Hi Linda, *The aggregated site cost change rate is comparable with the rate of adding or removing application instances at locations to adapt to the workload distribution changes.*
[RR] What Les and myself have been trying to highlight here is that the above model does not effectively work well in the underlay layer. The moment you adjust such cost will not really spread workload distribution, but shift it between servers - members of given anycast address. The forwarding decision will happen at the first common P core underlay node from the server side and not the ingress to the network - where is what you would really want. Only in very specific topologies you may see some more control, but I would say that this is rather an exception then a rule. Thx, R. On Wed, Jan 19, 2022 at 4:52 AM Linda Dunbar <linda.dun...@futurewei.com> wrote: > Robert, > > > > In the new version of the draft, we have: > > *“The aggregated site cost associated with a prefix (i.e., ANYCAST prefix) > can be a value configured on the router to which the prefix is attached. > The aggregated site cost can be computed based on an algorithm configured > on router for specific prefixes. The detailed algorithm of computing the > aggregated site cost is out of the scope of document. * > > *As the cost change can impact the path computation, there is a Minimum > Interval for Metrics Change Advertisement which is configured on the > routers to avoid route oscillations. Default is 30s. * > > *The aggregated site cost change rate is comparable with the rate of > adding or removing application instances at locations to adapt to the > workload distribution changes. The rate of change could be in weeks or > days. On rare occasions, there might need rate changes in hours..”* > > > > Your comments and suggestions are greatly appreciated. > > > > Linda > > > > *From:* Robert Raszuk <rob...@raszuk.net> > *Sent:* Monday, January 17, 2022 5:29 AM > *To:* Aijun Wang <wangai...@tsinghua.org.cn> > *Cc:* Acee Lindem (acee) <acee=40cisco....@dmarc.ietf.org>; Linda Dunbar < > linda.dun...@futurewei.com>; John E Drake <jdrake= > 40juniper....@dmarc.ietf.org>; Les Ginsberg (ginsberg) <ginsb...@cisco.com>; > Gyan Mishra <hayabusa...@gmail.com>; lsr <lsr@ietf.org> > *Subject:* Re: [Lsr] Seeking feedback to the revised > draft-dunbar-lsr-5g-edge-compute > > > > Aijun, > > > > Such metric will be same(because of the ANYCAST address be advertised > simultaneously via R1/R2/R3 at the same time for one application server, > for example, S1/aa08::4450). > > > > That is not really correct. > > > > On each router R1 or R2 or R3 when you for example redistribute or > originate in any other way host route for example S1/aa08::4450 you can > apply a different metric to it. > > > > That is why I keep asking what is the mechanism in which routers will be > informed what host routes to advertise and what metric to use for each IP > address of the server or application on the server. The most precise answer > received so far was "it is out of scope". And that is important > irrespective if we are talking about using passive interfaces, stub > interfaces or simply static routes. > > > > Thx, > > R. >
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