1 © 1999 BMC SOFTWARE, INC. 2/10/00 SNMP in Patrol Eugene Golovinsky BMC Software, SNMP technology group

2 © 1999 BMC SOFTWARE, INC. 2/10/00 SNMP Simple Network Management Protocol

3 © 1999 BMC SOFTWARE, INC. 2/11/00 Why was SNMP invented ? Designed to run on non-OS systems, later used in various ways for monitoring No “BRAINS” SNMP Agent THE “BRAINS” SNMP Manager u Maybe no (Free) Cpu u Maybe no (Free) Memory u Must be able to run everywhere u Real OS u Contained all intelligence u Made all decisions

4 © 1999 BMC SOFTWARE, INC. 2/11/00 Protocol, its versions and extentions What is SNMP About the protocol versions SNMPv1, SNMPv2 ( c ) and SNMPv3 Some other things : RMON, RMON 2, SMI's and MIB's SNMPv3 - as a future path for SNMP community ?

5 © 1999 BMC SOFTWARE, INC. 2/11/00 SNMP implementations  Transport Transport protocol (UDP/IP) BER (iso 8825) - Basic Encoding Rules  TLV (Type, Length, Value) encoding  Versions SNMPv1 SNMPv2 SNMPv3  OSI network management implementation CMIP - CMOT ( used primarily in telephony along with SNMP)

6 © 1999 BMC SOFTWARE, INC. 2/11/00 SNMP Syntax - SMI ASN.1 (iso “abstract notation one”)  SMI uses a subset of ASN.1  Well defined syntax for information exchange  comparable in functionality with XML

7 © 1999 BMC SOFTWARE, INC. 2/11/00 SNMPv3  New Draft Standard with enhanced Security User Based security model (rfc 2574) Administration Security (authentication, privacy and message integrity) View based access (VACM)

8 © 1999 BMC SOFTWARE, INC. 2/11/00 RMON (Remote Network Monitoring)  IETF rfc 1271 / rfc 1757 / rfc 1513  Physical Layer Management using probes (HW-SW)  Extend SNMP functionality RMON MIB : contains RMON data Preventive Management : threshold based notification Statistics/History of data, Packet capturing, Host tables,… Operation modes  Online  Offline  On Demand

9 © 1999 BMC SOFTWARE, INC. 2/11/00 RMON2  Continued on RMON (rfc 2021)  Statistics on network and upper layers  All of the leading probe vendors support it NetScout, Technically Elite, Solcom, HP, 3Com, Bay, Cisco, Cabletron  Difficult to use all features because of vendor specific implementations

10 © 1999 BMC SOFTWARE, INC. 2/11/00 SNMP References SNMP v1 RFCs  1155SMI  1157protocol  1212Concise MIB  1213MIB2  1215traps SNMP v2 RFCs  historical See also : The Simple Web SNMP v2C RFCs  SNMP v3 RFCs   

11 © 1999 BMC SOFTWARE, INC. 2/11/00 UDP vs. TCP connection UDP RM Agents Console Agents TCP connectionless scalable not reliable connection oriented used to be non-scalable reliable

12 © 1999 BMC SOFTWARE, INC. 2/11/00 SNMP : Underlying Transport UDP/IP implications unreliable  no confirmation or guarantee  order uncertain  may duplicate unsecure  No authentication on transport layer  No verification of origin (message spoofing)  No integrity (message can be tampered with)

13 © 1999 BMC SOFTWARE, INC. 2/11/00 The SNMP Agent What is an SNMP agent ?  Components : MIB (the MIB in memory) request handling trap sending

14 © 1999 BMC SOFTWARE, INC. 2/11/00 Multiple SNMP Agents on 1 system Conflict : only 1 process can listen on a port Solutions :  SMUX (SNMP Multiplexer)  AgentX - Agent Extensibility (rfc 2741)  Emanate (proprietary SNMP Research) 161 Master Agent Sub agent Application Device

15 © 1999 BMC SOFTWARE, INC. 2/11/00 MIB (Management Information Base)  The MIB definition textual description of MIB layout Written in SMI : Structure of Management Information  SMI (the MIB definition language) Support for multiple datatypes Support for data definitions : indexed tables, structures, values,...

