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[67.169.103.239]) by smtp.gmail.com with ESMTPSA id e10sm11747191pgd.63.2021.03.08.19.11.58 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 08 Mar 2021 19:11:58 -0800 (PST) Sender: Tony Li Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.40.0.2.32\)) From: Tony Li In-Reply-To: <6E0281D2-7755-499A-B084-CA8472949683@chinatelecom.cn> Date: Mon, 8 Mar 2021 19:11:57 -0800 Cc: Aijun Wang , Gyan Mishra , "Acee Lindem (acee)" , draft-wang-lsr-prefix-unreachable-annoucement , lsr Content-Transfer-Encoding: quoted-printable Message-Id: References: <22FDE3EA-B5D1-4E4D-B698-1D79173E8637@tony.li> <6E0281D2-7755-499A-B084-CA8472949683@chinatelecom.cn> To: Aijun Wang X-Mailer: Apple Mail (2.3654.40.0.2.32) Archived-At: Subject: Re: [Lsr] https://tools.ietf.org/html/draft-wang-lsr-prefix-unreachable-annoucement-05 X-BeenThere: lsr@ietf.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Link State Routing Working Group List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Mar 2021 03:12:03 -0000 Hi Aijun, > [WAJ] We just want to avoid such silent discard behavior, especially = for the scenario that there is BGP session run on such failure prefix.=20= Stuffing things in the IGP seems like a poor way of determining that = there=E2=80=99s a BGP failure. Wouldn=E2=80=99t BFD be a more = appropriate way of determining the loss of connectivity? Or aggressive = BGP keepalive timers? > The other side of BGP peer can quickly remove the BGP session when it = receives such PUA message which tell it the other peer is down now. = Other BGP peer protection procedures can then take effects on. > The immediate notification of the failure prefix can certainly = accelerate the switchover of BGP control plane and also the service = traffic that such BGP session carries. The IGP is a very poor way of delivering service liveness information. >>> For scenarios 2, because the specified prefixes can be accessed via = another ABR, then we can let this ABR to advertise the details prefixes = information for the specified address, which behavior is similar with = RIFT, as also mentioned in the presentation materials. >>=20 >>=20 >> Agreed. >=20 > [WAJ] Even for this scenario, the advertisement of the detail prefixes = is trigger also via the PUA message from other ABR. That seems 100% unnecessary as the longer prefix will attract the = traffic in the way that you want. Tony