1. OWAMP One-Way Active Measurement Protocol (Sample Implementation)
Jeff Boote
Internet2
18 November 2018

2. What is it? A control protocol A test protocol
A sample implementation of both
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3. Why the OWAMP protocol?
There have been many implementations to do OWD over the years (Surveyor, Ripe…)
The real problem is interoperability.
The solution is standards.
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4. OWAMP Protocol
Now possible due to growing availability of good time sources
Wide deployment of “open” servers could allow measurement of one-way delay to become as commonplace as measurement of RTT using ICMP tools such as ping.
Current Draft:
Sample implementation available
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5. OWAMP Control protocol
Supports authentication and authorization (encryption possible)
Used to request tests
Used to start/stop tests
Used to retrieve results
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6. OWAMP Test protocol Endpoint controlled port numbers
Extremely configurable send schedule
Configurable packet sizes
Packets can be “clear”, “authenticated”, or “Encrypted”
Provisions for dealing with partial session results
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7. Sample Implementation
Applications
owampd daemon
owping client
Built upon protocol abstraction library
Supports one-off applications
Allows authentication/policy hooks to easily be incorporated
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8. Functionality (owping client)
owping client application communicates with the “other” endpoint of the test
Communication can be “open”, “authenticated”, or “encrypted”
Requests include a full parameterization of the test
OWD tests can be in either direction
Supports the setup of many tests concurrently
Supports the buffering of results on the server for later retrieval
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9. Functionality (owampd)
Accepts requests for OWD tests including start time and parameters for test
Responds with accepted/denied
Tests are formally started with a StartSessions message from the client. (start times in the past are adjusted to “current time”)
Runs tests
Sessions “toward” the server are saved for retrieval
Can add a timeout so that “start session” message must be received within a given timeout to thwart DOS
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10. Resource Allocation Model
Spheres of control
Is the basic parameterization of the requested test allowed?
Does the owampd have enough resources to allow test?
Does this host have enough resources?
Does this <higher level…> have enough resources?
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11. Resource Allocation (owampd)
Each connection is “classified” (authentication)
Each classification is associated with a set of hierarchical limits
owampd.limits
(no time dependant dimension to resource allocation in owampd)
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12. Architecture
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13. Specific difficulties
Time:
Operational issues predominate
Determining an accurate timestamp “error” is in many ways more difficult than getting a “very good” timestamp
Working as an “open” server requires UTC time source (For predefined test peers, other options available)
Firewalls:
Port filter trade-off
Administrators like pre-defined port numbers
Vendor manufactures would probably like to “prioritize” test traffic
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14. Future Steps Administrator specified port ranges for “test” traffic
Support “partial results” protocol extensions
Open source development
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15. Availability http://e2epi.internet2.edu/owamp/ Currently available
Mail lists:
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