A new VXLAN troubleshooting tool, VXLAN Ping, is available to verify VXLAN VTEP connectivity. The VXLAN Ping command is available from interactive CLI and SNMP.
This tool allows the operator to specify a wide range of variables to influence how the packet is forwarded from the VTEP source to VTEP termination. The ping function requires the operator to specify a different test-id (equates to originator handle) for each active and outstanding test. The required local service identifier from which the test is launched determines the source IP (the system IP address) to use in the outer IP header of the packet. This IP address is encoded into the VXLAN header Source IP TLV. The service identifier also encodes the local VNI. The outer-ip-destination must equal the VTEP termination point on the remote node, and the dest-vni must be a valid VNI within the associated service on the remote node. The outer source IP address is automatically detected and inserted in the IP header of the packet. The outer source IP address uses the IPv4 system address by default.
If the VTEP is created using a non-system source IP address through the vxlan-src-vtep command, the outer source IP address uses the address specified by vxlan-src-vtep. The remainder of the variables are optional.
The VXLAN PDU is encapsulated in the appropriate transport header and forwarded within the overlay to the appropriate VTEP termination. The VXLAN router alert (RA) bit is set to prevent forwarding OAM PDU beyond the terminating VTEP. Because handling of the router alert bit was not defined in some early releases of VXLAN implementations, the VNI Informational bit (I-bit) is set to ‟0” for OAM packets. This indicates that the VNI is invalid, and the packet should not be forwarded. This safeguard can be overridden by including the i-flag-on option that sets the bit to ‟1”, valid VNI. Ensure that OAM frames meant to be contained to the VTEP are not forwarded beyond its endpoints.
The supporting VXLAN OAM ping draft includes a requirement to encode a reserved IEEE MAC address as the inner destination value. However, at the time of implementation, that IEEE MAC address had not been assigned. The inner IEEE MAC address defaults to 00:00:00:00:00:00, but may be changed using the inner-l2 option. Inner IEEE MAC addresses that are included with OAM packets are not learned in the local Layer 2 forwarding databases.
The echo responder terminates the VXLAN OAM frame, and takes the appropriate response action, and include relevant return codes. By default, the response is sent back using the IP network as an IPv4 UDP response. The operator can choose to override this default by changing the reply-mode to overlay. The overlay return mode forces the responder to use the VTEP connection representing the source IP and source VTEP. If a return overlay is not available, the echo response is dropped by the responder.
Support is included for:
IPv4 VTEP
Optional specification of the outer UDP Source, which helps downstream network elements along the path with ECMP to hash to flow to the same path
Optional configuration of the inner IP information, which helps the operator test different equal paths where ECMP is deployed on the source. A test only validates a single path where ECMP functions are deployed. The inner IP information is processed by a hash function, and there is no guarantee that changing the IP information between tests selects different paths.
Optional end system validation for a single L2 IEEE MAC address per test. This function checks the remote FDB for the configured IEEE MAC Address. Only one end system IEEE MAC Address can be configured per test.
Reply mode UDP (default) or Overlay
Optional additional padding can be added to each packet. There is an option that indicates how the responder should handle the pad TLV. By default, the padding is not reflected to the source. The operator can change this behavior by including the reflect-pad option. The reflect-pad option is not supported when the reply mode is set to UDP.
Configurable send counts, intervals, times outs, and forwarding class
The VXLAN OAM PDU includes two timestamps. These timestamps are used to report forward direction delay. Unidirectional delay metrics require accurate time of day clock synchronization. Negative unidirectional delay values are reported as ‟0.000”. The round trip value includes the entire round trip time including the time that the remote peer takes to process that packet. These reported values may not be representative of network delay.
The following example commands and outputs show how the VXLAN Ping function can be used to validate connectivity. The echo output includes a new header to better describe the VXLAN ping packet headers and the various levels.
oam vxlan-ping test-id 1 service 1 dest-vni 2 outer-ip-destination 10.20.1.4
interval
0.1 send-count 10
TestID 1, Service 1, DestVNI 2, ReplyMode UDP, IFlag Off, PadSize 0, ReflectPad No,
SendCount 10, Interval 0.1, Timeout 5
Outer: SourceIP 10.20.1.3, SourcePort Dynamic, DestIP 10.20.1.4, TTL 10, FC be, Prof
ile
In
Inner: DestMAC 00:00:00:00:00:00, SourceIP 10.20.1.3, DestIP 127.0.0.1
! ! ! ! ! ! ! ! ! !
