Network Monitoring and Management ICMP and SNMP. ICMP Internet Control Message Protocol RFC 792 Transfer of (control) messages from routers and hosts

Network Monitoring and Management

ICMP and SNMP

ICMP

Internet Control Message Protocol RFC 792 Transfer of (control) messages from

routers and hosts to hosts Feedback about problems

– e.g. time to live expired Encapsulated in plain IP datagram

– Not reliable

incoming frame

RARPARP

UDP

Application Application

TCP

Application Application

IGMPICMP

EthernetDriver

IP

Application

Transport

Network

Link

(Ethernet frame types in hex, others in decimal)

destaddr

sourceaddrEthernet frame type data CRC

destaddr

sourceaddr dataprotocol typeIP header

hdrcksum

ARP

IP

dataTCP src port headerTCP dest port

FTPserver

telnetserver SMTP23

7

2521

UDP 1761 TCP

IPIP

TCPTCP

x0800

x0806

ICMP

ICMP Types

ICMP Uses IP but is a separate protocol in the network layer ICMP messages contain

– Type

– Code

– 1st 8 bytes of “bad” datagram

IP HEADERPROTOCOL = 1

TYPE CODE CHECKSUM

REMAINDER OF ICMP MESSAGE (FORMAT IS TYPESPECIFIC)

IP HEADER

IP DATA

ICMP Message Formats

Destination UnreachableTYPE CODE CHECKSUM

UNUSED

IP HEADER + 64 bits data from original DG

TYPE = 3CODE

0 = Net unreachable1 = Host unreachable2 = Protocol unreachable3 = Port unreachable4 = Fragmentation needed but DF set5 = Source route failed6 = Dest network unknown7 = Dest host unknown

Source QuenchTYPE CODE CHECKSUM

UNUSED


TYPE = 4; CODE = 0Flow control:• Indicates that a router has dropped the original DG or may indicate that a router is approaching its capacity limit.

• Correct behavior for source host is not defined.

Time Exceeded

TYPE CODE CHECKSUM

UNUSED


TYPE = 11CODE

0 = Time to live exceeded in transit1 = Fragment reassembly time exceeded

Redirect

TYPE CODE CHECKSUM

NEW ROUTER ADDRESS


TYPE = 5CODE =

0 = Network redirect1 = Host redirect2 = Network redirect for specific TOS3 = Host redirect for specific TOS

Redirection Concept

Internet

QUERY Message: Echo and Echo Reply

TYPE CODE CHECKSUM

IDENTIFIER SEQUENCE #

DATA ….

TYPE = 8 = ECHO; 0 = ECHO REPLYCODE = 0IDENTIFIER

An identifier to aid in matching echoes and repliesSEQUENCE #

Same use as for IDENTIFIERUNIX “ping” uses echo/echo reply

Replaced by Network Time Protocol (NTP)

Using Ping[wirth:~] [4:15pm] -> ping www.uakron.eduPING arwen.uakron.edu (130.101.81.50) 56(84) bytes of data.64 bytes from arwen.uakron.edu (130.101.81.50): icmp_seq=0 ttl=62 time=0.512 ms64 bytes from arwen.uakron.edu (130.101.81.50): icmp_seq=1 ttl=62 time=0.449 ms64 bytes from arwen.uakron.edu (130.101.81.50): icmp_seq=2 ttl=62 time=1.38 ms64 bytes from arwen.uakron.edu (130.101.81.50): icmp_seq=3 ttl=62 time=0.439 ms64 bytes from arwen.uakron.edu (130.101.81.50): icmp_seq=4 ttl=62 time=0.448 ms64 bytes from arwen.uakron.edu (130.101.81.50): icmp_seq=5 ttl=62 time=0.496 ms64 bytes from arwen.uakron.edu (130.101.81.50): icmp_seq=6 ttl=62 time=0.449 ms

--- arwen.uakron.edu ping statistics ---7 packets transmitted, 7 received, 0% packet loss, time 6001msrtt min/avg/max/mdev = 0.439/0.596/1.383/0.323 ms, pipe 2[wirth:~] [4:16pm] ->

Extended Ping

IP header options can be used along with ICMP: • route recording,• timestamping, • source routing

