[Isis-wg] 答复: 答复: 答复: 答复: 答复: [OSPF] Inconsistency between OSPF extention and IS-IS extension for segment routing

Peter,

In my understanding, the OSPF EP LSAs containing SID/label bindings just play the role of label distribution protocols. Since LDP can support the longest-matching algorithm for LFIB installation, why OSPF EP LSAs could not support that capability?

BR
Xiaohu

________________________________________
发件人: Peter Psenak [ppsenak@cisco.com]
发送时间: 2013年11月9日 4:58
收件人: Xuxiaohu
抄送: ospf@ietf.org; isis-wg@ietf.org
主题: Re: 答复: [Isis-wg] 答复:  答复: 答复: [OSPF] Inconsistency between OSPF extention and IS-IS extension for segment routing

Xiaohu,

I understand what you started this thread with.

What I'm trying to say is that even if OSPF separates the advertisement
of prefix and prefix SID/label, you should not be using the SID/label
advertisement without the actual prefix reachability advertisement.

thanks,
Peter

On 11/8/13 12:50 , Xuxiaohu wrote:
> Hi Peter,
>
> You misunderstood what I have said. On the contrary, the OSPF extension draft looks fine to me. It's the ISIS extension draft that I believed should follow the similar approach defined in the OSPF extension draft.
>
> Best regards,
> Xiaohu
>
> ________________________________________
> 发件人: Peter Psenak [ppsenak@cisco.com]
> 发送时间: 2013年11月9日 4:37
> 收件人: Xuxiaohu
> 抄送: ospf@ietf.org; isis-wg@ietf.org
> 主题: Re: [Isis-wg] 答复:  答复: 答复: [OSPF] Inconsistency between OSPF extention and IS-IS extension for segment routing
>
> Xiaohu,
>
> OSPF SR draft clearly states that newly defined Extended Prefix Opaque
> LSAs do not contribute to the prefix reachability. What you are asking
> for is to negate that and install forwarding entries based on what is in
> the EP-LSA, without prefix being advertised in any regular LSA. Once you
> start to do that you will end up with all sorts of problems. I would
> like to keep the current definition in place.
>
>
> thanks,
> Peter
>
>
> On 11/8/13 12:04 , Xuxiaohu wrote:
>> Hi Peter,
>>
>> Sure. However, why not borrow the idea of longest-matching algorithm proposed in that RFC to SR?
>>
>> BR,
>> Xiaohu
>>
>> ________________________________________
>> 发件人: isis-wg-bounces@ietf.org [isis-wg-bounces@ietf.org] 代表 Peter Psenak [ppsenak@cisco.com]
>> 发送时间: 2013年11月9日 3:56
>> 收件人: Xuxiaohu
>> 抄送: ospf@ietf.org; isis-wg@ietf.org
>> 主题: Re: [Isis-wg] 答复: 答复: [OSPF] Inconsistency between OSPF extention and IS-IS extension for segment routing
>>
>> Xiaohu,
>>
>> there is no LDP in the SR network, so RFC5283 is not applicable.
>>
>> thanks,
>> Peter
>>
>> On 11/7/13 17:28 , Xuxiaohu wrote:
>>> Hi Peter,
>>>
>>> The 'longest-match algorithm' for LIB installation has been proposed by RFC5283.
>>>
>>> Best regards,
>>> Xiaohu
>>>
>>> ________________________________________
>>> 发件人: Peter Psenak [ppsenak@cisco.com]
>>> 发送时间: 2013年11月8日 8:39
>>> 收件人: Xuxiaohu
>>> 抄送: ospf@ietf.org; isis-wg@ietf.org
>>> 主题: Re: 答复: [OSPF] Inconsistency between OSPF extention and IS-IS extension for segment routing
>>>
>>> Xiaohu,
>>>
>>> On 11/7/13 16:23 , Xuxiaohu wrote:
>>>>
>>>> Hi Peter,
>>> ]
>>>> if you aggregate on area/L1L2 boundary, SIDs/labels for individual
>>>> prefixes that are covered by the aggregate are useless in the area to
>>>> which you aggregate - there will be no FIB entries for these individual
>>>> prefixes in such area. So if you aggregate, there is no need to
>>>> propagate SIDs/labels for aggregated prefixes.
>>>>
>>>> [Xiaohu] "In the multi-area/level
>>>>        scenario where route summary between areas/levels is required, the IP
>>>>        longest-match algorithm SHOULD be used by SR-capable routers when
>>>>        processing label bindings advertised by the mapping server" For more details, please read the Introduction section of http://tools.ietf.org/html/draft-xu-rtgwg-global-label-adv-00
>>>
>>> I don't understand. If you summarize, then only the summary prefix will
>>> be visible in the backbone (and remote areas) and installed in the FIB
>>> on all routers in these areas.
>>>
>>> Where would you apply 'longest-match algorithm' when you only see the
>>> single summary? How would you use the SID/label for prefixes that are
>>> covered by the summary?
>>>
>>> thanks,
>>> Peter
>>>
>>
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>