> -----邮件原件----- > 发件人: Henderickx, Wim (Wim) [mailto:[email protected]] > 发送时间: 2013年11月28日 15:44 > 收件人: Xuxiaohu; [email protected] > 抄送: [email protected] > 主题: Re: 答复: 答复: 答复: 答复: 答复: 答复: 答复: New Version > Notification for draft-xu-l3vpn-virtual-subnet-02.txt > > > > On 28/11/13 08:33, "Xuxiaohu" <[email protected]> wrote: > > > > > > >> -----邮件原件----- > >> 发件人: Henderickx, Wim (Wim) > [mailto:[email protected]] > >> 发送时间: 2013年11月28日 14:13 > >> 收件人: Xuxiaohu; [email protected] > >> 抄送: [email protected] > >> 主题: Re: 答复: 答复: 答复: 答复: 答复: 答复: New Version Notification > for > >> draft-xu-l3vpn-virtual-subnet-02.txt > >> > >> > >> > >> On 28/11/13 04:02, "Xuxiaohu" <[email protected]> wrote: > >> > >> > > >> > > >> >> -----邮件原件----- > >> >> 发件人: Henderickx, Wim (Wim) > >> [mailto:[email protected]] > >> >> 发送时间: 2013年11月28日 1:53 > >> >> 收件人: Xuxiaohu; [email protected] > >> >> 抄送: [email protected] > >> >> 主题: Re: 答复: 答复: 答复: 答复: 答复: New Version Notification for > >> >> draft-xu-l3vpn-virtual-subnet-02.txt > >> >> > >> >> > >> >> > >> >> On 27/11/13 09:12, "Xuxiaohu" <[email protected]> wrote: > >> >> > >> >> > > >> >> > > >> >> >> -----邮件原件----- > >> >> >> 发件人: Henderickx, Wim (Wim) > >> >> [mailto:[email protected]] > >> >> >> 发送时间: 2013年11月27日 14:14 > >> >> >> 收件人: Xuxiaohu; [email protected] > >> >> >> 抄送: [email protected] > >> >> >> 主题: Re: 答复: 答复: 答复: 答复: New Version Notification for > >> >> >> draft-xu-l3vpn-virtual-subnet-02.txt > >> >> >> > >> >> >> You are changing the forwarding plane of a L3 service and as > >> >> >>such this is not implementable in merchant silicon so far. You > >> >> >>need a flexible network processor to do this and I am not sure > >> >> >>about the performance implications. > >> >> > > >> >> >Future merchant silicon could be adapted to support such TTL > >> >> >handling requirement as long as Layer3 forwarding for > >> >> >intra-subnet traffic is worthwhile in practice. In addition, even > >> >> >with the existing L3 forwarding chips which don't support that > >> >> >TTL handling requirement, the > >> >> >Layer3 overlay could still be applicable to most applications > >> >> >except a few ones where TTL is set to 1. > >> >> WH> even with what you say you break basic applications like trace > >> >> WH> route, > >> > > >> >No, it will not break the trace-route application. It has been > >> >successfully verified in our implementation. > >> WH> can you show an output. W/o the TTL handling your hops will be > >> incorrect > > > > > >In the example illustrated at Figure 4 of the draft, the trace route > >output on Host A is as follows (note that 2.2.2.1 is a vrf interface > >address of PE-3): > > > >[Host_1]tracert 2.2.2.1 > > traceroute to 2.2.2.1(2.2.2.1), max hops: 30 ,packet length: 40,press > >CTRL_C t o break > > 1 1.1.1.1 60 ms 50 ms 50 ms > > 2 2.2.2.1 90 ms 60 ms 80 ms > > WH> figure 4 is addressing 1.1.1.x not 2.2.2.x and the output should be > from a intra-subnet
Please look at the VRF table instance in that example. The packet destined for 2.2.2.x is forwarded according to the default route advertised by PE-3. Since each PE acts as a default GW, there is no impact to the output of the trace route for an IP address which is not within the same subnet as the trace-route originator (IMO, this is the major usage of trace route). If you just want to try a trace route for an IP address which is within the same subnet of the trace-route originator, there are just two more hops (i.e., ingress PE and egress PE) in the output (see below), does it matter in practice? <Host_1>tracert 1.1.1.5 traceroute to 1.1.1.5(1.1.1.5), max hops: 30 ,packet length: 40,press CTRL_C t o break 1 1.1.1.1 40 ms 40 ms 50 ms 2 1.1.1.1 120 ms 80 ms 110 ms 3 1.1.1.5 140 ms 100 ms 90 ms <Host_1> > >> >> etc. SO I don’t want to adopt it at all with such impact