Patent ID: 8223745

Claim:
A method of routing transactions via a shared infrastructure, the method comprising: at an ingress switch port of the shared infrastructure, receiving a transaction packet that has a packet length and includes a transaction packet header and an end-to-end cyclical redundancy check (ECRC) value; at the ingress switch port of the shared infrastructure, modifying the transaction packet by adding additional routing information to the header that is included in the transaction packet, wherein the additional routing information comprises a hierarchy tag with a hierarchy tag integrity check, and wherein the additional routing information is added to the transaction packet by substituting known bit values at predetermined bit positions in the transaction packet header with the additional routing information, and wherein both the ECRC value and the packet length remain unchanged after the transaction packet is modified; routing the modified transaction packet using the additional routing information; verifying the hierarchy tag of the modified transaction packet at an infrastructure point intermediate to the ingress switch port and an egress switch port of the shared infrastructure using the hierarchy tag integrity check; and at the egress switch port, reinstating the known bit values at the predetermined bit positions in the transaction packet header by replacing the additional routing information with the known bit values.