628 lines
14 KiB
Groff
628 lines
14 KiB
Groff
.\"
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.\" ===================================
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.\" HARP | Host ATM Research Platform
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.\" ===================================
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.\"
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.\"
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.\" This Host ATM Research Platform ("HARP") file (the "Software") is
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.\" made available by Network Computing Services, Inc. ("NetworkCS")
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.\" "AS IS". NetworkCS does not provide maintenance, improvements or
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.\" support of any kind.
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.\"
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.\" NETWORKCS MAKES NO WARRANTIES OR REPRESENTATIONS, EXPRESS OR IMPLIED,
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.\" INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY
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.\" AND FITNESS FOR A PARTICULAR PURPOSE, AS TO ANY ELEMENT OF THE
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.\" SOFTWARE OR ANY SUPPORT PROVIDED IN CONNECTION WITH THIS SOFTWARE.
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.\" In no event shall NetworkCS be responsible for any damages, including
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.\" but not limited to consequential damages, arising from or relating to
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.\" any use of the Software or related support.
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.\"
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.\" Copyright 1994-1998 Network Computing Services, Inc.
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.\"
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.\" Copies of this Software may be made, however, the above copyright
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.\" notice must be reproduced on all copies.
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.\"
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.\" @(#) $FreeBSD$
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.\"
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.\"
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.Dd August 21, 1998
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.Dt SCSPD 8
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.Os
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.Sh NAME
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.Nm scspd
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.Nd "SCSP daemon"
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.Sh SYNOPSIS
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.Nm
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.Op Fl f Aq Ar cfg\-file
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.Op Fl d
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.Op Fl T Ns Aq Ar options
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.Sh DESCRIPTION
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.Nm Scspd
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is an implementation of the Server Cache Synchronization
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Protocol (SCSP) for the Host ATM Research Platform (HARP)
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networking software.
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.Nm Scspd
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synchronizes the cache(s) of server(s)
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running on a host with the caches of servers on remote hosts.
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SCSP is defined for a number of different protocols, but the present
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version of
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.Nm
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only supports ATMARP.
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.Pp
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By using
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.Nm
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and
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.Xr atmarpd 8 ,
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one can provide multiple
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ATMARP servers in a single ATM LIS.
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This might be useful, for example, when a LIS consists of a number of
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local-area ATM networks connected by long-distance links.
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Each local-area network could have its own ATMARP server, with all the
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servers' caches being synchronized by SCSP.
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Then, if a long-distance link fails, hosts on a local-area network
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will still have connectivity to other local hosts (since they all use
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the local ATMARP server); when the long-distance link is restored,
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SCSP will re-synchronize the servers' caches, restoring
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connectivity to remote hosts.
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Both
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.Nm
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and
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.Xr atmarpd 8
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must be running before any ATMARP
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cache synchronization can take place.
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.Pp
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.Nm Scspd
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implements SCSP as specified in RFC 2334,
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.%T "Server Cache Synchronization Protocol (SCSP)"
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and
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.Pa draft\-ietf\-ion\-scspd\-atmarpd\-00.txt ,
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.%T "A Distributed ATMARP Service using SCSP" .
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.Pp
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When
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.Nm
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starts, it parses its command line and puts
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itself into the background.
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.Sh TERMINOLOGY
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Some of the vocabulary associated with SCSP can be confusing.
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In this document, the following definitions are used:
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.Pp
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.Em "Client server"
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or
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.Em "local server"
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means the server running on
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the same host as
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.Nm
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whose cache is to be synchronized with that
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of one or more remote servers.
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When the word
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.Em server
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is used alone, it means
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.Em "client server" .
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.Pp
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.Em "Remote server"
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means a server running on some host other than
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the one where
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.Nm
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is running.
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.Pp
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.Em "Directly Connected Server"
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(DCS) means a remote server that
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.Nm
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communicates with directly.
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The remote server will also be running an implementation of SCSP.
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.Pp
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.Em "Cache Alignment"
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(CA) has two meanings.
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The Cache Alignment protocol is a part of the SCSP protocol
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specification, and the Cache Alignment finite state machine (FSM)
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is a finite state machine that implements the Cache Alignment
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protocol.
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.Pp
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.Sh OPTIONS
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The command-line options are:
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.Bl -tag -width "-f <cfg\-file>"
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.It Fl f Aq Ar cfg\-file
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Specifies the name of the configuration file.
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If this option is not specified,
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.Nm
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looks for the
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file
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.Pa /etc/scspd.conf .
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.It Fl d
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Specifies that
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.Nm
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is to be run in debug mode.
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In debug mode, the daemon is not put into the background.
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Log messages are written to standard output instead of to
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the log file specified in the configuration file.
