=head1 NAME

Smokeping::probes::CiscoRTTMonEchoICMP - Probe for SmokePing

=head1 SYNOPSIS

 *** Probes ***

 +CiscoRTTMonEchoICMP

 forks = 5
 offset = 50%
 step = 300
 timeout = 15

 # The following variables can be overridden in each target section
 ioshost = RTTcommunity@Myrouter.foobar.com.au # mandatory
 iosint = 10.33.22.11
 packetsize = 56
 pings = 5
 tos = 160
 vrf = INTERNET

 # [...]

 *** Targets ***

 probe = CiscoRTTMonEchoICMP # if this should be the default probe

 # [...]

 + mytarget
 # probe = CiscoRTTMonEchoICMP # if the default probe is something else
 host = my.host
 ioshost = RTTcommunity@Myrouter.foobar.com.au # mandatory
 iosint = 10.33.22.11
 packetsize = 56
 pings = 5
 tos = 160
 vrf = INTERNET

=head1 DESCRIPTION

A probe for smokeping, which uses the ciscoRttMon MIB functionality ("Service Assurance Agent", "SAA") of Cisco IOS to measure ICMP echo ("ping") roundtrip times between a Cisco router and any IP address. 

=head1 VARIABLES

Supported probe-specific variables:

=over

=item forks

Run this many concurrent processes at maximum

Example value: 5

Default value: 5

=item offset

If you run many probes concurrently you may want to prevent them from
hitting your network all at the same time. Using the probe-specific
offset parameter you can change the point in time when each probe will
be run. Offset is specified in % of total interval, or alternatively as
'random', and the offset from the 'General' section is used if nothing
is specified here. Note that this does NOT influence the rrds itself,
it is just a matter of when data acqusition is initiated.
(This variable is only applicable if the variable 'concurrentprobes' is set
in the 'General' section.)

Example value: 50%

=item step

Duration of the base interval that this probe should use, if different
from the one specified in the 'Database' section. Note that the step in
the RRD files is fixed when they are originally generated, and if you
change the step parameter afterwards, you'll have to delete the old RRD
files or somehow convert them. (This variable is only applicable if
the variable 'concurrentprobes' is set in the 'General' section.)

Example value: 300

=item timeout

How long a single 'ping' takes at maximum

Example value: 15

Default value: 5

=back

Supported target-specific variables:

=over

=item ioshost

The (mandatory) ioshost parameter specifies the Cisco router, which will
execute the pings, as well as the SNMP community string on the router.

Example value: RTTcommunity@Myrouter.foobar.com.au

This setting is mandatory.

=item iosint

The (optional) iosint parameter is the source address for the pings
sent. This should be one of the active (!) IP addresses of the router to
get results. IOS looks up the target host address in the forwarding table
and then uses the interface(s) listed there to send the ping packets. By
default IOS uses the (primary) IP address on the sending interface as
source address for a ping. The RTTMon MIB versions before IOS 12.0(3)T
didn't support this parameter.

Example value: 10.33.22.11

=item packetsize

The packetsize parameter lets you configure the packetsize for the pings
sent. The minimum is 8, the maximum 16392. Use the same number as with
fping, if you want the same packet sizes being used on the network.

Default value: 56

=item pings

How many pings should be sent to each target, if different from the global
value specified in the Database section. Note that the number of pings in
the RRD files is fixed when they are originally generated, and if you
change this parameter afterwards, you'll have to delete the old RRD
files or somehow convert them.

Example value: 5

=item tos

The (optional) tos parameter specifies the value of the ToS byte in
the IP header of the pings. Multiply DSCP values times 4 and Precedence
values times 32 to calculate the ToS values to configure, e.g. ToS 160
corresponds to a DSCP value 40 and a Precedence value of 5. The RTTMon
MIB versions before IOS 12.0(3)T didn't support this parameter.

Example value: 160

Default value: 0

=item vrf

The the VPN name in which the RTT operation will be used. For regular RTT
operation this field should not be configured. The agent
will use this field to identify the VPN routing Table for
this operation.

Example value: INTERNET

=back


=head1 AUTHORS

Joerg.Kummer at Roche.com 

=head1 NOTES

=head2 IOS VERSIONS

It is highly recommended to use this probe with routers running IOS 12.0(3)T or higher and to test it on less critical routers first. I managed to crash a router with 12.0(9) quite consistently ( in IOS lingo 12.0(9) is older code than 12.0(3)T ). I did not observe crashes on higher IOS releases, but messages on the router like the one below, when multiple processes concurrently accessed the same router (this case was IOS 12.1(12b) ):

Aug 20 07:30:14: %RTT-3-SemaphoreBadUnlock: %RTR: Attempt to unlock semaphore by wrong RTR process 70, locked by 78

Aug 20 07:35:15: %RTT-3-SemaphoreInUse: %RTR: Could not obtain a lock for RTR. Process 80


=head2 INSTALLATION

To install this probe copy ciscoRttMonMIB.pm files to ($SMOKEPINGINSTALLDIR)/lib/Smokeping and CiscoRTTMonEchoICMP.pm to ($SMOKEPINGINSTALLDIR)/lib/Smokeping/probes. V0.97 or higher of Simon Leinen's SNMP_Session.pm is required.

The router(s) must be configured to allow read/write SNMP access. Sufficient is:

	snmp-server community RTTCommunity RW
 
If you want to be a bit more restrictive with SNMP write access to the router, then consider configuring something like this 

	access-list 2 permit 10.37.3.5
	snmp-server view RttMon ciscoRttMonMIB included
	snmp-server community RTTCommunity view RttMon RW 2

The above configuration grants SNMP read-write only to 10.37.3.5 (the smokeping host) and only to the ciscoRttMon MIB tree. The probe does not need access to SNMP variables outside the RttMon tree.

=head1 BUGS

The probe sends unnecessary pings, i.e. more than configured in the "pings" variable, because the RTTMon MIB only allows to set a total time for all pings in one measurement run (one "life"). Currently the probe sets the life duration to "pings"*2+3 seconds (2 secs is the ping timeout value hardcoded into this probe). 

=head1 SEE ALSO

L<http://oss.oetiker.ch/smokeping/>

L<http://www.switch.ch/misc/leinen/snmp/perl/>

The best source for background info on SAA is Cisco's documentation on L<http://www.cisco.com> and the CISCO-RTTMON-MIB documentation, which is available at:
L<ftp://ftp.cisco.com/pub/mibs/v2/CISCO-RTTMON-MIB.my>

=cut