ping

ndnping and ndnpingserver

Introduction

ndnping and ndnpingserver are reachability testing tools for Named Data Networking. They test the reachability between two nodes. The client sends an Interest intended for a node running ndnpingserver. The ping server then sends Data in response. The client then calculates the roundtrip time for the Interest-Data exchange, or marks it as a timeout if the Data is not received within the timeout period.

Using the Client

The client can be invoked by calling ndnping with a name to ping. For example, to ping ndn:/edu/arizona, one would execute::

ndnping ndn:/edu/arizona

There are also a variety of options to control the behavior of the ping client. For example, to send only four pings to ndn:/edu/arizona, displaying a timestamp with each received Data or timeout, type::

ndnping -c 4 -t ndn:/edu/arizona

A list of the available options can be found with man ndnping.

Using the Server

The server can be invoked by calling ndnpingserver with a name to listen for pings to. For example, to listen for pings to ndn:/edu/arizona, one would execute::

ndnpingserver ndn:/edu/arizona

There are also a variety of options to control the behavior of the ping server. For example, to satisfy only 4 ping requests before exiting, execute the following::

ndnpingserver -p 4 ndn:/edu/arizona

A list of the available options can be found with man ndnpingserver.

ndnping Protocol

This section briefly describes ndnping's protocol, in order to allow alternate implementations to be compatible with this implementation. The current protocol version is ndnping protocol version 1. This version number will be incremented in case there's an incompatible change.

Probe Interests

The client expresses probe Interests that are intended to be forwarded to the server without being aggregated. The Interests MUST have one of the following name structures:

ndn:/<prefix>/ping/<seq>
ndn:/<prefix>/ping/<client-identifier>/<seq>

where:

• <prefix> is the server prefix that contains zero or more NameComponents.
• <seq> is one NameComponent whose value is an unsigned 64-bit integer, represented as a decimal number in ASCII encoding.
• <client-identifier> is one NameComponent with arbitrary value.

If a client expresses multiple probe Interests, it is RECOMMENDED for those Interests to have consecutive increasing integers in <seq> field.

If a client uses the name structure with <client-identifier> field, it is RECOMMENDED to use one or more printable characters only, to make it easier for a human operator to read the logs. A client implementation MAY restrict this field to be non-empty and have printable characters only.

The probe Interest SHOULD carry MustBeFresh selector by default. A client implementation MAY allow the operator to turn off MustBeFresh selector.

Reply Data

The server SHOULD register the prefix ndn:/<prefix>/ping, and MUST reply to probe Interests under this prefix with Data. The Data MUST have the same name as the probe Interest.

The Data MUST have BLOB as its ContentType. The Data MAY have arbitrary payload in its Content field. A server implementation MAY allow the operator to configure the length and contents of the payload.

The Data SHOULD have a valid signature. The server SHOULD use DigestSha256 signature by default. A server implementation MAY allow the operator to configure a different signature algorithm. The client SHOULD NOT verify the signature by default. A client implementation MAY allow the operator to enable signature verification.