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SNMP: The Basics
Uses UDP (User Datagram Protocol)
- Uses UDP instead of TCP (Transmission Control Protocol) because it is connectionless. It has low overhead.
- Unreliable, but that's OK.
- There is SNMP over TCP, but “but this is more for special-case situations”
Uses ports 161 (for polling) and 162 (for traps).
Notes:
III.SNMP: The Basics
A. Uses UDP
i. UDP is a connectionless protocol, which means there is no guarantee that the UDP packets are delivered to their destination.
ii. At first, this doesn't seem good for something intended to manage networks. But, it really is.
a) Also, the use of UDP instead of TCP allows the data to be transferred faster since there isn't the overhead of the protocol exchange.
b) If TCP was used, and things started going down, the network would be saturated with re-tries.
c) Essential SNMP mentions that there is SNMP over TCP, “but this is more for special-case situations...” – Essential SNMP, section 2.1.
B. Uses ports 161 and 162.
i. Port 161 is for polling the agents.
ii. Port 162 is for sending traps.