On 3/12/15 08:02 , [email protected] wrote:

Hi Rabah,

If the nexthop learnt from the mapping message is the nexthop to the
prefix of non SR node,
as shown in the figure:

The SRMS allocates a SID label 105 to a non SR node LR5,
SR1 learns the message, and the nexthop of SR1 to LR5 is to R4,
SR4 and LR5 is a normal IGP adjancency without label.
When SR1 sending out a packet with a top label 105, the nexthop is to R4,

given that SR is not running on a link between SR1 and SR4, SR1 would send packet as unlabeled to R4.

Peter

R4 receives the mpls packet, but it doesn’t have a label forwarding
entry, it will drop the packet.

Best Regards.
Ting

"spring" <[email protected]> 写于 2015-03-11 18:08:02:

 > >Hi, Please see inline[Rabah]
 >
 > De : [email protected] [mailto:[email protected]]
 > Envoyé : mercredi 11 mars 2015 10:33
 > À : GUEDREZ Rabah IMT/OLN; Peter Psenak (ppsenak); Stefano Previdi
(sprevidi)
 > Cc : [email protected]; spring
 > Objet : Re: [spring] New Version Notification for draft-lw-spring-
 > sid-allocation-01.txt
 >
 >
 > Hi rabah,peter,stefano,
 >
 > Thanks for your reviews and comments. The SID allocation proposal is
used to
 > solve the automatic SID configuration based on the operator's
 > requirment of zero configuration for the nodes.
 > It includes the following differences with SRMS:
 >
 > 1.  It has a mechanism to ensure the uniqueness of SID allocation.
 > When two or more SRMNs(SR management nodes described in this draft)
 > allocate different SIDs to the same prefix,
 > we provide a method for the SR nodes to choose one of the SID in
theproposal.
 >
 > 2.  The SRMN only allocates SID to SR node in this draft.
 > I wonder there may be some problem if SRMS can allocates SID to non-
 > SR node and SR node.
 >
 > For example, the SRMS is in charge of mapping a SID( SID A) to a non
SR node(
 > node A)originally,
 > and then SRMS floods the mapping message to SR domain, when a SR
 > node(node B) receives  the message,
 > node B learns an entry of SID A with a nexthop, where  the nexthop
 > is the shortest path to SRMS but not to node A.
 > Of course the SRMS can be used to allocate a SID(SID C)to a SR
 > node(node C),
 > when SR node B learns  this message , it still learns the nexthop is
 > the shortest path to SRMS,
 > and in this case,the nexthop should be to node C.
 > >[Rabah]  No this not true upon the reception of  the mapping SID-A
 > prefix Z by any SR-Node , the node IGP-SPF will match the SID A
 > prefix with its routing table and calculate
 >   the shortest path(exit interface) to that prefix and install an
 > entry in the NHFE( Next Hop Label   Forwarding Entry).
 >
 >
 > In this proposal, the nexthop is to SR node C.
 >
 > 3.  In the allocation TLV described in this draft, it can carry
 > other SR related configuration such as algorithm, MT number,
 > and in a TLV, it can carry one or more ip addresses, no matter the
 > addresses are consecutive or inconsecutive.
 >
 > Best Regards.
 > Ting
 >
 > "spring" <[email protected]> 写于 2015-03-10 21:49:49:
 >
 > > The mapping server is attended to bind prefixes and SID of  non
 > > SPRING nodes, not to configure a SPRING node see https://tools.ietf.
 > >
org/html/draft-filsfils-spring-segment-routing-ldp-interop-02#section-4.2
 > >
 > > Configuring SPRING nodes can be done manually or via a centralized
entity,
 > > The centralized entity can be an SDN controller or an extended
 > > mapping server, configs can be pushed using OpenFlow or NETCONFIG
/YANG see
 > > https://tools.ietf.org/id/draft-litkowski-spring-sr-yang-00.txt
 > >
 > > In my opinion we should work on the process of configuring SPRING
 > > nodes, the architecture(SR-client and SR-controller) and defining
 > > the minimum configs for a node to function properly.
 > >
 > > Nether the proposed draft nor the section on the mapping server
 > > addressed those requirements.
 > >
 > > There are two types of configurations that need to be pushed to
 > > SPRING nodes  : Required and Optional
 > > Required configs : are all the information that has global