Used for path MTU discovery

Traceroute UNIX utility - displays router used to get to a specified

Internet Host (Van Jacobson, 1988) Operation

– router sends ICMP Time Exceeded message to source if TTL is decremented to 0

– if TTL starts at 5, source host will receive Time Exceeded message from router that is 5 hops away

Traceroute sends a series of UDP probes (to port ~33500) with different TTL values… and records the source address of the ICMP Time Exceeded message for each

Probes are formatted so that the destination host will send an ICMP Port Unreachable message

Traceroute and ICMP (2) Trace the route of an IP packet

Router 1

Source

Router 2 Destination

Timeline: TTL=1

Router 1 known TTL=2

Router 2 known TTL=3

Destination known

Traceroute and ICMP (3) Trace the route of an IP packet

– Upon reaching destination,• No “Time exceeded” message generated• How do you know when final destination is

reached?

– Traceroute sends to unused UDP port (>30000), generating an ICMP “destination unreachable” message• With code “port unreachable”

Taceroutemymachine:~% traceroute www.cis.ksu.edutraceroute to polaris.cis.ksu.edu (129.130.10.93), 30 hops max, 40 byte packets 1 wraith.facnet.mcs.kent.edu (131.123.46.1) 0.878 ms 0.620 ms 0.553 ms 2 ghost.uis-mcs.mcs.kent.edu (131.123.40.1) 6.000 ms 3.366 ms 2.632 ms 3 lib2-255x248-e37-lib.gate.kent.edu (131.123.255.254) 7.170 ms 3.552 ms 4.477 ms 4 twcneo-cw.neo.rr.com (204.210.223.3) 9.515 ms 15.167 ms 18.687 ms 5 bordercore4-hssi1-0.NorthRoyalton.cw.net (166.48.233.253) 17.864 ms 10.971 ms

14.652 ms 6 core4.WillowSprings.cw.net (204.70.4.73) 23.438 ms 22.099 ms 17.397 ms 7 wsp-sprint2-nap.WillowSprings.cw.net (206.157.77.94) 18.367 ms 22.854 ms 20.267 ms 8 sl-bb11-chi-2-1.sprintlink.net (144.232.10.157) 23.518 ms 24.528 ms 18.757 ms 9 sl-bb12-chi-5-1.sprintlink.net (144.232.10.6) 21.197 ms 31.452 ms 15.050 ms10 sl-bb10-kc-7-1.sprintlink.net (144.232.9.117) 46.752 ms * 40.125 ms11 sl-gw5-kc-0-0-0.sprintlink.net (144.232.2.62) 38.360 ms 48.002 ms 44.795 ms12 sl-uok-1-0-0.sprintlink.net (144.232.132.14) 93.256 ms 67.070 ms 61.727 ms13 ks-1-ks-ksu.r.greatplains.net (164.113.232.193) 77.743 ms 64.566 ms 67.117 ms14 164.113.212.250 (164.113.212.250) 59.988 ms 46.188 ms 55.616 ms15 129.130.252.9 (129.130.252.9) 68.211 ms 67.881 ms 75.441 ms16 polaris.cis.ksu.edu (129.130.10.93) 76.462 ms 54.838 ms *

PMTU-DTCP: path-MTU discovery

SNMP

Where did it come from ?– Internet Engineering Task Force

• Network Management Area

– SNMP v1– MIBv1, MIBv2– SNMP v2 (?)– SNMP v3 (?)

SNMPv1 History

RFC 1157, 1990: – “A Simple Network Management Protocol

(SNMP)” RFC 1155, 1158, 1213, 1990:

– Specification of the MIBv2 Written in ASN.1

Protocol context of SNMP

SNMPv1 Protocol

Five Simple Messages: get-request get-next-request get-response set-request trap

SNMP - SNMP Message Handling -

SNMP Manager SNMP Agent

GetRequest (What is the value of MIB?)

GetResponse (The value is XXXX!)

GetNextRequest (What is the next value of MIB Tree ?)



SetRequest (Modify the value of OID)

Trap (Problem happened!)