---- vxlan-id 2 ip-address 10.20.1.4 PING Statistics ----
10 packets transmitted, 10 packets received, 0.00% packet loss
10 non-errored responses(!), 0 out-of-order(*), 0 malformed echo responses(.)
0 send errors(.), 0 time outs(.)
0 overlay segment not found, 0 overlay segment not operational
forward-delay min = 1.097ms, avg = 2.195ms, max = 2.870ms, stddev = 0.735ms
round-trip-delay min = 1.468ms, avg = 1.693ms, max = 2.268ms, stddev = 0.210ms
oam vxlan-ping test-id 2 service 1 dest-vni 2 outer-ip-destination 10.20.1.4 outer-
ip-source-udp 65000 outer-ip-ttl 64 inner-l2 d0:0d:1e:00:00:01 inner-ip-source
192.168.1.2 inner-ip-destination 127.0.0.8 reply-mode overlay send-count 20
interval
1 timeout 3 padding 1000 reflect-pad fc nc profile out
TestID 2, Service 1, DestVNI 2, ReplyMode overlay, IFlag Off, PadSize 1000, ReflectP
ad
Yes, SendCount 20, Interval 1, Timeout 3
Outer: SourceIP 10.20.1.3, SourcePort 65000, DestIP 10.20.1.4, TTL 64, FC nc, Profil
e
out
Inner: DestMAC d0:0d:1e:00:00:01, SourceIP 192.168.1.2, DestIP 127.0.0.8
===================================================================================
rc=1 Malformed Echo Request Received, rc=2 Overlay Segment Not Present, rc=3 Overlay
Segment Not Operational, rc=4 Ok
===================================================================================
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=1 ttl=255 rtt-time=1.733ms fwd
-time=0.302ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=2 ttl=255 rtt-time=1.549ms fwd
-time=1.386ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=3 ttl=255 rtt-time=3.243ms fwd
-time=0.643ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=4 ttl=255 rtt-time=1.551ms fwd
-time=2.350ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=5 ttl=255 rtt-time=1.644ms fwd
-time=1.080ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=6 ttl=255 rtt-time=1.670ms fwd
-time=1.307ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=7 ttl=255 rtt-time=1.636ms fwd
-time=0.490ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=8 ttl=255 rtt-time=1.649ms fwd
-time=0.005ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=9 ttl=255 rtt-time=1.401ms fwd
-time=0.685ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=10 ttl=255 rtt-time=1.634ms fwd
-time=0.373ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=11 ttl=255 rtt-time=1.559ms fwd
-time=0.679ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=12 ttl=255 rtt-time=1.666ms fwd
-time=0.880ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=13 ttl=255 rtt-time=1.629ms fwd
-time=0.669ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=14 ttl=255 rtt-time=1.280ms fwd
-time=1.029ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=15 ttl=255 rtt-time=1.458ms fwd
-time=0.268ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=16 ttl=255 rtt-time=1.659ms fwd
-time=0.786ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=17 ttl=255 rtt-time=1.636ms fwd
-time=1.071ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=18 ttl=255 rtt-time=1.568ms fwd
-time=2.129ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=19 ttl=255 rtt-time=1.657ms fwd
-time=1.326ms. rc=4
1132 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=20 ttl=255 rtt-time=1.762ms fwd
-time=1.335ms. rc=4
---- vxlan-id 2 ip-address 10.20.1.4 PING Statistics ----
20 packets transmitted, 20 packets received, 0.00% packet loss
20 valid responses, 0 out-of-order, 0 malformed echo responses
0 send errors, 0 time outs
0 overlay segment not found, 0 overlay segment not operational
forward-delay min = 0.005ms, avg = 0.939ms, max = 2.350ms, stddev = 0.577ms
round-trip-delay min = 1.280ms, avg = 1.679ms, max = 3.243ms, stddev = 0.375ms
oam vxlan-ping test-id 1 service 1 dest-vni 2 outer-ip-destination 10.20.1.4 send
-count 10 end-system 00:00:00:00:00:01 interval 0.1
TestID 1, Service 1, DestVNI 2, ReplyMode UDP, IFlag Off, PadSize 0, ReflectPad No,
EndSystemMAC 00:00:00:00:00:01, SendCount 10, Interval 0.1, Timeout 5
Outer: SourceIP 10.20.1.3, SourcePort Dynamic, DestIP 10.20.1.4, TTL 10, FC be, Prof
ile
In
Inner: DestMAC 00:00:00:00:00:00, SourceIP 10.20.1.3, DestIP 127.0.0.1
2 2 2 2 2 2 2 2 2 2
---- vxlan-id 2 ip-address 10.20.1.4 PING Statistics ----
10 packets transmitted, 10 packets received, 0.00% packet loss
10 non-errored responses(!), 0 out-of-order(*), 0 malformed echo responses(.)
