Re: [Status] 答复: Status of Spring

LDP has not removed any limitation. If you use MPLS you still need to
send all host FECs in LDP. There is no magic transit nodes are not
aware about your overlay application .. they can not demux on their
own. Label must be specific to the transport endpoint.

RFC5283 just reduces IGP and RIB size - not LDP:

   "Note that LDP re-advertises to its peers the specific FEC element
   FEC1, and not the aggregated prefix found in the IP RIB during the
   longest-match search."

If you use IP encapsulation you don't need any additional signalling
to send your overlay application between any two end points in the
network yet benefit from natural aggregation of IP subnets at any
point.

Likewise when SR SIDs are MPLS labels they can not be aggregated. When
SR SIDs are IP addresses they can be nicely aggregated for example at
the IGP or AS area boundaries.

r.

On Sat, Oct 12, 2013 at 5:05 AM, Xuxiaohu <xuxiaohu@huawei.com> wrote:
>
>
>> -----邮件原件-----
>> 发件人: status-bounces@ietf.org [mailto:status-bounces@ietf.org] 代表
>> Hannes Gredler
>> 发送时间: 2013年10月11日 22:11
>> 收件人: Robert Raszuk
>> 抄送: status@ietf.org; AshwoodsmithPeter
>> 主题: Re: [Status] Status of Spring
>>
>> On Fri, Oct 11, 2013 at 03:00:02PM +0200, Robert Raszuk wrote:
>> | > please have a look at
>> | >
>> http://sourceforge.net/apps/mediawiki/mpls-linux/index.php?title=Main_Page
>> |
>> | [ ... ] Please point me to any
>> | linux distribution which officially supports this. Also please point
>> | me to the official linux kernel which supports mpls kernel project.
>>
>> i am not sure if there is such a thing as an "official linux kernel"
>>   of course there is linus' and his lieutenants git trees - however
>>   every major linux distribution pulls from there and adds a ton
>>   of patches to it. - the linux MPLS extensions are basically
>>   kernel patches plus userspace utilizities - nothing more.
>>   so if you want to get it to work - get your favourite
>>   (linux from scratch) distro and apply the patches ...
>>   i did it with 'gentoo' linux and as far as i can tell it works fine
>>   even with l2vpn services on top of the transport LSPs.
>>     note that there are also pre-cooked debian ISO images with everything
>>     applied if you do not want to compile your kernel by yourself.
>>
>> | > can you point me to the text which says so.
>> | > i could not find such a claim in rfc3031 ?
>> |
>> | Not in rfc3031 but in rfc5036 .. pretty much the only practical
>> | signalling protocol for mpls transport (not an overlay mpls
>> | signalling):
>> |
>> |    "Prefix SHOULD NOT use the label for forwarding unless its routing
>> |     table contains an entry that exactly matches the FEC Element."
>>
>> oh yes, and this is indeed problematic ... and its fixed here:
>> http://www.ietf.org/rfc/rfc5283.txt
>
> Great that LDP has removed that limitation. When using ISIS or OSPF for label distribution purpose, we should follow the same principle. In this way, the scalability of IGP would not be impacted by the SPRING architecture.
>
> Best regards,
> Xiaohu
>
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