16 © 1999 BMC SOFTWARE, INC. 2/11/00 NAMING in SNMP Naming hierarchy unique identifier, down to the instance of any object is the OID of the BMC Software subtree; Object identifier is the name iso 1 3 org 6dod 1 internet 2 mgmt 4 private 1enterprises enterpriseID peer BMC Company X Whatever you like

17 © 1999 BMC SOFTWARE, INC. 2/11/00 SNMP Management Remote Management : From a geographically separate location  configure  monitor  control a remote system  application  device  OS Management console Mgmt info, i.e., interesting info “application” Managed system Mgmt protocol

18 © 1999 BMC SOFTWARE, INC. 2/11/00 Management Operations, SNMP requests and responses  Get, Get Next, Set SNMPv1 responses are sent back  Get Bulk (SNMPv2)  Unsolicited Traps from Agent (v1)  Informs (v2 and v3) - confirmed traps

19 © 1999 BMC SOFTWARE, INC. 2/11/00 Request handling  SNMP Agent gets request from mgr listens on specific port : typically 161 receives request : request ID + OID  Lookup of OID in memory  Performs operation if possible  SNMP Agent sends response request ID OID value error status + index  Similar for get-next operation returns next OID in tree

20 © 1999 BMC SOFTWARE, INC. 2/11/00 Trap sending SNMP Agent sends  7 predefined Generic trap types (0-6) 0-5 = Standard traps 6 = Enterprise Specific  Sends to port 162 (default) on trap receiving machine  Trap destinations has to be configured Patrol : /snmp/piV1m_list

21 © 1999 BMC SOFTWARE, INC. 2/11/00 The SNMP Manager What is an SNMP manager ? Components :  present MIB info (display MIB files)  send requests  listen for traps

22 © 1999 BMC SOFTWARE, INC. 2/11/00 Sending Requests  Timebased polling  User based requests Authentication :  SNMPv1 : community names for r/w (most of the times, just private/public)  SNMPv3 does it with MD5

23 © 1999 BMC SOFTWARE, INC. 2/11/00 Listening for traps Only one process can listen on a port That means only one trap listener per system ! Solution :  PATROL : trap demultiplexer (Dietmar Hildebrand)  No PATROL : (write your own)

24 © 1999 BMC SOFTWARE, INC. 2/11/00 SNMP++ Initial HP initiative, now Open Source  Object oriented development approach to SNMPv1,v2c,v3  High level API  Primary focus on network management application developer References :

25 © 1999 BMC SOFTWARE, INC. 2/10/00 ??? Questions ???

26 © 1999 BMC SOFTWARE, INC. 2/10/00 PATROL SNMP Functionality

27 © 1999 BMC SOFTWARE, INC. 2/11/00 Patrol SNMP Master and Sub Agent Only needed when accessing PATROL MIB data !! Patrol MIB data is KM data Not needed for :  receiving traps  sending traps  get/set/walk/... operations

28 © 1999 BMC SOFTWARE, INC. 2/11/00 Patrol SNMP Master agent configuration  See file./lib/snmpmagt.cfg default port used to be 1161, community public  No need for BMC master agent if SMUX compatible Master Agent available (eg. AIX)  What about HP ? They use emanate master agent (proprietary from SNMP Research) Run 2 master agents, one on 161 (default) and one on 1161 (Patrol)

29 © 1999 BMC SOFTWARE, INC. 2/11/00 Starting Patrol SNMP sub-agent PATROL SNMP sub-agent can be manually started and stopped from PSL  snmp_agent_start() starts SNMP sub-agent  snmp_agent_stop() stops SNMP sub-agent  snmp_agent_config() tells if SNMP agent functionality is active

30 © 1999 BMC SOFTWARE, INC. 2/11/00 PATROL Agent as SNMP sub agent  Ability to send traps  Has an accessible MIB To access MIB, the master agent must be set up correctly

31 © 1999 BMC SOFTWARE, INC. 2/11/00 SNMP Traps in Patrol  Automatically : When Patrol event occurs Trap destinations : piV1m_List ( + /snmp/trapMibTable=yes) Filter possibility (see config.default for filter options) Through Master Agent or without Master Agent trapMibTable(yes), trapConfTable (no) - default  From PSL snmp_trap_send : full control snmp_trap_raise_std_trap : uses piV1m_List

