Fujitsu Corporation

Sushil Pandhi

Robert A Sultan

Ajay Sahai

Michael Green

Zubao Yang

The number of managed network elements within a SONET network is configured to exceed the number addressable elements in a given address area. This is achieved through the use of SONET extension network elements and a special TL1 command message protocol. Any network element that has only one optical path (protected or unprotected) to an adjacent network in the SONET network can become an extension network element. TL1 command messages may be targeted to an extension network element through its only adjacent network element based on the network element's physical port connecting the network element to the extension network element.

Method and apparatus for extending synchronous optical networks

A data communications network includes a ring configured for spatial reuse, such as a resilient packet ring. A first bridge is coupled to the ring and to an end station such as an interworking bridge or router. A second bridge coupled to the ring learns an association between the first bridge and the end station by monitoring packets originated in the network by the end station and sent on the ring by the first bridge. The second bridge learns the association by obtaining an identifier of the first bridge and an address of the end station from received packets. When the second bridge receives packets destined for the end station, the packets are forwarded as broadcast transmissions on the ring if the association between the first bridge and the end station has not yet been learned, and are forwarded as unicast transmissions to the first bridge on the ring if the association between the first bridge and the end station has been learned.

Spatial reuse and multi-point interconnection in bridge-interconnected ring networks

A ring network provides transparent local area network (LAN) service by allocating respective proportions of data transmission capacity of the ring to different closed user groups (CUGs), each including a plurality of LAN clients. At each node of the ring, the use of a connected segment of the ring is monitored for both pass-through and locally-generated traffic by the LAN clients on a per-CUG basis. When it is detected that use of the connected segment for a CUG is approaching the allocated proportion, an active LAN client of the CUG is selected and sent a throttle message indicating that the LAN client is to reduce its data transmission rate. Rate monitoring for is accomplished using a 'leaky bucket' mechanism. A 'rate cache' identifying the active senders and their transmission rates can also be used in selecting a LAN client for receiving the throttle message.

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Mahwah, NJ, United States of America

Sushil Pandhi