contains a status object with special semantics that help to arbitrate among the managers. If an attempt is made with the row addition mechanism to create such a status object and that object already exists, an error is returned. When more than one manager simultaneously attempts to create the same conceptual row, only the first can succeed. The others will receive an error. When a manager wishes to create a new control entry, it needs to choose an index for that row. It may choose this index in a variety of ways, hopefully minimizing the chances that the index is in use by another manager. If the index is in use, the mechanism mentioned previously will guard against collisions. Examples of schemes to choose index values include random selection or scanning the control table looking for the first unused index. Because index values may be any valid value in the range and they are chosen by the manager, the agent must allow a row to be created with any unused index value if it has the resources to create a new row. Some tables in this MIB reference other tables within this MIB. When creating or deleting entries in these tables, it is generally allowable for dangling references to exist. There is no defined order for creating or deleting entries in these tables. 4. Conventions The following conventions are used throughout the RMON MIB and its companion documents. Good Packets Good packets are error-free packets that have a valid frame length. For example, on Ethernet, good packets are error-free packets that are between 64 octets long and 1518 octets long. They follow the form defined in IEEE section 3.2.all. Bad Packets Bad packets are packets that have proper framing and are therefore recognized as packets, but contain errors within the packet or have an invalid length. For example, on Ethernet, bad packets have a valid preamble and SFD, but have a bad CRC, or are either shorter than 64 octets or longer than 1518 octets. Waldbusser Standards Track [Page 11]

12 5. Definitions RMON-MIB DEFINITIONS ::= BEGIN IMPORTS MODULE-IDENTITY, OBJECT-TYPE, OBJECT-IDENTITY, NOTIFICATION-TYPE, mib-2, Counter32, Integer32, TimeTicks FROM SNMPv2-SMI TEXTUAL-CONVENTION, DisplayString MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP FROM SNMPv2-TC FROM SNMPv2-CONF; -- Remote Network Monitoring MIB rmonmibmodule MODULE-IDENTITY LAST-UPDATED " Z" May, 2000 ORGANIZATION "IETF RMON MIB Working Group" CONTACT-INFO "Steve Waldbusser Phone: Fax: "Remote network monitoring devices, often called monitors or probes, are instruments that exist for the purpose of managing a network. This MIB defines objects for managing remote network monitoring devices." REVISION " Z" May, 2000 "Reformatted into SMIv2 format. This version published as RFC 2819." REVISION " Z" -- 1 Feb, 1995 "Bug fixes, clarifications and minor changes based on implementation experience, published as RFC1757 [18]. Two changes were made to object definitions: 1) A new status bit has been defined for the capturebufferpacketstatus object, indicating that the packet order within the capture buffer may not be identical to the packet order as received off the wire. This bit may only Waldbusser Standards Track [Page 12]

13 be used for packets transmitted by the probe. Older NMS applications can safely ignore this status bit, which might be used by newer agents. 2) The packetmatch trap has been removed. This trap was never actually approved and was not added to this document along with the risingalarm and fallingalarm traps. The packetmatch trap could not be throttled, which could cause disruption of normal network traffic under some circumstances. An NMS should configure a risingalarm threshold on the appropriate channelmatches instance if a trap is desired for a packetmatch event. Note that logging of packetmatch events is still supported--only trap generation for such events has been removed. In addition, several clarifications to individual object definitions have been added to assist agent and NMS implementors: - global definition of good packets and bad packets - more detailed text governing conceptual row creation and modification - instructions for probes relating to interface changes and disruptions - clarification of some ethernet counter definitions - recommended formula for calculating network utilization - clarification of channel and capturebuffer behavior for some unusual conditions - examples of proper instance naming for each table" REVISION " Z" -- 1 Nov, 1991 "The original version of this MIB, published as RFC1271." ::= { rmonconformance 8 } rmon OBJECT IDENTIFIER ::= { mib-2 16 } -- textual conventions OwnerString ::= TEXTUAL-CONVENTION Waldbusser Standards Track [Page 13]