SNMPv1: UDP ports

Manager Agent

get_request

get_next_request

get_response port 161

port 161

port 161

port 161port 162

get_response

get_responseset_request

trap

SNMPv1 Packet Format

UDPHeader

Version CommunityPDUType

RequestID

ErrorStatus

ErrorIndex

name value name ...

SNMP version (0 is for version 1) Community (read-only, read-write):

– Shared “password” between agent and manager

PDU: Specifies request type Request ID Error Status Error Index

Community Names

Community names are used to define where an SNMP message is destined for.

•Set up your agents to belong to certain communities.

•Set up your management applications to monitor and receive traps from certain community names.

RFC 1065 (MIB Structure) “Structure and Identification of Management

Information for TCP/IP-based Internets (SMI)” Uses Abstract Syntax Notation 1 (ASN.1) Types of information

– Network Address– IP Address– Counter (32 bit monotonically increasing)– Gauge (32 bit variable)– Timeticks (time in hundredths of a second)– Opaque (arbitrary syntax for text data)

Adopted as a full standard in RFC 1155 (basically unchanged)

MIB definitions

RFC 1066 - MIB definitions using RFC 1065 (RFC 1155) (Rose & McCloghrie)

First version of the MIB now called MIB-I Adopted as a full standard in RFC 1156

(essentially unchanged from 1066) RFC 1158 - extends MIB-I and defines MIB-II Adopted as a full standard in RFC 1213

Vendor extensions to MIB

RFC 1156 (MIB-I) allowed for vendor specific extensions to be included in the MIB

Allows for additional management information about devices not provided for in the standard MIB

For example: CPU utilisation Normal for devices to support all of MIB-II

PLUS have their own vendor-specific extensions

SNMP NAMESSNMP Name Structure

1 - directory

1 - sysDescr 2 - sysObjectID

1 - system

1 - ifIndex 2 - ifDescr 3 - ifType ........ 10 - ifInOctets

1 - ifEntry

1 - ifTable

2 - interfaces

1 - mib

2 - mgmt 3 - expt

9 - cisco

1 - Enterprise

4 - private

1 - Internet

6 - dod

3 - org

1 - iso

OSI Object Identifier Tree

SNMP - MIB Tree -

Objects are managed by the tree Expressed in a row of values divided by the period

root

iso(1)ccitt(0) Joint-iso-ccitt(2)

org(3)

dod(6)

Internet(1)

directory(1) mgmt(2) exprimental(3) private(4)

mib-2(1) enterprise(1)

Standard MIBs Vendor-specific MIBs

SNMP Namingquestion: how to name every possible standard

object (protocol, data, more..) in every possible network standard??

answer: ISO Object Identifier (OID) tree: – hierarchical naming of all objects– each branchpoint has name, number

1.3.6.1.2.1.7.1ISO

ISO-ident. Org.US DoDInternet

udpInDatagramsUDPMIB2management

SNMP - OID -

OID Expression – iso(1). org(3). dod(6). internet(1). mgmt(2). mib2(1)

-> .1.3.6.1.2.1

e.g. sysDscr = .1.3.6.1.2.1.1.1 = mib-2.1.1 = system.1

Subtree Name

OID Description

system 1.3.6.1.2.1.1 Defines a list of objects that pertain to system operation, such as the system uptime, system contact, and system name.

interfaces 1.3.6.1.2.1.2Keeps track of the status of each interface on a managed entity. The interfaces group monitors which interfaces are up or down and tracks such things as octets sent and received, errors and discards, etc.

at 1.3.6.1.2.1.3 The address translation (at) group is deprecated and is provided only for backward compatibility. It will probably be dropped from MIB-III.

ip 1.3.6.1.2.1.4 Keeps track of many aspects of IP, including IP routing.

icmp 1.3.6.1.2.1.5 Tracks things such as ICMP errors, discards, etc.

tcp 1.3.6.1.2.1.6 Tracks, among other things, the state of the TCP connection (e.g., closed, listen, synSent, etc.).

udp 1.3.6.1.2.1.7 Tracks UDP statistics, datagrams in and out, etc.

egp 1.3.6.1.2.1.8 Tracks various statistics about EGP and keeps an EGP neighbor table.

transmission 1.3.6.1.2.1.10 There are currently no objects defined for this group, but other media-specific MIBs are defined using this subtree.

snmp 1.3.6.1.2.1.11Measures the performance of the underlying SNMP implementation on the managed entity and tracks things such as the number of SNMP packets sent and received.

