Symptom

IVP6 with VPC and VXLAN is involved - IPV6 RA that is leaving the Nexus CPU ( seen in ethanalyzer) is not making it out of the egress port. SWA# interface Vlan100 no shutdown vrf member externals no ip redirects ip address 192.158.67.193/26 ipv6 address xx00:cb00:36:1030::1/64———————>Same on both peers: anycast gateway. ipv6 nd prefix xx00:cb00:36:1030::/64 2592000 0 no ipv6 redirects fabric forwarding mode anycast-gateway ip dhcp relay address 192.158.65.252 use-vrf default ip dhcp relay source-interface loopback0 SWA# sh ipv6 nd interf vl 100 ICMPv6 ND Interfaces for VRF "externals" Vlan100, Interface status: protocol-up/link-up/admin-up IPv6 address: xx00:cb00:36:1030::1/64 [VALID] IPv6 link-local address: fe80::2cf:5cff:fea1:ab1e [VALID] ND mac-extract : Disabled ICMPv6 active timers: Last Neighbor-Solicitation sent: 00:00:51 Last Neighbor-Advertisement sent: 00:00:01 Last Router-Advertisement sent: 00:00:46 Next Router-Advertisement sent in: 00:04:19 Router-Advertisement parameters: Periodic interval: 200 to 600 seconds Send "Managed Address Configuration" flag: false Send "Other Stateful Configuration" flag: false Send "Default Router Preference" value: Medium Send "Current Hop Limit" field: 64 Send "MTU" option value: 1500 Send "Router Lifetime" field: 1800 secs Send "Reachable Time" field: 0 ms Send "Retrans Timer" field: 0 ms Suppress RA: Disabled Suppress MTU in RA: Disabled Suppress Route Information Option in RA: Disabled Neighbor-Solicitation parameters: NS retransmit interval: 1000 ms ND NUD retry base: 1 ND NUD retry interval: 1000 ND NUD retry attempts: 3 ICMPv6 error message parameters: Send redirects: false (1) Send unreachables: false ICMPv6 DAD parameters: Maximum DAD attempts: 1 L3VNI : interface Vlan1100 no shutdown vrf member externals no ip redirects ip forward ipv6 forward no ipv6 redirects Ethanalyzer captures which shows the IPV6 RA leaving the switch CPU : SWA# ethanalyzer local interface inband display-filter "icmpv6.type == 134 and eth.addr == 33:33:00:00:00:01" limit-captured-frames 0 Capturing on inband 2018-01-25 20:35:45.212953 fe80::2cf:5cff:fea1:ab1e -> ff02::1 ICMPv6 Router advertisement 2018-01-25 20:41:40.219564 fe80::2cf:5cff:fea1:ab1e -> ff02::1 ICMPv6 Router advertisement Detailed packet : SWA# ethanalyzer local interface inband display-filter "icmpv6.type == 134 and eth.addr == 33:33:00:00:00:01" limit-captured-frames 0 de Frame 28995 (118 bytes on wire, 118 bytes captured) Arrival Time: Jan 25, 2018 20:00:52.183181000 [Time delta from previous captured frame: 0.002482000 seconds] [Time delta from previous displayed frame: 161.550372000 seconds] [Time since reference or first frame: 237.311918000 seconds] Frame Number: 28995 Frame Length: 118 bytes Capture Length: 118 bytes [Frame is marked: False] [Protocols in frame: eth:ipv6:icmpv6] Ethernet II, Src: 00:cf:5c:a1:ab:1e (00:cf:5c:a1:ab:1e), Dst: 33:33:00:00:00:01 (33:33:00:00:00:01) Destination: 33:33:00:00:00:01 (33:33:00:00:00:01) Address: 33:33:00:00:00:01 (33:33:00:00:00:01) .... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast) .... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default) Source: 00:cf:5c:a1:ab:1e (00:cf:5c:a1:ab:1e) Address: 00:cf:5c:a1:ab:1e (00:cf:5c:a1:ab:1e) .... ...0 .... .... .... .... = IG bit: Individual address (unicast) .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default) Type: IPv6 (0x86dd) Internet Protocol Version 6 0110 .... = Version: 6 [0110 .... = This field makes the filter "ip.version == 6" possible: 6] .... 1110 0000 .... .... .... .... .... = Traffic class: 0x000000e0 .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000 Payload length: 64 Next header: ICMPv6 (0x3a) Hop limit: 255 Source: fe80::2cf:5cff:fea1:ab1e (fe80::2cf:5cff:fea1:ab1e) Destination: ff02::1 (ff02::1) Internet Control Message Protocol v6 Type: 134 (Router advertisement) Code: 0 Checksum: 0x46a9 [correct] Cur hop limit: 64 Flags: 0x00 0... .... = Not managed .0.. .... = Not other ..0. .... = Not Home Agent ...0 0... = Router preference: Medium Router lifetime: 1800 Reachable time: 0 Retrans timer: 0 ICMPv6 Option (Source link-layer address) Type: Source link-layer address (1) Length: 8 Link-layer address: 00:cf:5c:a1:ab:1e ICMPv6 Option (Prefix information) Type: Prefix information (3) Length: 32 Prefix length: 64 Flags: 0xc0 1... .... = Onlink .1.. .... = Auto ..0. .... = Not router address ...0 .... = Not site prefix Valid lifetime: 2592000 Preferred lifetime: 0 Prefix: 2400:cb00:36:1030:: ICMPv6 Option (MTU) Type: MTU (5) Length: 8 MTU: 1500 This packet does not reach the connected host. Could not see this packet in the span captures taken on the egress port which implies that this packet is not leaving the switch.

Conditions

IVP6 with VPC and VXLAN is involved Issue seen on : Platform : N9K-C93180YC-EX Version : 7.0(3)I7(2)

Workaround

None

Further Problem Description