A wide variety of enhancements to the Internet architecture have been proposed over the past several years, many of which require attaching metadata, or state, to packets as they flow through the network. Examples of such extensions are IP traceback and XCP. The IP specification supports an "options" mechanism as an extensible way to couple state with packets. However, as we will show in this paper, IP options are not well supported in the Internet. We make use of the PlanetLab planetary scale network testbed to quantify the fate of IP-option enabled packets in the wide-area. We measured wide-area paths with both standard IP packets and packets with options. We discovered that approximately half of Internet paths drop packets with options, raising serious dependability issues. Surprisingly, our findings indicate that it is feasible to restore support for options in the wide-area. We discovered that the core of the network drops very few options packets, with the vast majority of those drops occurring in edge AS networks. Furthermore, these drops are concentrated in a minority of the ASes.




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