1. RMON2 RFC4502 (2021 Obsolete) Remote Monitor are often called “Monitor” or “Probe” Decode packets at layer 3 through 7 of the OSI Model – An RMON probe can monitor traffic on the basis of network-layer protocol – The probe can record traffic to and from host for particular applications

2. Network layer Visibility Network Manager can answer these questions – If there is excessive load on the LAN due to incoming router traffic, what networks or hosts account for the bulk of incoming traffic? – If a router is overloaded because of high amount of outgoing traffic, what networks or hosts account for the bulk of outgoing traffic or to what destination networks or hosts is that traffic directed – If there is a high load of pass-through traffic (arriving via one router and departing via another router ), what networks or hosts are responsible for the bulk of this traffic

3. Application Level Visibility RMON2 probe is capable of seeing above the IP layer by reading the enclosed higher-level headers such as TCP/UDP and viewing the headers at the application protocol level This information is useful in controlling load and maintaining performance – NMS can be implemented that will generate charts and graphs depicting traffic percentage by protocols or by applications

4. RMON MIB (1&2)

5. RMON2 MIB (1) protocol directory – a master of directory off all protocols that probe can interpret protocol distribution – aggregate statistics on the amount of traffic generated by each protocol per LAN segment address map – match each network address to a specific MAC level address and port on an attached device and the physical address on this subnetwork network layer host – statistics on the amount of traffic into and out of hosts on the basis of the network-layer address

6. RMON2 MIB (2) network-layer matrix – statistics on the amount of traffic between pairs of hosts on the basis of network address application-layer host - statistics on the amount of traffic into and out of hosts on the basis of application-level address application-layer matrix - statistics on the amount of traffic between pairs of hosts on the basis of application-level address

7. RMON2 MIB (3) User history collection – periodically samples user- specified variables and logs that data based on user-defined parameters – Ex. Collect data on a router-to-router connection Probe configuration – define standard configuration parameters for RMON probes – To solve interoperability problems

8. New features in RMON2 (1) Indexing with external objects – Reduce control index object in data table – To access instance of the data entry in RMON 1 Vs RMON2 Rm1datavalue.Rm1controlindex.Rm1dataindex – Rm1datavalue.2.89 – 2 – Rm1controlindex / 89 – Rm1dataindex Rm2datavalue.X.Rm2dataindex – X – the value of index that specifying set of data rows by the Xth row (external object) – Rm2datavalue.2.89 – 2 – external object / 89 – Rm2dataindex

10. New features in RMON2 (2) Time filtering Indexing – Typically, a network management app. is periodically to poll all probes for the values of objects – It is desirable to have the probe return values only for those objects whose value have changed since the last poll – No direct way in SNMP, but RMON2 has a mechanism

11. Example of time filtering

12. FooTable

13. EX1. Time filtering (1) Suppose fooTable has 2 values of index – 1,2 – If no fooTimeMark, a management station can see only two counter – With fooTimeMark, it is possible to request the values of these counter only if they have been updated since a given time

14. EX1. Time filtering (2) For example, current value of – The counter associated with fooIndex = 1 is 5 and most recently updated at time 6 – The counter associated with fooIndex=2 is 9 and most recently updated at time 8 – Then, at time 10, a manager issues the request GetRequest(fooCounts.7.1, fooCounts.7.2) To get the value updated since time 7 The agent will response fooCounts.7.2=9

16. EX2. Time Filtering (1)

17. EX2. Time Filtering (2) Assume that basic row 1 (fooIndex=1) was updated as follows: sysUptimefooCount.*.1value 5001 9002 23003

18. EX2. Time Filtering (3) Assume that basic row 2 (fooIndex=2) was updated as follows: sysUptimefooCount.*.2value 11001 14002

