Network Working Group V. Kalusivalingam
Request for Comments: 4075 Cisco Systems (India) Private Limited
Category: Standards Track May 2005
Simple Network Time Protocol (SNTP) Configuration Option for DHCPv6
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2005).
Abstract
This document describes a new DHCPv6 option for passing a list of
Simple Network Time Protocol (SNTP) server addresses to a client.
1. Introduction
This document describes a new option, called the SNTP [3] servers
option, for passing information about SNTP servers in DHCPv6 [1].
2. Requirements
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
document, are to be interpreted as described in RFC 2119 [2].
3. Terminology
This document uses terminology specific to IPv6 and DHCPv6 as defined
in the "Terminology" section of the DHCPv6 specification [1].
4. Simple Network Time Protocol (SNTP) Servers Option
The Simple Network Time Protocol servers option provides a list of
one or more IPv6 addresses of SNTP [3] servers available to the
client for synchronization. The clients use these SNTP servers to
synchronize their system time to that of the standard time servers.
Clients MUST treat the list of SNTP servers as an ordered list. The
server MAY list the SNTP servers in decreasing order of preference.
Kalusivalingam Standards Track [Page 1]
RFC 4075 SNTP Configuration Option for DHCPv6 May 2005
The option defined in this document can only be used to configure
information about SNTP servers that can be reached using IPv6. The
DHCP option to configure information about IPv4 SNTP servers can be
found in RFC 2132 [4]. Mechanisms for configuring IPv4/IPv6 dual-
stack applications are being considered, but are not specified in
this document.
The format of the Simple Network Time Protocol servers option is as
shown below:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_SNTP_SERVERS | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| SNTP server (IPv6 address) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| SNTP server (IPv6 address) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code: OPTION_SNTP_SERVERS (31)
option-len: Length of the 'SNTP server' fields, in octets;
it must be a multiple of 16
SNTP server: IPv6 address of SNTP server
5. Appearance of This Option
The SNTP servers option MUST NOT appear in messages other than the
following: Solicit, Advertise, Request, Renew, Rebind, Information-
Request, and Reply. If this option appears in messages other than
those specified above, the receiver SHOULD ignore it.
The option number for this option MAY appear in the Option Request
Option [1] in the following messages: Solicit, Request, Renew,
Rebind, Information-Request, and Reconfigure. If this option number
appears in the Option Request Option in messages other than those
specified above, the receiver SHOULD ignore it.
Kalusivalingam Standards Track [Page 2]
RFC 4075 SNTP Configuration Option for DHCPv6 May 2005
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