Subject: [RTG-DIR] Routing Directorate Last Call Review for draft-ietf-grow-bmp-adj-rib-out-05.txt (inline diff since attachment seems to have blocked)

From: "Acee Lindem (acee)" <[email-masked]>
Date: Thu, 20 Jun 2019 17:05:13 +0000

Hello,

I have been selected as the Routing Directorate reviewer for this draft. The Routing Directorate seeks to review all routing or routing-related drafts as they pass through IETF last call and IESG review, and sometimes on special request. The purpose of the review is to provide assistance to the Routing ADs. For more information about the Routing Directorate, please see ​http://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDir

Although these comments are primarily for the use of the Routing ADs, it would be helpful if you could consider them along with any other IETF Last Call comments that you receive, and strive to resolve them through discussion or by updating the draft.

Document: draft-ietf-grow-bmp-adj-rib-out-05.txt
Reviewer: Acee Lindem
Review Date: June 20, 2018
IETF LC End Date: Not started yet.
Intended Status: Standards Track

Summary: The document extends BGP Monitoring Protocol to support per-peer Pre-Policy and Post-Policy Adj-RIB-Out monitoring similar to RFC 7854 support of Adj-RIB-In. The document is ready for publication.

Comments: A well-written clear and concise document.

Major Issues: N/A

Minor Issues:
    Use updated boilerplate text for “Reserved Words”.

    You will be undoubtedly asked to explain why the Adj-RIB-Out support doesn’t add any additional security considerations. However, I’ll leave that the security reviewers so that they can fulfill their divine mandate of securing the Internet.

Nits: See diff below including Peer Up and Peer Down capitalization consistent with RFC 7854.
*** draft-ietf-grow-bmp-adj-rib-out-05.txt.orig        2019-06-20 11:44:59.000000000 -0400
--- draft-ietf-grow-bmp-adj-rib-out-05.txt     2019-06-20 12:46:24.000000000 -0400
***************
*** 85,91 ****
     9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
       9.1.  BMP Peer Flags  . . . . . . . . . . . . . . . . . . . . .   7
       9.2.  BMP Statistics Types  . . . . . . . . . . . . . . . . . .   7
!      9.3.  Peer UP Information TLV . . . . . . . . . . . . . . . . .   8
     10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
       10.1.  Normative References . . . . . . . . . . . . . . . . . .   8
       10.2.  URIs . . . . . . . . . . . . . . . . . . . . . . . . . .   8
--- 85,91 ----
     9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
       9.1.  BMP Peer Flags  . . . . . . . . . . . . . . . . . . . . .   7
       9.2.  BMP Statistics Types  . . . . . . . . . . . . . . . . . .   7
!      9.3.  Peer Up Information TLV . . . . . . . . . . . . . . . . .   8
     10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
       10.1.  Normative References . . . . . . . . . . . . . . . . . .   8
       10.2.  URIs . . . . . . . . . . . . . . . . . . . . . . . . . .   8
***************
*** 96,102 ****
  1.  Introduction

     BGP Monitoring Protocol (BMP) defines monitoring of the received
!    (e.g.  Adj-RIB-In) Routing Information Bases (RIBs) per peer.  The
     Adj-RIB-In pre-policy conveys to a BMP receiver all RIB data before
     any policy has been applied.  The Adj-RIB-In post-policy conveys to a
     BMP receiver all RIB data after policy filters and/or modifications
--- 96,102 ----
  1.  Introduction

     BGP Monitoring Protocol (BMP) defines monitoring of the received
!    (e.g., Adj-RIB-In) Routing Information Bases (RIBs) per peer.  The
     Adj-RIB-In pre-policy conveys to a BMP receiver all RIB data before
     any policy has been applied.  The Adj-RIB-In post-policy conveys to a
     BMP receiver all RIB data after policy filters and/or modifications
***************
*** 120,136 ****
     use-case for enabling post-policy monitoring.

     In order for a BMP receiver to receive any BGP data, the BMP sender
!    (e.g. router) needs to have an established BGP peering session and
     actively be receiving updates for an Adj-RIB-In.

