RE: About the WG adoption of draft-xu-l3vpn-virtual-subnet-fib-reduction-00

[Xuxiaohu <[e-mail]>]

Hi Wim,

I just want to figure out in which scenario the host route to the VRF interface address of a remote PE router should be FIB-installed by default. If there is a scenario, I agree that your proposal of using communities is the best way.

Best regards,
Xiaohu

> -----Original Message-----
> From: Henderickx, Wim (Wim) [mailto:[e-mail]]
> Sent: Wednesday, July 30, 2014 5:37 PM
> To: Xuxiaohu; [e-mail]
> Subject: Re: About the WG adoption of
> draft-xu-l3vpn-virtual-subnet-fib-reduction-00
> 
> In that case you can argue why not do it for all routes as well.
> 
> On 30/07/14 11:30, "Xuxiaohu" <[e-mail]> wrote:
> 
> >Why do you need to distinguish them from each other? In other words,
> >why can't PE routers process the host route to a given VRF loopback
> >address of a remote PE router as a normal remote host route (i.e.,
> >on-demand installation)?
> >
> >Best regards,
> >Xiaohu
> >
> >-----Original Message-----
> >From: Henderickx, Wim (Wim) [mailto:[e-mail]]
> >Sent: Wednesday, July 30, 2014 5:20 PM
> >To: Xuxiaohu; [e-mail]
> >Subject: Re: About the WG adoption of
> >draft-xu-l3vpn-virtual-subnet-fib-reduction-00
> >
> >Why not, if I configure a loopback in the VRF it has to be advertised,
> >this is generic VRF functionality, nothing to do with virtual subnet. I
> >am not talking to the IP address on the virtual subnet interface.
> >In this case you need to distinguish between host routes and these VRFs.
> >Using communities is the best way afais.
> >
> >On 30/07/14 10:59, "Xuxiaohu" <[e-mail]> wrote:
> >
> >>Hi Wim,
> >>
> >>In the Virtual Subnet context, the host route corresponding to the VRF
> >>interface address doesn't need to be advertised.
> >>
> >>Best regards,
> >>Xiaohu
> >>
> >>> -----Original Message-----
> >>> From: Henderickx, Wim (Wim)
> >>> [mailto:[e-mail]]
> >>> Sent: Wednesday, July 30, 2014 4:55 PM
> >>> To: Xuxiaohu; [e-mail]
> >>> Subject: Re: About the WG adoption of
> >>> draft-xu-l3vpn-virtual-subnet-fib-reduction-00
> >>>
> >>> Real loopbacks. E.g. A loopback /32 or /128 configured in the VRF
> >>>
> >>> On 30/07/14 10:52, "Xuxiaohu" <[e-mail]> wrote:
> >>>
> >>> >Hi Wim,
> >>> >
> >>> >Did you mean PE's loopback addresses by "real loopbacks"?
> >>> >
> >>> >Best regards,
> >>> >Xiaohu
> >>> >
> >>> >> -----Original Message-----
> >>> >> From: Henderickx, Wim (Wim)
> >>> >> [mailto:[e-mail]]
> >>> >> Sent: Wednesday, July 30, 2014 4:31 PM
> >>> >> To: Xuxiaohu; [e-mail]
> >>> >> Subject: Re: About the WG adoption of
> >>> >> draft-xu-l3vpn-virtual-subnet-fib-reduction-00
> >>> >>
> >>> >> What I would like to see is a way to identify the host routes
> >>> >>since there are 2
> >>> >> levels: real loopbacks that need to be installed by default and
> >>> >>real host routes  that can be installed on demand. It would be
> >>> >>good to show how the control  plane could distinguish them using
> >>> >>communities or the likes.
> >>> >>
> >>> >> On 30/07/14 08:54, "Xuxiaohu" <[e-mail]> wrote:
> >>> >>
> >>> >> >Hi all,
> >>> >> >
> >>> >> >Virtual Subnet
> >>> >> >(http://tools.ietf.org/html/draft-ietf-l3vpn-virtual-subnet) is
> >>> >> >intended for building L3 network virtualization overlays within
> >>> >> >and/or across data centers. Since a subnet is extended across
> >>> >> >multiple PE routers, CE host routes need to be exchanged among
> >>> >> >PE routers. As a result, the forwarding table size of PE routers
> >>> >> >(e.g., some old ToR
> >>> >> >switches) may become a big concern in large-scale data center
> >>> >> >environments. In fact, some folks had already expressed their
> >>> >> >concerns about this potential FIB scaling issue during the WG
> >>> >> >adoption poll of
> >>> >>the Virtual
> >>> >> Subnet draft.
> >>> >> >
> >>> >> >As CE host routes may still need to be maintained on the control
> >>> >> >plane of PE routers in some cases (e.g.. MVPN scenario), this
> >>> >> >draft
> >>> >> >(http://tools.ietf.org/html/draft-xu-l3vpn-virtual-subnet-fib-re
> >>> >> >d
> >>> >> >uct
> >>> >> >ion
> >>> >> >-00
> >>> >> >) proposes a very simple mechanism for reducing the FIB size of
> >>> >> >PE routers without any change to the RIB and even the routing
> >>>table.
> >>> >> >
> >>> >> >During the L3VPN WG session at Toronto, many people had
> >>> >> >expressed their supports for the WG adoption of this work
> >>> >> >(Thanks a lot for your supports). However, there are still a few
> >>> >> >people who are not in favor of the WG adoption. According to WG
> co-chairs'
> >>> >> >suggestion, I would like to request those opposers to explain
> >>> >> >their reasons so that we could further improve the draft if
> >>>possible.
> >>> >> >
> >>> >> >Best regards,
> >>> >> >Xiaohu (on behalf of all co-authors)
> >>> >> >
> >>> >
> >>
> >