14 "This data type is used to model an administratively assigned name of the owner of a resource. Implementations must accept values composed of well-formed NVT ASCII sequences. In addition, implementations should accept values composed of well-formed UTF-8 sequences. It is suggested that this name contain one or more of the following: IP address, management station name, network manager s name, location, or phone number. In some cases the agent itself will be the owner of an entry. In these cases, this string shall be set to a string starting with monitor. SNMP access control is articulated entirely in terms of the contents of MIB views; access to a particular SNMP object instance depends only upon its presence or absence in a particular MIB view and never upon its value or the value of related object instances. Thus, objects of this type afford resolution of resource contention only among cooperating managers; they realize no access control function with respect to uncooperative parties." SYNTAX OCTET STRING (SIZE (0..127)) EntryStatus ::= TEXTUAL-CONVENTION "The status of a table entry. Setting this object to the value invalid(4) has the effect of invalidating the corresponding entry. That is, it effectively disassociates the mapping identified with said entry. It is an implementation-specific matter as to whether the agent removes an invalidated entry from the table. Accordingly, management stations must be prepared to receive tabular information from agents that corresponds to entries currently not in use. Proper interpretation of such entries requires examination of the relevant EntryStatus object. An existing instance of this object cannot be set to createrequest(2). This object may only be set to createrequest(2) when this instance is created. When this object is created, the agent may wish to create supplemental object instances with default values to complete a conceptual row in this table. Because the Waldbusser Standards Track [Page 14]

15 creation of these default objects is entirely at the option of the agent, the manager must not assume that any will be created, but may make use of any that are created. Immediately after completing the create operation, the agent must set this object to undercreation(3). When in the undercreation(3) state, an entry is allowed to exist in a possibly incomplete, possibly inconsistent state, usually to allow it to be modified in multiple PDUs. When in this state, an entry is not fully active. Entries shall exist in the undercreation(3) state until the management station is finished configuring the entry and sets this object to valid(1) or aborts, setting this object to invalid(4). If the agent determines that an entry has been in the undercreation(3) state for an abnormally long time, it may decide that the management station has crashed. If the agent makes this decision, it may set this object to invalid(4) to reclaim the entry. A prudent agent will understand that the management station may need to wait for human input and will allow for that possibility in its determination of this abnormally long period. An entry in the valid(1) state is fully configured and consistent and fully represents the configuration or operation such a row is intended to represent. For example, it could be a statistical function that is configured and active, or a filter that is available in the list of filters processed by the packet capture process. A manager is restricted to changing the state of an entry in the following ways: To: valid createrequest undercreation invalid From: valid OK NO OK OK createrequest N/A N/A N/A N/A undercreation OK NO OK OK invalid NO NO NO OK nonexistent NO OK NO OK In the table above, it is not applicable to move the state from the createrequest state to any other state because the manager will never find the variable in that state. The nonexistent state is not a value of the enumeration, rather it means that the entrystatus variable does not exist at all. Waldbusser Standards Track [Page 15]

16 An agent may allow an entrystatus variable to change state in additional ways, so long as the semantics of the states are followed. This allowance is made to ease the implementation of the agent and is made despite the fact that managers should never exercise these additional state transitions." SYNTAX INTEGER { valid(1), createrequest(2), undercreation(3), invalid(4) } statistics OBJECT IDENTIFIER ::= { rmon 1 } history OBJECT IDENTIFIER ::= { rmon 2 } alarm OBJECT IDENTIFIER ::= { rmon 3 } hosts OBJECT IDENTIFIER ::= { rmon 4 } hosttopn OBJECT IDENTIFIER ::= { rmon 5 } matrix OBJECT IDENTIFIER ::= { rmon 6 } filter OBJECT IDENTIFIER ::= { rmon 7 } capture OBJECT IDENTIFIER ::= { rmon 8 } event OBJECT IDENTIFIER ::= { rmon 9 } rmonconformance OBJECT IDENTIFIER ::= { rmon 20 } -- The Ethernet Statistics Group Implementation of the Ethernet Statistics group is optional. -- Consult the MODULE-COMPLIANCE macro for the authoritative -- conformance information for this MIB The ethernet statistics group contains statistics measured by the -- probe for each monitored interface on this device. These -- statistics take the form of free running counters that start from -- zero when a valid entry is created This group currently has statistics defined only for -- Ethernet interfaces. Each etherstatsentry contains statistics -- for one Ethernet interface. The probe must create one -- etherstats entry for each monitored Ethernet interface -- on the device. etherstatstable OBJECT-TYPE SYNTAX SEQUENCE OF EtherStatsEntry MAX-ACCESS not-accessible "A list of Ethernet statistics entries." ::= { statistics 1 } Waldbusser Standards Track [Page 16]

