As per Relevance of the word messages, we have this rfc below:
Network Working Group S.
Request for Comments: 1376 Network Systems
November 1992
The PPP DECnet Phase IV Control Protocol (DNCP
Status of this
This RFC specifies an IAB standards track protocol for the
community, and requests discussion and suggestions for improvements
Please refer to the current edition of the "IAB Official
Standards" for the standardization state and status of this protocol
Distribution of this memo is unlimited
The Point-to-Point Protocol (PPP) [1] provides a standard method
encapsulating Network Layer protocol information over point-to-
links. PPP also defines an extensible Link Control Protocol,
proposes a family of Network Control Protocols (NCPs)
establishing and configuring different network-layer protocols
This document defines the NCP for establishing and
Digital's DNA Phase IV Routing protocol (DECnet Phase IV) over PPP
This document applies only to DNA Phase IV Routing messages (
data and control), and not to other DNA Phase IV protocols (MOP, LAT
etc.).
1.
There are two basic approaches to running the DNA Phase IV
protocol over a serial line
1. The approached that several router vendors have taken which is
treat the serial link as an Ethernet, using the same data
control messages an Ethernet would use
2. The approach defined by Digital, which uses DDCMP and
different control messages
This document will define a method that uses the first approach
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RFC 1376 PPP DNCP November 1992
2. Overview Of Phase IV DNA
The Phase IV DNA protocols which act as data link clients are
o DNA Phase IV
The Phase IV Digital Network Architecture (DNA)
protocol is a network layer protocol providing services
to that of DoD IP. It routes messages in Phase IV
networks and manages the packet flow. The complete
of the DNA Phase IV Routing protocol can be found in [2].
o DNA System
The Digital Network Architecture (DNA) System Console
is a maintenance protocol providing low level access to
system for the functions of
. Identify
. Read data link
. Boot
. Console carrier (a general purpose i/o channel
The complete definition of the DNA System Console protocol
be found in [3].
o Digital Customer
The Digital Customer Use protocol type is a value reserved
use by Digital customers. It allocates a type for private
which will not conflict with Digital or other vendor protocols
o DNA
The Digital Network Architecture (DNA) Diagnostics
type is reserved to allow diagnostic software communications
parallel with other data link clients
o DNA Naming Service (DNS
The Digital Network Architecture Naming Service (DNS)
a distributed naming service. It allows clients to
named objects and to bind a set of attributes to the objects
a distributed database
o DNA Time Service (DTS
The Digital Network Architecture Time Service (DTS) is
protocol providing global clock synchronization in
distributed environment
o DNA Load/
The Digital Network Architecture (DNA) Load/Dump protocol is
maintenance protocol for copying the contents of
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RFC 1376 PPP DNCP November 1992
memory to or from a remote system. For example, a
manager can load an operating system into an unattended,
system. The complete definition of the Phase IV DNA Load/
protocol can be found in [3].
o DNA Experimental
The Digital Network Architecture (DNA) Experimental
protocol type allows Digital experimental protocols to share
data link with other data link clients. It is for use
Digital Equipment Corporation only
o DNA Communications
The Digital Network Architecture (DNA) Communications
protocol is a maintenance protocol for testing the data
communications path. The complete definition of the
Communications Test protocol can be found in [3].
o Digital Protocol X
The Digital X1 protocol is a network layer protocol
private to Digital
This document defines the NCP for establishing and
Digital's DNA Phase IV Routing protocol (DECnet Phase IV) over PPP
This document applies only to DNA Phase IV Routing messages (
data and control), and not to other DNA Phase IV protocols (MOP, LAT
etc.).
3. A PPP Network Control Protocol for DNA Phase IV
The DNA Phase IV Routing Control Protocol (DNCP) is responsible
configuring, enabling, and disabling the DNA Phase IV
protocol modules on both ends of the point-to-point link. DNCP
the same packet exchange mechanism as the Link Control
(LCP). DNCP packets may not be exchanged until PPP has reached
Network-Layer Protocol phase. DNCP packets received before
phase is reached should be silently discarded
The DNA Phase IV Routing Control Protocol is exactly the same as
Link Control Protocol [1] with the following exceptions
Frame
The packet may utilize any modifications to the basic frame
which have been negotiated during the Link Establishment phase
Data Link Layer Protocol
Exactly one DNCP packet is encapsulated in the Information
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RFC 1376 PPP DNCP November 1992
of a PPP Data Link Layer frame where the Protocol field
type hex 8027 (DNA Phase IV Control Protocol).
