Transcript Introduction and Overview of Performance Analyzer Application

“CHATTER”
Agent-Based Network Monitoring in
Converged Network Analyzer (CNA) 3.1
Module 1:
Introduction
Pilot Training Materials
July 2006
© 2005 Avaya Inc. All rights reserved.
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CNA 3.1 Chatter
§1-Introduction
What is Chatter?
Chatter is the component of CNA 3.1 that provides an Agent-Based Network Monitoring
Capability
– The chatter technology was originally prototyped in the Statistics Research Department of
Avaya Labs Research (ALR) by Akshay Adhikari, Lorraine Denby, Jean Meloche and Balaji
Rao
– Chatter technology was added to the AAN product line in Aug 2005, in CNA 3.0
Chatter provides what we call a “mesh view” of the network
– Supports visualization of the L3 network topology with a “real-time” performance overlay
– Can see the paths connecting the “CNA Agents” distributed throughout the network
– Can see performance results for simulated traffic between regions/subnets of interest
Automated root cause analysis helps to identify where problems originate
– Manual interaction typically required to isolate troubles
– Interpretation of chatter charts requires an understanding of what they show
Chatter supports configurable alarms and notifications
– Both relative (“control chart” type) and absolute alarm thresholds available
– Email, SNMP and Syslog alarm notifications
Designed to be relatively scalable and fault tolerant
– However, implementation issues limit scalability
– Future designs will address these issues and other current limitations
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CNA 3.1 Chatter
§1-Introduction
Illustration:
Agent-Based
Monitoring
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CNA 3.1 Chatter
Example of Agent-Based Monitoring (animation)
§1-Introduction
Open Port
CNA
to Close
receive
AGENT
Slave ReqRTPPort
test
OK
C
H
Commit
A
T
Results
T
E
R
packets
Enterprise
Network
And/or
Internet
(Current Path)
Test
Start Sending
CNA
MASTER REQ
RTP
test packets
Completed
AGENT
Results
CNA
SERVER
“RTP Test” Message Flow
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Chatter’s Initial Requirements
What it Was Designed to Do
CNA 3.1 Chatter
§1-Introduction
Assess network performance between any two points of interest without requiring the
installation of specialized test gear at either end
– CNA Agents can be embedded in Avaya and partner devices, offering a competitive
advantage
Avoid placing a significant load on the network
– Chatter tests and messages between chatter components were designed and intended to
generate an insignificant traffic load
Display a dynamic L3 IP network topology
– The goal was to update it rapidly – but not necessarily in real time - in response to
changes in the network
Raise an alarm whenever the observed network performance (QoS) appears to be rapidly
changing for any L3 link or route in the network
– Can also alarm when an arbitrary QoS threshold is exceeded
Provide ability to scale for large network deployments
– Uses a novel but somewhat “controversial” mechanism to avoid the need for N 2
tests/round with N Agents
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Some Key Chatter Terms
CNA 3.1 Chatter
§1-Introduction
“The Hive”
Zone Hierarchy, Zones and Subzones
Cells
Edges
Scatter Plots
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CNA 3.1 Chatter
§1-Introduction
What is a Hive
When two or more CNA Servers exist in a single network, their chatterd
modules can be joined into a peer-to-peer distributed system called a Hive
Joining the chatterd modules in a multi-server CNA system into a Hive offers
additional benefits over n single-server systems. These benefits include:
– A more comprehensive topology of the customer’s network
– Eliminating the need for separate administration of the chatter configuration
on each Server
– Fault tolerance
– Ability to handle larger numbers of Agents and larger zone hierarchies
– A single CNA Server working with several CNA Agents can function
perfectly adequately as a chatter system. However, as more Agents are
added and the topology and zone hierarchies grow, it may become
desirable at some point to add another Server to improve performance
• The load limit on a single Server is “4000 load units” (load units are defined in
Mod 3)
When CNA Servers are joined in a Hive, their chatterd modules all regularly
share the following information with each other
– Data structures, e.g., agents, edges, cells, nodes
– All changes to the “module chatter” configuration
– Security keys
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CNA 3.1 Chatter
§1-Introduction
More on Chatter Hives
Two or more Servers joined in Hive perform many
operations that are not needed or performed in
single Server systems
Any “mod chatter” configuration commands are
