Hi Acee, The motivation for these two drafts (http://tools.ietf.org/html/draft-xu-isis-ipv6-router-id-00 and http://tools.ietf.org/html/draft-xu-ospf-ipv6-router-id-00) is very simple: the IPv6 ISIS|OSPF capability TLV/RI-LSA which are used for advertising router capabilities can be flooded across areas, however, only a 4-octect router ID is carried in them. As a result, it’s hard for routers in one area to establish correlations between IPv6 addresses and capabilities of routers in another area. For example, assume IS-IS router A in one area has established a L3VPN session with IS-IS router B in another area over their own IPv6 addresses. When router A needs to send L3VPN traffic to router B via a MPLS-SR tunnel, router A wants to know whether router B has the ELC (http://tools.ietf.org/html/draft-xu-isis-mpls-elc-00) before inserting an EL into the MPLS-SR packet . However, the Capability TLV originated by router B doesn’t carried an IPv6 address of its own. As a result, it’s hard for router A to know the ELC of router B.
Best regards, Xiaohu > -----邮件原件----- > 发件人: Acee Lindem [mailto:[email protected]] > 发送时间: 2014年5月6日 21:14 > 收件人: Xuxiaohu > 抄送: joel jaeggli; Acee Lindem; George, Wes; [email protected]; OSPF List; > [email protected]; [email protected]; [email protected] > 主题: Re: [OSPF] 答复: [Isis-wg] [sunset4] IPv6 router IDs > > > On May 5, 2014, at 9:48 PM, Xuxiaohu <[email protected]> wrote: > > > > > > >> -----邮件原件----- > >> 发件人: Isis-wg [mailto:[email protected]] 代表 joel jaeggli > >> 发送时间: 2014年5月5日 23:55 > >> 收件人: Acee Lindem; Xuxiaohu; George, Wes > >> 抄送: [email protected]; [email protected]; [email protected]; > >> [email protected]; [email protected] > >> 主题: Re: [Isis-wg] [sunset4] IPv6 router IDs > >> > >> On 5/5/14, 9:28 AM, Acee Lindem wrote: > >>> Xiaohu – what are precisely the situations that you think you need > >>> this > >>> IPv6 address? > >>> Acee > >> > >> if you're using router-id's as equivalency as an ipv4 unicast addresses. > >> you're doing so at your peril because there is zero assurance that > >> those actually map. the first time you have a router id of > >> 11100000000000000000000000000101 well bummer. > > > > The IPv6 router ID sub-TLV of the ISIS router capability TLV must carry a > "routable" IPv6 address. If the name of the sub-TLV seems confusing, it can be > changed to IPv6 address sub-TLV. > > Independent of what you call it, you didn’t answer my question. Other than TE, > what the use cases where it is needed? > > Acee > > > > > > Best regards, > > Xiaohu > > > >> I don't find the embedding of semantic meaning in router-ids to be > >> more compelling then it was in ip addresses. > >> > >>> From: Xuxiaohu <[email protected] > <mailto:[email protected]>> > >>> Date: Sunday, May 4, 2014 1:29 AM > >>> To: "George, Wes" <[email protected] > >>> <mailto:[email protected]>> > >>> Cc: OSPF - OSPF WG List <[email protected] <mailto:[email protected]>>, > >>> "[email protected] <mailto:[email protected]>" <[email protected] > >>> <mailto:[email protected]>>, "[email protected] > >>> <mailto:[email protected]>" <[email protected] > >>> <mailto:[email protected]>>, "[email protected] > >>> <mailto:[email protected]>" <[email protected] > >>> <mailto:[email protected]>>, "[email protected] > >> <mailto:[email protected]>" > >>> <[email protected] <mailto:[email protected]>> > >>> Subject: Re: [Isis-wg] [sunset4] IPv6 router IDs > >>> > >>> Hi Wes, > >>> > >>> > >>> > >>> Thanks for pointing out these two drafts. > >>> > >>> > >>> > >>> The motivation for these two drafts > >>> (http://tools.ietf.org/html/draft-xu-isis-ipv6-router-id-00 and > >>> http://tools.ietf.org/html/draft-xu-ospf-ipv6-router-id-00) is very > >>> simple: the IPv6 ISIS|OSPF capability TLV/RI-LSA which are used for > >>> advertising router capabilities can be flooded across areas, > >>> however, only a 4-octect router ID is carried in them. As a result, > >>> it’s hard for routers in one area to establish correlations between > >>> IPv6 addresses and capabilities of routers in another area. For > >>> example, assume IS-IS router A in one area has established a L3VPN > >>> session with IS-IS router B in another area over their own IPv6 > >>> addresses. When router A needs to send L3VPN traffic to router B via > >>> a MPLS-SR tunnel, router A wants to know whether router B has the > >>> ELC (http://tools.ietf.org/html/draft-xu-isis-mpls-elc-00) before > >>> <http://tools.ietf.org/html/draft-xu-isis-mpls-elc-00)%20before> > >>> inserting an EL into the MPLS-SR packet . However, the Capability > >>> TLV originated by router B doesn’t carried an IPv6 address of its > >>> own. As a result, it’s hard for router A to know the ELC of router B. > >>> > >>> > >>> > >>> Best regards, > >>> > >>> Xiaohu > >>> > >>> > >>> > >>> *发件人:*George, Wes [mailto:[email protected]] > >>> *发送时间:*2014年5月2日1:51 > >>> *收件人:*Xuxiaohu > >>> *抄送:*[email protected] <mailto:[email protected]>; > >>> [email protected] <mailto:[email protected]>; > >>> [email protected] <mailto:[email protected]> > >>> *主题:*Re: [sunset4] IPv6 router IDs > >>> > >>> > >>> > >>> I got a bounce-back on all 3 draft aliases, trying again with the > >>> authors’s email addresses directly. > >>> > >>> > >>> > >>> *From: *<George>, "George, Wes" <[email protected] > >>> <mailto:[email protected]>> > >>> *Date: *Thursday, May 1, 2014 at 1:42 PM > >>> *To: *"[email protected] > >>> <mailto:[email protected]>" > >>> <[email protected] > >>> <mailto:[email protected]>>, > >>> "[email protected] > >>> <mailto:[email protected]>" > >>> <[email protected] > >>> <mailto:[email protected]>> > >>> *Cc: *"[email protected] > >>> <mailto:[email protected]>" > >>> <[email protected] > >>> <mailto:[email protected]>>, > >>> "[email protected] <mailto:[email protected]>" <[email protected] > >>> <mailto:[email protected]>> > >>> *Subject: *[sunset4] IPv6 router IDs > >>> > >>> > >>> > >>> I see that you have submitted two drafts for IPv6 router IDs in ISIS > >>> and OSPF, noting that the existing router ID is only 4 octets. This > >>> has also come up in IDR for BGP. The authors of that draft are > >>> copied. I’ll give you a similar set of feedback to what I gave > >>> them - > >>> > >>> > >>> > >>> It is important to distinguish between places where a unique > >>> identifier is needed, and by *convention* an IPv4 address assigned > >>> to the device has been used to provide that unique ID, vs. places > >>> where the actual IP address has some sort of importance to the > >>> protocol (I.e. That information must be available to take action on). > >>> > >>> In other words, is the protocol requirement that the ID be unique > >>> across some domain, but that the actual value does not matter, or is > >>> the protocol requirement that the value must correspond to something > >>> on the router? In many of the former cases, the fact that the value > >>> isn’t relevant has been used to make recommendations that are easier > >>> for humans to deal with (I.e. Tying the router ID to an IP address) > >>> but that value as a human-readable set of info does not necessarily > >>> justify changes to the protocol to support that convention as we > >>> move to IPv6. > >>> > >>> I would argue that the router ID used in routing protocols must > >>> merely be unique, but it doesn’t have to be an IP address at all. > >>> Thus it is not strictly necessary to create a new field to carry > >>> IPv6 addresses when operating without IPv4 addresses on a network. > >>> If you believe otherwise, the justification needs to be documented > >>> in the draft. > >>> > >>> > >>> > >>> There are many places in IETF protocols where a 32 bit unique > >>> identifier is needed, and by convention an IPv4 address has been > >>> used. It would be far more useful to write a general draft > >>> identifying this problem and discussing several solutions, including > >>> simply generating unique IDs manually, systematically generating a > >>> random ID, etc. the place for such a draft may be in Sunset4, > >>> either as a part of the existing gap analysis draft or as another > >>> standalone draft. > >>> > >>> > >>> > >>> There was rather a long discussion about this on IDR, thread > >>> here: > >>> https://mailarchive.ietf.org/arch/search/?qdr=a&email_list=idr&q=%22 > >>> %5 > >>> Bidr%5D+%5Bv6ops%5D+BGP+Identifier%22&as=1&gbt=1 > >>> > >>> > >>> > >>> And in the IDR meeting, minutes: > >>> > >>> http://www.ietf.org/proceedings/89/minutes/minutes-89-idr (see > >>> page 11) > >>> > >>> > >>> > >>> I’d encourage the authors of these drafts to work together on this. > >>> > >>> > >>> > >>> Thanks, > >>> > >>> > >>> > >>> Wes George > >>> > >>> > >>> > >>> Anything below this line has been added by my company’s mail server, > >>> I have no control over it. > >>> > >>> ----------- > >>> > >>> > >>> > >>> > >>> -------------------------------------------------------------------- > >>> -- > >>> -- > >>> > >>> This E-mail and any of its attachments may contain Time Warner Cable > >>> proprietary information, which is privileged, confidential, or > >>> subject to copyright belonging to Time Warner Cable. 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If you have received this E-mail in error, please notify > >>> the sender immediately and permanently delete the original and any > >>> copy of this E-mail and any printout. > >>> > >>> > >>> > >>> _______________________________________________ > >>> sunset4 mailing list > >>> [email protected] > >>> https://www.ietf.org/mailman/listinfo/sunset4 > >>> > >> > > > > _______________________________________________ > > OSPF mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/ospf _______________________________________________ OSPF mailing list [email protected] https://www.ietf.org/mailman/listinfo/ospf
