Method and system for internal data loop back in a high data rate switch

A packet switch comprising:

• an ingress buffer manager for receiving and buffering data packets;
• an ingress header processor for receiving packet headers of the data packets from the ingress buffer manager, the ingress header processor processing the packet headers and prepending signature information to the packet headers including information about a destination port to which to send the data packets;
• and
• an ingress traffic manager for scheduling the data packets to be sent by the ingress buffer manager to the destination port indicated by the signature information in the packet headers, wherein if further processing is needed, the data packets are sent back to an input of the ingress buffer manager over a loopback data path.

A method for processing data packets received at a packet switch comprising:

• receiving a data packet into a multiplexer of the packet switch, the data packet received from an incoming interface;
• processing the data packet at an ingress processing engine;
• determining if further packet processing is required;
• providing a loopback data path for the data packet to be reintroduced to an input of the multiplexer if further processing is required;
• and
• iteratively processing layers of the data packet at the ingress processing engine.

A method for processing data packets received at a packet switch comprising:

• receiving an IP datagram destined to a set of hosts that form a multicast group;
• processing the IP datagram at a processing engine;
• sending the IP datagram to a switch fabric to forward the IP datagram to a host of the multicast group;
• providing a loopback data path for data to be reintroduced to an input of the processing engine if further processing is required;
• and
• sending a copy of the IP datagram over the loopback data path to the input of the processing engine;
• sending the copy of the IP datagram to a switch fabric to forward the copy of the IP datagram to another host of the multicast group;
• and
• iteratively sending copies of the IP datagram over the loopback data path to the input of the processing engine in order to send the copies of the IP datagram to all of the hosts of the multicast group.

A method comprising:

• receiving a packet including N distinct layers of header information;
• a header processing engine processing the packet a first time to process K layers of the header information, wherein the header processing engine is capable of handling in one pass at most K layers of header information;
• and
• processing the remaining (N−K) distinct layers of header information by looping back the packet to an input of the header processing engine [floor(N/K)] times, where K layers of header information is processed during each time.