Bob, My read of the relevant RFCs is that the DHCP Line-ID option specifies the use of the "NVT" character set.
The character set specification is implicit, applying to all DHCP options, rather than having been written explicitly for this single DHCP option. One has to really study the full set of DHCP RFCs (i.e. the full daisy-chain of RFC citations from the References backwards) to see this, but it is consistent with every DHCP implementation that I can identify. I can't find ANY DHCP implementations that permit "arbitrary bytes" to be entered into the Line-ID option field. I can't think of any DHCP implementation that permits, for example, LINEFEED or CARRIAGE-RETURN to be entered into ANY DHCP-related field. Many have problems with inputs other than printable characters from ISO-8859, for example. The word "opaque" in the DHCP Line-ID option specification refers to the packet processing for the DHCP packet, not to the contents of the field or how that field is entered (presumably via a CLI or perhaps web page someplace) or how that field is to be displayed to humans. The DHCP Line-ID option does not use the word "opaque" to indicate absence of a character set. That is a mis-reading of the DHCP RFC set. As a former ISP person, I can assure that the Line-ID values absolutely DO get displayed to operators and others in network operations. It is important to be able to configure the Line-ID values and to view them in order to troubleshoot real networks (e.g. a DSL deployment). So the assumption that the DHCP Line-ID option does not have any specified character set is not actually correct. Now, if one's goal is *strict* compatibility with the DHCP Line-ID option, then the NVT character set (originally specified in very early RFCs) ought to be specified. I think, however, it would be reasonable to choose some alternative such as US-ASCII, ISO-8859-1, or (maybe -- possibly more risky given existing DHCP implementations -- but more globally suitable) UTF-8. Yours, Ran -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