on the DP. > >> >> > > >> >> >> So why I am against this draft is because it has a big impact > >> >> >>on the data-plane. > >> >> > > >> >> >Does EVPN have no impact on the data-plane? Are you against that > >> >> >draft as well due to its impact on the data plane? > >> >> WH> not in its basic form > >> > > >> >However, the major selling-point of that technology (i.e., > >> >active-active > >> >multi-homing) is lost in its basic form accordingly. > >> WH> no its not > > > >If no change to the existing data plane, how to realize the following > >split-horizon function? > > > >9.3 Split Horizon > > > > Consider a CE that is multi-homed to two or more PEs on an Ethernet > > segment ES1 operating in All-Active mode. If the CE sends a > > broadcast, unknown unicast, or multicast (BUM) packet to one of the > > non-DF (Designated Forwarder) PEs, say PE1, then PE1 will forward > > that packet to all or subset of the other PEs in that EVPN instance > > including the DF PE for that Ethernet segment. In this case the DF PE > > that the CE is multi-homed to MUST drop the packet and not forward > > back to the CE. This filtering is referred to as "split horizon" > > filtering in this document. > > > > > > > >Sajassi, et al. Expires January 15, 2014 [Page 17] > > > >INTERNET DRAFT BGP MPLS Based Ethernet VPN July 15, > 2013 > > > > > > In order to achieve this split horizon function, every BUM packet > > originating from a non-DF PE is encapsulated with an MPLS label that > > identifies the Ethernet segment of origin (i.e. the segment from > > which the frame entered the EVPN network). This label is referred to > > as the ESI label, and MUST be distributed by all PEs when operating > > in All-Active multi-homing mode using the "Ethernet A-D route per > > WH> when you use virtual chassis all works naturally and split horizon > WH> is > handled by the VC. > >> >> >> The fundamental difference between the proposals is that you > >> >> >>have on egress a mapping in the label that determines the > >> >> >>forwarding behaviour to be applied, rather than having to check > >> >> >>src/dst IP matches + LPM lookups. > >> >> > > >> >> >Are you still talking about L3 overlay service for intra-subnet > >> >>traffic? > >> >> WH> I am talking about this draft > >> > > >> >If you are talking about the Virtual Subnet draft, then your above > >> >argument is incorrect. The egress PE would perform IP lookup in the > >> >corresponding VRF table. > >> WH> I am talking about the fact when proper TTL handling has to be > >> applied, you need to determine whether or not to decrement the TTL > >>and as such you end up doing additional lookups to determine this. As > >>such you will impact performance. > > > >Have you seen performance degradation on your routers once an ACL entry > >or uRPF check is enabled on interfaces? > > WH> urpf/ACL are handled naturally, but you create a new pipeline and > WH> look > at the operations you have to do to check the intra/inter-subnet forwarding. > This is whats avoids to use merchant silicon and what impact performance. > > > >Xiaohu > > > >> >Xiaohu > >> > > >> >> >Xiaohu > >> >> > > >> >> >> On 27/11/13 02:31, "Xuxiaohu" <[email protected]> wrote: > >> >> >> > >> >> >> >Fine. In my draft, both intra-subnet and inter-subnet IP > >> >> >> >traffic are forwarded at layer3 while in the draft you > >> >> >> >mentioned below only inter-subnet traffic would be forwarded > >> >> >> >at layer3. They are totally different approaches and therefore > >> >> >> >it's meaningless to say which one is easier or not. > >> >> >> > > >> >> >> >Xiaohu > >> >> >> > > >> >> >> >> -----邮件原件----- > >> >> >> >> 发件人: Henderickx, Wim (Wim) > >> >> >> [mailto:[email protected]] > >> >> >> >> 发送时间: 2013年11月25日 19:16 > >> >> >> >> 收件人: Xuxiaohu; [email protected] > >> >> >> >> 抄送: [email