Кем?
Enhance MPLS LDP traceroute process to accommodate devices which do not support RFC6424 - LSP ping with TLV 20, DDMT. While traceroute is sent from Juniper to Huawei, Huawei replies with 'One or more of the TLVs was not understood (2)'. Huawei does not support the TLV 20 (DDMT) and they expect TLV 2 (DSMAP). Juniper devices will start sending DSMAP TLV in the request, if received 'One or more of the TLVs was not understood (2)'. Also note, juniper router donot validate the error tlvs received in the response, there can be cases where some other TLV is not understood and juniper receive 'One or more of the TLVs was not understood (2)', but error tlvs will be sent only for mandatory tlvs that are not understood/supported in the request. Here DDMT TLV is not a mandatory TLV. So, Juniper router cannot expect this TLV getting encoded in the error TLV from other vendors. Hence, Juniper router do not validate or check the presence of DDMT TLV in error TLV. Juniper router tries to sending DSMAP, it may or may not get a reply, but traceroute will proceed by incrementing the ttl after sending DSMAP TLV in the request.