Yao, BGP-LS was designed to solve also the distribution of link-state information between BGP speakers (see Figure 1 from RFC 7752 below). Just ask yourself: why would one want to use a point to multipoint state replication protocol as complex as BGP for *just* client server alike replication ?
We wanted from day-1 to leverage the graph independent replication abilities of BGP - so doing inter BGP-LS graphs is a legit use-case. HTH, /hannes --- The collection of link-state and TE information and its distribution to consumers is shown in the following figure. +-----------+ | Consumer | +-----------+ ^ | +-----------+ | BGP | +-----------+ | Speaker | | Consumer | +-----------+ +-----------+ ^ ^ ^ ^ | | | | +---------------+ | +-------------------+ | | | | | +-----------+ +-----------+ +-----------+ | BGP | | BGP | | BGP | | Speaker | | Speaker | . . . | Speaker | +-----------+ +-----------+ +-----------+ ^ ^ ^ | | | IGP IGP IGP Figure 1: Collection of Link-State and TE Information --- > On 29.07.2020, at 03:57, liu.ya...@zte.com.cn wrote: > > Hi Acee, > > Thanks for reading the draft. > > Yes, the main purpose of this draft is to carry the segment segment > information via IGP so only one node per AS need to be connected with the > controller through BGP-LS. > > With the existing BGP-LS extension draft, it is certainly one solution to > configure BGP sessions between all the service function nodes and controller, > and each node sends the SF information to the controller individually. > > And if I get you right, we can also select one node to have a BGP session > with the controller and configure BGP sessions between the selected node and > SF nodes. > > But how the selected node get the SF information from SF nodes via BGP needs > to be solved, since BGP-LS is typically used for exchanging information > between the south and north rather than nodes of the same level, and there's > no other existing BGP extension for distribute SIDs information between nodes > . > > This draft aims to provide an alternate way if the operators prefer running > IGP on SF nodes. > > So we would like to collect comments on the WG session to see how others > think about it. > > > > Regards, > > Yao > > > > > > > > 原始邮件 > 发件人：AceeLindem(acee) <a...@cisco.com> > 收件人：刘尧00165286;zzhang_i...@hotmail.com <zzhang_i...@hotmail.com>; > 抄送人：firstname.lastname@example.org <email@example.com>; > 日 期 ：2020年07月29日 01:53 > 主 题 ："IGP Extensions for Segment Routing Service Segment" > -draft-lz-lsr-igp-sr-service-segments-02 > Speaking as WG member: > > > > It seems the sole purpose of this draft is to get service segment information > from nodes in the IGP domain to the IGP node that has a BGP session with the > controller. You don’t need to put this information into the IGP in order to > do this. Simply configure BGP sessions for the BGP-LS AF between the nodes > with service functions and the node selected to have a BGP session with the > controller. > > > > Speaking as WG Chair – please let me know if we can omit this draft from the > agenda. > > > > Thanks, > > Acee > > > > _______________________________________________ > Lsr mailing list > Lsr@ietf.org > https://www.ietf.org/mailman/listinfo/lsr
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