protected] > >> >> >> >> 主题: Re: 答复: 答复: 答复: New Version Notification for > >> >> >> >> draft-xu-l3vpn-virtual-subnet-02.txt > >> >> >> >> > >> >> >> >> Lets debate the technical solutions iso blogs. > >> >> >> >> > >> >> >> >> On 25/11/13 08:52, "Xuxiaohu" <[email protected]> wrote: > >> >> >> >> > >> >> >> >> >I suggest you read the following blog post by Yakov > >> >> >> >> >(http://opencontrail.org/why-contrail-is-using-bgpmpls/). > >> >> >> >> > > >> >> >> >> >> -----邮件原件----- > >> >> >> >> >> 发件人: Henderickx, Wim (Wim) > >> >> >> >> [mailto:[email protected]] > >> >> >> >> >> 发送时间: 2013年11月25日 15:27 > >> >> >> >> >> 收件人: Xuxiaohu; [email protected] > >> >> >> >> >> 抄送: [email protected] > >> >> >> >> >> 主题: Re: 答复: 答复: New Version Notification for > >> >> >> >> >> draft-xu-l3vpn-virtual-subnet-02.txt > >> >> >> >> >> > >> >> >> >> >> There are easier ways to do this which don’t required > >> >> >> >> >>data-plane changes. > >> >> >> >> >> > >> >> >> >> >>https://tools.ietf.org/html/draft-sajassi-l2vpn-evpn-inter > >> >> >> >> >>-su > >> >> >> >> >>bne > >> >> >> >> >>t-f > >> >> >> >> >>orw > >> >> >> >> >>ard > >> >> >> >> >>in > >> >> >> >> >> g-02 > >> >> >> >> >> > >> >> >> >> >> On 25/11/13 07:40, "Xuxiaohu" <[email protected]> wrote: > >> >> >> >> >> > >> >> >> >> >> > > >> >> >> >> >> > > >> >> >> >> >> >> -----邮件原件----- > >> >> >> >> >> >> 发件人: Henderickx, Wim (Wim) > >> >> >> >> >> [mailto:[email protected]] > >> >> >> >> >> >> 发送时间: 2013年11月25日 14:29 > >> >> >> >> >> >> 收件人: Xuxiaohu; [email protected] > >> >> >> >> >> >> 抄送: [email protected] > >> >> >> >> >> >> 主题: Re: 答复: New Version Notification for > >> >> >> >> >> >> draft-xu-l3vpn-virtual-subnet-02.txt > >> >> >> >> >> >> > >> >> >> >> >> >> It is not about TTL 1, no TTL decrement should happen > >> >> >> >> >> >>for intra-subnet forwarding at all On top you need to > >> >> >> >> >> >>modify the data-plane to achieve this, since it now > >> >> >> >> >> >>needs to find out if it is intra or inter subnet where > >> >> >> >> >> >>current > >> >> >> >> >> >>PE(s) don’t have to do > >> >> >> >>this. > >> >> >> >> >> > > >> >> >> >> >> >Sure, it needs some change to the implementation of PE > >> >>routers. > >> >> >> >> >> >That's why we need a draft to specify the implementation > >> >> >> >>requirements. > >> >> >> >> >> > > >> >> >> >> >> >> On 25/11/13 07:22, "Xuxiaohu" <[email protected]> > >>wrote: > >> >> >> >> >> >> > >> >> >> >> >> >> >Wim, > >> >> >> >> >> >> > > >> >> >> >> >> >> >It said clearly "if the source and destination > >> >> >> >> >> >> >addresses of a packet whose TTL is set to 1 belong to > >> >> >> >> >> >> >the same extended subnet, both ingress and egress PE > >> >> >> >> >> >> >routers MUST NOT decrement the TTL of such packet." > >> >> >> >> >> >> >Did you doubt that the PE routers could know whether > >> >> >> >> >> >> >the source and destination address belong to the same > >> >> >> >> extended subnet? > >> >> >> >> >> >> > > >> >> >> >> >> >> >Xiaohu > >> >> >> >> >> >> > > >> >> >> >> >> >> >> -----邮件原件----- > >> >> >> >> >> >> >> 发件人: Henderickx, Wim (Wim) > >> >> >> >> >> >> [mailto:[email protected]] > >> >> >> >> >> >> >> 发送时间: 2013年11月25日 14:08 > >> >> >> >> >> >> >> 收件人: Xuxiaohu; [email protected] > >> >> >> >> >> >> >> 抄送: [email protected] > >> >> >> >> >> >> >> 主题: Re: New Version Notification for > >> >> >> >> >> >> >>draft-xu-l3vpn-virtual-subnet-02.txt > >> >> >> >> >> >> >> > >> >> >> >> >> >> >> On the TTL issue I believe this is not addressing > >> >> >> >> >> >> >> the > >> >>issue. > >> >> >> >> >> >> >>We can say don’t decrement but when and how will > >> >> >> >> >> >> >>the > >> >> >> >> >> >> >>PE(s) do or > >> >> >> >> >>don’t. > >> >> >> >> >> >> >> > >> >> >> >> >> >> >> On 25/11/13 03:22, "Xuxiaohu" <[email protected]> > >> >>wrote: > >> >> >> >> >> >> >> > >> >> >> >> >> >> >> >Hi all, > >> >> >> >> >> >> >> > > >> >> >> >> >> >> >> >Major changes since the -01 version include: > >> >> >> >> >> >> >> > > >> >> >> >> >> >> >> >1) add a section about TTL consideration; > >> >> >> >> >> >> >> >2) remove the section of PE Router FIB Reduction; > >> >> >> >> >> >> >> >3) remove the section of PE Router RIB Reduction; > >> >> >> >> >> >> >> > > >> >> >> >> >> >> >> >Any further comments are welcome. BTW, the removed > >> >> >> >> >> >> >> >sections as mentioned above would be described in > >> >>separate > >> >> docs. > >> >> >> >> >> >> >> > > >> >> >> >> >> >> >> >Best regards, > >> >> >> >> >> >> >> >Xiaohu > >> >> >> >> >> >> >> > > >> >> >> >> >> >> >> >> -----邮件原件----- > >> >> >> >> >> >> >> >> 发件人: [email protected] > >> >> >> >> >> >> >> >>[mailto:[email protected]] > >> >> >> >> >> >> >> >> 发送时间: 2013年11月25日 10:10 > >> >> >> >> >> >> >> >> 收件人: Brendan Fee; Susan Hares; Fan Yongbing; > >> >> >> >> >> >> >> >>Xuxiaohu; Xuxiaohu; Christian Jacquenet; Truman > >> >> >> >> >> >> >> >>Boyes; Yongbing Fan > >> >> >> >> >> >> >> >> 主题: New Version Notification for > >> >> >> >> >> >> >> >>draft-xu-l3vpn-virtual-subnet-02.txt > >> >> >> >> >> >> >> >> > >> >> >> >> >> >> >> >> > >> >> >> >> >> >> >> >> A new version of I-D, > >> >> >> >> >> >> >> >>draft-xu-l3vpn-virtual-subnet-02.txt > >> >> >> >> >> >> >> >> has been successfully submitted by Xiaohu Xu and > >> >> >> >> >> >> >> >>posted to the IETF repository. > >> >> >> >> >> >> >> >> > >> >> >> >> >> >> >> >> Filename: draft-xu-l3vpn-virtual-subnet > >> >> >> >> >> >> >> >> Revision: 02 > >> >> >> >> >> >> >> >> Title: Virtual Subnet: A L3VPN-based > >> >> >> >> >> >> >> >> Subnet > >> >>Extension > >> >> >> >> >>Solution > >> >> >> >> >> >> >> >> Creation date: 2013-11-25 > >> >> >> >> >> >> >> >> Group: Individual Submission > >> >> >> >> >> >> >> >> Number of pages: 13 > >> >> >> >> >> >> >> >> URL: > >> >> >> >> >> >> >> >> > >> >> >> >> >> >> >>http://www.ietf.org/internet-drafts/draft-xu-l3vpn-v > >> >> >> >> >> >> >>irt > >> >> >> >> >> >> >>ual > >> >> >> >> >> >> >>-su > >> >> >> >> >> >> >>bne > >> >> >> >> >> >> >>t-0 > >> >> >> >> >> >> >>2.t > >> >> >> >> >> >> >>xt > >> >> >> >> >> >> >> >> Status: > >> >> >> >> >> >> >> >>http://datatracker.ietf.org/doc/draft-xu-l3vpn-vi > >> >> >> >> >> >> >> >>rtu > >> >> >> >> >> >> >> >>al- > >> >> >> >> >> >> >> >>sub > >> >> >> >> >> >> >> >>net > >> >> >> >> >> >> >> >> Htmlized: > >> >> >> >> >> >> >> >>http://tools.ietf.org/html/draft-xu-l3vpn-virtual > >> >> >> >> >> >> >> >>-su > >> >> >> >> >> >> >> >>bne > >> >> >> >> >> >> >> >>t-0 > >> >> >> >> >> >> >> >>2 > >> >> >> >> >> >> >> >> Diff: > >> >> >> >> >> >> >> >> > >> >> >> >> >> >> >> >>http://www.ietf.org/rfcdiff?url2=draft-xu-l3vpn-v > >> >> >> >> >> >> >> >>irt > >> >> >> >> >> >> >> >>ual > >> >> >> >> >> >> >> >>-su > >> >> >> >> >> >> >> >>bne > >> >> >> >> >> >> >> >>t-0 > >> >> >> >> >> >> >> >>2 > >> >> >> >> >> >> >> >> > >> >> >> >> >> >> >> >> Abstract: > >> >> >> >> >> >> >> >> This document describes a Layer3 Virtual > >> >> >> >> >> >> >> >> Private Network > >> >> >> >> >> >>(L3VPN)- > >> >> >> >> >> >> >> >> based subnet extension solution referred to > >> >> >> >> >> >> >> >> as Virtual Subnet, > >> >> >> >> >> >> >>which > >> >> >> >> >> >> >> >> can be used as a kind of Layer3 network > >> >> >> >> >> >> >> >> virtualization > >> >> >> >> >>overlay > >> >> >> >> >> >> >> >> approach for data center interconnect. > >> >> >> >> >> >> >> >> > >> >> >> >> >> >> >> >> > >> >> >> >> >> >> >> >> > >> >> >> >> >> >> >> >> > >> >> >> >> >> >> >> >> 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 > >> >> >> >> >> >> >> > > >> >> >> >> >> >> > > >> >> >> >> >> > > >> >> >> >> > > >> >> >> > > >> >> > > >> > > >
