System and method for flexibly crossing packets of different protocols

A system, comprising:

• a first bus interface having a first number of ingress lanes;
• a second bus interface having a second number of ingress lanes, wherein the first number of ingress lanes is greater than the second number of ingress lanes;
• a first number of ingress memories, each ingress memory having an input coupled to one of the ingress lanes of the first bus interface, an output, a read enable input coupled to a first finite state machine synchronized to a first clock, a write enable input coupled to a second finite state machine synchronized to a second clock;
• and
• a second number of ingress selectors, each ingress selector having an output coupled to one of the ingress lanes of the second bus interface, each ingress selector having a plurality of inputs including an input for each lane of the first ingress bus;
• and
• wherein the second finite state machine controls a select input of each of the plurality of ingress selectors.

A method, comprising:

• at a first time synchronized with a first bus clock:
• receiving a set of data units of a first ingress packet from a plurality of ingress lanes of a first bus, respective ones of the plurality of ingress lanes providing a respective one of the set of data units,
• storing each data unit in a respective ingress memory, the number of ingress memories equal to the number of the plurality of ingress lanes,
• writing a first descriptor to an ingress descriptor memory, the descriptor including an identification of valid data units in the received packet;
• and
• at a second time synchronized with a second bus clock:
• reading the first descriptor from the ingress descriptor memory, and
• for each of a plurality of valid data units identified in the first descriptor:
• select the ingress memory containing the respective valid data unit,
• route the respective valid data unit to one of a plurality of ingress lanes of a second bus, and
• assert a read enable on the ingress memory containing the respective valid data unit.