1419 results about "IPv4" patented technology

Disclosed are methods and apparatus for avoiding problems caused by converting between two different protocols, such as IPv4 and IPv6. These problems may include, but are not limited to, fragmentation of packets, dropping of packets, and retransmission of packets. Avoiding these problems will reduce the incidence of transmission delays, bandwidth degradation, and additional processing in the packet's transmission path due to such problems. In general terms, the present invention provides mechanisms for modifying a protocol parameter, such as a TCP or UDP parameter, to avoid problems associated with protocol translation, such as fragmentation. In one implementation, the protocol parameter limits the size of a particular portion of the a packet transmitted by a sending computer node or device. For example, a packet size indicator is communicated to the sending computer node so that the sending computer node sends packets limited by the packet size indicator to thereby avoid associated with the size of such packets. In specific TCP embodiments, the size indicator specifies a window size and / or a maximum segment size. For example, if packets transmitted by a sending node to a receiving node are converted from IPv4 to IPv6 and the window size indicated to the sending node (e.g., by the receiving node) is 512 bytes, the window size is adjusted to 500 bytes before reaching the sending node. The adjustment amount may be based on an estimated size increase resulting from converting from IPv4 to IPv6. In this example, the window size is decreased by 12 bytes since a conversion from IPv4 to IPv6 where one 4 byte IPv4 address is changed to a 16 byte Ipv6 address has an associated size difference of 12 bytes. In a specific embodiment, actual changes in packet size may tracked and the adjusted size indicator may be dynamically based on such tracked changes. In other embodiments, the changes in packet size are predicted, and the adjusted size is preemptively changed as needed.

A method and system capable of providing mobility support for IPv4 / IPv6 inter-networking to a mobile node is disclosed. The mobile node in the system has an address mapper, an IPv4 protocol stack and an IPv6 protocol stack in the network layer. When moving from IPv4 to IPv6 networks, the mobile node registered an IPv4 address receives router advertisement packets from an IPv6 router, so as to obtain a IPv6 care-of-address, and resolve the IPv6 care-of-address by an IPv4 care-of-address. The address mapper issues an IPv4 message to register the IPv4 care-of-address. When moving from IPv6 to IPv4 networks, the mobile node registered an IPv6 address receives agent advertisement messages from a foreign agent, so as to obtain an IPv4 care-of-address, resolve the IPv4 care-of-address by an IPv6 care-of-address. The address mapper issues an IPv6 message to register and update binding information by the IPv6 care-of-address.

A system, apparatus and method to use private IP addresses to designate host devices or nodes in different networks for communication purposes are described. Various embodiments of the invention address the problem of a shortage of public IP addresses under IPv4 architecture. In one embodiment of the invention, dynamic NAT penetration capabilities are provided which consequently expand the capability of running peer-to-peer applications on the Internet.

Since the Mobile IP is defined under the assumption that a mobile node roams between networks conforming to the same communications protocols, mobile communications between IPv4 and IPv6 are not possible. Further, a translation of the location registration messages also requires translating the format between different protocol layers. To solve this problem, a mobile proxy apparatus 2 is provided between a home network 1a and a foreign network 1b governed by different communications protocols. The mobile proxy apparatus 2 has a DNS-ALG function, a translator function and a Mobile IP function, and, by combining these functions, performs address translation and format translation on Mobile IP messages and user packets. The MN4 has Mobile IPv4 and Mobile IPv6 functions and executes communication suitable for the communications protocol governing the network to which it moves.

Even if a mistaken reply to a host name resolution request of IPv6 is issued by a DNS contents server, a requesting terminal can still acquire an IPv4 address. When a host name resolution request of IPv6 (AAAA query) is received, a DNS proxy server generates a host name resolution request of IPv4 having an identical domain name, transmits this together with the AAAA query to the DNS contents server, and determines the DNS reply which should be returned to the terminal from the contents of the DNS reply of IPv6 (AAAA reply) and the DNS reply (A reply) of IPv4 received from the DNS contents server. Hence, even if a reply message showing a domain name error is received from the DNS contents server, if the A reply is correct, the DNS proxy server generates an AAAA reply showing that the desired address does not exist, and returns this to the terminal.

A LPM search engine includes a plurality of exact match (EXM) engines and a moderately sized TCAM. Each EXM engine uses a prefix bitmap scheme that allows the EXM engine to cover multiple consecutive prefix lengths. Thus, instead of covering one prefix length L per EXM engine, the prefix bitmap scheme enables each EXM engine to cover entries having prefix lengths of L, L+1, L+2 and L+3, for example. As a result, fewer EXM engines are potentially underutilized, which effectively reduces quantization loss. Each EXM engine provides a search result with a determined fixed latency when using the prefix bitmap scheme. The results of multiple EXM engines and the moderately sized TCAM are combined to provide a single search result, representative of the longest prefix match. In one embodiment, the LPM search engine supports 32-bit IPv4 (or 128-bit IPv6) search keys, each having associated 15-bit level 3 VPN identification values.

A SIP server having the function of accepting simultaneous IPv4 / IPv6 registrations from an IPv4 / IPv6 dual SIP terminal, recognizing a protocol communicable with a communication partner terminal, and notifying the IPv4 / IPv6 dual SIP terminals of the result of the recognition if necessary, thereby to allow VOIP communication between the IPv4 / IPv6 dual SIP terminal and an IPv4 terminal or an IPv6 terminal to be the communication partner.