SNMP

The Simple Network Management Protocol (SNMP) is used in network management systems to monitor attached hardware for changes in operation activity. SNMP provides a standardized approach to monitoring and managing network systems.
For information on configuring your TMedia product to use the SNMP protocol, see the section labeled "Related Tasks".

TelcoBridges and SNMP

TelcoBridges offers basic support for SNMP versions 1, 2, and 3. More specifically, this grants users the ability to remotely poll (or GET) system variables, known as Managed Objects, which are represented in files known as MIB modules. TelcoBridges currently offers polling on standard MIB modules (RTP, SONET, DS1, DS3, ISDN, etc...) and on the TelcoBridges privately defined module (TB-MIB).

Supported SNMP MIB modules

1. RFC 1213 MIB II (RFC1213-MIB)
   • All tables of the RFC1213-MIB are supported, with the exception of:
     • ipRouteTable
     • EGP group
     • atTable
2. RFC 1573 Evolution of Interfaces Group of MIB-II (IF-MIB)
   • The following tables are supported:
     • ifTable
     • ifStackTable
3. RFC 2495 DS1, J1, E1, DS2, and E2 Interfaces (DS1-MIB)
   • The following tables of the DS1-MIB are supported:
     • Dsx1ConfigTable
     • Dsx1CurrentTable
     • Dsx1IntervalTable
     • Dsx1TotalTable
4. RFC 2496 - Definitions of Managed Object for the DS3/E3 Interface Type (DS3-MIB)
   • The following tables of the DS3-MIB are supported:
     • Dsx3ConfigTable
     • Dsx3CurrentTable
     • Dsx3IntervalTable
     • Dsx3TotalTable
5. RFC 1595 - Definitions of Managed Object for the SONET/SDH Interface Type (SONET-MIB)
   • The following tables of the SONET-MIB are supported:
     • sonetMediumTable
     • sonetSectionCurrentTable
     • sonetSectionIntervalTable
     • sonetLineCurrentTable
     • sonetLineIntervalTable
     • sonetFarendLineCurrentTable
     • sonetFarendLineIntervalTable
     • sonetPathCurrentTable
     • sonetPathIntervalTable
     • sonetFarendPathCurrentTable
     • sonetFarendPathIntervalTable
     • sonetVtCurrentTable
     • sonetVtIntervalTable
     • sonetFarendVtCurrentTable
     • sonetFarendVtIntervalTable
6. RFC 2127 - ISDN Management Information Base using SMIv2 (ISDN-MIB)
   • The following tables of the ISDN-MIB are supported:
     • isdnBearerGroup
     • isdnSignalingGroup
7. Telcobridges Private MIB module (TB-MIB)
   • tbMtp2
   • tbM2pa
   • tbM2ua
   • tbM3ua
   • tbIua
   • CPU Usage
   • Memory Usage

SNMP IF-MIB ifTable interface type

The table below provides the interfaces type supported by TelcoBridges (ifTable) with their corresponding description. The ifType are described in Internet Assigned Number Authority (IANA) in IANAifType-MIB

IANA ifType	TelcoBridges Interface description
ethernetCsmacd(6)	Baseboard Ethernet interfaces
ds1(18)	Trunks Line Interface
ds3(30)	DS3 Line Interface
sonet(39)	SONET/SDH Line Interface
sonetPath(50)	SONET/SDH Line Service PATH (VC4/VC3/STS1/DS3)
sonetVT(51)	SONET/SDH Line Service SECTION (VC11/VC12/VT15/VT2)
isdn(63)	ISDN Stack
lapd(77)	ISDN LAPD Link (Primary)
lapd(77)	ISDN LAPD Link (Backup)
	IUA Link
	IUA Peer
lapd(77)	LAPD Link
	SS7 M2PA Link
	SS7 M2UA Link
	SS7 M2UA Peer
	Ss7 M3ua Sap
	Ss7 M3ua Psp
	Ss7 M3ua Psrv
ss7SigLink (156)	Ss7 Mtp2 Link

SNMP traps

The SNMP traps module of TelcoBridges products monitor the operation status of some MIBS OIDs and generates notifications when the states change. The default monitoring polling period is set to 1 minute, this value can be modified in the "Advanced SNMP Parameters" of the tbsnmpagent application configuration.

IF-MIB SNMP Trap/Notification

• linkDown (1.3.6.1.6.3.1.1.5.3) OBJECTS { ifIndex, ifAdminStatus, ifOperStatus }
• linkUp (1.3.6.1.6.3.1.1.5.4) OBJECTS { ifIndex, ifAdminStatus, ifOperStatus }

Example of packet capture:

tcpdump port 162 -i mgmt0 -s 0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on mgmt0, link-type EN10MB (Ethernet), capture size 65535 bytes
14:08:51.491789 IP 10.7.0.13.37452 > 10.7.0.221.snmptrap: V2Trap(144) system.sysUpTime.0=9546160 S:1.1.4.1.0=S:1.1.5.4
interfaces.ifTable.ifEntry.ifIndex.452160.26=26 interfaces.ifTable.ifEntry.ifAdminStatus.452160.26=1 
interfaces.ifTable.ifEntry.ifOperStatus.452160.26=1  S:1.1.4.3.0=E:8072.3.2.10

SNMP SET

The SNMP SET command is not supported by TelcoBridges products.

Related Tasks

• Configuring the tbSnmpAgent application
• Introduction to the TelcoBridges Private MIB Module (TB-MIB)
• Installing NetSNMP from an External Host
• How to relay SNMP on TMG products (IMPORTANT: This link is only meaningful if you need SNMPv1 only.)

Other Tasks

• How to install and start NTP on TMG products

External Sources

• Wikipedia article on SNMP
• NetSNMP implementation of the SNMP protocol