19. EX2. Time Filtering (4) A manager station polls a probe every 15 seconds (clock nms records time in hundredths of second) 1 At nms=1000, the manager does the baseline poll to get everything since the last agent restart (Timefilter =0) GetRequest (sysUpTime.0,fooCounts.0.1,fooCount.0.2) Response(sysUpTime.0=600,fooCounts.0.1=1,fooCount.0.2=0 ) 2 At nms=2500 (15 second later), the manager get an update on all changes since the last report (agent time=600) GetRequest (sysUpTime.0, fooCounts.600.1, fooCount.600.2) Response(sysUpTime.0=2100,fooCounts.600.1=2,fooCount.600.2=2)

20. EX2. Time Filtering (5) The agent received the request at a local time of 2100 ; a counter 1 was incremented at time 900 counter 2 was incremented at 1100 and 1400 3 At nms=4000, the manager get an update on all changes since the last report (agent time=2100) GetRequest (sysUpTime.0, fooCounts.2100.1, fooCount.2100.2) Response(sysUpTime.0=3600,fooCounts.2100.1=3) A counter 1 was incremented at time 2300 counter 2 has not changed since 2100, so no value returned

21. EX2. Time Filtering (6) 4 At nms=5500, the manager get an update on all changes since the last report (agent time=3600) GetRequest (sysUpTime.0, fooCounts.3600.1, fooCount.3600.2) Response(sysUpTime.0=5500,) Neither counter has been updated since time 3600, so no value returned

22. Protocol Directory Group It provides a single central point for storing information about types of protocols One entry in the table for each protocol for which the probe can decode and count protocol data unit (PDU) One scalar objects – protocolDirLastChange which contains the time of the last table change One columnar object (Table) – protocolDirTable – The table covers MAC, network and higher layer protocols

23. protocolDirTable Fig 10.5

24. Protocol identification protocolDirID object contains a unique octet string for a specific protocol. Octet string identifiers for protocols are arranged in a tree structured hierarchy. – Each layer is identified by 32 bit value which is encoded as dot decimal format [a.b.c.d] – EX. Ethernet is hexadecimal 1 which is encoded as [0.0.0.1] and referred to symbolically as ether2

25. Protocol Assignments Each layer is identified by a 32 bit number (four octets) For MAC level protocols – ether2 = 1 [0.0.0.1] – llc = 2 [0.0.0.2] – snap = 3 [0.0.0.3] – vsnap = 4 [0.0.0.4] – ianaAssigned = 5 [0.0.0.5] Protocol consideration – network layer, use type field of Ethernet frame (IP =0.0.8.0) – transport layer, use protocol field of IP header (UDP = 0.0.0.17) – application layer, use port field of UDP/TCP header (0.0.0.161)

26. Entry in protocolDirEntry (1) EX. Identification of SNMP running over UDP/IP on Ethernet – 16.0.0.0.1.0.0.8.0.0.0.0.17.0.0.0.161 – 16 : the number of octets to follow So, for previous example the probe is capable of – Interpreting all incoming Ethernet frames – Looking past the Ethernet header and trailer and interpreting the encapsulated IP datagram – Looking past the IP header and interpreting the encapsulated UDP segment – Looking past the UDP header and interpreting the encapsulated SNMP PDU

27. Entry in protocolDirEntry (2) A separate entry is needed for each protocol that the probe can interpret and count Then the four entries are needed in protocolDirEntry and the protocolDirID values would be – Ether2 (4.0.0.0.1) – Ether2.ip (8.0.0.1.0.0.8.0) – Ether2.ip.udp (12.0.0.0.1.0.0.8.0.0.0.0.17) – Ether2.ip.udp.snmp (16.0.0.0.1.0.0.8.0.0.0.0.17.0.0.0.161)

28. Format of index values for protocolDirTable

29. Protocol parameter (1) The second index object for protocolDirTable is protocolDirParameters This object instance contains information about the probe’s capability with the respect to a particular protocol The value is structured as a one-octet count field followed by a set of N-octet parameters, one for each protocol layer in protocolDirID Each bit in the parameter octet is encoded separately to define a particular capability