 > > signification like node-SID, anycast-SID,++ ..., or when decided to
 > > use the same SRGB on all the SPRING nodes, those config must be done
 > > manually or pushed from centralized entity.
 > > Optional configs : all the decision that can be made locally by the
 > > "SR-client"  like assigning Adj-SIDs to the node interfaces.
 > >
 > >
 > > -----Message d'origine-----
 > > De : spring [mailto:[email protected]] De la part de Stefano
 > > Previdi (sprevidi)
 > > Envoyé : mardi 10 mars 2015 13:07
 > > À : Peter Psenak (ppsenak)
 > > Cc : [email protected]; <[email protected]>
 > > Objet : Re: [spring] New Version Notification for draft-lw-spring-
 > > sid-allocation-01.txt
 > >
 > > I agree. We already have interop tests done on the SRMS so what is
 > > the real added value of another proposal ?
 > >
 > > s.
 > >
 > >
 > > On Mar 10, 2015, at 12:46 PM, Peter Psenak <[email protected]> wrote:
 > >
 > > > Ting,
 > > >
 > > > there is a concept of SR Mapping Server, which can be used to
 > > advertise SIDs for prefixes from the central place.
 > > >
 > > > draft-ietf-ospf-segment-routing-extensions defines the OSPF
 > > Extended Prefix Range TLV in section 4 which is used to advertise
 > > the SID mappings by SRMS. Similarly ISIS SR drafts defines a similar
 > > mechanism in ISIS. There are already implementations that support SRMS.
 > > >
 > > > What you defined in your draft looks very similar to SRMS and we
 > > definitely do not need two different ways to achieve the same goal.
 > > >
 > > > regards,
 > > > Peter
 > > >
 > > > On 3/10/15 07:02 , [email protected] wrote:
 > > >>
 > > >> Hi all,
 > > >>
 > > >> New version of SID Allocation has been published and description
has
 > > >> been revised according to comments from the mailing list.
 > > >> Comments are welcome and discussions in Dallas are expected.
 > > >>
 > > >> Best Regards.
 > > >> Ting
 > > >> ----- 转发人 廖婷038768/user/zte_ltd 时间 2015-03-10 08:48 -----
 > > >>
 > > >> [email protected] 写于 2015-03-09 14:39:17:
 > > >>
 > > >> >
 > > >> > A new version of I-D, draft-lw-spring-sid-allocation-01.txt
 > > >> > has been successfully submitted by Fangwei Hu and posted to the
 > > >> > IETF repository.
 > > >> >
 > > >> > Name:      draft-lw-spring-sid-allocation
 > > >> > Revision:   01
 > > >> > Title:      SPRING SID Allocation
 > > >> > Document date:   2015-03-08
 > > >> > Group:      Individual Submission
 > > >> > Pages:      12
 > > >> > URL:
  http://www.ietf.org/internet-drafts/draft-lw-spring-
 > > >> > sid-allocation-01.txt
 > > >> > Status:         https://datatracker.ietf.org/doc/draft-lw-spring-
 > > >> > sid-allocation/
 > > >> > Htmlized:
 > > >> http://tools.ietf.org/html/draft-lw-spring-sid-allocation-01
 > > >> > Diff:           http://www.ietf.org/rfcdiff?url2=draft-lw-spring-
 > > >> > sid-allocation-01
 > > >> >
 > > >> > Abstract:
 > > >> >    Segment Routing (SR) allows for a flexible definition of
end-to-end
 > > >> >    paths within IGP topologies by encoding paths as sequences of
 > > >> >    topological sub-paths, called "segments".  These segments are
 > > >> >    advertised by the link-state routing protocols (IS-IS and
 > OSPF).  And
 > > >> >    a segment is identified by a Segment Routing ID (SID).
 > This document
 > > >> >    proposes a method to reduce the SID configuration in a SR
domain.
 > > >> >    Only the selected SR nodes which named Segment Routing
Management
 > > >> >    Nodes (SRMNs) are configured by NMS, while other SRs in the
domain
 > > >> >    need zero-SR-configuration.
 > > >> >
 > > >> >
 > > >> >
 > > >> >
 > > >> > 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
 > > >> >
 > > >>
 > > >>
 > > >> _______________________________________________
 > > >> spring mailing list
 > > >> [email protected]
 > > >> https://www.ietf.org/mailman/listinfo/spring
 > > >>
 > > >
 > > > _______________________________________________
 > > > spring mailing list
 > > > [email protected]
 > > > https://www.ietf.org/mailman/listinfo/spring
 > >
 > > _______________________________________________
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