17 etherstatsentry OBJECT-TYPE SYNTAX EtherStatsEntry MAX-ACCESS not-accessible "A collection of statistics kept for a particular Ethernet interface. As an example, an instance of the etherstatspkts object might be named etherstatspkts.1" INDEX { etherstatsindex } ::= { etherstatstable 1 } EtherStatsEntry ::= SEQUENCE { etherstatsindex etherstatsdatasource etherstatsdropevents etherstatsoctets etherstatspkts etherstatsbroadcastpkts etherstatsmulticastpkts etherstatscrcalignerrors etherstatsundersizepkts etherstatsoversizepkts etherstatsfragments etherstatsjabbers etherstatscollisions etherstatspkts64octets etherstatspkts65to127octets etherstatspkts128to255octets etherstatspkts256to511octets etherstatspkts512to1023octets etherstatspkts1024to1518octets etherstatsowner etherstatsstatus } Integer32, OBJECT IDENTIFIER, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, OwnerString, EntryStatus etherstatsindex OBJECT-TYPE SYNTAX Integer32 ( ) "The value of this object uniquely identifies this etherstats entry." ::= { etherstatsentry 1 } etherstatsdatasource OBJECT-TYPE SYNTAX OBJECT IDENTIFIER Waldbusser Standards Track [Page 17]

18 "This object identifies the source of the data that this etherstats entry is configured to analyze. This source can be any ethernet interface on this device. In order to identify a particular interface, this object shall identify the instance of the ifindex object, defined in RFC 2233 [17], for the desired interface. For example, if an entry were to receive data from interface #1, this object would be set to ifindex.1. The statistics in this group reflect all packets on the local network segment attached to the identified interface. An agent may or may not be able to tell if fundamental changes to the media of the interface have occurred and necessitate an invalidation of this entry. For example, a hot-pluggable ethernet card could be pulled out and replaced by a token-ring card. In such a case, if the agent has such knowledge of the change, it is recommended that it invalidate this entry. This object may not be modified if the associated etherstatsstatus object is equal to valid(1)." ::= { etherstatsentry 2 } etherstatsdropevents OBJECT-TYPE SYNTAX Counter32 "The total number of events in which packets were dropped by the probe due to lack of resources. Note that this number is not necessarily the number of packets dropped; it is just the number of times this condition has been detected." ::= { etherstatsentry 3 } etherstatsoctets OBJECT-TYPE SYNTAX Counter32 UNITS "Octets" "The total number of octets of data (including those in bad packets) received on the network (excluding framing bits but including FCS octets). Waldbusser Standards Track [Page 18]

19 This object can be used as a reasonable estimate of 10-Megabit ethernet utilization. If greater precision is desired, the etherstatspkts and etherstatsoctets objects should be sampled before and after a common interval. The differences in the sampled values are Pkts and Octets, respectively, and the number of seconds in the interval is Interval. These values are used to calculate the Utilization as follows: Pkts * ( ) + (Octets *.8) Utilization = Interval * 10,000 The result of this equation is the value Utilization which is the percent utilization of the ethernet segment on a scale of 0 to 100 percent." ::= { etherstatsentry 4 } etherstatspkts OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" "The total number of packets (including bad packets, broadcast packets, and multicast packets) received." ::= { etherstatsentry 5 } etherstatsbroadcastpkts OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" "The total number of good packets received that were directed to the broadcast address. Note that this does not include multicast packets." ::= { etherstatsentry 6 } etherstatsmulticastpkts OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" "The total number of good packets received that were directed to a multicast address. Note that this number does not include packets directed to the broadcast Waldbusser Standards Track [Page 19]

20 address." ::= { etherstatsentry 7 } etherstatscrcalignerrors OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" "The total number of packets received that had a length (excluding framing bits, but including FCS octets) of between 64 and 1518 octets, inclusive, but had either a bad Frame Check Sequence (FCS) with an integral number of octets (FCS Error) or a bad FCS with a non-integral number of octets (Alignment Error)." ::= { etherstatsentry 8 } etherstatsundersizepkts OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" "The total number of packets received that were less than 64 octets long (excluding framing bits, but including FCS octets) and were otherwise well formed." ::= { etherstatsentry 9 } etherstatsoversizepkts OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" "The total number of packets received that were longer than 1518 octets (excluding framing bits, but including FCS octets) and were otherwise well formed." ::= { etherstatsentry 10 } etherstatsfragments OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" Waldbusser Standards Track [Page 20]