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.It Fl T Ns Aq Ar options
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Specifies that
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.Nm
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will trace specified events and messages
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as it executes.
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The
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.Fl T
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flag is followed by one or more of the following
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options:
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.Pp
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.Bl -tag -width 4n -compact
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.It Cm c
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trace
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.Nm Ns 's
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CA Finite State Machine (FSM),
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.It Cm h
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trace
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.Nm Ns 's
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Hello FSM,
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.It Cm i
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trace
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.Nm Ns 's
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Client Interface FSM,
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.It Cm C
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trace CA, CSUS, CSU Request, and CSU Reply messages,
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.It Cm H
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trace Hello messages,
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.It Cm I
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trace interface messages to and from
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.Nm Ns 's
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clients.
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.El
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.El
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.Sh CONFIGURATION
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The configuration file consists of a sequence of configuration
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statements.
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These statements specify information about the servers,
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both local and remote, whose
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caches are to be synchronized by
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.Nm .
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RFC 2334,
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.%T "Server Cache Synchronization Protocol (SCSP)"
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and
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.Pa draft\-ietf\-ion\-scspd\-atmarpd\-00.txt ,
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.%T "A Distributed ATMARP Service using SCSP"
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will be valuable in understanding how to configure
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.Nm .
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.Pp
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A configuration statement other than a comment is terminated by a
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semicolon.
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Some statements contain blocks, delimited by braces
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.No ( Dq Li {
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and
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.Dq Li } ) .
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Configuration statement keywords are not case-sensitive,
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but some parameters (e.g. interface names) are.
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Configuration statements can span multiple lines.
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.Ss Comments
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Three types of comments are allowed:
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.Bl -hang
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.It Sy "# comments" :
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any characters from
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.Dq Li #
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to the end of the line are ignored.
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.It Sy "C comments" :
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any characters between
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.Dq Li /*
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and
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.Dq Li */
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are ignored.
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.It Sy "C++ comments" :
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any characters from
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.Dq Li //
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to the end of the line are ignored.
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.El
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.Ss Statements
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The configuration statements recognized by
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.Nm
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are:
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.Bd -literal
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Server <name> {
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Protocol <protocol ID>;
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Netif <if_name>;
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ServerGroupID <ID>;
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FamilyID <ID>;
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DCS {
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ATMaddr <ATM address>;
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ID <host>;
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CAReXmitInt <int>;
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CSUSReXmitInt <int>;
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CSUReXmitInt <int>;
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CSUReXmitMax <cnt>;
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HelloDead <cnt>;
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HelloInt <int>;
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Hops <cnt>;
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};
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};
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Log {
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File <file name>;
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Syslog;
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};
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.Ed
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.Pp
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Where a host address needs to be specified in the configuration file,
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either a DNS name or an IP address in dotted decimal format can
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be used.
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.Pp
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ATM addresses are specified as strings of hex digits, with an
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optional leading
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.Dq Li 0x .
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Fields within the address may be separated by periods, but periods
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are for readability only and are ignored.
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ATM addresses are 20 bytes long.
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The full address, including any leading zeroes, must be given.
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For example:
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.Pp
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.Dl "0x47.0005.80.ffe100.0000.f21a.0170.0020481a0170.00"
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.Ss "Server Statement"
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The
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.Ic server
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statement specifies a client server whose cache
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to be synchronized with the caches of other servers
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running on remote hosts.
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There will be one
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.Ic server
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statement in the configuration file
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for each client server whose cache is to be synchronized by
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.Nm .
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The format of the
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.Ic server
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statement is:
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.Bd -ragged -offset indent
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.Ic Server
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.Aq Ar name
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{
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.Aq Ar statements
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};
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.Ed
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.Pp
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A
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.Ar name
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must be specified on the
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.Ic server
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statement, but it is
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not used by
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.Nm .
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It is expected to give a brief description of the server's purpose.
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.Pp
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The
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.Ic server
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statement has several sub-statements
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that specify the details of the
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.Nm Ns 's
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configuration.
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They are:
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.Bl -tag -width indent
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.It Ic Protocol Cm ATMARP ;
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The only protocol supported by the current version of
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.Nm
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is
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.Cm ATMARP .
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The
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.Ic protocol
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statement must always be specified.
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.It Ic Netif Aq Ar intf ;
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The
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.Ic netif
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statement specifies the name of the ATM network
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interface on which a client server is providing service.
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The
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.Ic netif
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statement must always be specified.
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.It Ic ServerGroupID Aq Ar ID ;
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The
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.Ic ServerGroupID
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statement specifies an identifier for the
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group of servers being synchronized by
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.Nm .
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The
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.Ar ID
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is specified as a decimal number in the range 0 - 65,535.
