The value of tnOamPingCtlSize specifies the size of the OAM Echo message. This parameter is optional and is valid only if tnOamPingCtlTestMode has a value of 'sdpPing', 'macPing', 'lspPing', 'vprnPing', 'mfibPing', 'vccvPing', 'icmpPing', 'p2mpLspPing', 'ethCfmLoopback', or 'ethCfmTwoWaySlm'. The minimum, maximum, and default values for the tnOamPingCtlTestMode cases are: 'ethCfmLoopback' : 0, 1500, 0 'ethCfmTwoWaySlm': 0, 1500, 0 'ethCfmTwoWayDelay': 0, 1500, 0 'ethCfmOneWayDelay': 0, 1500, 0 'icmpPing' : 0, 16384, 56 'lspPing' : 80, 9198, 80 - LSP prefix specified : 92, 9198, 92 - LSP name specified 'macPing' : 1, 9198, 72 'mfibPing' : 1, 9198, 72 'p2mpLspPing' : 92|97, 9198, 92 - LSP name, 0 S2L specified : 104|109, 9198, 104 - LSP name, 1 S2L specified : 112|117, 9198, 112 - LSP name, 2 S2L specified : 120|125, 9198, 120 - LSP name, 3 S2L specified : 128|133, 9198, 128 - LSP name, 4 S2L specified : 136|141, 9198, 136 - LSP name, 5 S2L specified : 88|93, 9198, 88 - LDP id, 0 leaf-addr specified : 100|105, 9198, 100 - LDP id, 1 leaf-addr specified : 108|113, 9198, 108 - LDP id, 2 leaf-addr specified : 116|121, 9198, 116 - LDP id, 3 leaf-addr specified : 124|129, 9198, 124 - LDP id, 4 leaf-addr specified : 132|137, 9198, 132 - LDP id, 5 leaf-addr specified : 92|97, 9198, 92 - LDP SSM, 0 leaf-addr specified : 104|109, 9198, 104 - LDP SSM, 1 leaf-addr specified : 112|117, 9198, 112 - LDP SSM, 2 leaf-addr specified : 120|125, 9198, 120 - LDP SSM, 3 leaf-addr specified : 128|133, 9198, 128 - LDP SSM, 4 leaf-addr specified : 136|141, 9198, 136 - LDP SSM, 5 leaf-addr specified 'sdpPing' : 72, 9198, 72 'vccvPing' : 88, 9198, 88 - FEC 128 pseudowire : 120, 9198, 120 - FEC 129 pseudowire 'vprnPing' : 1, 9198, 72 An RSVP-TE P2MP LSP consists of source-to-leaf (S2L) sub-LSPs. For P2MP LSP ping, a gap in the supported range of tnOamPingCtlSize arises from the inclusion of the Pad TLV (see RFC 4379 section 3.4). For example, when no S2L sub-LSP is specified for a RSVP P2MP LSP, the minimum ping size is 92. But the next valid minimum ping size is 97 due to the inclusion of the Pad TLV. When the OAM message is encapsulated in an IP/GRE SDP, the IP 'DF' (Don't Fragment) bit is set. If any segment of the path between the sender and receiver cannot handle the message size, the message is discarded. MPLS LSPs are not expected to fragment the message either, as the message contained in the LSP is not an IP packet. When tnOamPingCtlTestMode has a value of 'ethCfmLoopback', or 'ethCfmTwoWaySlm' the value of this object specifies the number of octets in the Value field of the Data TLV of the Ethernet CFM packet. If zero is specified, the packet has no Data TLV. When tnOamPingCtlTestMode has a value of 'icmpPing', the value of this object specifies the payload size following the ICMP header. When tnOamPingCtlTestMode has a value of 'mtuPing', changing the message size is a method of checking the ability of an SDP to support a particular path-mtu value. The size of the message does not include the SDP encapsulation, VC-Label (if applied) or any DLC headers or trailers. Before 6.0 release, the minimum size in 'sdpPing' is 40 octets. Such shorter packet has no timestamp information but should still be accepted for interoperability purpose. However, new 'sdpPing' should include the timestamp information.