Re: [OSPF] 答复: 答复: [Isis-wg] [sunset4] IPv6 router IDs

[Karsten Thomann <[e-mail]>]

Hi Xiaohu,

I think I've understand your problem now, but please don't call it a 
Router ID, the router ID must not be an IP address.
To avoid any confusion about it please call it a router ip or router 
address within the TLV.
Please correct me if I'm wrong, but if I understand your drafts right 
you're not requesting a real IPv6 Router ID instead of the (arbitrary) 
32bit ID, but a simple TLV to carry the routable IPv6 address of the 
router which advertises the capability.

If I understand it right, we should maybe fix the text of the other rfc 
to refect that it is an routable IP address, instead of a (possible) 
arbitrary but unique Router ID.

Kind regards
Karsten

Am 09.05.2014 02:53, schrieb Xuxiaohu:
> Hi Anton,
>
> When ISIS capability TLVs are flooded across areas, routers in one area may need to establish correlations between IP 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. When router A needs to send L3VPN traffic to router B via a MPLS-SR tunnel, router A wants to know whether router B (identified by an IP address) has the ELC (http://tools.ietf.org/html/draft-xu-isis-mpls-elc-00) before inserting an EL into the MPLS-SR packet. In such case, it needs to contain at least one routable IP address in the capability TLV which has been flooded across area boundaries. In the IPv4 network, the 4-octect router ID field could contain such routable IPv4 address. However, in the IPv6 network, there is no counterpart field to contain a routable IPv6 address.
>
> Best regards,
> Xiaohu
>
>> -----邮件原件-----
>> 发件人: Anton Smirnov [mailto:[e-mail]]
>> 发送时间: 2014年5月8日 22:49
>> 收件人: Xuxiaohu
>> 抄送: [e-mail]; George, Wes; [e-mail]; joel jaeggli;
>> OSPF List; [e-mail]; [e-mail]
>> 主题: Re: [OSPF] 答复: 答复: [Isis-wg] [sunset4] IPv6 router IDs
>>
>>      Hello Xiaohu,
>>      this whole thread started from George Wes stating that even in pure
>> IPv4 world Router ID in many protocols is NOT an IPv4 address. For convenience
>> it frequently is but on the binary scale "ID guaranteed to be routable IPv4
>> address"/"ID is just a number" - the Router ID is NOT an IPv4 address.
>>
>>      So, before you convince people that IPv6 Rtr ID is needed you must start
>> from discussing when and why Router ID is being used as IPv4 address in pure
>> IPv4 world. I believe this in other words is what Acee asking you.
>>
>> Anton
>>
>>
>> On 05/07/2014 03:10 AM, Xuxiaohu wrote:
>>> 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 fo
>> r router A to know the ELC of router B.
>>> Best regards,
>>> Xiaohu
>>>
>>>> -----邮件原件-----
>>>> 发件人: Acee Lindem [mailto:[e-mail]]
>>>> 发送时间: 2014年5月6日 21:14
>>>> 收件人: Xuxiaohu
>>>> 抄送: joel jaeggli; Acee Lindem; George, Wes; [e-mail]; OSPF
>>>> List; [e-mail]; [e-mail];
>>>> [e-mail]
>>>> 主题: Re: [OSPF] 答复: [Isis-wg] [sunset4] IPv6 router IDs
>>>>
>>>>
>>>> On May 5, 2014, at 9:48 PM, Xuxiaohu <[e-mail]> wrote:
>>>>
>>>>>
>>>>>> -----邮件原件-----
>>>>>> 发件人: Isis-wg [mailto:[e-mail]] 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: [e-mail]; [e-mail]; [e-mail];
>>>>>> [e-mail]; [e-mail]
>>>>>> 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 <[e-mail]
>>>> <mailto:[e-mail]>>
>>>>>>> Date: Sunday, May 4, 2014 1:29 AM
>>>>>>> To: "George, Wes" <[e-mail]
>>>>>>> <mailto:[e-mail]>>
>>>>>>> Cc: OSPF - OSPF WG List <[e-mail] <mailto:[e-mail]>>,
>>>>>>> "[e-mail] <mailto:[e-mail]>" <[e-mail]
>>>>>>> <mailto:[e-mail]>>, "[e-mail]
>>>>>>> <mailto:[e-mail]>" <[e-mail]
>>>>>>> <mailto:[e-mail]>>, "[e-mail]
>>>>>>> <mailto:[e-mail]>" <[e-mail]
>>>>>>> <mailto:[e-mail]>>, "[e-mail]
>>>>>> <mailto:[e-mail]>"
>>>>>>> <[e-mail]
>> <mailto:[e-mail]>>
>>>>>>> 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:[e-mail]]
>>>>>>>      *发送时间:*2014年5月2日1:51
>>>>>>>      *收件人:*Xuxiaohu
>>>>>>>      *抄送:*[e-mail] <mailto:[e-mail]>;
>>>>>>>      [e-mail] <mailto:[e-mail]>;
>>>>>>>      [e-mail]
>> <mailto:[e-mail]>
>>>>>>>      *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" <[e-mail]
>>>>>>>      <mailto:[e-mail]>>
>>>>>>>      *Date: *Thursday, May 1, 2014 at 1:42 PM
>>>>>>>      *To: *"[e-mail]
>>>>>>>      <mailto:[e-mail]>"
>>>>>>>      <[e-mail]
>>>>>>>      <mailto:[e-mail]>>,
>>>>>>>      "[e-mail]
>>>>>>>      <mailto:[e-mail]>"
>>>>>>>      <[e-mail]
>>>>>>>      <mailto:[e-mail]>>
>>>>>>>      *Cc: *"[e-mail]
>>>>>>>      <mailto:[e-mail]>"
>>>>>>>      <[e-mail]
>>>>>>>      <mailto:[e-mail]>>,
>>>>>>>      "[e-mail] <mailto:[e-mail]>" <[e-mail]
>>>>>>>      <mailto:[e-mail]>>
>>>>>>>      *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.
>>>>>>>
>>>>>>>      -----------
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
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