SNMP - MIB & OID -

SNMP Manager can acquire the management information defined by MIB(Management Information Base) from Agent

– Current version : MIBv2 RFC 1213– MIB is the aggregate of object (information) on the

equipment which SNMP Agent holds– Identifier is defined for each object = OID– MIB performed by Agent is roughly divided into:

• MIBv2 : standard, public, specified by IETF• Enterprise MIB : private, specified by vendor company

SNMP MIB

OBJECT TYPE:

OBJECT TYPE:OBJECT TYPE:

objects specified via SMIOBJECT-TYPE construct

MIB module specified via SMI(Structure of Management Information)

MODULE-IDENTITY(100 standardized MIBs, more vendor-

specific)

MODULE

SMI: Object, module examplesOBJECT-TYPE:

ipInDelivers

MODULE-IDENTITY: ipMIB

ipInDelivers OBJECT TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION “The total number of input datagrams successfully delivered to IP user- protocols (including ICMP)”::= { ip 9}

ipMIB MODULE-IDENTITY LAST-UPDATED “941101000Z” ORGANZATION “IETF SNPv2 Working Group” CONTACT-INFO “ Keith McCloghrie ……” DESCRIPTION “The MIB module for managing IP and ICMP implementations, but excluding their management of IP routes.” REVISION “019331000Z” ………::= {mib-2 48}

MIB example: UDP moduleObject ID Name Type Comments

1.3.6.1.2.1.7.1 UDPInDatagrams Counter32 total # datagrams delivered

at this node

1.3.6.1.2.1.7.2 UDPNoPorts Counter32 # underliverable datagrams

no app at portl

1.3.6.1.2.1.7.3 UDInErrors Counter32 # undeliverable datagrams

all other reasons

1.3.6.1.2.1.7.4 UDPOutDatagrams Counter32 # datagrams sent

1.3.6.1.2.1.7.5 udpTable SEQUENCE one entry for each port

in use by app, gives port #

and IP address

ASN.1: Abstract Syntax Notation 1 ISO standard X.680 defined data types, object constructors

– like SMI BER: Basic Encoding Rules

– specify how ASN.1-defined data objects are to be transmitted

– each transmitted object has Type, Length, Value (TLV) encoding

Syntax uses ASN.1 (Abstract Syntax Notation)

– binary encoding 02 01 06 is a 1 byte integer, value 6

Primitive Types INTEGER, OCTECT STRING, OBJECT IDENTIFIER, NULL

Constructor Types SEQUENCE <primitive-type> ... ie. a record SEQUENCE OF <primitive-type> ... ie. an array

Defined Data TypesIpAddress what you expectCounter non-negative integer that wrapsGauge non-negative integer that latchesTimeTicks time in hundredths of seconds

TLV EncodingIdea: transmitted data is self-identifying

– T: data type, one of ASN.1-defined types– L: length of data in bytes– V: value of data, encoded according to ASN.1

standard

1234569

BooleanIntegerBitstringOctet stringNullObject IdentifierReal

Tag Value Type

TLV encoding: example

Value, 5 octets (chars)Length, 5 bytes

Type=4, octet string

Value, 259Length, 2 bytes

Type=2, integer

SNMP - SNMP Message Handling

Command examplesGetRequest

inetapan@tools:~> snmpget -v2c -c xxxx tpr2.jp.apan.net .1.3.6.1.2.1.2.2.1.4.136IF-MIB::ifMtu.136 = INTEGER: 9192

GetNextRequestinetapan@tools:~> snmpget -v2c -c xxxx tpr2.jp.apan.net systemSNMPv2-MIB::system = No Such Object available on this agent at this OIDinetapan@tools:~> snmpwalk -v2c -c xxxx tpr2.jp.apan.net systemSNMPv2-MIB::sysDescr.0 = STRING: m20 internet router, kernel 6.2R3.10SNMPv2-MIB::sysObjectID.0 = OID: SNMPv2-SMI::enterprises.2636.1.1.1.2.2DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (423280751) 48 days, 23:46:47.51SNMPv2-MIB::sysContact.0 = STRING:SNMPv2-MIB::sysName.0 = STRING: tpr2SNMPv2-MIB::sysLocation.0 = STRING:SNMPv2-MIB::sysServices.0 = INTEGER: 4