dynamically replicated across all of the servers in a
hive within a few seconds
– More recent entries override earlier ones
– In the event of inconsistent configurations,
“majority rules.” If there’s a tie, the Server with
the lowest Eth0 IP address “wins”
Chatterd modules in different Servers can – to a
partial extent - “fill in” for each other when one goes
down
While responsibility for scheduling tests and storing
test results is partitioned among Servers, a user will
see the same view of the data no matter which of the
Servers they log in to
– chapld modules in each server “pull down” data
from other servers as needed to ensure a single
view of the data across all Hive members
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The Chatter Zone Hierarchy
CNA 3.1 Chatter
§1-Introduction
CNA agents – in order to be utilized – must be organized into a hierarchy of
Zones and Subzones after they register with a CNA Server
– The way you design the zone hierarchy affects how tests are scheduled
between CNA Agents and also how the data are presented to the user
You can arrange the zone hierarchy in a variety of different ways
– There must always be a single root zone representing the entire customer
network
– You can set up a flat zone hierarchy in which each subzone represents a
different customer location or site
– A flat zone hierarchy can also be used to organize a customer’s network
into a series of regions, or departments, all at the same level
– A multi-level hierarchy might be a good match for a branch office
configuration, in which a few HQ offices are each connected to several
regional offices, each of which is connected to several branch offices
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CNA 3.1 Chatter
§1-Introduction
Illustrative Flat Zone Hierarchy
Root
CNALab
Zone
Subzone
Subzone
TH1
Subzone
TH2
Subzone
C14
Subzone
TH9
Subzone
You can have up to 500 zones in a hive, arranged however you want
(subject to some constraints that will be covered in a later course
module)
– However, data presentation may become unwieldy if there
are too many subzones at the same level
• What is “too many?” I would say around 20, but some folks might say
fewer, and others might say more
Adding levels to the zone hierarchy improves the scalability of data
presentation for End-to-End performance data by breaking up one very
large Zone Matrix into several smaller ones
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Illustrative Chatter Multi-Level Zone Hierarchy
CNA 3.1 Chatter
§1-Introduction
RootAUZone
Zone2
Zone1
Zone3
CB!
Zone5
SG1
Zone4
SG2
CB2
MG1
CB5
Zone6
CB3
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Zone7
Zone8
CB4
MG2
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CNA 3.1 Chatter
Zone Matrix (End-to-End) Display Fundamentals
§1-Introduction
One or more Zone Matrices are produced by the
design of the Zone Hierarchy
– There will be one Zone Matrix display for
each “Parent” Zone
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• A Parent Zone is one with Child Zones (aka
subZones)
• A flat zone hierarchy (all Zones are children of
the Root Zone) has only one zone matrix
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emea
– In a Zone Matrix, each cell captures
unidirectional test results for one pair of
Zones (e.g., FROM Zone A TO Zone B)
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ZONE MATRIX
ZONE HIERARCHY
© 2006 Avaya Inc. All rights reserved.
• Plus the diagonal captures WITHIN-ZONE
(Intra-Zone) test results for zones with 2 or
more CNA Agents in the hierarchy below them
• However, intra-zone testing may be disabled
for Agents within a Zone
waterloo
The Zone Matrix display is very simple to
understand compared to topology display
– It’s a natural way of showing end-to-end test
results
– Traceroute (per-hop) results are not
supported
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CNA 3.1 Chatter
§1-Introduction
Scatter Plots
Scatter Plots
allow you to
see the last
150 test
results for a
given cell or
edge, plotted
over time
Note the
“bimodal”
distribution (2
horizontal
bands) of test
results on the
example
shown here
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Scatter Plots – Data Tab
CNA 3.1 Chatter
§1-Introduction
On the “Data”
Tab, you can
sort the test
results by any
column
Note how
sorting on the
value column
allows you to
see easily that
the extremely
long Hop RTT’s
are due to one
CNA Agent
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Edges in the Topology Display
CNA 3.1 Chatter
§1-Introduction
Chatter produces a
Layer 3 topology through
the use of a traceroute
mechanism
Nodes in the display
include routers and CNA
Agents
Edges are the
directional links
connecting these nodes
– Note that each edge
has one or two “fins”
indicating the
direction of traffic
over that edge
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