Zhibo,
On 03/08/2022 21:09, Huzhibo wrote:
Hi Peter:
Please see inline.
-----Original Message-----
From: Peter Psenak [mailto:ppse...@cisco.com]
Sent: Wednesday, August 3, 2022 11:20 PM
To: Huzhibo <huzh...@huawei.com>
Cc: lsr@ietf.org
Subject: Re: Question about draft-ppsenak-lsr-igp-ureach-prefix-announce
Hi Zhibo,
On 29/07/2022 20:49, Huzhibo wrote:
Hi Peter:
Supplement to yesterday's online questions, If a node that does not
support IP Flexalgo, which has a default route, should the node
process the IP Flexalgo prefix as a UPA?
- I assume you are talking about the algo 0 default route. Because IP Flex-algo
default route does not make much sense really.
- If the node does not support IP flex-algo, than it would not use any IP algo
prefix as BGP service endpoint or for any other purpose.
Which IP Algo prefix as BGP service endpoint is not determined by the ingress
node, Such as VXLAN and SRv6 VPN.
When the ingress node receives an BGP Service cayyied a IP algo prefix as
endpoint and it has a algo 0 default route,
it should be process this BGP service. and this can not be affected by the IGP Flexalgo prefix.
sorry, but above is completely wrong.
When you want to use IP flex-algo forwarding, you must advertise the
prefix as algo prefix, relying on the algo 0 default would not give you
algo forwarding.
Advertising IP algo prefix at the egress and relying in algo 0 default
at the ingress is going to cause all sorts of problems. You CAN NOT
mix/change algos along the path through the network - if you do, you may
end up in a permanent loop.
Therefore,
the IGP does only not generate the RIB/Fib for LSinfinity Metric prefix, but
can not trigger BGP Service Down.
In addition, LSinfinity Metric may be applied to other scenarios in the future.
We cannot guarantee that LSinfinity Metric
will not conflict with other purposes when being processed as a UPA.
no, it can not, because the LSinfinity has a very strict definition - it
means unreachable, which is exactly what the UPA is about.
Peter
- If such node receives the IP algo prefix and even if it treats it as UPA,
given
that such IP algo prefix was never reachable before on this node, the UPA
would result in no action.
thanks,
Peter
Thanks
Zhibo
_______________________________________________
Lsr mailing list
Lsr@ietf.org
https://www.ietf.org/mailman/listinfo/lsr
