Aruba Networks, HPE

saumya.dikshit@hpe.com

Hewlett Packard Enterprise

mukul.srivastava@hpe.com

New H3C Technologies

linchangwang.04414@h3c.com

Routing GROW BMP, Routing Policy, Statistics, BGP This document defines few generic BGP Monitoring Protocol (BMP) statistics for monitoring route modifications or changes due to applying Routing Policy. These statistics are reported per BGP peer using the BMP Statistics Report message.

and defines different BMP statistics, and extends these BMP statistics to provide more insights into the BGP RIBs. Routing Policy are widely used in BGP to modify route attributes. Monitoring which route attributes are modified and how often can provide valuable insights for network operators. This document defines few BMP statistics to report such route modifications in a generic and address-family-independent manner. The format of the BMP statistics message remains same as defined in . Besides address family and gauge in the Stat Data (value) , these statistics also provide attribute types of route changes. This route attribute could be the BGP path attributes or additional route attributes for Qos and forwarding-related parameters.

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 when, and only when, they appear in all capitals, as shown here. The BCP14 is used to stress importance for operators but are not required as formal implementation requirement.

The ability to track route modifications via Routing Policy enables operators to understand policy impact, detect misconfigurations, and analyze routing behavior. The attribute type and gauge allow external collectors to derive distribution insights.

The BMP peer statistics report message is reported per BGP peer. Therefore, each route attribute modification count is associated with a specific peer, enabling peer-level policy analysis. For locally originated routes applying routing policy, the peer is regarded as the local router itself, per Section 8.2 of .

These statistics defined in this document indicate which route attribute were modified by routing policy using a 16-bit attribute type value followed by a 64-bit Gauge. and These statistics are applicable to all BGP address families, represented by Address Family Identifier (AFI) and Subsequent Address Family Identifier (SAFI) . Therefore, the value (Stat Data) of these statistics is structured as: 2-byte AFI, 1-byte SAFI, 16-bit Attribute Type, followed by a 64-bit Gauge, as shown in the figure below.

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 2-byte AFI | 1-byte SAFI | 1-byte NUM | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 16-bit Attribute Type (first) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 64-bit Gauge (first) | | ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ 16-bit Attribute Type (last) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ 64-bit Gauge (last) ~ ~ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

AFI: The AFI value is defined in IANA Address Family Numbers. SAFI: The SAFI value is defined in IANA SAFI Values. NUM: Indicates that the number of attribute types included in the same message. Attribute Type: Indicates which route attribute was modified by applying routing policy. The attribute type supports up to 2^16 types. In addition to the types defined in this document, new attribute types of route change may be defined in the future. The attribute type defined in this document is as follows: Attribute Type = 0x0001: Local Preference. Attribute Type = 0x0002: AS Path. Attribute Type = 0x0003: MED. Attribute Type = 0x0004: Community. Attribute Type = 0x0005: Extended Community. Attribute Type = 0x0006: Large Community. Attribute Type = 0x0007: Origin. Attribute Type = 0x0008: Next Hop. Attribute Type = 0x0009: ESI. Attribute Type = 0x000A: AIGP. Attribute Type = 0x000B: Prefix SID. Attribute Type = 0x000C: DSCP. Attribute Type = 0x000D: VPN Peer ID. Attribute Type = 0x000E: Preferred Value. Attribute Type = 0x000F: IP Precedence. Attribute Type = 0x0010: QoS Local ID. Attribute Type = 0x0011: Traffic Index. Attribute Type = 0x0012: MPLS EXP. Attribute Type = 0x0013-0xFFFF: Reserved, Vendor-specific route attribute range. These statistics only apply to the AFI/SAFIs that a BGP speaker supports and negotiates with its peer. These statistics for the Attribute Type that hasn't been modified by routing policy, MUST NOT be reported via the BMP Statistics Report Message. For these statistics defined in this document, the routes that are rejected by inbound or outbound policy are not considered.

Stat Type = TBD_01: (64-bit Gauge) Number of routes with specific change attribute in per-AFI/SAFI post-policy Adj-RIB-In due to the application of inbound policy. Stat Type = TBD_02: (64-bit Gauge) Number of routes with specific change attribute in per-AFI/SAFI post-policy Adj-RIB-Out due to the application of outbound policy.

Procedures and protocol extensions defined in this document do not affect the BMP security model. All security and authentication mechanisms required by Section 11 of , and Section 8 of are also applicable to the gauges defined in this document. This document does not add any additional security considerations.

IANA has assigned the following new parameters in the BMP Statistics Types registry, part of the BMP parameters registry group. This document requests IANA to update these entries as follows. Also, the document requests IANA to update the reference cited for the entries. Type = TBD_01: Number of routes with specific change attribute in per-AFI/SAFI post-policy Adj-RIB-In due to the application of inbound policy. Type = TBD_02: Number of routes with specific change attribute in per-AFI/SAFI post-policy Adj-RIB-Out due to the application of outbound policy.