     Being able to only monitor the Adj-RIB-In puts a restriction on what
!    data is available to BMP receivers via BMP senders (e.g. routers).
     This is an issue when the receiving end of the BGP peer is not
     enabled for BMP or when it is not accessible for administrative
     reasons.  For example, a service provider advertises prefixes to a
     customer, but the service provider cannot see what it advertises via
     BMP.  Asking the customer to enable BMP and monitoring of the Adj-
!    RIB- In is not feasible.

     This document updates the BGP Monitoring Protocol (BMP) RFC 7854
     [RFC7854] peer header by adding a new flag to distinguish Adj-RIB-In
--- 120,136 ----
     use-case for enabling post-policy monitoring.

     In order for a BMP receiver to receive any BGP data, the BMP sender
!    (e.g., router) needs to have an established BGP peering session and
     actively be receiving updates for an Adj-RIB-In.

     Being able to only monitor the Adj-RIB-In puts a restriction on what
!    data is available to BMP receivers via BMP senders (e.g., routers).
     This is an issue when the receiving end of the BGP peer is not
     enabled for BMP or when it is not accessible for administrative
     reasons.  For example, a service provider advertises prefixes to a
     customer, but the service provider cannot see what it advertises via
     BMP.  Asking the customer to enable BMP and monitoring of the Adj-
!    RIB-In is not feasible.

     This document updates the BGP Monitoring Protocol (BMP) RFC 7854
     [RFC7854] peer header by adding a new flag to distinguish Adj-RIB-In
***************
*** 138,150 ****

     Adding Adj-RIB-Out provides the ability for a BMP sender to send to a
     BMP receiver what it advertises to BGP peers, which can be used for
!    outbound policy validation and to monitor RIBs that were advertised.

  2.  Terminology

     The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
!    "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
!    document are to be interpreted as described in RFC 2119 [RFC2119].

  3.  Definitions

--- 138,152 ----

     Adding Adj-RIB-Out provides the ability for a BMP sender to send to a
     BMP receiver what it advertises to BGP peers, which can be used for
!    outbound policy validation and to monitor routes that were advertised.

  2.  Terminology

     The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
!    "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
!    "OPTIONAL" in this document are to be interpreted as described in BCP
!    14 [RFC2119] [RFC8174] when, and only when, they appear in all
!    capitals, as shown here.

  3.  Definitions

***************
*** 186,192 ****
     The existing flags are defined in section 4.2 [RFC7854] and the
     remaining bits are reserved for future use.  They SHOULD be
     transmitted as 0 and their values MUST be ignored on receipt.  The
!    following fields in Per-Peer Header are redefined:

     o  Peer Address: The remote IP address associated with the TCP
        session over which the encapsulated PDU is sent.
--- 188,194 ----
     The existing flags are defined in section 4.2 [RFC7854] and the
     remaining bits are reserved for future use.  They SHOULD be
     transmitted as 0 and their values MUST be ignored on receipt.  The
!    following fields in the Per-Peer Header are redefined:

     o  Peer Address: The remote IP address associated with the TCP
        session over which the encapsulated PDU is sent.
***************
*** 202,213 ****
  5.1.  Post-Policy

     The primary use-case in monitoring Adj-RIB-Out is to monitor the
!    updates transmitted to the BGP peer after outbound policy has been
     applied.  These updates reflect the result after modifications and
!    filters have been applied (e.g.  Adj-RIB-Out Post-Policy).  Some
     attributes are set when the BGP message is transmitted, such as next-
     hop.  Adj-RIB-Out Post-Policy MUST convey what is actually
!    transmitted to the peer, next-hop and any attribute set during
     transmission should also be set and transmitted to the BMP receiver.

     The L flag MUST be set to 1 to indicate post-policy.
--- 204,215 ----
  5.1.  Post-Policy

     The primary use-case in monitoring Adj-RIB-Out is to monitor the
!    updates transmitted to a BGP peer after outbound policy has been
     applied.  These updates reflect the result after modifications and
!    filters have been applied (e.g., Adj-RIB-Out Post-Policy).  Some
     attributes are set when the BGP message is transmitted, such as next-
     hop.  Adj-RIB-Out Post-Policy MUST convey what is actually
!    transmitted to the peer, next-hop and any attributes set during
     transmission should also be set and transmitted to the BMP receiver.

