Hi Peter, Thanks for your comment. Please see some replies inline:
> -----Original Message----- > From: Lsr [mailto:[email protected]] On Behalf Of Peter Psenak > Sent: Wednesday, September 16, 2020 4:46 PM > To: [email protected]; [email protected] > Subject: Re: [Lsr] 回复: New Version Notification for > draft-zhu-lsr-isis-sr-vtn-flexalgo-01.txt > > Yongqing, > > I have two basic comments: > > 1. Using L2 Bundle Member Attributes TLV for advertising attributes for VTNs > seems like a hack. Yes, the combination of Flex-Algo and L2 bundle can provide the required functionality of VTN. > > 2. > > "In order to correlate the virtual or physical member links with the > corresponding VTNs, each member link SHOULD be assigned with a > dedicated Admin Group or Extended Admin Group, which is included in > the definition of the Flex-Algo of the corresponding VTN. Note that > in this case the Admin Group or Extended Admin Group of the Layer 3 > link SHOULD be set to the union of all the Admin Groups or Extended > Admin Groups of its virtual or physical member links. This is to > ensure that the Layer 3 link is always included in the Flex-Algo > specific constraint path computation of the VTNs it participates in." > > Above proposal does not work. Here's the simple example: > > Flex-algo 128, FAD include RED > Flex-algo 129, FAD exclude RED > > Now you have two VTNs, one for FA 128 (VT1) and one for 129 (VT2). > So your VT1 member link will have affinity RED and your VT2 will not have any > affinity set (I presume). Maybe the text in draft is not clear enough. Take your example, it should be: Flex-Algo 128, FAD include RED Flex-Algo 129, FAD include BLUE On one L3 link (either a physical L2 bundle or not), the member link for VTN-1 will have affinity RED, the member link for VTN-2 will have affinity BLUE, and the L3 link SHOULD be set with affinity RED and BLUE (i.e. the union of its member links). > Your L3 will have affinity RED set based on your proposal. As a result the L3 > link > will be be excluded for FA 129, but that is not what you want, because your > VTN2 > does not have affinity RED set. Based on the affinity of the L3 link (RED and BLUE), the L3 link will be used for path computation in both FA-128 and FA-129. Then in forwarding plane, a received packet with prefix-SID of FA-128 will be steered to use the member link for VTN-1, and a received packet with prefix-SID of FA-129 will be steered to use the member link for VTN-2. This is the expected behavior. > > The fundamental problem is that FA works on L3 data only. You are trying to > make > it work for L2, but that is not going to work. The FA based path computation is still based on L3 link attribute, the member link attribute is used to correlate a subset of link resource with a Flex-Algo, which can be used for forwarding packet which carries the FA-specific SIDs. Best regards, Jie > > thanks, > Peter > > > On 16/09/2020 08:13, [email protected] wrote: > > Hi WG, > > > > We just submitted a new revision of draft-zhu-lsr-isis-sr-vtn-flexalgo. This > document specifies a mechanism to use Flex-Algo together with small extensions > to IS-IS L2 bundle to distribute the topology and resource attribute of SR > based > VTN. Your review and comments are appreciated. > > B.R. > > Zhu Yongqing > > > > -----邮件原件----- > > 发件人: [email protected] <[email protected]> > > 发送时间: 2020年9月11日 17:11 > > 收件人: Dongjie (Jimmy) <[email protected]>; Yongqing Zhu > > <[email protected]>; Huzhibo <[email protected]> > > 主题: New Version Notification for > > draft-zhu-lsr-isis-sr-vtn-flexalgo-01.txt > > > > > > A new version of I-D, draft-zhu-lsr-isis-sr-vtn-flexalgo-01.txt > > has been successfully submitted by Jie Dong and posted to the IETF > > repository. > > > > Name: draft-zhu-lsr-isis-sr-vtn-flexalgo > > Revision: 01 > > Title: Using Flex-Algo for Segment Routing based VTN > > Document date: 2020-09-11 > > Group: Individual Submission > > Pages: 8 > > URL: > https://www.ietf.org/id/draft-zhu-lsr-isis-sr-vtn-flexalgo-01.txt > > Status: > https://datatracker.ietf.org/doc/draft-zhu-lsr-isis-sr-vtn-flexalgo/ > > Htmlized: > https://datatracker.ietf.org/doc/html/draft-zhu-lsr-isis-sr-vtn-flexalgo > > Htmlized: > https://tools.ietf.org/html/draft-zhu-lsr-isis-sr-vtn-flexalgo-01 > > Diff: > https://www.ietf.org/rfcdiff?url2=draft-zhu-lsr-isis-sr-vtn-flexalgo-01 > > > > Abstract: > > As defined in I-D.ietf-teas-enhanced-vpn, enhanced VPN (VPN+) aims to > > provide enhanced VPN service to support the needs of enhanced > > isolation and stringent performance requirements. VPN+ requires > > integration between the overlay VPN and the underlay network. A > > Virtual Transport Network (VTN) is a virtual network which consists > > of a subset of network topology and network resources allocated from > > the underlay network. A VTN could be used as the underlay for one or > > a group of VPN+ services. > > > > I-D.dong-lsr-sr-enhanced-vpn defines the IGP mechanisms with > > necessary extensions to build a set of Segment Routing (SR) based > > VTNs. This document describes a simplified mechanism to build the SR > > based VTNs using SR Flex-Algo together with minor extensions to IGP > > L2 bundle. > > > > > > > > > > > > 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 > > > > > > > > _______________________________________________ > > Lsr mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/lsr > > > > > > _______________________________________________ > Lsr mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/lsr _______________________________________________ Lsr mailing list [email protected] https://www.ietf.org/mailman/listinfo/lsr
