|ENRP, Enpoint Name Resolution Protocol|
|Protocol type:||Application layer protocol.|
|Ports:||9901 (SCTP, UDP).|
9902 over TLS.
|Links:||IANA: RSerPool parameters.|
The Endpoint Handlespace Redundancy Protocol is designed to work in conjunction with the Aggregate Server Access Protocol to accomplish the functionality of the Reliable Server Pooling (RSerPool) requirements and architecture. Within the operational scope of RSerPool, ENRP defines the procedures and message formats of a distributed, fault-tolerant registry service for storing, bookkeeping, retrieving, and distributing pool operation and membership information.
|MAC header||IP header||SCTP | UDP header||ENRP header||Data :::|
Message. 8 bits.
Message specific flag bits.
Total length of the message in bytes.
ENRP client channel.
(RFC 5353) The communication channel through which an ASAP User (either a Pool Element (PE) or Pool User (PU)) requests ENRP handlespace service. The client channel is usually defined by the transport address of the Home ENRP server and a well-known port number.
ENRP server channel.
(RFC 5353) Defined by a list of IP addresses (one for each ENRP server in an operational scope) and a well-known port number. All ENRP servers in an operational scope can send "group-cast" messages to other servers through this channel. In a "group-cast", the sending server sends multiple copies of the message, one to each of its peer servers, over a set of point-to-point Stream Control Transmission Protocol associations between the sending server and the peers. The "group-cast" may be conveniently implemented with the use of the "SCTP_SENDALL" option on a one-to-many style SCTP socket.
(RFC 5353) A cohesive structure of pool handles and relations that may be queried by an internal or external agent.
Home ENRP server.
(RFC 5353) The ENRP server to which a PE or PU currently belongs. A PE MUST only have one Home ENRP server at any given time, and both the PE and its Home ENRP server MUST keep track of this master/slave relationship between them. A PU SHOULD select one of the available ENRP servers as its Home ENRP server.
(RFC 5353) The part of the network visible to pool users by a specific instance of the reliable server pooling protocols.
Pool (or server pool).
(RFC 5353) A collection of servers providing the same application functionality.
PE, Pool element.
(RFC 5353) A server entity having registered to a pool.
Pool element handle (or endpoint handle).
(RFC 5353) A logical pointer to a particular pool element in a pool, consisting of the pool handle and a destination transport address of the pool element.
(RFC 5353) A logical pointer to a pool. Each server pool will be identifiable in the operational scope of the system by a unique pool handle.
PU, Pool user.
(RFC 5353) A server pool user.
[RFC 5351] An Overview of Reliable Server Pooling Protocols.
[RFC 5353] Endpoint Handlespace Redundancy Protocol (ENRP).
[RFC 5354] Aggregate Server Access Protocol (ASAP) and Endpoint Handlespace Redundancy Protocol (ENRP) Parameters.
[RFC 5355] Threats Introduced by Reliable Server Pooling (RSerPool) and Requirements for Security in Response to Threats.
[RFC 5356] Reliable Server Pooling Policies.