SetRequestinetapan@tools:~> snmpset –v2c –c xxxx tppr.jp.apan.net system.sysLocation.0 system.sysLocation.0 = "" inetapan@tools:~> snmpset –v2c –c yyyy tppr.jp.apan.net system.sysLocation.0 s “Tokyo, JP“system.sysLocation.0 = “Tokyo, JP" inetapan@tools:~> snmpset –v2c –c xxxx tppr.jp.apan.net system.sysLocation.0system.sysLocation.0 = “Tokyo, JP"

SNMP - Trap Message -

The way for Agent to inform Manager about event of something undesirable

Trap originates from Agent and is sent to the trap destination, as configured within Agent itself

When Manager receives a trap, it needs to know how to interpret it PDU

– Enterprise • vendor identification (OID) for the agent

– AgentAddress• The IP address of the node where the trap was generated.

– Trap Type• Generic / Specific (not used)

– Timestamp• The length of time between the last re-initialization of the agent that issued a trap and the moment at

which the trap was issued

SNMP

SNMP Traps– unsolicited notification of events– can include variable list– ColdStart, WarmStart– LinkUp, LinkDown– Authentication Failure– EGP Neighbour Loss– Enterprise Specific

Traps Forwarded automatically from agent to

station(s) in response to an event with the device

Traps defined in MIB-II– Cold-start of system– Warm-start of system– Link down– Link up– Failure of authentication– Exterior Gateway Protocol (EGP) neighbour loss– Enterprise specific

SNMPv2 History

RFC 1441, 1993: “Introduction to version 2 of the Internet-standard Network Management Framework”

RFC 1446, 1993: “Security Protocols for version 2 of the Simple Network Management Protocol”

Written to address security and feature deficiencies in SNMPv1

SNMPv2 Protocol

Extension to SNMPv1 Provided security model 2 new commands

– get-bulk-request– inform-request

SNMPv2 Protocol continued...

privDst dstParty srcParty context PDU



privDst

privDst

authInfo

0-length OCTET STRING

General Format

Nonsecure Message

digest dstTime srcTime

dstParty srcParty context PDUdigest dstTime srcTime

dstParty srcParty context PDU0-length OCTET STRING

Authenticated, not encrypted

Private, not authenticated

Private and authenticated

Format of SNMPv1 messages

Version Community PDU Request 0 0 Name X Value X … String type ID

Version Community PDU Request Error Error Name X Value X … String type ID status index

Version Community PDU Enter- Agent Generic Specific Time Name X Value X String type prise Addr trap trap

Get-Request, Get-Next-Request, Set-Request

Get-Response

Trap

62

Coexistence by Means of Proxy Agent

ProxyAgent

SNMPv1agent

SNMPv2manager

SNMPv2 environment SNMPv1 environment

GetRequest GetRequest

GetNextRequest GetNextRequest

SetRequest SetRequest

GetBulkRequest GetNextRequest

Response GetResponse

SNMPv2-Trap Trap

SNMPv2 manager-to-agentPDUs

SNMPv1 manager-to-agentPDUs

SNMPv2 agent-to-manager PDUs

SNMPv1 agent-to-manager PDUs

SNMPv1 and SNMPv2 SNMPv1 is a subset of SNMPv2 Managers usually can send requests in either

format depending on the capability of the agents Requires an update of the agent and manager

software to migrate from SNMPv1 to SNMPv2 Many manufacturers are resisting SNMPv2 for a

variety of reasons leading to an SNMPv3 specification

Almost all manufacturers currently support SNMPv1

Network Monitoring Tools

Ways of MonitoringClassified into three monitoring ways

– In Internal Network (mostly) – Via External Network– Non-network (Emergency case)

1, Monitoring in internalNetwork (mostly)