Code
Only Codes 1 through 7 (Configure-Request, Configure-Ack
Configure-Nak, Configure-Reject, Terminate-Request, Terminate-
and Code-Reject) are used. Other Codes should be treated
unrecognized and should result in Code-Rejects
DNCP packets may not be exchanged until PPP has reached
Network-Layer Protocol phase. An implementation should
prepared to wait for Authentication and Link Quality
to finish before timing out waiting for a Configure-Ack or
response. It is suggested that an implementation give up
after user intervention or a configurable amount of time
Configuration Option
DNCP has no Configuration Options
4. Sending DNA Phase IV Routing
Before any DNA Phase IV Routing packets may be communicated, PPP
reach the Network-Layer Protocol phase, and the DNA Phase IV
Control Protocol must reach the Opened state
Exactly one octet-count field and one DNA Phase IV Routing packet
encapsulated in the information field of a PPP Data Link Layer
where the Protocol field indicates type hex 0027 (DNA Phase
Routing). The octet-count contains a count of the number of
in the DNA Phase IV Routing packet. It is two octets in
itself, and is stored in VAX byte ordering, to be more
with DNA Phase IV Routing over Ethernet (i.e. least significant
first). It is needed to disambiguate optional padding octets
real information
The maximum length of an DNA Phase IV Routing packet transmitted
a PPP link is the same as the maximum length of the Information
of a PPP data link layer frame minus 2 octets (for the Length field).
The format of the packets themselves is the same as the format
over Ethernet, without the Ethernet header, Pad, and FCS fields
A summary of the information field is shown below. The fields
transmitted from left to right
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length LSB | Length MSB | DATA | ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length
Least significant byte of length
Length
Most significant byte of length
DNA Phase IV Routing data, as specified in [2]
5. General
When a topology change in the network occurs, DNA Phase IV
nodes immediately propagate changes via Level 1 and Level 2
messages, with a 1 second minimum delay between updates. DNA
IV Routing nodes also periodically retransmit the complete Level 1
and Level 2 distance vectors to guard against data corruption in
memory, and (in the case of Ethernet) loss of packets due to
errors. Because Digital's serial links run a protocol
guarantees delivery of packets (DDCMP), the recommended
retransmit time is long (600 seconds), whereas for Ethernet,
packet delivery is not guaranteed, the recommended default is
(10 seconds), as documented in [2]. To achieve convergence of
within a satisfactory time, the interval between updates should
based upon the error rate of underlying data link. As such, it
recommended that the time between routing updates be
configurable per PPP interface
The Hello timer and Listen timer should be set according to
recommendations for broadcast links (15 and 45 seconds
respectively).
Routers are not required to send routing updates if the remote
connected via the PPP link is an endnode. Endnodes are required
discard all routing updates received over a PPP link. The type of
node (endnode versus routing) can be determined from the
messages received from it
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RFC 1376 PPP DNCP November 1992
[1] Simpson, W., "The Point-to-Point Protocol (PPP)", RFC 1331,
Daydreamer, May 1992.
[2] Digital Equipment Corporation, "DNA Routing Layer
Specification", Version 2.0.0, Order No. AA-X435A-TK
[3] Digital Equipment Corporation, "DNA Maintenance
Functional Specification", Version 3.0.0, Order No. AA-X436A-TK
Some of the text in this document is taken from previous
produced by the Point-to-Point Protocol Working Group of the
Engineering Task Force (IETF).
The author wishes to thank Jim Muchow (Network Systems Corporation),
and Arthur Harvey (Digital Equipment Corporation) for their input
this memo
Security
Security issues are not discussed in this memo
Chair's
The working group can be contacted via the current chair
Brian
Lloyd &
3420 Sudbury
Cameron Park, California 95682
Phone: (916) 676-1147
EMail: brian@lloyd.
Author's
Questions about this memo can also be directed to the author
Steven J.
Network Systems
7600 Boone Avenue
Minneapolis, Minnesota 55428
Phone: (612) 424-4888
EMail: sjs@network.
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if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
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