Re: [Idr] Mirja Kühlewind's No Objection on draft-ietf-idr-bgp-extended-messages-33: (with COMMENT)
"Enke Chen (enkechen)" <enkechen@cisco.com> Wed, 31 July 2019 01:53 UTC
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From: "Enke Chen (enkechen)" <enkechen@cisco.com>
To: Randy Bush <randy@psg.com>, Alvaro Retana <aretana.ietf@gmail.com>
CC: "idr@ietf.org" <idr@ietf.org>, "\"Mirja Kühlewind via Datatracker\"" <noreply@ietf.org>, "draft-ietf-idr-bgp-extended-messages@ietf.org" <draft-ietf-idr-bgp-extended-messages@ietf.org>, The IESG <iesg@ietf.org>, "idr-chairs@ietf.org" <idr-chairs@ietf.org>, "Enke Chen (enkechen)" <enkechen@cisco.com>
Thread-Topic: [Idr] Mirja Kühlewind's No Objection on draft-ietf-idr-bgp-extended-messages-33: (with COMMENT)
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Date: Wed, 31 Jul 2019 01:53:00 +0000
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References: <156449387998.2643.18137174091685834097.idtracker@ietfa.amsl.com> <m27e7zxpv1.wl-randy@psg.com> <CAMMESsxccHKqaXeGKO1sD9jAiEM7McT9_+VUx4G_nqt_2TX3GA@mail.gmail.com> <m2zhkvw8in.wl-randy@psg.com> <m21ry7vvzk.wl-randy@psg.com>
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Subject: Re: [Idr] Mirja Kühlewind's No Objection on draft-ietf-idr-bgp-extended-messages-33: (with COMMENT)
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Hi, Randy and Alvaro: Here is a patch that would clarify the capability definition, the issue that I brought up before. It also include changing "BGP listener" to "BGP speaker" in two places. Thanks. -- Enke *** bgp-large-msg-34.txt.orig Tue Jul 30 18:24:32 2019 --- bgp-large-msg-34.txt Tue Jul 30 18:34:07 2019 *************** Internet-Draft Extended Message sup *** 120,148 **** defined with Capability code 6 and Capability length 0. To advertise the BGP Extended Message Capability to a peer, a BGP speaker uses BGP Capabilities Advertisement [RFC5492]. By advertising the BGP Extended Message Capability to a peer, a BGP ! speaker conveys that it is able to send, receive, and properly handle, see Section 4, BGP Extended Messages. - A peer which does not advertise this capability MUST NOT send BGP - Extended Messages, and BGP Extended Messages MUST NOT be sent to it. - Peers that wish to use the BGP Extended Message capability MUST support Error Handling for BGP UPDATE Messages per [RFC7606]. 4. Operation The Extended Message Capability applies to all messages except for the OPEN and KEEPALIVE messages. The former exception is to reduce the complexity of providing backward compatibility. ! A BGP speaker that is capable of sending and receiving BGP Extended Messages SHOULD advertise the BGP Extended Message Capability to its peers using BGP Capabilities Advertisement [RFC5492]. A BGP speaker ! MAY send Extended Messages to a peer if the Extended Message Capability was received from that peer. An implementation that advertises the BGP Extended Message capability MUST be capable of receiving a message with a Length up to and including 65,535 octets. --- 120,145 ---- defined with Capability code 6 and Capability length 0. To advertise the BGP Extended Message Capability to a peer, a BGP speaker uses BGP Capabilities Advertisement [RFC5492]. By advertising the BGP Extended Message Capability to a peer, a BGP ! speaker conveys that it is able to receive, and properly handle, see Section 4, BGP Extended Messages. Peers that wish to use the BGP Extended Message capability MUST support Error Handling for BGP UPDATE Messages per [RFC7606]. 4. Operation The Extended Message Capability applies to all messages except for the OPEN and KEEPALIVE messages. The former exception is to reduce the complexity of providing backward compatibility. ! A BGP speaker that is capable of receiving BGP Extended Messages SHOULD advertise the BGP Extended Message Capability to its peers using BGP Capabilities Advertisement [RFC5492]. A BGP speaker ! MAY send Extended Messages to a peer only if the Extended Message Capability was received from that peer. An implementation that advertises the BGP Extended Message capability MUST be capable of receiving a message with a Length up to and including 65,535 octets. *************** Internet-Draft Extended Message sup *** 157,168 **** 4,096 octet pre- Extended Message limit, so as not to require downstream routers to decompose for peers that do not support Extended Messages. See Section 8. If a BGP message with a Length greater than 4,096 octets is received ! by a BGP listener who has not advertised the Extended Message ! Capability, the listener will generate a NOTIFICATION with the Error Subcode set to Bad Message Length ([RFC4271] Sec 6.1). Bush, et al. Expires January 31, 2020 [Page 3] --- 154,165 ---- 4,096 octet