2, Monitoring via ExternalNetwork - via Peering Network - via the Internet

3, Independent access(Emergency case) - ISDN, PSTN

Internal network

External network

Monitoring Machine

Network Management Software

SNMP Agents– provided by all router vendors– many expanded (enterprise) MIBs– bridges, wiring concentrators, toasters


Public Domain– Application Programming Interfaces

available from CMU and MIT– include variety of applications


Commercially– many offerings, UNIX and PC based

• HP OpenView• SunNet Manager• Cabletron Spectrum• *MANY* others

Commercial SNMP Applications

•http://www.hp.com/go/openview/ HP OpenView

•http://www.tivoli.com/ IBM NetView

•http://www.novell.com/products/managewise/ Novell ManageWise

•http://www.sun.com/solstice/ Sun MicroSystems Solstice

•http://www.microsoft.com/smsmgmt/ Microsoft SMS Server

•http://www.compaq.com/products/servers/management/ Compaq Insight Manger

•http://www.redpt.com/ SnmpQL - ODBC Compliant

•http://www.empiretech.com/ Empire Technologies

•ftp://ftp.cinco.com/users/cinco/demo/ Cinco Networks NetXray

•http://www.netinst.com/html/snmp.html SNMP Collector (Win9X/NT)

•http://www.netinst.com/html/Observer.html Observer

•http://www.gordian.com/products_technologies/snmp.html Gordian’s SNMP Agent

•http://www.castlerock.com/ Castle Rock Computing

•http://www.adventnet.com/ Advent Network Management

•http://www.smplsft.com/ SimpleAgent, SimpleTester

Monitoring Targets

Target suitable for checking normality of network service

– Router Dead or Alive? Status? Performance? Routing?

– Server Dead or Alive? Status? Damon? Service Port?

– Traffic, etc. Increase or decrease? Dos Attack? Performance? Environment?

Monitoring Method

How to monitor the target – Active monitor or Passive monitor

• Polling = Monitoring machines give message in watching target – Useful for checking the current status

ICMP/SNMP polling…• Receive trap message from target

– Useful for detecting the status changeSNMP trap, syslog…

• Statistics data– Useful for grasping the trend and transition

– Select the Monitoring Tool• Ping (ICMP), SNMP, Monitoring Tool, Original Tool, etc.

– Check the monitoring Route to Target• Internal or External network

- ICMP/Ping Polling -

Check IP reachability by ICMP echo/reply

– Additional information• RTT (Round Trip Time)• Packet Loss• TTL (Time to Live)

Most standard way of checking node activity Time series RTT/Packet loss data becomes important

information when measuring link performance

ICMP echo

ICMP echo reply

RTT: xx msecPacket Loss: xx %

TTL: xx

UDP/TCP polling

Effective in monitoring service ports of server– Using client for service

• DNS - nslookup

– Using telnet • WWW,SMTP,POP

– Using tool • Radius - radping

Telnet with service port

reply

bash-2.05$ telnet ns.jp.apan.net 80Trying 203.181.248.3...Connected to ns.jp.apan.net.Escape character is '^]'.get<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"><html><head><title>501 Method Not Implemented</title> :

Monitoring Software - HP OpenView -

HP OpenView Network Node Manager Overview

– Auto discovery and mapping– Drill-down views (Hierarchy Map) – Fault monitoring : ICMP / SNMP polling– Event monitoring : Trap receiving/Event configuration – SNMP tools : Status polling– MIB Browser– Web-based reports– Extended software is enhanced – Platform : Windows 2000/XP, Solaris 8/9, HP-UX

Monitoring Software - HP OpenView Sample 1-

OpenView Contracture

Event log

ICMP polling for connectivity check

Network map

Router map Network sub-map

Monitoring Software - HP OpenView Sample 2-

OpenView Tools

Snmp configuration for polling - parameters - community

Event configuration

Data collection & Thresholds for SNMP

MRTG (Multi-Router Traffic Grapher)

Overview – Monitors the load of network equipment using SNMP, mainly used for

creation of traffic graph

– Excellent graphing tool developed by Tobias Oetiker

– Plots graph with any two variables against time, It is graph-ized with PNG format on HTML page

