3 ms·
If I remember correctly, BE helps in switching networks for routing packets. A packet would start with the big-endian destination address. If that address was h
by rhn_mk1 7y ago
If I remember correctly, BE helps in switching networks for routing packets. A packet would start with the big-endian destination address. If that address was hierarchical, i.e. most significant bytes signify the network (interface) it was in (like IP), then only a few of the first bits need to be processed in order to find which interface to direct the packet to. The transmission out therefore begins just after the few first bits are received.
E.g. for a switch connected to networks A: 0xa, B: 0x1, C: 0x3, a only the first byte 0x1 of the packet destined to 0x1234 needs to be processed before forwarding, saving some time compared to LE, where the entire address 0x4321 would have to be processed to find out that it's at the 0x1 network.
- baybal2 7y agoRegisters on anything today will be way wider than few bytes, moreover on network hardware. The gate savings on doing endiannes specific circuits are close to zero in comparison to many many other things a typical logic block comes with today.
- bestouff 7y agoIt's not intended to save gates but time. Bits are (were) serially encoded on the wire, so you could start switching sooner, before even having received the whole header.
- baybal2 7y agoI understand the rationale, but all that hardware today will probably get more bits on input in a single clock cycle than at the time this was a concern. Today, you have to process way way more bytes in a single clock cycle anyways. Internally, for a chip designer, almost all modern high speed serial busses look way wider than a single byte. And all of its serialness is kept inside the transmitter/serdes/interface blocks without any external exposure.