21 "The total number of packets received that were less than 64 octets in length (excluding framing bits but including FCS octets) and had either a bad Frame Check Sequence (FCS) with an integral number of octets (FCS Error) or a bad FCS with a non-integral number of octets (Alignment Error). Note that it is entirely normal for etherstatsfragments to increment. This is because it counts both runts (which are normal occurrences due to collisions) and noise hits." ::= { etherstatsentry 11 } etherstatsjabbers OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" "The total number of packets received that were longer than 1518 octets (excluding framing bits, but including FCS octets), and had either a bad Frame Check Sequence (FCS) with an integral number of octets (FCS Error) or a bad FCS with a non-integral number of octets (Alignment Error). Note that this definition of jabber is different than the definition in IEEE section (10BASE5) and section (10BASE2). These documents define jabber as the condition where any packet exceeds 20 ms. The allowed range to detect jabber is between 20 ms and 150 ms." ::= { etherstatsentry 12 } etherstatscollisions OBJECT-TYPE SYNTAX Counter32 UNITS "Collisions" "The best estimate of the total number of collisions on this Ethernet segment. The value returned will depend on the location of the RMON probe. Section (10BASE-5) and section (10BASE-2) of IEEE standard states that a station must detect a collision, in the receive mode, if three or more stations are transmitting simultaneously. A repeater port must detect a collision when two or more Waldbusser Standards Track [Page 21]

22 stations are transmitting simultaneously. Thus a probe placed on a repeater port could record more collisions than a probe connected to a station on the same segment would. Probe location plays a much smaller role when considering 10BASE-T (10BASE-T) of IEEE standard defines a collision as the simultaneous presence of signals on the DO and RD circuits (transmitting and receiving at the same time). A 10BASE-T station can only detect collisions when it is transmitting. Thus probes placed on a station and a repeater, should report the same number of collisions. Note also that an RMON probe inside a repeater should ideally report collisions between the repeater and one or more other hosts (transmit collisions as defined by IEEE 802.3k) plus receiver collisions observed on any coax segments to which the repeater is connected." ::= { etherstatsentry 13 } etherstatspkts64octets OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" "The total number of packets (including bad packets) received that were 64 octets in length (excluding framing bits but including FCS octets)." ::= { etherstatsentry 14 } etherstatspkts65to127octets OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" "The total number of packets (including bad packets) received that were between 65 and 127 octets in length inclusive (excluding framing bits but including FCS octets)." ::= { etherstatsentry 15 } etherstatspkts128to255octets OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" Waldbusser Standards Track [Page 22]

23 "The total number of packets (including bad packets) received that were between 128 and 255 octets in length inclusive (excluding framing bits but including FCS octets)." ::= { etherstatsentry 16 } etherstatspkts256to511octets OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" "The total number of packets (including bad packets) received that were between 256 and 511 octets in length inclusive (excluding framing bits but including FCS octets)." ::= { etherstatsentry 17 } etherstatspkts512to1023octets OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" "The total number of packets (including bad packets) received that were between 512 and 1023 octets in length inclusive (excluding framing bits but including FCS octets)." ::= { etherstatsentry 18 } etherstatspkts1024to1518octets OBJECT-TYPE SYNTAX Counter32 UNITS "Packets" "The total number of packets (including bad packets) received that were between 1024 and 1518 octets in length inclusive (excluding framing bits but including FCS octets)." ::= { etherstatsentry 19 } etherstatsowner OBJECT-TYPE SYNTAX OwnerString Waldbusser Standards Track [Page 23]

