Hi Peter, > -----邮件原件----- > 发件人: Peter Psenak [mailto:[email protected]] > 发送时间: 2014年1月27日 16:41 > 收件人: Xuxiaohu > 抄送: [email protected]; [email protected] > 主题: Re: [OSPF] fwd: New Version Notification for > draft-xu-ospf-global-label-sid-adv-00.txt > > Xiaohu, > > > 1. draft-psenak-ospf-segment-routing-extensions has already defined the > mapping server functionality - please read the section 4.2 and 6.1
According to the description about mapping servers (see below) which is in -01 version of the use case draft but is removed in -02 version of that draft, it seems that the mapping server is deemed to advertise the mappings on behalf of non-SR-capable routers. In contrast, my draft proposes to allow the mapping server to allocate and advertise mappings on behalf of SR-capable routers. Those two distinct design goals cause different implications on the implementation and usage. "The mappings advertised by an SR mapping server result from local policy information configured by the operator. IF PE3 had been SR capable, the operator would have configured PE3 with node segment 103. Instead, as PE3 is not SR capable, the operator configures that policy at the SRMS and it is the latter which advertises the mapping."---quoted from -01 version of the use case draft. > 2. TLVs that you defined in section 3 and 4 are very close to those defined in > draft-psenak-ospf-segment-routing-extensions and have the exact same > functionality as the ones defined in > draft-psenak-ospf-segment-routing-extensions If I understand your draft correctly, the prefix SID sub-TLV defined in your draft is intended to advertise index, rather than SID or global label. In contrast, the Label Binding Sub-TLV and SID Binding Sub-TLV defined in my draft are intended to advertise global labels and SIDs respectively. Besides, the Label Binding Sub-TLV and SID Binding sub-TLV are just intended for label or SID distribution without any correlation with the algorithm and MT-ID, which is different from the prefix SID sub-TLV, IMHO. > 3. The only new sub-TLV you defined is Label Request Sub-TLV. > > First, given that we already have OSPF SR draft, you should have defined this > as > a sub-TLV of the OSPF Extended Prefix TLV that is defined in > draft-psenak-ospf-segment-routing-extensions. > Second, you proposed to use Opaque LSA that is flooded either area or domain > wide as a request mechanism between the router and mapping server. This > means that all routers in an area/domain would have to store and maintain such > 'request' LSAs, even though they would never use them locally. I seriously > question if flooding of the LSA is the right mechanism to achieve what you > want. Agree that it may not be attractive in the OSPF case. However, this choice may be attractive in the IS-IS case since the label/SID request information can be carried in the IP reachability advertisement. Anyway, as said in the draft, the advertisement of label/SID request is just one option. Best regards, Xiaohu > regards, > Peter > > > > On 1/27/14 04:34 , Xuxiaohu wrote: > > Hi all, > > > > Any comments are welcome. > > > > Best regards, > > Xiaohu > > > >> -----邮件原件----- > >> 发件人: [email protected] [mailto:[email protected]] > >> 发送时间: 2014年1月21日 13:53 > >> 收件人: Mach Chen; Mach Chen; Xuxiaohu; Xuxiaohu > >> 主题: New Version Notification for > >> draft-xu-ospf-global-label-sid-adv-00.txt > >> > >> > >> A new version of I-D, draft-xu-ospf-global-label-sid-adv-00.txt > >> has been successfully submitted by Xiaohu Xu and posted to the IETF > repository. > >> > >> Name: draft-xu-ospf-global-label-sid-adv > >> Revision: 00 > >> Title: Advertising Global Labels or SIDs Using OSPF > >> Document date: 2014-01-21 > >> Group: Individual Submission > >> Pages: 7 > >> URL: > >> http://www.ietf.org/internet-drafts/draft-xu-ospf-global-label-sid-ad > >> v-00.txt > >> Status: > >> https://datatracker.ietf.org/doc/draft-xu-ospf-global-label-sid-adv/ > >> Htmlized: > >> http://tools.ietf.org/html/draft-xu-ospf-global-label-sid-adv-00 > >> > >> > >> Abstract: > >> Segment Routing (SR) is a new MPLS paradigm in which each > SR-capable > >> router is required to advertise global MPLS labels or Segment IDs > >> (SID) for its attached prefixes by using link-state IGPs, e.g., OSPF. > >> One major challenge associated with such global MPLS label or SID > >> advertisement mechanism is how to avoid a given global MPLS label or > >> SID from being allocated by different routers to different prefixes. > >> Although such global label or SID allocation collision problem can be > >> addressed through manual allocation , it is error-prone and > >> nonautomatic therefore may not be suitable in large-scale SR network > >> environments. This document proposes an alternative approach for > >> allocating and advertising global MPLS labels or SIDs via OSPF so as > >> to eliminate the potential risk of label allocation collision. > >> > >> > >> > >> > >> Please note that it may take a couple of minutes from the time of > >> submission until the htmlized version and diff are available at > >> tools.ietf.org. > >> > >> The IETF Secretariat > > > > _______________________________________________ > > OSPF mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/ospf > > _______________________________________________ OSPF mailing list [email protected] https://www.ietf.org/mailman/listinfo/ospf
