On 30 May 2013, at 00:02, Owen DeLong <[email protected]> wrote: > Personally, I think this is an inherently bad idea. > > IP addresses need less overloading of semantics, not more. > > We already use IP addresses for two conflicting purposes… Topology locator > and End System Identifier. > > This overloading is at the heart of our current scaling issues with respect > to the routing table. While these issues are currently less critical than > they have been in the past and will likely get quite a bit less critical in > IPv6, that is only because we have given up a fair amount of functionality to > preserve scalability in this regard. > > If we did not have this overloading, then an entity could obtain a set of > end-system identifiers and keep them throughout their lifetime, regardless of > topological changes. Today, where the addresses are overloaded with both > semantics, we either have to force most entities to change their numbers when > they change topology or we face unsustainable growth in the routing tables. > > The idea of adding more semantics to addressing rather than seeking to reduce > this overloading seems a step in the wrong direction, IMHO.
I agree. That said, an ISP, enterprise or group of organisations can follow whatever semantics they wish within their own borders. Just don't expect anyone else to follow or use those semantics. What Sheng is proposing is clearly stated as only being for interpretation between agreeing organisations. There are examples of organisations or protocols already doing this, be it embedding VLAN IDs or port number representations in addresses. And of protocols - in particular 6rd comes to mind as an example of an IPv6 addressing scheme with embedded semantics, which only has meaning within one ISP. It's not that different to DSCP semantics, which for example have been widely applied across academic networks, except of course the DSCP can be rewritten in transit. Whether someone outside the organisation can infer "private" information from the semantics may be an open question. I think people will do this type of thing, so an Informational document discussing the pros and cons, and how semantics can be used, is probably a good thing. Perhaps a "Potential Pitfalls" type section after the "Potential Benefits" section would balance the document a little better? Tim > Owen > > On May 29, 2013, at 12:06 AM, Sheng Jiang <[email protected]> wrote: > >> IP addresses are designed as topology locator, so that every packet can be >> routed to its network destination. >> >> However, even in IPv4 era, some network operators have mapped their IP >> address with certain semantic locally. These kind of mechanism explicitly >> express the semantic properties of every packet. Consequently, these network >> operators can inspect the properties of packets easily by mapping the >> addresses back to semantic. >> >> Network operators, who have large IPv6 address space, may also choose to >> embedded some semantics into IPv6 addresses by assigning additional >> significance to specific bits within the prefix. >> draft-jiang-v6ops-semantic-prefix documents a framework method that network >> operations may use their addresses with embedded semantics. These semantics >> bits are only meaningful within a single network, or group of interconnected >> networks which share a common addressing policy. Based on these embedded >> semantic bits in source/destination addresses, the network operators can >> accordingly treat network packets differently and efficiently. >> >> http://tools.ietf.org/html/draft-jiang-v6ops-semantic-prefix-03 >> >> Could you please review this draft and comments? It will help the document >> become more useful information to be shared. >> >> Best regards, >> >> Sheng >> >>> -----Original Message----- >>> From: [email protected] [mailto:[email protected]] >>> Sent: Tuesday, May 28, 2013 10:28 AM >>> To: Qiong Sun; Ian Farrer; Sheng Jiang; Boyang >>> Subject: New Version Notification for >>> draft-jiang-v6ops-semantic-prefix-03.txt >>> >>> >>> A new version of I-D, draft-jiang-v6ops-semantic-prefix-03.txt >>> has been successfully submitted by Sheng Jiang and posted to the >>> IETF repository. >>> >>> Filename: draft-jiang-v6ops-semantic-prefix >>> Revision: 03 >>> Title: A Framework for Semantic IPv6 Prefix >>> Creation date: 2013-05-28 >>> Group: Individual Submission >>> Number of pages: 19 >>> URL: >>> http://www.ietf.org/internet-drafts/draft-jiang-v6ops-semantic-prefix-03.txt >>> Status: >>> http://datatracker.ietf.org/doc/draft-jiang-v6ops-semantic-prefix >>> Htmlized: >>> http://tools.ietf.org/html/draft-jiang-v6ops-semantic-prefix-03 >>> Diff: >>> http://www.ietf.org/rfcdiff?url2=draft-jiang-v6ops-semantic-prefix-03 >>> >>> Abstract: >>> This document describes a framework method that network operations >>> may use their addresses. Network operators, who have large IPv6 >>> address space, may choose to embedded some semantics into IPv6 >>> addresses by assigning additional significance to specific bits >>> within the prefix. By embedded semantics into IPv6 prefixes, the >>> semantics of packets can be inspected easily. Routers and other >>> intermediary devices can easily apply relevant policies as required. >>> Packet-level differentiation can also enable flow-level and user- >>> level differentiation. Consequently, the network operators can >>> accordingly treat network packets differently and efficiently. The >>> management and maintenance of networks can be much simpler. >>> >>> >>> >>> >>> The IETF Secretariat >> >> _______________________________________________ >> v6ops mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/v6ops > > _______________________________________________ > v6ops mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/v6ops -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
