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RFC 347 UNKNOWN ARPANET · TESTING

Echo process

A suggested service that returns received data unchanged for debugging and measurement.

On rfc-editor.org ↗
PUBLISHED
May 1972
AUTHORS
J. Postel
STREAM
Legacy
RETURNED DATA
Bit for bit, without modification
DOI
10.17487/RFC0347

RFC text

Original text · RFC Editor View on rfc-editor.org ↗ 
Network Working Group                           Jon Postel
Request for Comments : 347                      Computer Science
                                                UCLA-NMC
NIC  10426                                      30 May 72

Categories: Standard Processes


                                Echo Process


I suggest that for debugging and measurement purposes those hosts which
are willing implement an "Echo" process.
This echo process would listen for a request for connection and execute
the Initial Connection Protocol (ICP) as specified in NIC 7104 the
"Current Network Protocols" notebook.  Upon completion of the ICP the
echo process would wait for data from the network.  When the data is
received from the network it is echoed at once, (and the buffer space is
re-allocated).  By echoed I mean that the data received is sent back
over the network, bit for bit with no modification by the echo process.
The echo process is terminated by closing the network connections.
Note that BBN-TENEX has had such an echo process available for use for a
long time.







       [ This RFC was put into machine readable form for entry ]
       [ into the online RFC archives by BBN Corp. under the   ]
       [ direction of Alex McKenzie.                   12/96   ]

ISO Plain Language

On this page
PROBLEMHosts could use a simple service for debugging and network measurement.
MECHANISMA willing host accepts a connection using ICP and sends each received data block back bit for bit without modification.
THE PROPOSALThe RFC suggests that hosts implement the process voluntarily and notes that BBN-TENEX already had one.

§1A Voluntary Echo Service

Jon Postel suggests that hosts willing to do so implement an Echo process for debugging and measurement. The proposal does not require every host to offer the service.

Hosts are invited, but not required, to provide an Echo process. The stated uses are debugging and measurement.

§2How Echo Works

The process listens for a connection and performs the Initial Connection Protocol (ICP) described in the Current Network Protocols notebook. After ICP completes, it waits for data from the network.

When data arrives, the process sends it back immediately, bit for bit, without modification, and reallocates buffer space. It ends when the network connections are closed.

The process establishes a connection, waits for data and sends that data back unchanged. Closing the network connections ends the process.

§3Existing Example

The RFC notes that BBN-TENEX had offered an Echo process for a long time. It gives no other host implementation requirements.

BBN-TENEX is named as an existing example. The suggestion remains voluntary for other hosts.