Re: [Status] 答复: fwd: New Version Notification for draft-xu-rtgwg-global-label-adv-00.txt

[Hannes Gredler <[e-mail]>]

On Jul 25, 2013, at 10:07 AM, Xuxiaohu wrote:

> Hi Hannes,
> 
>> -----邮件原件-----
>> 发件人: Hannes Gredler [mailto:[e-mail]]
>> 发送时间: 2013年7月25日 15:40
>> 收件人: Xuxiaohu
>> 抄送: Peter Psenak; [e-mail]; Robert Raszuk
>> 主题: Re: [Status] fwd: New Version Notification for
>> draft-xu-rtgwg-global-label-adv-00.txt
>> 
>> xuxiaohu,
>> 
>> the best proposal i have seen so far for resolving potential clashes
>> with global labels is roberts draft:
>> 
>> http://tools.ietf.org/html/draft-raszuk-mpls-domain-wide-labels-00
>> 
>> the draft proposes to use a context label for keying off in a separate
>> 'domain-wide' label space - i.e. no clash with anybody in the networking
>> doing local label allocation.
> 
> Yes, there is no clash with existing transport or application labels which are locally significant. However, you still need some mechanism to ensure that a given domain-wide labels would not be assigned to different FECs (i.e., different node segments).

yes and that mechanism is administrative policy. if you treat a MPLS
label as global identifier you have to ensure that it does
to get allocated twice.

>> note that i am still not convinced that we need domain-wide labels
>> (if we have SPT labels as per the latest SR protocol extensions).
> 
> What does the SPT label mean?

an SPT label  is a label inside a label block. the actual label
is determined by an index advertised by egress routers.
the path to the egress router gets determined using an SPT
calculation.

see

http://tools.ietf.org/html/draft-previdi-isis-segment-routing-extensions-02
http://tools.ietf.org/html/draft-psenak-ospf-segment-routing-extensions-02

and

http://tools.ietf.org/html/draft-gredler-isis-label-advertisement-03
http://tools.ietf.org/html/draft-gredler-ospf-label-advertisement-03

for manifestations of this.


>> On Jul 23, 2013, at 3:06 AM, Xuxiaohu wrote:
>> 
>>> Peter,
>>> 
>>>> -----邮件原件-----
>>>> 发件人: Peter Psenak [mailto:[e-mail]]
>>>> 发送时间: 2013年7月22日 19:07
>>>> 收件人: Xuxiaohu
>>>> 抄送: [e-mail]
>>>> 主题: Re: [Status] fwd: New Version Notification for
>>>> draft-xu-rtgwg-global-label-adv-00.txt
>>>> 
>>>> Xiaohu,
>>>> 
>>>> On 7/22/13 05:19 , Xuxiaohu wrote:
>>>> 
>>>>>> 
>>>>>> - nothing in existing SR drafts prevents you to advertise SIDs/labels
>>>>>> from mapping server even for prefixes connected to SR capable routers.
>>>>> 
>>>>> Yes, it doesn't prevent that case explicitly. However, I haven't seen any
>>>> description of that case in the existing SR drafts.
>>>> 
>>>> does not mean you can not do it.
>>> 
>>> 
>>>>> 
>>>>> As you pointed out, the flooding scope of the OSPFv2 Extended Prefix
>> Opaque
>>>> DEPENDS on the content inside the LSA in the SR draft. However, In my
>> draft,
>>>> the flooding scope of the OSPFv2 Prefix Opaque LSA DOESN'T DEPEND on the
>>>> content inside the LSA.
>>>> 
>>>> given that OSPFv2 Extended Prefix Opaque LSA as defined in existing OSPF
>>>> SR draft allows you to do what you need, there is no need to define a
>>>> new LSA.
>>> 
>>> The major difference lies in the TLVs and sub-TLVs contained in that prefix
>> specific opaque LSA rather than the opaque LSA itself which only needs a
>> Opaque type code to be assigned.
>>> 
>>> Best regards,
>>> Xiaohu
>>> 
>>>> regards,
>>>> Peter
>>>> 
>>>>> 
>>>>> Best regards,
>>>>> Xiaohu
>>>>> 
>>> 
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>> 
>> 
> 
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