3 ms·
The problem is that the fragmentation header in IPv6 is not deterministic, so it can't be parsed in constant time, which is what makes it "anathema to a switch"
by skywhopper 9y ago
The problem is that the fragmentation header in IPv6 is not deterministic, so it can't be parsed in constant time, which is what makes it "anathema to a switch" which needs to be able to guarantee certain levels of packet throughput. IPv4-style fragmentation can be done in constant time.
- pas 9y agoIt is still bounded time, which is still O(1). Yes, the standard doesn't limit the number of extension headers, but looking at the fixed header, and at most 5-6 extenion headers is the maximum time required to process a packet. And that'd be enough for 100% of traffic. The exact limit is the number of header types known to the processing node. Because encountering an unknown header should result in Parameter Error, and only one header can be used multiple times (the Destination Options), but that should be after the Frag one anyway.