30. Protocol parameter (2) 2 LSB are reserved for all protocols – CountFragment (bit0) : Higher-layer protocols encapsulated within this protocol will be counted correctly even if this protocol fragments the upper-layer PDUs into multiple fragments – tracksSessions (bit1) :Correctly attributes all packets of a port- mapped protocol, that is a protocol start session on a well- known port or socket and then transfer them to dynamically assigned ports or sockets for the duration of the session TFTP (Trivial File Transfer Protocol)

31. Protocol parameter (3) SNMP running over UDP/IP/Ethernet with fragments counted correctly for IP or above, the following encoding is for the two objects (protocolDirID, protocolDirParameter) 16.0.0.0.1.0.0.8.0.0.0.0.17.0.0.0.161.4.0.1.0.0

32. Protocol Directory Table (1) protocolDirType This object describes 2 attributes of this protocol directory entry. SYNTAX – Bits {extensible(0), addressRecognitionCapable(1) }

33. Protocol Directory Table (2) protocolDirType – extensible(0) if the agent or manager may extend this table by creating entries that are children of this protocol An example of an entry that will often allow extensibility is'ip.udp'. The probe may automatically populate some children of this node, such as 'ip.udp.snmp' and 'ip.udp.dns'. – addressRecognitionCapable(1) If this bit is set, the agent will recognize network-layer addresses for this protocol and populate the network- and application- layer host and matrix tables with these protocols.

34. Protocol Directory Table (3) protocolDirAddressMapConfig SYNTAX – Integer {notSupported(1), supportedOff(2 supportedOn(3)} This object describes and configures the probe's support for address mapping for this protocol. – notSupported(1) : if not capable of performing address mapping – If capable then the value may be set to supportedOff(2) or supportedOn(3)

35. Protocol Directory Table (4) protocolDirHostConfig SYNTAX – Integer {notSupported(1), supportedOff(2 supportedOn(3)} This object describes and configures the probe's support for the network-layer and application-layer host tables for this protocol. – If the value of this object is notSupported(1), the probe will not track the nlHostTable or alHostTable for this protocol – If the value of this object is supportedOn(3), the probe supports tracking of the nlHostTable and alHostTable for this protocol and is configured to track both tables for this protocol for all control entries and all interfaces.

36. Protocol Directory Table (5) protocolDirMatrixConfig SYNTAX – Integer {notSupported(1), supportedOff(2 supportedOn(3)} This object describes and configures the probe's support for the network-layer and application-layer matrix tables for this protocol. – If the value of this object is notSupported(1), the probe will not track either of the nlMatrixTables or the alMatrixTables – If the value of this object is supportedOn(3), the probe supports tracking of both of the nlMatrixTables and (if implemented) both of the alMatrixTables for this protocol and is configured to track these tables for this protocol for all control entries and all interfaces.

37. Protocol Distribution Group (1) It summarizes how many octets and packets have been sent from each of the protocols supported protocolDistControlTable – controls collection of basic statistics for all supported protocols protocolDistStatsTable – records the data

39. Protocol Distribution Group (2) Each row in protocolDistControlTable refers to a unique network interface for this probe and controls a number of rows of protocolDistStatsTable, one for each protocol recognized on that interface

40. Protocol Distribution Group (3) protocolDistControlTable consists of – protocolDistControlIndex : an integer that uniquely identifies a row in the protocolDistControlTable – protocolDistControlDatasource : identifies the interface that is th source of the data for this row – protocolDistControlDroppedFrames : total number of received frames for this interface that the probe chose not to count (out of resources) – protocolDistControlCreateTime : the value of sysUptime when this control entry was activated

41. Protocol Distribution Group (4) The protocolDistStatsTable includes one row for each protocol in protocolDirTable for which at least one packet has been seen It is indexed by protocolDistControlIndex and by protocolDirLocalIndex

42. Protocol Distribution Group (5) protocolDistStatsTable consists of – protocolDistStatsPkts: the number of packets received for this protocol – protocolDistStatsOctets: the number of octets transmitted to this address since it was added to nlHostTable

