Network Management Flashcards
SNMP
Simple Network management Protocol (Port 161):
SNMP manager sends/receives messages to managed devices (routers/switches/servers)
SET = Sends info GET = Requests info TRAP = receives unsolicited info from managed devices
Logical Network Diagram
Illustrates the flow of data across a network & shows how devices communicate with each other
Wiring Diagram
Labels which cables are connected to which ports
Radio Frequency (Wireless) Site Survey
Planning & designing a wireless network to deliver the required solution
Wired Site Survey
Determines if a site has the right amount of power, space, & cooling to support a new upgrade/installation
Audit & Assessment Report
Delivered after a formal assessment has been conducted
Executive summary Scope & objectives Assumptions & limitations Methods & tools Environment & system diagram Security requirements Findings & recommendations Audit results
Baseline Configurations
Set of specifications for an info system or configuration item within a system, that has been formally reviewed & agreed on
Changes will be properly tested & approved to be part of the new baseline
Performance Metrics: Latency
Time that it takes for data to reach its destination across a network
Performance Metrics: Bandwidth
Maximum rate of data transfer across a given network
Performance Metrics: Throughput
Actual measure of how much data is successfully transferred from the source to a destination
Performance Metrics: Jitter
When a time delay in the sending of data packets over a network connection occurs
Minor Temperature Threshold
Used to set off an alarm when a rise in temperature is detected but hasn’t reached dangerous levels yet
Major Temperature Threshold
Used to set off an alarm when temperature reaches dangerous levels
NetFlow Data: Full Packet Capture
Used to capture the entire packet, including the header & the payload for all traffic entering & leaving a network
NetFlow Data: Flow Analysis
Relies on a flow collector to record the metadata & statistics about network traffic rather than recording each frame
Highlights trends/patterns
NetFlow
Defines a particular traffic flow based on the different packets that share the same characteristics
(Protocol, IP version, source/destination IP, source/destination port, IP service type)
NetFlow Data: Zeek
Passively monitors a network like a sniffer, but only logs full packet capture data of potential interest
Performs normalization of the data & store it as a tab-delimited or JSON-formatted text files
NetFlow Data: MRTG
Multi Router Traffic Grapher:
Creates graphs showing traffic flows through the network interfaces of routers & switches by polling the appliances using SNMP
Link State
Communicates whether a given interface has a cable connected to it and
a valid protocol to use for communication
Drop
Used to count the number of packets that have been dropped
Flush
Used to count Selective Packet Discards (SPD) that have occurred
SPD
Selective Packet Discards:
Drops low priority packets when the CPU is too busy so it can save
capacity for higher priority packets as a form of QoS
Runt
An Ethernet frame that is less than 64 bytes in size
Giant
Any Ethernet frame that exceeds the 802.3 frame size of 1518 bytes
Throttle
Occurs when the interface fails to buffer the incoming packets
CRC
Cyclic Redundancy Checksum:
Number of packets received that failed the cyclic redundancy checksum,
or CRC check upon receipt
Ignored
Used to count the number of packets that the interface ignored since the
hardware interface was low on internal buffers
Late Collision
Used to count the number of collisions that occur after the interface has
started transmitting its frame
Environmental Monitoring
Network devices operate between 50-90 ºF
Maintain humidity range of 40-60%
Ideal: Cool, right humidity, clean power, flood-free
OID
Object Identifier:
An address used to uniquely identify managed devices and their statuses
Frame
Used to count the number of packets where a CRC error and a noninteger number of octets was received
Overrun
Used to count how often the interface was unable to receive traffic due
to an insufficient hardware buffer
Underrun
Number of times the sender has operated faster than the router can
handle, causing buffers or dropped packets
Babble
Used to count any frames that are transmitted and are larger than 1518
bytes
Deferred
Used to count the number of frames that were transmitted successfully
after waiting because the media was busy
Output Buffer Failure
Number of times a packet was not output from the output hold queue
because of a shortage of shared memory
Output Buffer Swapped Out
Number of packets stored in main memory when the queue is full
