[Isis-wg] 答复: Comments on draft-xu-isis-flooding-reduction-in-msdc-00

[Xuxiaohu <[e-mail]>]

Hi Hannes,

That's great! It would make the hybrid routing protocol (i.e., mix of centralized link-state dissemination and distributed SPF calculation) as described in this draft more deployable in MSDC networks.

Best regards,
Xiaohu

> -----邮件原件-----
> 发件人: Hannes Gredler [mailto:[e-mail]]
> 发送时间: 2017年4月26日 8:54
> 收件人: Erik Auerswald; Xuxiaohu
> 抄送: [e-mail]
> 主题: Re: [Isis-wg] Comments on draft-xu-isis-flooding-reduction-in-msdc-00
> 
> +1
> 
> i'd like to add to erik's observations that mesh-group support is available in
> contemporary router software since 15+ years
> 
> /hannes
> 
> On 4/25/17 12:26, Erik Auerswald wrote:
> > Hi Xiaohu,
> >
> > please see my response inline (content not relevant to this response
> > removed).
> >
> > On Tue, Apr 25, 2017 at 08:46:06AM +0000, Xuxiaohu wrote:
> >>> -----邮件原件-----
> >>> 发件人: Erik Auerswald [mailto:[e-mail]]
> >>> This idea can be realized using existing implementations, with
> >>> additional possible optimizations via IS-IS extensions. In fact I
> >>> built a lab today to play with the idea, using a couple of switches,
> >>> one of which was used as controller, and the others as fabric switches.
> >>
> >> It would be great if you could share more information about your
> >> experiment:)
> >
> > Nothing big, I just took four Extreme Networks X460[-G2] switches from
> > the company lab, connected three switches in a row to build the "fabric"
> > (you could think of the middle one as "spine" and the two at the ends
> > as "leafs"), and then connected the fourth switch to all three "fabric"
> > switches to act as "controller". I then configured IS-IS on the
> > switches, configured a high metric on the links to/from the
> > "controller" switch, and used the "meshBlocked" attribute from RFC
> > 2973 to restrict flooding inside the "fabric." To do this I configured
> > "meshBlocked" on all links between "fabric" switches.
> >
> > Show outputs for transmitted LSPs showed flooding reduction (e.g. when
> > adding a new loopback interface on a "leaf" switch), with full IP
> > connectivity over the fabric. The "management" links to the "controller"
> > were not used for "leaf" to "leaf" traffic due to the higher metric.
> >
> >>> RFC 2973, IS-IS Mesh Groups, can be used to prevent flooding on the
> >>> data path links.
> >>
> >> Could you explain more about how to apply the ISIS mesh group in the CLOS
> topology?
> >
> > Please see above. RFC 2973 describes a method to configure individual
> > links to inhibit flooding of LSPs using the "meshBlocked" attribute.
> >
> > Thanks,
> > Erik
> >