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

[Peter Psenak <[e-mail]>]

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