Hitachi, Ltd.

Yu Mitsui

Tetsuhiko Takahashi

Toshiyuki Saito

Takahiro Yoshida

Ryuji Ishii

Masatoshi Takihiro

Munetoshi Tsuge

Takaaki Toyama

In a broadband access network, calls can be kept active even when a telephone network fails. A voice gateway function captures callee telephone number information sent from a caller subscriber telephone to the telephone network and, when the telephone network fails, keeps the call active by retaining the connection between the caller and the callee. Furthermore, when the telephone network fails, the operation mode of the voice gateway and all ONTs is switched from an H.248 gateway mode to an SIP softswitch mode, allowing the voice gateway function to relay communication packets between ONTs and new call connections to be made in the broadband access network.

Gateway device, optical network terminal, and passive optical network system

A MVAC spoofed frame or a loop frame generated by a user is prevented from obstructing communication and the source port ID of a fraud is reported to the network administrator. A MAC frame forwarding apparatus adds the input port ID and the source MAC address of a received frame. The MAC frame forwarding apparatus has a frame forwarding management table and a frame discarding management table. The frame discarding management table has a MAC address to be discarded, indicating a received frame to be discarded if the address matches the source MAC address of the received frame, a target port ID, and the number of discarded frames. A management apparatus discards a received frame if the source MAC address matches the MAC address to be discarded and counts the number of discarded frames. If the number of discarded frames exceeds a predetermined level, the port ID, the MAC address, and the number of discarded frames are reported to the management apparatus, and the source port of the fraud is reported to the administrator.

Frame forwarding apparatus

Growing community of inventors

Fujisawa, Japan

Yu Mitsui