Hi Albert, > The 8-bit "next header" field, the first byte, uses the same coding as > the IPv4 Protocol field. And the next 8 bits after that provide the > length of the EH. > > Why can't the intermediate node work its way down all unknown EHs until > it reaches a "next header" you can identify? This should always occur. How can a node know it is a new Extension Header (which follows the format as specified in the new draft) or another upper layer protocol? There can be two unknowns - unknown upper layer protocol and unknown EH.
Say if we get a value of x, which is unknown in the Next Header field, there is no way we can assume the next header is either EH or an upper layer protocol. So there is no way to say the Next Header follows the format as specified in the EH. Thanks, Vishwas On Thu, Mar 20, 2008 at 2:32 PM, Manfredi, Albert E <[EMAIL PROTECTED]> wrote: > > -----Original Message----- > > From: Markku Savela [mailto:[EMAIL PROTECTED] > > > The part of draft, that proposes new extension headers follow the TLV > > format is OK. Although, I have always assumed that this was already > > implicit or even specified. If not, the draft could be seen as an > > emendation to the existing drafts. > > > > What irks me, is the talk of intermediates skipping "unknowns", which > > depends on them somehow recognizing the header as "extension > > header". But, if they recognize it, it is not *unknown* anymore. Seems > > to be a "thought loop". > > The 8-bit "next header" field, the first byte, uses the same coding as > the IPv4 Protocol field. And the next 8 bits after that provide the > length of the EH. > > Why can't the intermediate node work its way down all unknown EHs until > it reaches a "next header" you can identify? This should always occur. > > Bert > > > -------------------------------------------------------------------- > IETF IPv6 working group mailing list > ipv6@ietf.org > Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 > -------------------------------------------------------------------- > -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
