The Sitemaps Protocol allows a webmaster to inform search engines about URLs on a website that are available for crawling. Webmaster needs to create a sitemap file in an XML format that lists the URLs for a site. It allows webmasters to include additional information about each URL: when it was last updated, how often it changes, and how important it is in relation to other URLs in the site. This allows search engines to crawl the site more intelligently. Sitemaps are a URL inclusion protocol, and complement robots.txt, a URL exclusion protocol.
Web crawlers usually discover pages from links within the site and from other sites. Sitemaps supplement this data to allow crawlers that support Sitemaps to pick up all URLs in the Sitemap and learn about those URLs using the associated metadata. Using the Sitemap protocol does not guarantee that web pages are included in search engines, but provides hints for web crawlers to do a better job of crawling your site.
Sitemaps protocol is offered under the terms of the Attribution-ShareAlike Creative Commons License and has wide adoption, including support from Google, Yahoo!, and Microsoft.
Sample XML Sitemap
The following example shows a Sitemap that contains just one URL and uses all optional tags. The optional tags are in italics.
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<url>
<loc>http://www.example.com/</loc>
<lastmod>2005-01-01</lastmod>
<changefreq>monthly</changefreq>
<priority>0.8</priority>
</url>
</urlset>
XML tag definitions
The available XML tags are described below.
| Attribute | Description | |
| <urlset> | required | Encapsulates the file and references the current protocol standard. |
| <url> | required | Parent tag for each URL entry. The remaining tags are children of this tag. |
| <loc> | required | URL of the page. This URL must begin with the protocol (such as http) and end with a trailing slash, if your web server requires it. This value must be less than 2,048 characters. |
| <lastmod> | optional | The date of last modification of the file. This date should be in W3C Datetime format. This format allows you to omit the time portion, if desired, and use YYYY-MM-DD. Note that this tag is separate from the If-Modified-Since (304) header the server can return, and search engines may use the information from both sources differently. |
| <changefreq> | optional |
How frequently the page is likely to change. This value provides general information to search engines and may not correlate exactly to how often they crawl the page. Valid values are:
The value "always" should be used to describe documents that change each time they are accessed. The value "never" should be used to describe archived URLs. Please note that the value of this tag is considered a hint and not a command. Even though search engine crawlers may consider this information when making decisions, they may crawl pages marked "hourly" less frequently than that, and they may crawl pages marked "yearly" more frequently than that. Crawlers may periodically crawl pages marked "never" so that they can handle unexpected changes to those pages. |
| <priority> | optional |
The priority of this URL relative to other URLs on your site. Valid values range from 0.0 to 1.0. This value does not affect how your pages are compared to pages on other sites—it only lets the search engines know which pages you deem most important for the crawlers. The default priority of a page is 0.5. Please note that the priority you assign to a page is not likely to influence the position of your URLs in a search engine's result pages. Search engines may use this information when selecting between URLs on the same site, so you can use this tag to increase the likelihood that your most important pages are present in a search index. Also, please note that assigning a high priority to all of the URLs on your site is not likely to help you. Since the priority is relative, it is only used to select between URLs on your site. |
Protocol Sponsor: The sitemaps protocol is defined by the Sitemaps.org
Reference Links: Http://www.sitemaps.org/protocol.php: Sitemaps protocol format