Stevens@A.ISI.EDU.UUCP (06/16/87)
Several messages appeared in April and May 87 about ICMP echo,
suggestions for new ICMP options, need for echoes at all protocol
layers, etc. I just wanted to pass on an overview from similar work
in the DARPA Survivable Adaptable Networks (SURAN) program. (A SURAN
network is made up packet radios (PRs) and lies below the internet.)
This message describes the Journey and Route Tracing protocol designed
for SURAN. (Note that only part has been implemented to date.) The
protocol tells the PRs how to make a packet travel a particular journey
and optionally tells the PRs how to make a packet travel a particular
route on one leg of the journey, what trace data to capture along the
journey, and/or what trace data to capture along one leg of the journey.
A leg is equivalent to an end-to-end path or route which is made up of
one or more hops, while a journey is made up of one or more legs. A
leg is equivalent to sending an IP packet on a path from a source to a
destination and a journey then is the concatenation of several legs.
For example, an ICMP echo and associated ICMP echo reply are equivalent
to a journey of 2 legs.
An example of the use of the journey and route protocol is:
Suppose that a network monitor at node A wants to record the
route from node B to C. Well the network monitor would build
a journey packet which contains the following commands:
(1) journey destination #1 = B
route command for B = perform route tracing to
next journey destination (node)
(2) journey destination #2 = C
no route command for C
(3) journey destination #3 = A
Thus the packet will be routed from A to B. Next the packet
will be routed from B to C and the route will be recorded
(in a fashion similar to IP record route option). Finally,
the packet will be routed from C to A with the desired recorded
route from B to C.
The journey and route trace protocol is designed to lie above (or
within) either the SURAN network or transport protocols. Note that the
internet contains similar type processing above both layers as well (IP
options and ICMP within Internet Protocol and the echo port above TCP &
UDP). Basically, the journey processing is performed above (or within)
the transport protocol while the optional leg processing is performed
above (or within) the network protocol.
For further information:
On SURAN Protocols in general - John Jubin & Janet Tornow, "The
DARPA Packet Radio Network Protocols", IEEE Proceedings, Jan 1987.
On Journey and Route Tracing in particular - Jim Stevens, SRNTN
#49, "Journey and Route Tracing". (SRNTN stands for SURAN
Technical Note (SRNTN) and is similar to an RFC). DARPA has
declared that the distribution of SRNTN #49 is limited to U.S.
Government agencies and their contractors and that SRNTN #49
contains technical data whose export is restricted by the Arms
Export Control Act. SRNTN #49 should soon be available from the
Defense Technical Information Center (DTIC), Cameron Center,
Alexandria, Virginia 22314.
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