43. Address Map Group (1) It matches each network address to a specific MAC-level address It is helpful in node discovery and network topology applications for pinpointing the specific path of the network traffic 3 scalars objects, one control table (addressMapControlTable) and one data table (addressMapTable)

45. Address Map Group (1) 3 scalar objects are – addressMapInserts : the number of times an address- mapping entry has been inserted into the data table – addressMapDeletes: the number of times an address- mapping entry has been deleted into the data table – addressMapMaxDesiredEntries : the desired maximum number of entries in addressMapTable (if this value is set to -1, the probe may create any number of entries in addressMapTable) Data table size = addressMapInserts - addressMapDeletes

46. Address Map Group (2) The addressMapControlTable consists of – addressMapControlIndex: an integer that uniquely identifies a row in the addressMapControlTable – addressMapcontrolDatasource : identifies the interface that is the source of the data for this row and that this row is configured to analyze – addressMapControlDroppedFrames: total number of received frame for this interface that the probe chose not to count (out of resources)

47. Address Map Group (3) The addressMapTable will collect address mapping based on source MAC and network addresses seen in error-free MAC frames The table will create entries for all protocols in the protocol directory table whose value of protocolDirAddressMapConfig is equal to supportedOn(3)

48. Address Map Group (4) The addressMapTable consists of – addressMapTimeMark : a time filter for this entry – addressMapNetworkAddress : the network address for this entry – addressMapSource : the last interface which the associated network address was seen – addressMapPhysicalAddress : the last source MAC address on which the associated network address was seen – addressMapLastChange : the value of sysUpTime at the time this entry was most recently updated

49. Network-layer Host Group (1) nlHost group enables users to decode packets based on their network-layer address This group consists of 2 Tables – nlHostControlTable : control table – nlHostTable : data table

51. Network-layer Host Group (2) Each row in control table refers to a unique interface of the monitor nlHostControlTable – nlhostControlIndex : an integer that uniquely identifies a row in the nlHostControlTable – nlHostControlDataSource : identifies the interface that is the source of the data for the data tableentries defined by this row – nlHostControlNlDroppedFrames : total number of received frames for this interface that the probe chose not to count for the associated nlHost entries

52. Network-layer Host Group (3) – nlHostControlNlInserts : the number of times an nlHost entry has been inserted into the nlHostTable data table – nlHostControlNldeletes : the number of times an nlHost entry has been deleted from the nlHostTable data table – nlhostControlNlMaxDesiredEntries : the desired maximum number of entries in nlHostTable

53. Network-layer Host Group (4) – nlHostControlAlDroppedFrames : total number of received frames for this interface that the probe chose not to count for the associated alHost entries – nlHostControlAlInserts : the number of times an alHost entry has been inserted into the alHostTable data table – nlHostControlAldeletes : the number of times an alHost entry has been deleted from the alHostTable data table – nlhostControlAlMaxDesiredEntries : the desired maximum number of entries in alHostTable

54. Network-layer Host Group (5) nlHostTable will create entries for all network-layer protocols in the protocol directory table whose value of protocolDirNlHostConfig is equal to supportedOn(3) nlHostTable – nlHostTimeMark : a time filter for this entry – nlHostAddress : the network address for this entry – nlHostInPackets : the number of error-free packets transmitted to this address since it was added to the table

55. Network-layer Host Group (6) – nlHostOutPackets : the number of error-free packets transmitted from this address since it was added to the table – nlHostInOctets : the number of octets (error-free packets) transmitted to this address since it was added to the table – nlHostOutOctets : the number of octets (error- free packets) transmitted from this address since it was added to the table

56. Network-layer Host Group (7) – nlHostCreateTime : the value of sysUpTime when this control entry was activated – nlHostOutMacNonUnicastPkts : the number of packets transmitted by this address that were directed to the MAC broadcast address or ti any MAC multicast address since this entry was added to the table

