Subject: [Isms] SnmpSSHAddress

From: "David Harrington" <[email-masked]>
Date: Thu, 27 Sep 2007 12:40:34 -0400

Hi,

Bert and Jeff raised questions about the format for IPv4/IPv6
addresses and hostnames. Is the following acceptable? 

Is there an RFC that describes the textual representation of an IPv6
address?

Bert pointed out that MIB addresses have been inconsistent - some use
'/' to separate the port nunber and others use ':'. Jeff pointed out
that using a colon makes it difficult to determine where an IPv6
address ends and the port starts. Maybe we should use the ':'
separator for the hostname format, and the '/' separator for the IP
address formats to eliminate the ambiguity. RFC4181 has no guidance on
this point; are there other documents that provide guidance on the
separator character for hostnames and/or IP adddresses?

SnmpSSHAddress ::= TEXTUAL-CONVENTION
    DISPLAY-HINT "1a"
    STATUS      current
    DESCRIPTION
        "Represents either a hostname with a port number or an IP 
         address with a port number.

         The hostname must be encoded in ASCII, as specified in 
         RFC3490 (Internationalizing Domain Names in Applications) 
         followed by a colon ':' (ASCII character 0x3A) and a 
         decimal port number in ASCII. The name SHOULD be fully 
         qualified whenever possible.

         An IPv4 address must be a dotted decimal format followed 
         by a colon ':' (ASCII character 0x3A) and a decimal port 
         number in ASCII. 

         An IPv6 address must be a colon separated format, 
         surrounded by brackets, followed by a colon ':' (ASCII 
         character 0x3A) and a decimal port number in ASCII. 

         Values of this textual convention may not be directly useable
         as transport-layer addressing information, and may require
         runtime resolution. As such, applications that write them
         must be prepared for handling errors if such values are
         not supported, or cannot be resolved (if resolution occurs
         at the time of the management operation).

         The DESCRIPTION clause of TransportAddress objects that may
         have snmpSSHAddress values must fully describe how (and
         when) such names are to be resolved to IP addresses and vice
         versa.

         This textual convention SHOULD NOT be used directly in
         object definitions since it restricts addresses to a
         specific format. However, if it is used, it MAY be used
         either on its own or in conjunction with
         TransportAddressType or TransportDomain as a pair.

         When this textual convention is used as a syntax of an
         index object, there may be issues with the limit of 128
         sub-identifiers specified in SMIv2, STD 58. In this case,
         the OBJECT-TYPE declaration MUST include a 'SIZE' clause
         to limit the number of potential instance sub-identifiers."
    SYNTAX      OCTET STRING (SIZE (1..255))

David Harrington
[email-masked]
[email-masked]

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---

From: "tom.petch" <[email-masked]>
Date: Fri, 28 Sep 2007 18:56:48 +0200

----- Original Message -----
From: "David Harrington" <[email-masked]>
To: <[email-masked]>
Sent: Thursday, September 27, 2007 6:40 PM
Subject: [Isms] SnmpSSHAddress

> Is there an RFC that describes the textual representation of an IPv6

RFC4291 s2.2

The ABNF for this is somewhere unexpected (which I will stumble across
sometime).

But note that this section does not cover the interface number, which has
provoked discussion on URI because of the use of  the percent character, nor the
port number

Tom Petch