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The server group ID must be the same for all servers whose caches
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are being synchronized by an SCSP session.
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That is, the server group ID for a host must be the same for all
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Directly Connected Servers (DCSs) pointed to within a
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.Ic server
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statement.
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The
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.Ic ServerGroupID
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statement must always be specified.
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.It Ic FamilyID Aq Ar ID ;
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The
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.Ic familyID
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statement specifies an identifier for a family
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of parallel SCSP sessions running between a group of hosts (i.e. a
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set of SCSP sessions with different protocol IDs but the same set
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of servers).
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The
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.Ar ID
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is specified as a decimal number in the range 0 - 65,535.
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The family ID is currently not used by
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.Nm .
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.El
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.Ss "DCS Statement"
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The
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.Ic DCS
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statement is a sub-statement of the
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.Ic server
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statement
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that specifies the characteristics of a Directly Connected Server (DCS).
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The
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.Ic server
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statement will have one
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.Ic DCS
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statement for
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each DCS that
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.Nm
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is to exchange information with.
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The
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.Ic DCS
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statement has a number of sub-statements that specify the
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details of the configuration for the DCS.
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They are:
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.Bl -tag -width indent
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.It Ic ATMaddr Aq Ar ATM\ address ;
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The
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.Ic ATMaddr
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statement specifies the ATM address of the DCS.
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The
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.Ic ATMaddr
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statement must always be specified.
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.It Ic ID Aq Ar host ;
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The
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.Ic ID
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statement specifies the SCSP identifier of the DCS.
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For ATMARP, the ID is the IP address or DNS name associated with the
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ATM interface of the DCS.
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The
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.Ic ID
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statement must always be specified.
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.It Ic CAReXmitInt Aq Ar int ;
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The
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.Ic CAReXmitInt
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statement specifies the interval that is
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allowed to elapse between retransmissions of CA messages.
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If a CA message is sent and an acknowledgement is not received within
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.Ic CAReXmitInt
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seconds, the message will be retransmitted.
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The default value for
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.Ic CAReXmitInt
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is 3 seconds.
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.It Ic CSUSReXmitInt Aq Ar int ;
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The
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.Ic CSUSReXmitInt
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statement specifies the interval that is
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allowed to elapse between retransmissions of CSU Solicit messages.
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When a CSUS message is sent, any Cache State Advertisements (CSAs)
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requested by the CSUS that have
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not been received within
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.Ic CSUSReXmitInt
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seconds will be requested
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again by another CSUS message.
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The default value for
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.Ic CSUSReXmitInt
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is 3 seconds.
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Be careful not to confuse
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.Ic CSUSReXmitInt
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and
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.Ic CSUReXmitInt .
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.It Ic CSUReXmitInt Aq Ar int ;
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The
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.Ic CSUReXmitInt
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statement specifies the interval that is
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allowed to elapse between retransmissions of CSU Request messages.
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When a CSU Request message is sent, any CSAs that are not acknowledged
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by a CSU Reply message within
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.Ic CSUReXmitInt
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seconds will
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be retransmitted.
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The default value for
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.Ic CSUReXmitInt
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is 2 seconds.
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Be careful not to confuse
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.Ic CSUReXmitInt
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and
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.Ic CSUSReXmitInt .
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.It Ic CSUReXmitMax Aq Ar cnt ;
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The
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.Ic CSUReXmitMax
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statement specifies the number of times that
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a CSA will be retransmitted as described above before SCSP gives up
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on the CSA and discards it.
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The default value for
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.Ic CSUReXmitMax
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is 5.
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.It Ic HelloDead Aq Ar cnt ;
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The
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.Ic HelloDead
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statement specifies the Hello Dead Factor that
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will be sent to the DCS in Hello messages.
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A
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.Dq "DCS down"
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condition will be detected when nothing is received from
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a DCS in
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.Ic HelloDead No * Ic HelloInt
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seconds.
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The default value for
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.Ic HelloDead
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is 3.
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.It Ic HelloInt Aq Ar int ;
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The
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.Ic HelloInt
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statement specifies the Hello Interval that
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will be sent to the DCS in Hello messages.
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The default value for
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.Ic HelloInt
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is 3 seconds.
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.It Ic Hops Aq Ar cnt ;
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The
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.Ic Hops
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statement specifies the number of hops (DCS to DCS)
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that will be specified in CSAs originating from the local server.
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This number must be at least as large as the diameter of the
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server group.
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That is, it must be large enough for a CSA to be propagated from
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server to server all the way across the server group.
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The default value for
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.Ic Hops
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is 3.
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.El
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.Ss "Log Statement"
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The
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.Ic log
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statement specifies how
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.Nm
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is to log
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information about its operation.