– Able to create scripts to feed data into MRTG

– Implements data collection, image, web-page collection

– Very widely deployed in large networks and still being actively developed

– Platform : UNIX system / Windows NT

– Supports SNMPv2 : able to read 64bit counters

– http://people.ee.ethz.ch/~oetiker/webtools/mrtg/

http://people.ee.ethz.ch/~oetiker/webtools/mrtg/













MRTG - Workflow -

Display of graph Green area typically represents incoming

maximum bits per second Blue line typically represents outgoing

maximum bits per second

Workflow1.Read configuration file

2.Collect graphing data from network equipment, based on configuration

3.Update database file and generate graph

4.If required, generate HTML file– MRTG performs above workflow then completes

– Since MRTG collects data of the past 5 minutes (default value of source code), it is desirable to set “crontab” for every 5 minutes

MRTG - Data Storage -

Daily grafh/5min

Weekly grafh/30min

Monthly grafh/2hours

Yearly grafh/1day

Data Storage– Keeps 5 minute data only for 2.5 days.

The data is thrown away afterward.• There is no referring to historical data with high

resolution

• Keeps 1-day data for approx. 2 years

RougherResolution

Interval Num of record Storage period

Graph

5 minutes 600 2.5 days daily

30 minutes 600 12.5 days Weekly

2 hours 600 50 days Monthly

1 day 731 2 years Yearly

RRDtool (Round Robin Database Tool)

Overview– Successor to MRTG – Developed by the same developer of MRTG : Tobias Oetiker– Tool group for RRD can flexibly define data item, time interval, data

amount, graph depiction, etc.– Binary file format that can store data at any interval for any length of

time• File does not grow in size over time

– Ability to make custom graphs across user-defined intervals• Ability to graph multiple variables on a single graph

– Additional scripts are necessary in creating graphs and web-page• 25-30 percent faster than MRTG

– Does not have the function to collect data– http://people.ee.ethz.ch/~oetiker/webtools/rrdtool/

http://people.ee.ethz.ch/~oetiker/webtools/rrdtool/













RRDtool - Architecture -

Comparison of architecture between MRTG and RRD

router

router

server

text

SNMPengine

ATM Sw itch

Fram e R elaySw itch




FrontendProgram

FrontendProgram

Graph

Index

Graph

Index

RRD

log

Firew all

Firew all

RRDtool - Sample -

http://mrtg.jp.apan.net/cricket/router-interfaces/








Netflow - Overview -

Overview– Enables IP traffic flow analysis without probes

– Invented and patented by Cisco • Juniper (called cflowd), Foundry, ･･･ many venders are supporting

– Flow cash data on routers is exported

to a flow tool, so that traffic flow is to be analyzed

flow Definition: Source IP addressDestination IP addressSource portDestination portLayer 3 protocol typeTOS byte (DSCP)Input logical interface (ifIndex)

Core Network

Enable NetFlow Traffic

Collector(Solaris, HP-UX, or Linux)

UDP NetFlowExport

Packets

Application GUI

Netflow - Flow Data -

Flow data export– Enable NetFlow on the router

• There is difference in architecture between Cisco and Juniper routers• Take care! the load of a router does not become high! - Check CPU, memory, bandwidth, sampling rate

Flow data collection & Analysis– Prepare the software for receiving flow-export data

• flow-tools http://www.splintered.net/sw/flow-tools/• cflowd http://www.caida.org/tools/measurement/cflowd/• Cisco : NetflowCollector

– Analyze traffic from raw data with software• flow-scan http://net.doit.wisc.edu/~plonka/FlowScan/ (If you want to graph-ize analysis data, I recommend you to use RRDtool)• Cisco : CiscoWorks

– Source and destination IP address– Source and destination TCP/UDP ports– Packet and byte counts– Routing information (next-hop address, source autonomous system (AS) number,

destination AS number, source prefix mask, destination prefix mask)

http://www.splintered.net/sw/flow-tools/



http://www.caida.org/tools/measurement/cflowd/





http://net.doit.wisc.edu/~plonka/FlowScan/











Netflow - Example -

Netflow Example

Documents

Network Monitoring and Management ICMP and SNMP. ICMP Internet Control Message Protocol RFC 792 Transfer of (control) messages from routers and hosts