57. Network-layer Host Group (7) nlHostTable is indexed by four objects: – nlHostControlIndex : define interface – nlHostTimeMark : a time filter – protocolDirLocalIndex : the identity of the protocol – nlHostAddress : the network address

58. Application-Layer Host Group (1) The nlHostControlTable also controls alHostTable Only alHostTable in application-layer host group alHostTable will create entries for all application-level protocols in the protocol directory table whose value of protocolDirALHostConfig is equal to supportedOn(3)

60. Application-Layer Host Group (2) alHostTable – alHostTimeMark : a time filter for this entry – alHostInPackets : the number of error-free packets of this protocol type transmitted to this address since it was added to the table – alHostOutPackets : the number of error-free packets of this protocol type transmitted from this address since it was added to the table

61. Application-Layer Host Group (3) – alHostInOctets : the number of octets (error-free packets) of this protocol type transmitted to this address since it was added to the table – alHostOutOctets : the number of octets (error- free packets) of this protocol type transmitted from this address since it was added to the table – alHostCreateTime : the value of sysUpTime when this control entry was activated

62. Application-Layer Host Group (4) alHostTable is indexed by five objects: – nlHostControlIndex : define interface – alHostTimeMark : a time filter – protocolDirLocalIndex : the identity of the network layer protocol – nlHostAddress : the network address – protocolDirLocalIndex : the identity of the application layer protocol

63. Network Layer Matrix Group (1) It gathers statistics based on source and destination network-layer address For network layer statistic consists of one control table and 2 data tables – nlMatrixControlTable : control table for network layer matrix group and application layer matrix group – nlMatrixSDTable : stores statistics on traffic from a particular source network-layer address to a number of destinations – nlMatrixDSTable : stores statistics on traffic to a particular destination network-layer address from a number of sources

66. Network Layer Matrix Group (2) The nlMatrixSDTable is indexed – the row of nlMatrixControlTable that control it then – by a time filter: nlMatrixSDTimeMark then – by the network-layer protocol : protocolDirLocalIndex then – by the network layer source address : nlMatrixSDSourceAddress then – by the network layer destination address : nlMatrixSDDestAddress

67. Network Layer Matrix Group (3) The nlMatrixDSTable is indexed – the row of nlMatrixControlTable that control it then – by a time filter: nlMatrixDSTimeMark then – by the network-layer protocol : protocolDirLocalIndex then – by the network layer destination address : nlMatrixDSDestAddress – by the network layer source address : nlMatrixDSSourceAddress then

68. Network-Layer TopN Statistics (1) To determine which pairs of hosts rank in the top N according to some metric One control table and one datatable – nlMatrixTopNControlTable – nlMatrixTopNTaable

71. Network-Layer TopN Statistics (2) nlMatrixTopNControlTable – nlMatrixTopNRateBase : specifies one of two variables (nlMatrixTopNPackets(1) /nlMatrixTopNOctets(2) ) – nlMatrixTopNRequestedSize: the maximum number of matrix entries requested for the topN table

72. Network-Layer TopN Statistics (3) nlMatrixTopNtable – nlMatrixTopNPktRate – the number of packets seen from source host to destination host during this sampling interval – nlMatrixTopNReversePktRate – same as above (but destination to source) – nlMatrixTopNOctetRate – the number of octets seen from source host to destination host during this sampling interval – nlMatrixTopNReverseOctetRate – same as above (but destination to source)

73. Network-Layer TopN Statistics (4) The nlMatrixTopNTable is indexed by – nlMatrixTopNControlIndex – nlMatrixTopNIndex

74. Application-Layer Matrix Group (1) Statistical collection of information based on source and destination application address (port number) This group consists of 3 data tables and 1 control table – alMatrixSDTable – alMatrixDSTable – alMatrixTopNControlTable – alMatrixTopNTable

76. alMatrix Group (2) Fig 10.15

77. Application-Layer Matrix Group (2) The alMatrixSDTable (alMatrixDSTable) is indexed by – nlMatrixControlIndex : that identifies a unique subnetwork – nlMatrixSDTimeMark : time filter – protocolDirLocalIndex : the network-layer protocol – nlMatrixSDSourceAddress : the network layer source address – nlMatrixSDDestAddress : the network layer destination address – protocolDirLocalIndex : the application-layer protocol

