Re: [Idr] New Version Notification for draft-wang-idr-rd-orf-03.txt

[Wei Wang <[e-mail]>]

Hi Sergey,


Before route discarding, the router must parse the BGP updates, perform BGP best path algorithm. These processes will cost CPU cycles and further burden the overflowing PE.  Flitering these updates at the sender side can ease such process, this is the same aim as other ORF mechanism.



Best Regards,


Wei Wang
China Telecom


------------------ Original ------------------
From:                                                                                                                        "Fomin, Sergey (Nokia - US/Mountain View)"                                                                                    <[e-mail]&gt;;
Date:&nbsp;Wed, Aug 26, 2020 04:57 AM
To:&nbsp;"[e-mail]"<[e-mail]&gt;;
Cc:&nbsp;"idr"<[e-mail]&gt;;"UTTARO, JAMES"<[e-mail]&gt;;
Subject:&nbsp;Re: [Idr] New Version Notification for draft-wang-idr-rd-orf-03.txt



  
Hi Wei Wang,
 
&nbsp;
 
&gt;&gt; But the soft actions cannot reduce the burden of PE.&nbsp;
 
&gt;&gt; Because for the overflow PE, a local-only discard mechanism can't make it better. If it receive more VPN routes continuously, it must waste more resources to log them.
 
Probably we look at this from different perspectives, could you please clarify what exact burden and resources are we talking about?
 
&nbsp;
 
In my view, route discard is a cheap operation in terms of CPU cycles, and discarded routes use no RIB or FIB resources.
 
&nbsp;
  
--
 
Sergey
 
 
&nbsp;
   
From: [e-mail] <[e-mail]&gt; 
 Sent: Monday, August 24, 2020 7:12 PM
 To: UTTARO, JAMES <[e-mail]&gt;; Fomin, Sergey (Nokia - US/Mountain View) <[e-mail]&gt;
 Cc: idr <[e-mail]&gt;
 Subject: Re: RE: [Idr] New Version Notification for draft-wang-idr-rd-orf-03.txt
 
 
 
&nbsp;
   
Hi Sergey and Jim,
 
  
&nbsp;
 
  
Thanks for your review. Please see comments in-line.
 
  
&nbsp;
 
  
Best Regards,
 
 
  
&nbsp;
 
   
 
 
    
Wei Wang
 
  
China Telecom
 
  
&nbsp;
 
 
[e-mail]&nbsp; 
 &nbsp;
 
 
     
From:&nbsp;UTTARO,  JAMES
 
  
Date:&nbsp;2020-08-25 05:43
 
  
To:&nbsp;Fomin,  Sergey (Nokia - US/Mountain View); [e-mail]
 
  
CC:&nbsp;idr
 
  
Subject:&nbsp;RE: [Idr] New Version Notification for  draft-wang-idr-rd-orf-03.txt
 
 
 
   
Comments In-Line.
 
&nbsp;
 
Thanks,
 
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; Jim Uttaro
 
&nbsp;
   
From: Idr <[e-mail]&gt; On Behalf Of Fomin, Sergey (Nokia - US/Mountain View)
 Sent: Monday, August 24, 2020 4:28 PM
 To: [e-mail]
 Cc: idr <[e-mail]&gt;
 Subject: Re: [Idr] New Version Notification for draft-wang-idr-rd-orf-03.txt
 
 
 
&nbsp;
 
Hi Wei Wang,
 
&nbsp;
 
From your description of existing solutions:
 
&nbsp;
 
&gt; &nbsp; 4) Configure the Maximum Prefix for each VRF on edge nodes
 
&gt; 
 
&gt; &nbsp; When a VRF overflows, PE will break down the BGP session with RR
 
&gt; &nbsp; according to the Maximum Prefix mechanism.&nbsp; However, there may have
 
&gt; &nbsp; several VRFs on PE rely on the PE-RR session, this mechanism will
 
&gt; &nbsp; influence other VRFs.
 
This is not correct. A good implementation of _per-vrf prefix-limit_ does not mandate MP-BGP session teardown, it allows to use soft actions instead, such as discard routes + log.
 
[Jim U&gt;] Yup.. That is the way my implementations work.. The goal is to ensure maximum correctness of a given VPN. Tearing down the PE-RR session is killing a fly with a sledge hammer..
 
