109 lines
6.9 KiB
HTML
109 lines
6.9 KiB
HTML
|
<?xml version="1.0" encoding="UTF-8"?>
|
||
|
|
<!DOCTYPE html
|
||
|
|
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
||
|
|
<html lang="en-us" xml:lang="en-us">
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
||
|
|
<meta name="security" content="public" />
|
||
|
|
<meta name="Robots" content="index,follow" />
|
||
|
|
<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
|
||
|
|
<meta name="DC.Type" content="reference" />
|
||
|
|
<meta name="DC.Title" content="Server-to-client TFTP Option Acknowledgment" />
|
||
|
|
<meta name="abstract" content="The TFTP server sends an Option Acknowledgment (OACK) to a client in response to either a read request or a write request that includes additional TFTP options as described in Client to server TFTP Read Request (RRQ) options." />
|
||
|
|
<meta name="description" content="The TFTP server sends an Option Acknowledgment (OACK) to a client in response to either a read request or a write request that includes additional TFTP options as described in Client to server TFTP Read Request (RRQ) options." />
|
||
|
|
<meta name="DC.Relation" scheme="URI" content="rzal5tftpsub.htm" />
|
||
|
|
<meta name="DC.Relation" scheme="URI" content="rzal5rrqoptions.htm" />
|
||
|
|
<meta name="copyright" content="(C) Copyright IBM Corporation 2000, 2006" />
|
||
|
|
<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 2000, 2006" />
|
||
|
|
<meta name="DC.Format" content="XHTML" />
|
||
|
|
<meta name="DC.Identifier" content="rzal5oack" />
|
||
|
|
<meta name="DC.Language" content="en-us" />
|
||
|
|
<!-- All rights reserved. Licensed Materials Property of IBM -->
|
||
|
|
<!-- US Government Users Restricted Rights -->
|
||
|
|
<!-- Use, duplication or disclosure restricted by -->
|
||
|
|
<!-- GSA ADP Schedule Contract with IBM Corp. -->
|
||
|
|
<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
|
||
|
|
<link rel="stylesheet" type="text/css" href="./ic.css" />
|
||
|
|
<title>Server-to-client TFTP Option Acknowledgment</title>
|
||
|
|
</head>
|
||
|
|
<body id="rzal5oack"><a name="rzal5oack"><!-- --></a>
|
||
|
|
<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
|
||
|
|
<h1 class="topictitle1">Server-to-client TFTP Option Acknowledgment</h1>
|
||
|
|
<div><p>The TFTP server sends an Option Acknowledgment (OACK) to a client
|
||
|
|
in response to either a read request or a write request that includes additional
|
||
|
|
TFTP options as described in Client to server TFTP Read Request (RRQ) options.</p>
|
||
|
|
<div class="section"><p>An OACK that the servers sends in response to a transfer request
|
||
|
|
includes only responses to requested options that the server supports. The
|
||
|
|
server can also send an OACK to a client subsequently to the start of a subnet
|
||
|
|
broadcast transfer. This is done to indicate to the client whether it is the
|
||
|
|
master client in a subnet broadcast file group. An OACK packet that the server
|
||
|
|
sends subsequently to the start of a subnet broadcast transfer includes the
|
||
|
|
sbroadcast option.</p>
|
||
|
|
<p>The following is a list of supported options and
|
||
|
|
their descriptions:</p>
|
||
|
|
<dl><dt class="dlterm"><strong>blksize</strong></dt>
|
||
|
|
<dd>Null (0h) terminated <tt>blksize</tt> keyword that is followed by the
|
||
|
|
block size that is used for this file transfer. It is represented as a null-terminated
|
||
|
|
ASCII string. This is the response to a requested block size, and the value
|
||
|
|
returned here can be less than the requested block size. The server determines
|
||
|
|
the block size for the transfer based on the requested block size, the maximum
|
||
|
|
configured block size, and possibly the subnet broadcast transfers that are
|
||
|
|
already in progress.</dd>
|
||
|
|
<dt class="dlterm"><strong>sbroadcast</strong></dt>
