4 ms·
Seems like an attempt at being "clever". L2 equipment shouldn't care what kind of packet it is, but we're trying to subvert the original spec and come up with n
by uxp 10y ago
Seems like an attempt at being "clever". L2 equipment shouldn't care what kind of packet it is, but we're trying to subvert the original spec and come up with new hacks by "peeking" into the payload and make assumptions about what it is in order to rule or queue it differently.
Obviously in hindsight this is a bad idea and "idiotic", but I can't see the immediate fault of whomever first decided to try this a decade ago when MAC addresses were sequential, IPv4 was fairly abundant, and we didn't really even have smartphones and the explosion of connected devices.
- bogomipz 10y agoEthernet has always "cared" what type of upper payload its carrying. It has to, there are any other things besides IP that run directly on top of Ethernet frames. For instance 0x0800 means that the ethernet frame is carrying an IPv4 datagram. Here is a list of all the ethertypes it cares about: http://www.networksorcery.com/enp/Protocol/802/ethertypes.htm http://www.networksorcery.com/enp/Protocol/802/ethertypes.ht... Fire up wireshark and you will see these.
- colanderman 10y agoWhat the GP means is that layer 2 switches should forward traffic agnostic of what the Ethertype field says. That field only exists so layer 3 knows what it's dealing with.
- bogomipz 10y agoI see. I misunderstood then.
- qb45 10y agoThis is MPLS, not Ethernet. No protocol field, only endpoints know what's inside.