     The L flag MUST be set to 1 to indicate post-policy.
***************
*** 227,244 ****

     Depending on BGP peering session type (IBGP, IBGP route reflector
!    client, EBGP, BGP confederations, Route Server Client) the candidate
     routes that make up the Pre-Policy Adj-RIB-Out do not contain all
     local-rib routes.  Pre-Policy Adj-RIB-Out conveys only routes that
     are available based on the peering type.  Post-Policy represents the
     filtered/changed routes from the available routes.

     Some attributes are set only during transmission of the BGP message,
!    ie.  Post-Policy.  It is common that next-hop may be null, loopback,
     or similar during this phase.  All mandatory attributes, such as
     next-hop, MUST be either ZERO or have an empty length if they are
!    unknown at the Pre-Policy phase.  The BMP receiver will treat zero or
!    empty mandatory attributes as self originated.

     The L flag MUST be set to 0 to indicate pre-policy.

--- 229,246 ----

     Depending on BGP peering session type (IBGP, IBGP route reflector
!    client, EBGP, BGP confederation, Route Server Client) the candidate
     routes that make up the Pre-Policy Adj-RIB-Out do not contain all
     local-rib routes.  Pre-Policy Adj-RIB-Out conveys only routes that
     are available based on the peering type.  Post-Policy represents the
     filtered/changed routes from the available routes.

     Some attributes are set only during transmission of the BGP message,
!    i.e., Post-Policy.  It is common that next-hop may be null, loopback,
     or similar during this phase.  All mandatory attributes, such as
     next-hop, MUST be either ZERO or have an empty length if they are
!    unknown at the Pre-Policy phase completion.  The BMP receiver will
!    treat zero or empty mandatory attributes as self-originated.

     The L flag MUST be set to 0 to indicate pre-policy.

***************
*** 255,261 ****

  6.2.  Statistics Report

!    Statistics report message has Stat Type field to indicate the
     statistic carried in the Stat Data field.  Statistics report messages
     are not specific to Adj-RIB-In or Adj-RIB-Out and MUST have the O
     flag set to zero.  The O flag SHOULD be ignored by the BMP receiver.
--- 257,263 ----

  6.2.  Statistics Report

!    The Statistics report message has a Stat Type field to indicate the
     statistic carried in the Stat Data field.  Statistics report messages
     are not specific to Adj-RIB-In or Adj-RIB-Out and MUST have the O
     flag set to zero.  The O flag SHOULD be ignored by the BMP receiver.
***************
*** 289,306 ****

  6.3.  Peer Down and Up Notifications

!    PEER UP and DOWN notifications convey BGP peering session state to
     BMP receivers.  The state is independent of whether or not route
     monitoring or route mirroring messages will be sent for Adj-RIB-In,
     Adj-RIB-Out, or both.  BMP receiver implementations SHOULD ignore the
!    O flag in PEER UP and DOWN notifications.  BMP receiver
     implementations MUST use the per-peer header O flag in route
!    monitoring and mirroring messages in order to identify if the message
     is for Adj-RIB-In or Adj-RIB-Out.

  6.3.1.  Peer Up Information

!    The following peer UP information TLV types are added:

     o  Type = 4: Admin Label.  The Information field contains a free-form
        UTF-8 string whose length is given by the Information Length
--- 291,308 ----

  6.3.  Peer Down and Up Notifications

!    Peer Up and Down notifications convey BGP peering session state to
     BMP receivers.  The state is independent of whether or not route
     monitoring or route mirroring messages will be sent for Adj-RIB-In,
     Adj-RIB-Out, or both.  BMP receiver implementations SHOULD ignore the
!    O flag in Peer Up and Down notifications.  BMP receiver
     implementations MUST use the per-peer header O flag in route
!    monitoring and mirroring messages to identify if the message
     is for Adj-RIB-In or Adj-RIB-Out.

  6.3.1.  Peer Up Information

!    The following Peer Up message Information TLV type is added:

     o  Type = 4: Admin Label.  The Information field contains a free-form
        UTF-8 string whose length is given by the Information Length
***************
*** 308,316 ****
        requirement to terminate the string with null or any other
        character.

!       Multiple admin labels can be included in the Peer UP.  When
        multiple admin labels are included the BMP receiver MUST preserve
!       the order.

        The TLV is optional.