|
||
|
|
<dd>Null-terminated <tt>sbroadcast</tt> keyword that is followed by a null-terminated
|
||
|
|
ASCII string that includes the following fields separated by commas: <dl><dt class="dlterm">port</dt>
|
||
|
|
<dd>The ASCII representation of the port to which the subnet-directed broadcast
|
||
|
|
datagrams are broadcast. This is the well-known port that is registered with
|
||
|
|
the Internet Assigned Number Authority (IANA) with the keyword of <tt>subntbcst_tftp</tt> and
|
||
|
|
a decimal value of <tt>247</tt>. This field might be empty in OACK packets
|
||
|
|
that the server sends subsequently to the start of a subnet broadcast transfer.</dd>
|
||
|
|
<dt class="dlterm">sbid</dt>
|
||
|
|
<dd>The ASCII representation of a decimal number that is called the <tt>subnet
|
||
|
|
broadcast identifier</tt>. Possible values are 0 through 4 294 967 295
|
||
|
|
(FFFFFFFFh). This is used along with the server source port to determine if
|
||
|
|
a subnet-directed broadcast datagram is part of a requested transfer. This
|
||
|
|
field can be empty in OACK packets that the server sends subsequently to the
|
||
|
|
start of a subnet-based broadcast transfer.</dd>
|
||
|
|
<dt class="dlterm">mc</dt>
|
||
|
|
<dd>This is either an ASCII (31h) <tt>1</tt> or ASCII <tt>0</tt> (32h) to
|
||
|
|
indicate to the client whether it is currently the master client. A value
|
||
|
|
of <tt>1</tt> indicates that the client is the master client, and a value
|
||
|
|
of <tt>0</tt> indicates that the client is not the master client. <p>In response
|
||
|
|
to an OACK, the master client must send an ACK to the server. The master client
|
||
|
|
sets the block number in this ACK to the number of the block prior to the
|
||
|
|
first block that is required by the master client.</p>
|
||
|
|
<p>The master client
|
||
|
|
acknowledges subnet broadcast data (BDATA) packets by sending an ACK to the
|
||
|
|
server. The master client sets the block number in this ACK to the block prior
|
||
|
|
to the current block that the master client requires.</p>
|
||
|
|
<p>Clients that are
|
||
|
|
not indicated as being the master client respond to an OACK packet with an
|
||
|
|
ACK that has the block number set to zero.</p>
|
||
|
|
<div class="note"><span class="notetitle">Note:</span> The block number in ACK
|
||
|
|
packets is the 2-byte binary representation of the number in network byte
|
||
|
|
order.</div>
|
||
|
|
</dd>
|
||
|
|
</dl>
|
||
|
|
</dd>
|
||
|
|
<dt class="dlterm"><strong>tsize</strong></dt>
|
||
|
|
<dd>The null-terminated <tt>tsize</tt> keyword that is followed by the null-terminated
|
||
|
|
ASCII representation of the decimal number that represents the file size of
|
||
|
|
the requested file. The client uses this information to ensure that it has
|
||
|
|
enough space to store the file and to determine the last block number of the
|
||
|
|
file. <div class="note"><span class="notetitle">Note:</span> The client can also determine the file size and last block of
|
||
|
|
a transfer when it receives a block that contains less data than the block
|
||
|
|
size.</div>
|
||
|
|
</dd>
|
||
|
|
</dl>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
<div>
|
||
|
|
<div class="familylinks">
|
||
|
|
<div class="parentlink"><strong>Parent topic:</strong> <a href="rzal5tftpsub.htm" title="Broadcast storms are a performance problem that might occur when there are large numbers of systems that boot from the network.">TFTP Subnet Broadcast option</a></div>
|
||
|
|
</div>
|
||
|
|
<div class="relconcepts"><strong>Related concepts</strong><br />
|
||
|
|
<div><a href="rzal5rrqoptions.htm" title="This information includes the additional TFTP options that are supported and a description of their use.">Client-to-server TFTP Read Request options</a></div>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
</body>
|
||
|
|
</html>
|