Border Gateway Protocol (BGP) Tunnel Encapsulation 2026-03-14 BGP Tunnel Encapsulation Attribute Tunnel Types First Come First Served 0 Reserved 1 L2TPv3 over IP IETF 2 GRE IETF 3 Transmit tunnel endpoint (DEPRECATED) IETF 4 IPsec in Tunnel-mode (DEPRECATED) IETF 5 IP in IP tunnel with IPsec Transport Mode (DEPRECATED) IETF 6 MPLS-in-IP tunnel with IPsec Transport Mode (DEPRECATED) IETF 7 IP in IP IETF 8 VXLAN Encapsulation IETF 9 NVGRE Encapsulation IETF 10 MPLS Encapsulation IETF 11 MPLS in GRE Encapsulation IETF 12 VXLAN GPE Encapsulation IETF 13 MPLS in UDP Encapsulation IETF 14 IPv6 Tunnel 15 SR Policy IETF 16 Bare 17 SR Tunnel (DEPRECATED) IETF 18 Cloud Security 19 Geneve Encapsulation IETF 20 Any-Encapsulation 21 GTP Tunnel Type 22 Dynamic Path Selection (DPS) Tunnel Encapsulation 23 Originating PE (OPE) 24 Dynamic Path Selection (DPS) Policy 25 SDWAN-Hybrid 26 X-over-UDP 27 Distributed Etherlink Switch (DES) Tunnel Encapsulation 28 ESP-Protected-Payload 29-65535 Unassigned BGP Tunnel Encapsulation Attribute Sub-TLVs 1-63 Standards Action 64-125 First Come First Served 126-127 Experimental Use 128-191 Standards Action 192-252 First Come First Served 253-254 Experimental Use If the Sub-TLV Type is in the range from 0 to 127 (inclusive), the Sub-TLV Length field contains one octet. If the Sub-TLV Type is in the range from 128 to 255 (inclusive), the Sub-TLV Length field contains two octets. 0 Reserved IETF 1 Encapsulation IETF 2 Protocol Type IETF 3 IPsec Tunnel Authenticator (DEPRECATED) IETF 4 Color IETF 5 Load-Balancing Block IETF 6 Tunnel Egress Endpoint IETF 7 DS Field IETF 8 UDP Destination Port IETF 9 Embedded Label Handling IETF 10 MPLS Label Stack IETF 11 Prefix-SID IETF 12 Preference sub-TLV IETF 13 Binding SID sub-TLV IETF 14 ENLP sub-TLV IETF 15 Priority sub-TLV IETF 16 SPI/SI Representation Sub-TLV IETF 17-19 Unassigned 20 SRv6 Binding SID sub-TLV IETF 21-63 Unassigned 64 IPSEC-SA-ID draft-ietf-idr-sdwan-edge-discovery-04, Section 6.3 65 Extended Port Property draft-ietf-idr-sdwan-edge-discovery-04, Section 6.4 66 Underlay ISP Properties draft-ietf-idr-sdwan-edge-discovery-04, Section 6.5 67 IPsec SA Nonce draft-ietf-idr-sdwan-edge-discovery-04, Section 7.1 68 IPsec Public Key draft-ietf-idr-sdwan-edge-discovery-04, Section 7.2 69 IPsec SA Proposal draft-ietf-idr-sdwan-edge-discovery-04, Section 7.3 70 Simplified IPsec SA draft-ietf-idr-sdwan-edge-discovery-04, Section 7.4 71 IPsec Version 72-122 Unassigned 123 NRP 124 RPF 125 Tree Label Stack 126-127 Reserved for Experimental Use IETF 128 Segment List sub-TLV IETF 129 SR Policy Candidate Path Name sub-TLV IETF 130 SR Policy Name sub-TLV IETF 131-191 Unassigned 192 The WAN ID Sub-TLV 193 The Bytes Sub-TLV 194 IPSEC DIM sub-TLV 195 IPSEC Key Exchange sub-TLV 196 IPSEC SA Proposals sub-TLV 197 Service Segment List 198 Service Vtep 199 Distributed Etherlink Switch (DES) Adjacency 200-252 Unassigned 253-254 Reserved for Experimental Use IETF 255 Reserved IETF Flags Field of VXLAN Encapsulation Sub-TLVs Standards Action 0 V (VN-ID) 1 M (MAC Address) 2-7 Unassigned Flags Field of NVGRE Encapsulation Sub-TLVs Standards Action 0 V (VN-ID) 1 M (MAC Address) 2-7 Unassigned Embedded Label Handling Sub-TLVs Standards Action 0 Reserved 1 Payload of MPLS with embedded label 2 No embedded label in payload 3-255 Unassigned Color Extended Community Flags Standards Action 0-1 Color-only Types Field 2-15 Unassigned SR Policy Segment List Sub-TLVs IETF Review 0 Reserved 1 Type A Segment sub-TLV 2 Deprecated 3 Type C Segment sub-TLV 4 Type D Segment sub-TLV 5 Type E Segment sub-TLV 6 Type F Segment sub-TLV 7 Type G Segment sub-TLV 8 Type H Segment sub-TLV 9 Weight sub-TLV 10 Deprecated 11 Deprecated 12 Deprecated 13 Type B Segment sub-TLV 14 Type I Segment sub-TLV 15 Type J Segment sub-TLV 16 Type K Segment sub-TLV 17 ELP (TEMPORARY - registered 2026-01-06, expires 2026-01-06) 18 Unassigned 19 Segment List ID (TEMPORARY - registered 2025-12-19, expires 2026-12-19) 20-255 Unassigned SR Policy Binding SID Flags Standards Action 0 Specified-BSID-Only Flag (S-Flag) 1 Drop-Upon-Invalid Flag (I-Flag) 2-7 Unassigned SR Policy SRv6 Binding SID Flags Standards Action 0 Specified-BSID-Only Flag (S-Flag) 1 Drop-Upon-Invalid Flag (I-Flag) 2 SRv6 Endpoint Behavior & SID Structure Flag (B-Flag) 3-7 Unassigned SR Policy Segment Flags IETF Review 0 Segment Verification Flag (V-Flag) 1 SR Algorithm Flag (A-Flag) 2 SID Specified Flag (S-Flag) 3 SRv6 Endpoint Behavior & SID Structure Flag (B-Flag) 4-7 Unassigned Color Extended Community Color-Only Types Standards Action 0 Specific Endpoint Match 1 Specific or Null Endpoint Match 2 Specific, Null, or Any Endpoint Match 3 Unassigned Arista Networks mailto:dsf-dev&arista.com 2024-06-13 David Cronin Arista Networks mailto:davidcronin&arista.com 2024-06-12 Hongda Huang mailto:hongda&arista.com 2023-07-19 Jeffrey Haas mailto:jhaas&juniper.net 2023-03-22 Keyur Patel mailto:keyur&arrcus.com 2021-05-14 Martin Djernaes mailto:mdjernaes&juniper.net 2016-03-30 Nischal Sheth mailto:nsheth&juniper.net 2017-08-16 Priyesh Vakayil Palakandy mailto:priyesh&arista.com 2024-10-08 Ramesh Babu Yakkala mailto:ryakkala&cisco.com 2020-02-18 Sarah Chen mailto:sarahchen&arista.com 2022-02-01 Tetsuya Murakami mailto:tetsuya&arrcus.com 2021-05-14 Venkit Kasiviswanathan mailto:venkit&arista.com 2021-09-10