| Description: | 
|---|
| A request to a data source for information on available data (i.e. "catalog") or a request that defines the data to be archived. The request can be a general subscription intended to initiate a continuous or regular data stream or a specific request intended to initiate a one-time response from the recipient. | 
| Communications Standards: | 
|---|
| NTCIP C2C | AASHTO-17 | File Transfer Protocol (FTP) Application Profile | NTCIP 2303 | 
| NTCIP C2C | AASHTO-20 | Application Profile for DATEX-ASN (AP-DATEX) | NTCIP 2304 | 
| NTCIP C2C | AASHTO-21 | Octet Encoding Rules (OER) Base Protocol | NTCIP 1102 | 
| NTCIP C2C | AASHTO-28 | Ethernet Subnetwork Profile | NTCIP 2104 | 
| NTCIP C2C | AASHTO-39 | Center-to-Center Naming Convention Specification | NTCIP 1104 | 
| NTCIP C2C | AASHTO-XML | Application Profile for XML Message Encoding and Transport in ITS Center-to-Center Communications (C2C XML) | NTCIP 2306 | 
| NTCIP C2C | S-88 | Internet (TCP/IP and UDP/IP) Transport Profile | NTCIP 2202 | 
| Message Standards: | 
|---|
| ITE-TMDD21 | ITE-TMDD21 | Traffic Management Data Dictionary (TMDD) and Message Sets for External Traffic Management Center Communications (MS/ETMCC) | ITE TMDD | 
| Data Standards: | 
|---|
| No Data Standards |