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.Nm Scspd
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can write log information to a file, to the system log,
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or both.
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.Bl -tag -width indent
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.It Ic File Aq Ar file\ name ;
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The
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.Ic file
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statement specifies that
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.Nm
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is to write
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its log messages to the named file.
|
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Log messages will be appended to the end of the file if
|
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it already exists.
|
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.It Ic Syslog ;
|
|
The
|
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.Ic syslog
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statement specifies that
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.Nm
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is to write
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its log messages to the syslog facility.
|
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.Nm Scspd
|
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writes its messages to syslog with a facility code
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of
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.Dv LOG_DAEMON .
|
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.El
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.Pp
|
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If no
|
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.Ic log
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statement is specified,
|
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.Nm
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writes log
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messages to the system log.
|
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If both
|
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.Ic file
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and
|
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.Ic syslog
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|
are specified,
|
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.Nm
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will
|
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write log messages to both the named file and the system log.
|
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.Ss Examples
|
|
An example of a simple configuration file for
|
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.Nm
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|
might be:
|
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.Bd -literal -offset indent
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server atmarp_ni0 {
|
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protocol ATMARP;
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netif ni0;
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ServerGroupID 23;
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DCS {
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ID 10.1.1.2;
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ATMaddr 0x47.0005.80.ffdc00.0000.0002.0001.002048061de7.00;
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hops 2;
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};
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};
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.Ed
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.Pp
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This configuration would synchronize the cache of the ATMARP server
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operating on network interface ni0 with the cache of a second server
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running on a host whose IP address is 10.1.1.2.
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Log messages would be written to the system log.
|
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.Sh SIGNAL PROCESSING
|
|
The following signals can be used to control
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.Nm :
|
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.Bl -tag -width indent
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.It Dv SIGHUP
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|
Reread the configuration file and restart
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.Nm .
|
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.It Dv SIGINT
|
|
Dump debugging information to a file.
|
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When it receives a
|
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.Dv SIGINT
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signal,
|
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.Nm
|
|
dumps a summary of
|
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its control blocks to a text file (see
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.Sx FILES ) .
|
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.El
|
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.Sh FILES
|
|
.Bl -tag -width indent
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.It Pa /etc/scspd.conf
|
|
.Nm Scspd
|
|
default configuration file name.
|
|
A different file name can be specified with the
|
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.Fl f
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|
command-line
|
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option.
|
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.It Xo
|
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.Sm off
|
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.Pa /tmp/scspd.
|
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.Aq Ar pid
|
|
.Pa \&.
|
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.Aq Ar seq
|
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.Pa .out
|
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.Sm on
|
|
.Xc
|
|
Debugging information dump file name.
|
|
.Nm Scspd
|
|
writes a summary of its control blocks to this file
|
|
when it receives a
|
|
.Dv SIGINT
|
|
signal.
|
|
.Aq Ar pid
|
|
is the process ID of the daemon and
|
|
.Aq Ar seq
|
|
is a sequence
|
|
number which is incremented every time a dump is taken.
|
|
.It Xo
|
|
.Sm off
|
|
.Pa /tmp/scspd.
|
|
.Aq Ar pid
|
|
.Pa .trace
|
|
.Sm on
|
|
.Xc
|
|
Trace file.
|
|
.Nm Scspd
|
|
writes trace information to this file if the
|
|
.Fl T
|
|
option is specified on the command line.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr atm 8 ,
|
|
.Xr atmarpd 8
|
|
.Rs
|
|
.%O "RFC 2334"
|
|
.%T "Server Cache Synchronization Protocol (SCSP)"
|
|
.Re
|
|
.Rs
|
|
.%O "draft\-ietf\-ion\-scsp\-atmarpd\-00.txt"
|
|
.%T "A Distributed ATMARP Service Using SCSP"
|
|
.Re
|
|
.Sh BUGS
|
|
If
|
|
.Nm
|
|
terminates and is restarted, there will be a period of
|
|
instability while previously-synchronized cache entries time out and are
|
|
refreshed.
|
|
.Pp
|
|
Please report any bugs to
|
|
.Aq harp\-bugs@magic.net .
|
|
.Sh COPYRIGHT
|
|
Copyright (c) 1994-1998, Network Computing Services, Inc.
|
|
.Sh AUTHORS
|
|
.An John Cavanaugh ,
|
|
Network Computing Services, Inc.
|
|
.An Mike Spengler ,
|
|
Network Computing Services, Inc.
|
|
.An Joe Thomas ,
|
|
Network Computing Services, Inc.
|
|
.Sh ACKNOWLEDGMENTS
|
|
This software was developed with the support of the Defense
|
|
Advanced Research Projects Agency (DARPA).
|