[Wei Wang] But the soft actions cannot reduce the burden of PE.
 
&nbsp;
 
Additionally, if you insist that a local-only discard mechanism is not good enough (why?)
 
[Wei Wang] Because for the overflow PE, a local-only discard mechanism can't make it better. If it receive more VPN routes continuously, it must waste more resources to log them.
 
&nbsp;and you want to prevent route advertisement(s) from an RR/remote PE for a specific VRF, it is hard to see real-world benefits of the proposed solution vs, for example, extra logic on top of RTC (i.e. if you implement  a feature "withdraw an RTC route after FIB/memory utilization reaches 95%").
 
[Wei Wang] Yes, VRF with 0% reachability may be achieved in this way.
 
&nbsp;Yes, RD-ORF might be a bit more granular in such case, but does it bring any benefit? VRF with 50% reachability or VRF with 0% reachability from a given PE are both examples of unintended network state (and the  earlier could be worse) that requires intervention.
 
[Wei Wang] In my opinion, VRF with 50% reachability may be able to keep part of user traffic normal. It is better than VRF with 0% reachability.
 
&nbsp;
 
--
 
Sergey
 
&nbsp;
   
From: Idr <[e-mail]&gt; On Behalf Of [e-mail]
 Sent: Sunday, August 23, 2020 6:51 PM
 To: idr <[e-mail]&gt;
 Subject: Re: [Idr] New Version Notification for draft-wang-idr-rd-orf-03.txt
 
 
 
&nbsp;
  
Hi IDR experts,
 
  
&nbsp;
 
   
Based on the previous discussion, we update our draft as follows:
 
   
the description of the limitations of existing solutions is added

clarifying that the operation process of RD-ORF on each device is independent

modifying the withdraw mechanism of RD-ORF
 
  
&nbsp; &nbsp; Any comments are welcome.
 
 
&nbsp;
  
Best Regards.
 
 
  
&nbsp;
 
  
&nbsp;
 
     
 
 
 
 
    
Wei Wang
 
  
China Telecom
 
  
&nbsp;
 
  
[e-mail]
 
 
 
   
&nbsp;
 
    
From:&nbsp;internet-drafts
 
  
Date:&nbsp;2020-08-24 09:43
 
  
To:&nbsp;Haibo  Wang; Gyan S. Mishra; Wei Wang; Aijun Wang; Shunwan Zhuang; Jie Dong; Gyan Mishra
 
  
Subject:&nbsp;New Version Notification for draft-wang-idr-rd-orf-03.txt
 
 
 
   
&nbsp;
 
  
A new version of I-D, draft-wang-idr-rd-orf-03.txt
 
  
has been successfully submitted by Wei Wang and posted to the
 
  
IETF repository.
 
  
&nbsp;
 
  
Name: draft-wang-idr-rd-orf
 
  
Revision: 03
 
  
Title: Route Distinguisher Outbound Route Filter (RD-ORF) for BGP-4
 
  
Document date: 2020-08-24
 
  
Group: Individual Submission
 
  
Pages: 14
 
  
URL:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  https://www.ietf.org/internet-drafts/draft-wang-idr-rd-orf-03.txt
 
  
Status:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  https://datatracker.ietf.org/doc/draft-wang-idr-rd-orf/
 
  
Htmlized:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  https://tools.ietf.org/html/draft-wang-idr-rd-orf-03
 
  
Htmlized:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  https://datatracker.ietf.org/doc/html/draft-wang-idr-rd-orf
 
  
Diff:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  https://www.ietf.org/rfcdiff?url2=draft-wang-idr-rd-orf-03
 
  
&nbsp;
 
  
Abstract:
 
  
&nbsp;&nbsp; This draft defines a new Outbound Route Filter (ORF) type, called the
 
  
&nbsp;&nbsp; Route Distinguisher ORF (RD-ORF).&nbsp; RD-ORF is applicable when the
 
  
&nbsp;&nbsp; routers do not exchange VPN routing information directly (e.g.
 
  
&nbsp;&nbsp; routers in single-domain connect via Route Reflector, or routers in
 
  
&nbsp;&nbsp; Option B/Option AB/Option C cross-domain scenario).
 
  
&nbsp;
 
  
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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.
 
  
&nbsp;
 
  
The IETF Secretariat
 
  
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