What is the length of SNMP sysUpTime counter?

Question

What is the length of Cisco SNMP sysUpTime counter? 32 bits?

Answer 1

Did a quick test and it looks like the data is a type 'Timeticks' which is a 32 bit integer. From the RFC:

The TimeTicks type represents a non-negative integer which represents
the time, modulo 2^32 (4294967296 decimal), in hundredths of a second
between two epochs.  When objects are defined which use this ASN.1
type, the description of the object identifies both of the reference
epochs.

https://www.rfc-editor.org/rfc/rfc2578#section-7.1.8

[user@host ~]$ snmpwalk -v 2c -c $COMMUNITY $DEVICE sysUpTime
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (1342832478) 155 days, 10:05:24.78

Answer 2

sysUpTime is a 32-bit counter and will roll over after 496 days.

snmpEngineTime (.1.3.6.1.6.3.10.2.1.3) which returns the uptime in seconds and should not roll over for 135 years.

snmpwalk -v2c -c xx 10.xx.xxx.xxx .1.3.6.1.6.3.10.2.1.3
SNMP-FRAMEWORK-MIB::snmpEngineTime.0 = INTEGER: 1701562 seconds

snmpwalk -v2c -c xx 10.xx.xxx.xxx sysUpTime
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (170158257) 19 days, 16:39:42.57

Answer 3

Cisco v1 MIBs import the definition of TimeTicks from RFC1155-SMI. This mib is part of standard snmp utils (i.e. not included in the Cisco mib tarballs). Within RFC1155-SMI, TimeTicks is defined as:

   TimeTicks ::=
       [APPLICATION 3]
           IMPLICIT INTEGER (0..4294967295)