LDH: Difference between revisions
Dustin Loup (talk | contribs) Created page with "'''LDH,''' or '''Letter, Digit, Hyphen''', refers to the Domain Name System's (DNS) hostname rule that restricts domain names to the use of letters (a-z), numbers (0-9), a..." |
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With the Introduction of [[Internationalized Domain Name]]s in Application (IDNA) as the standard for IDNs, the LDH restriction no longer applies to domain names. IDNA makes this possible by using separate labels for display to end user and DNS processes. | With the Introduction of [[Internationalized Domain Name]]s in Application (IDNA) as the standard for IDNs, the LDH restriction no longer applies to domain names. IDNA makes this possible by using separate labels for display to end user and DNS processes. | ||
===U- | ===[[U-Label]]s=== | ||
IDNs are displayed to the end user using a Unicode encoding scheme. This is known as the '''U-Label.''' | IDNs are displayed to the end user using a Unicode encoding scheme. This is known as the '''U-Label.''' | ||
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The U-Label representation for [[.бг]], the [[ccTLD|country code top-level domain]] for Bulgaria, the Unicode codepoints are U+0431 (б) and U+0433 (г). | The U-Label representation for [[.бг]], the [[ccTLD|country code top-level domain]] for Bulgaria, the Unicode codepoints are U+0431 (б) and U+0433 (г). | ||
===A- | ===[[A-Label]]s=== | ||
Wt the DNS level, IDNs are processed using an ASCII-compatible encoding scheme. This is known as the '''A-Label.''' | Wt the DNS level, IDNs are processed using an ASCII-compatible encoding scheme. This is known as the '''A-Label.''' | ||
Revision as of 01:50, 5 February 2019
LDH, or Letter, Digit, Hyphen, refers to the Domain Name System's (DNS) hostname rule that restricts domain names to the use of letters (a-z), numbers (0-9), a hyphen (-) and a period (.) prior to internationalization of the DNS. The period is only allowed as a delimiter to separate different levels of a domain name.[1]
Introduction of IDNs[edit | edit source]
With the Introduction of Internationalized Domain Names in Application (IDNA) as the standard for IDNs, the LDH restriction no longer applies to domain names. IDNA makes this possible by using separate labels for display to end user and DNS processes.
U-Labels[edit | edit source]
IDNs are displayed to the end user using a Unicode encoding scheme. This is known as the U-Label.
Example:
The U-Label representation for .бг, the country code top-level domain for Bulgaria, the Unicode codepoints are U+0431 (б) and U+0433 (г).
A-Labels[edit | edit source]
Wt the DNS level, IDNs are processed using an ASCII-compatible encoding scheme. This is known as the A-Label.
Example:
The A-label for .бг is xn--90ae.[2]