0 send errors(.), 0 time outs(.)
0 overlay segment not found, 0 overlay segment not operational
0 end-system present(1), 10 end-system not present(2)
forward-delay min = 0.467ms, avg = 0.979ms, max = 1.622ms, stddev = 0.504ms
round-trip-delay min = 1.501ms, avg = 1.597ms, max = 1.781ms, stddev = 0.088ms
oam vxlan-ping test-id 1 service 1 dest-vni 2 outer-ip-destination 10.20.1.4 send
-count 10 end-system 00:00:00:00:00:01
TestID 1, Service 1, DestVNI 2, ReplyMode UDP, IFlag Off, PadSize 0, ReflectPad No,
EndSystemMAC 00:00:00:00:00:01, SendCount 10, Interval 1, Timeout 5
Outer: SourceIP 10.20.1.3, SourcePort Dynamic, DestIP 10.20.1.4, TTL 10, FC be, Prof
ile
In
Inner: DestMAC 00:00:00:00:00:00, SourceIP 10.20.1.3, DestIP 127.0.0.1
===================================================================================
rc=1 Malformed Echo Request Received, rc=2 Overlay Segment Not Present, rc=3 Overlay
Segment Not Operational, rc=4 Ok
mac=1 End System Present, mac=2 End System Not Present
===================================================================================
92 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=1 ttl=255 rtt-time=2.883ms fwd
-time=4.196ms. rc=4 mac=2
92 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=2 ttl=255 rtt-time=1.596ms fwd
-time=1.536ms. rc=4 mac=2
92 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=3 ttl=255 rtt-time=1.698ms fwd
-time=0.000ms. rc=4 mac=2
92 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=4 ttl=255 rtt-time=1.687ms fwd
-time=1.766ms. rc=4 mac=2
92 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=5 ttl=255 rtt-time=1.679ms fwd
-time=0.799ms. rc=4 mac=2
92 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=6 ttl=255 rtt-time=1.678ms fwd
-time=0.000ms. rc=4 mac=2
92 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=7 ttl=255 rtt-time=1.709ms fwd
-time=0.031ms. rc=4 mac=2
92 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=8 ttl=255 rtt-time=1.757ms fwd
-time=1.441ms. rc=4 mac=2
92 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=9 ttl=255 rtt-time=1.613ms fwd
-time=2.570ms. rc=4 mac=2
92 bytes from vxlan-id 2 10.20.1.4: vxlan_seq=10 ttl=255 rtt-time=1.631ms fwd
-time=2.130ms. rc=4 mac=2
---- vxlan-id 2 ip-address 10.20.1.4 PING Statistics ----
10 packets transmitted, 10 packets received, 0.00% packet loss
10 valid responses, 0 out-of-order, 0 malformed echo responses
0 send errors, 0 time outs
0 overlay segment not found, 0 overlay segment not operational
0 end-system present, 10 end-system not present
forward-delay min = 0.000ms, avg = 1.396ms, max = 4.196ms, stddev = 1.328ms
round-trip-delay min = 1.596ms, avg = 1.793ms, max = 2.883ms, stddev = 0.366ms