2.3.3 Naming and addressing mechanism: Endpoint IDs

2.3.3     Naming and addressing mechanism: Endpoint IDs

Internet address for TCP/IP identifies a node on the internet.  Internet address is a name or IP of a Web site Uniform Resource Locator (URL).  Abbreviation of Uniform Resource Locator (URL) it is the global address of documents and other resources on the World Wide Web. The first part of the address is called a protocol identifier and it indicates what protocol to use and the second part is called a resource name and it specifies the IP address or the domain name where the resource is located.  IP addresses are binary numbers, but they are usually stored in text files and displayed in human-readable notations, such as 172.16.254.1 (for IPv4), and 2001:db8:0:1234:0:567:8:1 (for IPv6). The protocol identifier and the resource name are separated by a colon and two forward slashes. Table 2.3 shows the two URLs below point to two different files at the domain website.com. The first specifies a file that should be fetched using the FTP protocol while the second specifies a Web page that should be fetched using the HTTP protocol.

ftp://www.website.com/file.exe http://www.website.com/index.html

Table 2.3: TCP/IP Endpoint ID

A URL is one type of Uniform Resource Identifier (URI). URI is the generic term for all types of names and addresses that refer to objects on the World Wide Web.

In a DTN, Bundle Protocol endpoints are identified by name. Bundle Protocol names are Uniform Resource Identifier (URI). Table 2.4 shows examples of Bundle Protocol name.

dtn://thismachine/ping dtn:pop:mailto:myemail@mymail.com

Table 2.4: DTN Endpoint ID

In URI terminology, each URI begins with a scheme name followed by a series of characters where the syntax is defined by the scheme. Each DTN node has a two part name consist of a region ID and entity ID as shown in Figure 2.20. Routing between regions is based only on region IDs, which are bound to their corresponding addresses throughout the DTN. Routing within regions is based only on entity IDs which are bound to their corresponding address only within that region. Thus each region uses a different mapping of entity IDs to address and no bandwidth is needed to copy name address mappings between regions. Gateways belong to two or more regions and move bundles between regions. It has multiple region IDs. Region IDs use the same namespace syntax as the internet DNS [9].

Figure 2.20: DTN Naming and addressing mechanism [9]