24 "The entity that configured this entry and is therefore using the resources assigned to it." ::= { etherstatsentry 20 } etherstatsstatus OBJECT-TYPE SYNTAX EntryStatus "The status of this etherstats entry." ::= { etherstatsentry 21 } -- The History Control Group -- Implementation of the History Control group is optional. -- Consult the MODULE-COMPLIANCE macro for the authoritative -- conformance information for this MIB The history control group controls the periodic statistical -- sampling of data from various types of networks. The -- historycontroltable stores configuration entries that each -- define an interface, polling period, and other parameters. -- Once samples are taken, their data is stored in an entry -- in a media-specific table. Each such entry defines one -- sample, and is associated with the historycontrolentry that -- caused the sample to be taken. Each counter in the -- etherhistoryentry counts the same event as its similarly-named -- counterpart in the etherstatsentry, except that each value here -- is a cumulative sum during a sampling period If the probe keeps track of the time of day, it should start -- the first sample of the history at a time such that -- when the next hour of the day begins, a sample is -- started at that instant. This tends to make more -- user-friendly reports, and enables comparison of reports -- from different probes that have relatively accurate time -- of day The probe is encouraged to add two history control entries -- per monitored interface upon initialization that describe a short -- term and a long term polling period. Suggested parameters are seconds for the short term polling period and 30 minutes for -- the long term period. historycontroltable OBJECT-TYPE SYNTAX SEQUENCE OF HistoryControlEntry MAX-ACCESS not-accessible Waldbusser Standards Track [Page 24]

25 "A list of history control entries." ::= { history 1 } historycontrolentry OBJECT-TYPE SYNTAX HistoryControlEntry MAX-ACCESS not-accessible "A list of parameters that set up a periodic sampling of statistics. As an example, an instance of the historycontrolinterval object might be named historycontrolinterval.2" INDEX { historycontrolindex } ::= { historycontroltable 1 } HistoryControlEntry ::= SEQUENCE { historycontrolindex Integer32, historycontroldatasource OBJECT IDENTIFIER, historycontrolbucketsrequested Integer32, historycontrolbucketsgranted Integer32, historycontrolinterval Integer32, historycontrolowner OwnerString, historycontrolstatus EntryStatus } historycontrolindex OBJECT-TYPE SYNTAX Integer32 ( ) "An index that uniquely identifies an entry in the historycontrol table. Each such entry defines a set of samples at a particular interval for an interface on the device." ::= { historycontrolentry 1 } historycontroldatasource OBJECT-TYPE SYNTAX OBJECT IDENTIFIER "This object identifies the source of the data for which historical data was collected and placed in a media-specific table on behalf of this historycontrolentry. This source can be any interface on this device. In order to identify Waldbusser Standards Track [Page 25]

26 a particular interface, this object shall identify the instance of the ifindex object, defined in RFC 2233 [17], for the desired interface. For example, if an entry were to receive data from interface #1, this object would be set to ifindex.1. The statistics in this group reflect all packets on the local network segment attached to the identified interface. An agent may or may not be able to tell if fundamental changes to the media of the interface have occurred and necessitate an invalidation of this entry. For example, a hot-pluggable ethernet card could be pulled out and replaced by a token-ring card. In such a case, if the agent has such knowledge of the change, it is recommended that it invalidate this entry. This object may not be modified if the associated historycontrolstatus object is equal to valid(1)." ::= { historycontrolentry 2 } historycontrolbucketsrequested OBJECT-TYPE SYNTAX Integer32 ( ) "The requested number of discrete time intervals over which data is to be saved in the part of the media-specific table associated with this historycontrolentry. When this object is created or modified, the probe should set historycontrolbucketsgranted as closely to this object as is possible for the particular probe implementation and available resources." DEFVAL { 50 } ::= { historycontrolentry 3 } historycontrolbucketsgranted OBJECT-TYPE SYNTAX Integer32 ( ) "The number of discrete sampling intervals over which data shall be saved in the part of the media-specific table associated with this historycontrolentry. Waldbusser Standards Track [Page 26]

27 When the associated historycontrolbucketsrequested object is created or modified, the probe should set this object as closely to the requested value as is possible for the particular probe implementation and available resources. The probe must not lower this value except as a result of a modification to the associated historycontrolbucketsrequested object. There will be times when the actual number of buckets associated with this entry is less than the value of this object. In this case, at the end of each sampling interval, a new bucket will be added to the media-specific table. When the number of buckets reaches the value of this object and a new bucket is to be added to the media-specific table, the oldest bucket associated with this historycontrolentry shall be deleted by the agent so that the new bucket can be added. When the value of this object changes to a value less than the current value, entries are deleted from the media-specific table associated with this historycontrolentry. Enough of the oldest of these entries shall be deleted by the agent so that their number remains less than or equal to the new value of this object. When the value of this object changes to a value greater than the current value, the number of associated mediaspecific entries may be allowed to grow." ::= { historycontrolentry 4 } historycontrolinterval OBJECT-TYPE SYNTAX Integer32 ( ) UNITS "Seconds" "The interval in seconds over which the data is sampled for each bucket in the part of the media-specific table associated with this historycontrolentry. This interval can be set to any number of seconds between 1 and 3600 (1 hour). Because the counters in a bucket may overflow at their Waldbusser Standards Track [Page 27]

