At&t Intellectual Property I, L.p.

At+t Corp.

Rudi Distler

Thusitha Jayawardena

Mostafa Hashem Sherif

Mark Neil Evans

Zan Pan

There are provided systems and methods for symmetric bi-directional routing in multi-homed IP networks which includes sending an IP packet having a source address from a first host and substituting the source address with an exterior routing address by a first network address translation gateway or firewall of the first host using conditional substitution. The IP packet, with the exterior routing address, is optionally routed via intermediate networks and firewalls and received by a first gateway or firewall of a second host. The second host responds to the first host along a route which traverses the same set of firewall gateways as the initial IP packet by using the exterior routing address as a destination address. The exterior routing address is converted back to the source address by the first network address translation gateway of the first host.

Method for bi-directional symmetric routing in multi-homed networks with stateful firewalls

A data communication network provides techniques for handling frame discard of non-delineable flows. When a data flow is established, it is evaluated to determine whether a frame delimiter value is required and, if so, whether it is present. If the frame delimiter is required and missing, then the flow is declared non-delineable. If, subsequently, a congestion threshold is reached for this data flow, cells are discarded until a) a frame delimiter value is received, b) congestion drops below the threshold or c) a predetermined number of cells are discarded. These techniques provide frame discard handling mechanisms that alleviate the need for NOC personnel to intervene in problems caused by non-delineable frame discard flows.

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Holmdel, NJ, United States of America

Rudi Distler