Programming Requirements (Windows CE 5.0)

Windows CE 5.0
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When you use the peer-to-peer APIs to develop networking applications, you must take the following programming considerations into account:

  • Peer-to-peer networking requires that IPv6 is installed and started on the computer to enable the functioning of peer-networking applications.

    PNRP uses IP addresses and supports IPv6 and IPv4 addresses for name resolution, but it only runs on IPv6.

    Note   All code examples in the Peer-to-Peer Infrastructure documentation use IPv6 addresses.
  • PNRP services utilize IPv6 ports 3587 (TCP) and 3540 (UDP). These ports must be open in an IPv6 Firewall for Peer-to-Peer applications to communicate. By default, these ports are opened on the local IPv6 Internet Connection Firewall when Windows peer-to-peer networking is enabled.
  • When you attempt to connect your computer to other IPv6 peer-to-peer nodes directly, that is without using peer-to-peer networking, ensure that the socket option IPV6_PROTECTION_LEVEL is set to PROTECTION_LEVEL_UNRESTRICTED.
  • When it uses PNRP, an application can publish one or more peer names that can be resolved. For each peer name registered with PNRP, there is an increase in the network bandwidth used by PNRP to publish the peer name and to keep it available to be resolved by other nodes. Even if no other computer resolves the peer name, there is still bandwidth usage that results from the registration.

    To prevent using too much bandwidth, applications should avoid registering large numbers of peer names on a computer. For example, an application that publishes pictures should not create a peer name for each picture, but should instead create a single peer name for the service that publishes pictures, and use a different protocol for clients to query the service for specific pictures.

  • Some applications may be required to register the same peer name on more than one computer. This typically happens if the peer name is associated with a person who uses more than one computer.

To register the same peer name on multiple computers

  1. Create a peer identity and peer name on a computer.
  2. Export the peer identity from that computer
  3. Import the peer identity on other computers.

    This allows the same secure peer name to be created on all the computers that have imported the peer identity.

See Also

Peer-to-Peer Application Development

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