Hi all, I have a problem with MPLS and LDP neighbor between FRR 6.0.2. and Cisco IOS 12.2 advk9. the log FRR side is: [CUT] 2019/01/22 01:03:12 LDP: discovery[recv]: iface enp2s0f0 lsr-id 2.2.2.2 transport-address 2.2.2.2 holdtime 15 2019/01/22 01:03:12 LDP: discovery[send]: iface enp2s0f0 (ipv4) holdtime 180 2019/01/22 01:03:12 LDP: nbr_fsm: event CONNECTION UP resulted in action SETUP NEIGHBOR CONNECTION and changing state for lsr-id 2.2.2.2 from PRESENT to INITIALIZED 2019/01/22 01:03:12 LDP: msg[out]: initialization: lsr-id 2.2.2.2 2019/01/22 01:03:12 LDP: nbr_fsm: event INIT SENT resulted in action NOTHING and changing state for lsr-id 2.2.2.2 from INITIALIZED to OPENSENT 2019/01/22 01:03:12 LDP: discovery[recv]: iface enp2s0f0 lsr-id 2.2.2.2 transport-address 2.2.2.2 holdtime 15 2019/01/22 01:03:12 LDP: msg[in]: initialization: lsr-id 2.2.2.2 2019/01/22 01:03:12 LDP: recv_init: lsr-id 2.2.2.2 announced the Dynamic Capability Announcement capability 2019/01/22 01:03:12 LDP: recv_init: lsr-id 2.2.2.2 announced the Typed Wildcard FEC capability 2019/01/22 01:03:12 LDP: nbr_fsm: event INIT RECEIVED resulted in action SEND KEEPALIVE and changing state for lsr-id 2.2.2.2 from OPENSENT to OPENREC 2019/01/22 01:03:12 LDP: nbr_fsm: event KEEPALIVE RECEIVED resulted in action START NEIGHBOR SESSION and changing state for lsr-id 2.2.2.2 from OPENREC to OPERATIONAL ... 2019/01/22 01:03:12 LDP: msg[in]: label mapping: lsr-id 2.2.2.2, fec 1.1.1.1/32, label 250 2019/01/22 01:03:12 LDP: msg[in]: notification: lsr-id 2.2.2.2, status Bad PDU Length (fatal error) 2019/01/22 01:03:12 LDP: nbr_fsm: event SESSION CLOSE resulted in action CLOSE SESSION and changing state for lsr-id 2.2.2.2 from OPERATIONAL to PRESENT 2019/01/22 01:03:12 LDP: session_close: closing session with lsr-id 2.2.2.2 2019/01/22 01:03:12 LDP: zebra[out]: prefix 10.226.135.0/30 nexthop 10.224.1.21 ifindex 2 labels 497/166 (add) [/CUT] Cisco side: [CUT] Jan 22 00:51:51.049 CET: %LDP-5-NBRCHG: LDP Neighbor 1.1.1.1:0 (2) is UP Jan 22 00:51:51.053 CET: %LDP-4-PTCL: peer 1.1.1.1:0, bad PDU hdr Jan 22 00:51:51.053 CET: PDU HDR: Jan 22 00:51:51.053 CET: 0x00 0x01 0x0F 0xFE 0x5D 0xBD 0xBF 0xFC 0x00 0x00 0x00 0x00 Jan 22 00:51:51.053 CET: %LDP-5-NBRCHG: LDP Neighbor 1.1.1.1:0 (2) is DOWN (Received bad message) Jan 22 00:51:53.241 CET: %LDP-5-NBRCHG: LDP Neighbor 1.1.1.12:0 (7) is UP Jan 22 00:51:53.245 CET: %LDP-4-PTCL: peer 1.1.1.1:0, bad PDU hdr Jan 22 00:51:53.245 CET: PDU HDR: Jan 22 00:51:53.245 CET: 0x00 0x01 0x0F 0xFE 0x5D 0xBD 0xBF 0xFC 0x00 0x00 0x00 0x00 Jan 22 00:51:53.245 CET: %LDP-5-NBRCHG: LDP Neighbor 1.1.1.1:0 (7) is DOWN (Received bad message) Jan 22 00:52:13.065 CET: %LDP-5-NBRCHG: LDP Neighbor 1.1.1.1:0 (2) is UP Jan 22 00:52:13.069 CET: %LDP-4-PTCL: peer 1.1.1.1:0, bad PDU hdr Jan 22 00:52:13.069 CET: PDU HDR: Jan 22 00:52:13.069 CET: 0x00 0x01 0x0F 0xFE 0x5D 0xBD 0xBF 0xFC 0x00 0x00 0x00 0x00 Jan 22 00:52:13.069 CET: %LDP-5-NBRCHG: LDP Neighbor 1.1.1.1:0 (2) is DOWN (Received bad message) Jan 22 00:52:15.953 CET: %LDP-5-NBRCHG: LDP Neighbor 1.1.1.1:0 (7) is UP Jan 22 00:52:15.957 CET: %LDP-4-PTCL: peer 1.1.1.1:0, bad PDU hdr Jan 22 00:52:15.957 CET: PDU HDR: Jan 22 00:52:15.957 CET: 0x00 0x01 0x0F 0xFE 0x5D 0xBD 0xBF 0xFC 0x00 0x00 0x00 0x00 Jan 22 00:52:15.957 CET: %LDP-5-NBRCHG: LDP Neighbor 1.1.1.1:0 (7) is DOWN (Received bad message) [/CUT] FRR configuration: interface dummy0 ip address 1.1.1.1/32 ! interface enp2s0f0 description CORE-1 ip address 10.224.1.22/30 ip ospf network point-to-point ! interface enp2s0f1 description CORE-2 ip address 10.224.1.26/30 ip ospf network point-to-point ! mpls ldp router-id 1.1.1.1 dual-stack cisco-interop ! address-family ipv4 discovery hello holdtime 180 discovery hello interval 15 discovery transport-address 1.1.1.1 label local advertise explicit-null ! interface enp2s0f0 ! interface enp2s0f1 ! exit-address-family ! ! Cisco configuration: mpls traffic-eng tunnels mpls ip default-route mpls label protocol ldp interface Loopback0 ip address 2.2.2.2 255.255.255.255 ! interface TenGigabitEthernet1/1 description ASBR-FRR-TEST mtu 1600 ip address 10.224.1.21 255.255.255.252 ip ospf network point-to-point mpls traffic-eng tunnels mpls ip ! The OSPF is up and Loopback are in both routing tables. I try with/with-out "mpls traffic-eng tunnels" with same result. Timers/MTU are corrects. The result is that the devices don't share the labels becouse neighbors are down This is a bug? or wrong configuration? regards Alessio