--- 310,318 ----
        requirement to terminate the string with null or any other
        character.

!       Multiple admin labels can be included in the Peer Up notification.  When
        multiple admin labels are included the BMP receiver MUST preserve
!       their order.

        The TLV is optional.

***************
*** 319,325 ****
  7.1.  Peer and Update Groups

     Peer and update groups are used to group updates shared by many
!    peers.  This is a level of efficiency in the implementation, not a
     true representation of what is conveyed to a peer in either Pre-
     Policy or Post-Policy.

--- 321,327 ----
  7.1.  Peer and Update Groups

     Peer and update groups are used to group updates shared by many
!    peers.  This is a level of efficiency in implementations, not a
     true representation of what is conveyed to a peer in either Pre-
     Policy or Post-Policy.

***************
*** 339,354 ****

     From a BMP perspective, this should be simple to include a group name
!    in the PEER UP, but it is more complex than that.  BGP
     implementations have evolved to provide comprehensive and structured
!    policy grouping, such as session, afi/safi, and template based group
     policy inheritances.

     This level of structure and inheritance of polices does not provide a
     simple peer group name or ID, such as wholesale peer.

     Instead of requiring a group name to be used, a new administrative
!    label informational TLV (Section 6.3.1) is added to the Peer UP
     message.  These labels have administrative scope relevance.  For
     example, labels "type=wholesale" and "region=west" could be used to
     monitor expected policies.
--- 341,356 ----

     From a BMP perspective, this should be simple to include a group name
!    in the Peer Up, but it is more complex than that.  BGP
     implementations have evolved to provide comprehensive and structured
!    policy grouping, such as session, AFI/SAFI, and template-based group
     policy inheritances.

     This level of structure and inheritance of polices does not provide a
     simple peer group name or ID, such as wholesale peer.

     Instead of requiring a group name to be used, a new administrative
!    label informational TLV (Section 6.3.1) is added to the Peer Up
     message.  These labels have administrative scope relevance.  For
     example, labels "type=wholesale" and "region=west" could be used to
     monitor expected policies.
***************
*** 368,374 ****

  9.1.  BMP Peer Flags

!    This document defines the following new per-peer header flags
     (Section 4):

     o  Flag 3 as O flag: The O flag indicates Adj-RIB-In if set to 0 and
--- 370,376 ----

  9.1.  BMP Peer Flags

!    This document defines the following per-peer header flags
     (Section 4):

     o  Flag 3 as O flag: The O flag indicates Adj-RIB-In if set to 0 and
***************
*** 376,382 ****

  9.2.  BMP Statistics Types

!    This document defines four new statistic types for statistics
     reporting (Section 6.2):

     o  Stat Type = 14: (64-bit Gauge) Number of routes in Adj-RIBs-Out
--- 378,384 ----

  9.2.  BMP Statistics Types

!    This document defines four statistic types for statistics
     reporting (Section 6.2):

     o  Stat Type = 14: (64-bit Gauge) Number of routes in Adj-RIBs-Out
***************
*** 404,413 ****
        Identifier (AFI), 1-byte Subsequent Address Family Identifier
        (SAFI), followed by a 64-bit Gauge.

! 9.3.  Peer UP Information TLV

!    This document defines the following new BMP PEER UP informational
!    message TLV types (Section 6.3.1):

     o  Type = 4: Admin Label.  The Information field contains a free-form
        UTF-8 string whose length is given by the Information Length
--- 406,415 ----
        Identifier (AFI), 1-byte Subsequent Address Family Identifier
        (SAFI), followed by a 64-bit Gauge.

! 9.3.  Peer Up Information TLV

!    This document defines the following BMP Peer Up Information
!    TLV type (Section 6.3.1):

     o  Type = 4: Admin Label.  The Information field contains a free-form
        UTF-8 string whose length is given by the Information Length
***************
*** 435,440 ****
--- 437,446 ----
                DOI 10.17487/RFC7854, June 2016,
                <https://www.rfc-editor.org/info/rfc7854>.

+    [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
+               2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
+               May 2017, <https://www.rfc-editor.org/info/rfc8174>.
+
  10.2.  URIs

     [1] https://www.iana.org/assignments/bmp-parameters/bmp-

Thanks,
Acee