pre- Extended Message limit, so as not to require downstream routers to decompose for peers that do not support Extended Messages. See Section 8. If a BGP message with a Length greater than 4,096 octets is received ! by a BGP speaker who has not advertised the Extended Message ! Capability, the speaker will generate a NOTIFICATION with the Error Subcode set to Bad Message Length ([RFC4271] Sec 6.1). Bush, et al. Expires January 31, 2020 [Page 3] *************** Internet-Draft Extended Message sup *** 175,190 **** speakers which may not support Extended Messages. Therefore, an announcement in an Extended Message where the size of the attribute set plus the NLRI is larger than 4,096 octets may cause lack of reachability. ! A BGP speaker with a mixture of peers some of which have advertised ! the BGP Extended Message capability and some which have not, may ! receive an UPDATE from one of its capable peers that produces an ongoing announcement that is larger than 4,096 octets. When propagating that UPDATE onward to a neighbor which has not advertised ! the BGP Extended Message capability, the sender SHOULD try to reduce the outgoing message size by removing attributes eligible under the "attribute discard" approach of [RFC7606]. If the message is still too big, then it must not be sent to the neighbor ([RFC4271], Section 9.2). Additionally, if the NLRI was previously advertised to that peer, it must be withdrawn from service ([RFC4271], --- 172,187 ---- speakers which may not support Extended Messages. Therefore, an announcement in an Extended Message where the size of the attribute set plus the NLRI is larger than 4,096 octets may cause lack of reachability. ! A BGP speaker that has advertised ! the BGP Extended Message capability to its peers, may ! receive an UPDATE from one of its peers that produces an ongoing announcement that is larger than 4,096 octets. When propagating that UPDATE onward to a neighbor which has not advertised ! the BGP Extended Message capability, the speaker SHOULD try to reduce the outgoing message size by removing attributes eligible under the "attribute discard" approach of [RFC7606]. If the message is still too big, then it must not be sent to the neighbor ([RFC4271], Section 9.2). Additionally, if the NLRI was previously advertised to that peer, it must be withdrawn from service ([RFC4271], -----Original Message----- From: Idr <idr-bounces@ietf.org> on behalf of Randy Bush <randy@psg.com> Date: Tuesday, July 30, 2019 at 6:23 PM To: Alvaro Retana <aretana.ietf@gmail.com> Cc: "idr@ietf.org" <idr@ietf.org>, "\"Mirja Kühlewind via Datatracker\"" <noreply@ietf.org>, "draft-ietf-idr-bgp-extended-messages@ietf.org" <draft-ietf-idr-bgp-extended-messages@ietf.org>, The IESG <iesg@ietf.org>, "idr-chairs@ietf.org" <idr-chairs@ietf.org> Subject: Re: [Idr] Mirja Kühlewind's No Objection on draft-ietf-idr-bgp-extended-messages-33: (with COMMENT) i have pushed -34, as there have been lots of small changes since -33 and iesg readers should not have to trip over old fixed junk, and instead find new junk. randy _______________________________________________ Idr mailing list Idr@ietf.org https://www.ietf.org/mailman/listinfo/idr
- [Idr] Mirja Kühlewind's No Objection on draft-iet… Mirja Kühlewind via Datatracker
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Alvaro Retana
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Mirja Kuehlewind
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Susan Hares
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Mirja Kuehlewind
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Susan Hares
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Alvaro Retana
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Randy Bush
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Randy Bush
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Alvaro Retana
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Randy Bush
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Randy Bush
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Randy Bush
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Enke Chen (enkechen)
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Alvaro Retana
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Randy Bush
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Susan Hares
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Susan Hares
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Enke Chen (enkechen)
- Re: [Idr] Mirja Kühlewind's No Objection on draft… John Scudder
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Susan Hares
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Susan Hares
- Re: [Idr] Mirja Kühlewind's No Objection on draft… Alvaro Retana