78. Application-Layer Matrix Group (3) alMatrixTopNControlTable has the same structure as the nlMatrixTopNControlTable Only difference is the definition of the rate base object: alMatrixTopNRateBase alMatrixTopNTerminalsPkts(1) count only protocol packets (no child protocol) alMatrixTopNTerminalsOctets(2) count only protocol octets (no child protocol) alMatrixTopNAllPkts(3) alMatrixTopNAllOctets(4 )

79. Application-Layer Matrix Group (4) alMatrixTopNtable – alMatrixTopNPktRate – the number of packets seen from source host to destination host during this sampling interval – alMatrixTopNReversePktRate – same as above (Destination to source)

80. User history collection group (1) User history collection group Collect particular statistics and variables then logs that data based on user-defined parameters User history collection group consists of usrHistoryControlTable, usrHistoryObjectTable,

81. User history collection group (2)

82. User history collection group (3) userControlTable – usrHistoryControlIndex – usrHistoryControlObjects – usrHistoryControlBucketsRequested – usrHistoryControlBucketsGranted – usrHistoryControlInterval – usrHistoryControlOwner – usrHistoryControlStatus

83. User history collection group (4) UsrHistoryObjectTable – usrHistoryObjectIndex – usrHistoryObjectVariable : Identify Variable to be collected – usrHistoryObjectSampleType : absolute or delta value

84. User history collection group (5) UsrHistoryTable – usrHistorySampleIndex – usrHistoryIntervalStart – usrHistoryIntervalEnd – usrHistoryAbsValue – usrHistoryValStatus

85. User history collection group (3)

86. Probe configuration group – To solve interoperability among RMON probe and managers

87. Security Consideration (1) The usrHistoryGroup periodically samples the values of user-specified variables on the probe and stores them in another table. – The agent MUST ensure that usrHistoryObjectVariable is not writable in MIB views that don't already have read access to the entire agent. Because the access control configuration can change over time, information could later be deemed sensitive that would still be accessible to this function.

88. Security Consideration (2) A probe implementing this MIB is likely to also implement RMON [RFC2819], which includes functions for returning the contents of captured packets, potentially including sensitive user data or passwords.RFC2819 – It is recommended that SNMP access to these functions be restricted

89. Security Consideration (3) There are a number of management objects defined in this MIB that have a MAX-ACCESS clause of read-write and/or read-create. – Such objects may be considered sensitive or vulnerable in some network environments. – The support for SET operations in a non-secure environment without proper protection can have a negative effect on network operations.

90. Security Consideration (4) Some of the readable objects in this MIB module (i.e., objects with a MAX-ACCESS other than not-accessible) may be considered sensitive or vulnerable in some network environments. – It is thus important to control even GET and/or NOTIFY access to these objects and possibly to even encrypt the values of these objects when sending them over the network via SNMP.

91. Security Consideration (5) SNMP versions prior to SNMPv3 did not include adequate security. Even if the network itself is secure (for example by using IPSec), even then, there is no control as to who on the secure network is allowed to access and GET/SET (read/change/create/delete) the objects in this MIB module. It is RECOMMENDED that implementers consider the security features as provided by the SNMPv3 framework (see [RFC3410], section 8), including full support for the SNMPv3 cryptographic mechanisms (for authentication and privacy).[RFC3410], section 8

92. Security Consideration (6) Deployment of SNMP versions prior to SNMPv3 is NOT RECOMMENDED. Instead, it is RECOMMENDED to deploy SNMPv3 and to enable cryptographic security. It is then a customer/operator responsibility to ensure that the SNMP entity giving access to an instance of this MIB module is properly configured to give access to the objects only to those principals (users) that have legitimate rights to indeed GET or SET (change/create/delete) them.

93. Practical Issues