Any node that forwards a packet sends it in the same direction it is already moving. Rules For ForwardingA node will forward an incoming packet to its outbound link if any of the following conditions are met.
Other Notes On ForwardingForwarding Into The End Of ChainAn attempt to forward a packet into the end of a chain (device has EOC bit set) will result in a rejected packet. How the rejection is handled on the link is described in the next section on packet rejection. In addition, error handling policy programmed into the end-of-chain device determines what additional action should be taken (log error, generate an interrupt, etc.). Refer to "End-Of-Chain Errors" on page 243 for a discussion about error handling by EOC devices. Forwarding If Initialization Is Not CompleteAnother aspect of forwarding involves the behavior of a device which detects a packet that should be forwarded, but the device has not yet completed its initialization ( EOC and Initialization Complete CSR bits still clear). Whether the incoming packet will be dropped or held pending initialization is then determined by the Drop on Uninitialized Link bit in the HyperTransport advanced capability Command Register. Refer to Chapter 13, entitled "Device Configuration," on page 305 for a detailed discussion of HyperTransport configuration. |