28 maximum value with no indication, a prudent manager will take into account the possibility of overflow in any of the associated counters. It is important to consider the minimum time in which any counter could overflow on a particular media type and set the historycontrolinterval object to a value less than this interval. This is typically most important for the octets counter in any media-specific table. For example, on an Ethernet network, the etherhistoryoctets counter could overflow in about one hour at the Ethernet s maximum utilization. This object may not be modified if the associated historycontrolstatus object is equal to valid(1)." DEFVAL { 1800 } ::= { historycontrolentry 5 } historycontrolowner OBJECT-TYPE SYNTAX OwnerString "The entity that configured this entry and is therefore using the resources assigned to it." ::= { historycontrolentry 6 } historycontrolstatus OBJECT-TYPE SYNTAX EntryStatus "The status of this historycontrol entry. Each instance of the media-specific table associated with this historycontrolentry will be deleted by the agent if this historycontrolentry is not equal to valid(1)." ::= { historycontrolentry 7 } -- The Ethernet History Group -- Implementation of the Ethernet History group is optional. -- Consult the MODULE-COMPLIANCE macro for the authoritative -- conformance information for this MIB The Ethernet History group records periodic statistical samples -- from a network and stores them for later retrieval. -- Once samples are taken, their data is stored in an entry -- in a media-specific table. Each such entry defines one Waldbusser Standards Track [Page 28]

29 -- sample, and is associated with the historycontrolentry that -- caused the sample to be taken. This group defines the -- etherhistorytable, for Ethernet networks. -- etherhistorytable OBJECT-TYPE SYNTAX SEQUENCE OF EtherHistoryEntry MAX-ACCESS not-accessible "A list of Ethernet history entries." ::= { history 2 } etherhistoryentry OBJECT-TYPE SYNTAX EtherHistoryEntry MAX-ACCESS not-accessible "An historical sample of Ethernet statistics on a particular Ethernet interface. This sample is associated with the historycontrolentry which set up the parameters for a regular collection of these samples. As an example, an instance of the etherhistorypkts object might be named etherhistorypkts.2.89" INDEX { etherhistoryindex, etherhistorysampleindex } ::= { etherhistorytable 1 } EtherHistoryEntry ::= SEQUENCE { etherhistoryindex etherhistorysampleindex etherhistoryintervalstart etherhistorydropevents etherhistoryoctets etherhistorypkts etherhistorybroadcastpkts etherhistorymulticastpkts etherhistorycrcalignerrors etherhistoryundersizepkts etherhistoryoversizepkts etherhistoryfragments etherhistoryjabbers etherhistorycollisions etherhistoryutilization } Integer32, Integer32, TimeTicks, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Counter32, Integer32 etherhistoryindex OBJECT-TYPE SYNTAX Integer32 ( ) Waldbusser Standards Track [Page 29]

30 "The history of which this entry is a part. The history identified by a particular value of this index is the same history as identified by the same value of historycontrolindex." ::= { etherhistoryentry 1 } etherhistorysampleindex OBJECT-TYPE SYNTAX Integer32 ( ) "An index that uniquely identifies the particular sample this entry represents among all samples associated with the same historycontrolentry. This index starts at 1 and increases by one as each new sample is taken." ::= { etherhistoryentry 2 } etherhistoryintervalstart OBJECT-TYPE SYNTAX TimeTicks "The value of sysuptime at the start of the interval over which this sample was measured. If the probe keeps track of the time of day, it should start the first sample of the history at a time such that when the next hour of the day begins, a sample is started at that instant. Note that following this rule may require the probe to delay collecting the first sample of the history, as each sample must be of the same interval. Also note that the sample which is currently being collected is not accessible in this table until the end of its interval." ::= { etherhistoryentry 3 } etherhistorydropevents OBJECT-TYPE SYNTAX Counter32 "The total number of events in which packets were dropped by the probe due to lack of resources during this sampling interval. Note that this number is not necessarily the number of packets dropped, it is just the number of times this condition has been Waldbusser Standards Track [Page 30]