Thanks for the heads up Mark... I see docs showing SRv6 not supported until XR 6.6, I put XR7 in my lab to start testing it... I have what seems to be a good test for vpnv4 mpls l3vpn over SRv6 IS-IS in core This is my first go at this so still learning. Srv6 has a strange locator thing with it. Here's a PE with a CEF entry showing the remote l3vpn subnet. Interesting about the SRv6 T.Encaps.Red thing RP/0/RP0/CPU0:r1#sh cef vrf one 1.1.1.0/30 Thu Sep 10 18:57:04.082 UTC 1.1.1.0/30, version 3, SRv6 Transit, internal 0x5000001 0x0 (ptr 0xe208f5c) [1], 0x0 (0xe3d45a8), 0x0 (0xf1ce1a8) Updated Sep 10 18:47:58.416 Prefix Len 30, traffic index 0, precedence n/a, priority 3 via fc00:0:0:4::/128, 3 dependencies, recursive [flags 0x6000] path-idx 0 NHID 0x0 [0xd905574 0x0] next hop VRF - 'default', table - 0xe0800000 next hop fc00:0:0:4::/128 via fc00:0:0:4::/64 SRv6 T.Encaps.Red SID-list {fc00:0:0:4:41::} I only used link local default fe80 on the transit core interfaces... Only added a rfc4193 fc00 address to each loopback to get bgp session to come up. Works Ce to ce can ping Interesting looking trace from pe lo0 to pe lo0 RP/0/RP0/CPU0:r4#traceroute fc00:0:1:1::1 source fc00:0:4:4::1 Thu Sep 10 19:02:55.211 UTC Type escape sequence to abort. Tracing the route to fc00:0:1:1::1 1 ::ffff:0.0.0.0 16 msec 7 msec 8 msec 2 ::ffff:0.0.0.0 6 msec 5 msec 6 msec 3 fc00:0:1:1::1 92 msec 86 msec 80 msec -Aaron