Transcript piPEs Server Discovery

piPEs Server Discovery –
Adding NDT testing to the
piPEs architecture
Rich Carlson
Internet2
[email protected]
April 20, 2004
Design Goals
 Allow users to run short test from
desktop/laptop computer
 Provide a single entry point into
measurement domain
 Multiple servers act in concert,
automating the server selection process
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Basic Assumptions
 A collection of testing servers are
placed at the network’s edge
 Test requests come from ‘outside’ the
network
 Users can test to the ingress or egress
point of the network
 User doesn’t know which server is at
ingress or egress
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Server Locations
Server Locations
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Ingress point Benefits
 Closer to client (user’s desktop)
 Shorter network path, fewer links to
analyze
 Reduces test traffic over network core
 Better for finding configuration problems
with client host/network
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Egress point Benefits
 Closer to destination
 Approximates the path an application
will use
 Better for finding E2E performance
problems
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piPEs Design Choice
 All information for ingress testing is
supplied in the initial connection request
• Packet goes to testing engine, indicating intent
• Packet contains client IP address
 Destination information needs to be
supplied for egress testing
 Testing service will support both, but will
prefer ingress point testing
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piPEs Design Choice
 Leverage existing NDT code to speed
up development
 Add in additional features to integrate
First/Last Mile (FLM) servers into piPEs
test environment
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Server Discovery
 User contacts any server in the piPEs
federation
 Server runs discovery process to find
ingress server
 Client re-directed to ingress server
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piPEs Approach – Build Traceroute
tree map
 Collection of servers S1 to S8 form
measurement domain
 All servers obtain traceroute data for all
peer servers in the domain
 Routes are stored in a tree based map
 Note: all servers perform this off-line task
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Sample Traceroute Tree map
S1
S2
R1
R3
R2
R6
R4
R5
S4
S5
S7
S3
R7
S8
S6
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piPEs Approach – When client
requests a test
 Client connects to server S1 requesting
a test
 Server S1 runs traceroute back to client
IP
 Server S1 compares client route to core
map
 Note: All servers will perform this task
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Sample Traceroute
from S1 to Client
S1
Client
Traceroute to Client
R1
Rc
R4
R5
Ra
Rb
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Sample Comparison between map
and path from S1 to client
 Traceroute to client
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•
•
•
•
•
•
•
S1
R1
R4
R5
Ra
Rb
Rc
Client
 Traceroute Map
•
•
•
•
•
S1
R1
R4
R5
S6
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piPEs Approach – Picking the
Ingress server
 Comparison showed that server S6 is
the ingress server, redirect client to S6
• Prefer configuration testing
 Server S1 creates a dynamic html
document that re-directs the client to
server S6
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Client re-directed to S6 for test
Client
Rc
R5
Ra
Rb
S6
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piPEs Approach – Picking the
Another server
 Allow client to find egress server
• Allow performance testing
• Client provides destination name/address
• Ingress server will use traceroute map to find
egress server and re-direct client
 Allow client to manually select any
server in the cloud
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Prototype implementations
 Modified NDT web server to:
• Perform server discovery process
• Dynamically generates re-direct page
 Modified NDT testing engine to
interoperate with other piPEs testing
functions (BWCTL, OWAMP)
• Schedules multiple requests in FIFO manner
• Will interact with meta-scheduler
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Next Steps
 Start deployment of NDT servers in
Abilene core
• Requires Web100 enhanced Linux server
• Generic name “ndt-city”
– http://ndt-seattle.abilene.ucaid.edu:7123
• Do we want/need a single central name?
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Additional info
 StarLight server now operational
• http://ndt.sl.startap.net
• No access from commodity Internet
 Command Line version of client code
under development (web100clt)
• Compiles and runs under Linux and FreeBSD
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