32 © 1999 BMC SOFTWARE, INC. 2/11/00 PATROL Agent MIB

33 © 1999 BMC SOFTWARE, INC. 2/11/00 Objects Table Contains all the “nodes” from the PATROL namespace, starting from the PATH defined in objectsCwd (=objects Current Working Dir)

34 © 1999 BMC SOFTWARE, INC. 2/11/00 variablesTable Contains all the “leaves” from the PATROL namespace, starting from the PATH defined in objectsCwd (=objects Current Working Dir)

35 © 1999 BMC SOFTWARE, INC. 2/11/00 Browsing PATROL namespace  Set objectCwd to the tree you want to inspect for example “/”  Go to the desired “node” get the “objectsTable”, you see NT_CPU set objectCwd to “/NT_CPU” … pick inst from objectsTable set objectCwd to “/NT_CPU/CPU_0”… pick param from objectsTable set objectCwd to “/NT_CPU/CPU_0/CPUCpuUtil”  Read the wanted values get the “variablesTable” to find all the attributes including its value  Problem : No way to protect objectsCwd : other PSL script can change its value in the same time !

36 © 1999 BMC SOFTWARE, INC. 2/11/00 applicationsTable Contains all the applications loaded in the agent and indexed by application ID

37 © 1999 BMC SOFTWARE, INC. 2/11/00 applInstTable Contains all the instances discovered in the agent. Indexed application ID and instance ID

38 © 1999 BMC SOFTWARE, INC. 2/11/00 parametersTable Contains all the parameters in the agent. Indexed by application ID, instance ID and parameter OID

39 © 1999 BMC SOFTWARE, INC. 2/11/00 Table relationships applicationsTable idnamestate…. 0SOLARIS0…. 1CPU0…. 2DISK0…. 3KERNEL0…. 4NFS0…....…. applInstTable idnamestatus…....…. 1.50CPU0…. 2.60sd50…. 2.61nfs10…. 2.70idehd010…....…. parametersTable idnamevalue…....… DSKTps0… DSKTps0… DSKBps0… DSKAvgS..0…....….

40 © 1999 BMC SOFTWARE, INC. 2/11/00 Accessing PATROL namespace  Look for the application in “applicationTable”  Use that index to get the instances from the application in “applInstTable”  Use both indexes to get the parameters from the “parametersTable”  Get the required attribute from your parameter  This method is “safe” but requires some processing

41 © 1999 BMC SOFTWARE, INC. 2/11/00 Direct namespace access  “Hooked” on OID of :.variablesTable.variableEntry.variableValue  Need conversion of namespace variable = length of namespace variable = ascii to value conversion of namespace variable for example : /CPU =  Simply get : bmc  Result : Fastest Namespace access not useful for namespace “discovery” Not “walk-able”

42 © 1999 BMC SOFTWARE, INC. 2/11/00 Execute PSL through SNMP  Set variable “agentExecuteCommand”  Agent will execute immediately  Fail/Success from return value of snmp_set()

43 © 1999 BMC SOFTWARE, INC. 2/11/00 PATROL Agent as SNMP Manager  Receiving traps  Getting information from SNMP agents  No Master Agent is needed for this !

44 © 1999 BMC SOFTWARE, INC. 2/11/00 Using PSL to Receive traps  PSL functions : snmp_trap_listen : start listening for traps (open socket) starts accumulating traps snmp_trap_ignore : close all listeners (close socket) snmp_trap_receive : process incoming traps (block/poll based) only 1 per agent

45 © 1999 BMC SOFTWARE, INC. 2/11/00 Using PSL to Get info from SNMP Agents What is an SNMP session in PATROL ? snmp_open() : opens an SNMP session snmp_close() : closes an SNMP session snmp_config() : lists the SNMP sessions  No real session (like TCP session) because SNMP = connectionless / stateless  just a memory structure, so... Easier for the developer … open session once, reuse the session with the session attributes ! Allows you to set timeouts/retries/port Faster

46 © 1999 BMC SOFTWARE, INC. 2/11/00 PSL functions for SNMP managers SNMPv1 management functions  snmp_(h_)...  snmp_... Plus  snmp_walk No support for v3 !!  Security and administration, get bulk, more datatypes

47 © 1999 BMC SOFTWARE, INC. 2/11/00 Q & A concerns and problems future