The MPLS WG Archive[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index][Thread Index][Author Index][Subject Index] Questions about Y.1711
Dear Sir, In section 6 of Y.1711,the OAM mechanisms are specified,however,I have some questions about them,could you please clarify them? 1. In section 6.1.1 Stack encoding,it states that "OAM packets are differentiated from normal user-plane traffic by an increase of one in the label stack depth at a given LSP level at which they are inserted. Therefore, they maintain this label stack difference of one (from normal user-plane traffic) as they traverse any lower layer server LSPs." Do you mean that the OAM Alert labelled header is inserted between the normal user-plane forwarding label and the CV payload(or FFD payload),e.g. The structure of an CV OAM frame is as follows: ____________________________________________________________________________ __________ |L2 Frame Header | User-plane | OAM Alert | Function | Reserved |LSP Trail Termination | Padding | BIP16| |__Header______ |_Label___ |__Label___ |_Type__ |______ _ |___Source Identifier_ |______ |_____ | Do you think if I catch it? 2. If OAM Alert Label is the bottom of the label stack,then the OAM Alert Label is only processed by the Egress LSR, i.e.OAM packets are transparent to intermediate LSRs, including the penultimate LSR,then what if the defect is happened in the intermediate LSR,then the OAM packets can't reach the Egress LSR,how can the OAM function be implemented? and how can this defect be detected? 3.In the Payload of FDI and BDI,the "Defect Location" field is formed by AS number,then the defect location can only be in granularity of AS,then how can the defect in the particular LSR of the defected AS be loacted? An AS is composed of many LSR,how can operator find out which LSR is doing wrong? Furthermore,a LSP is normally setup in a single AS,what is the significance to find out th AS number of the defected LSP? 4.A return LSP is important for BDI OAM packet,could you please how to setup the return LSP or select the return LSP from the existed LSP? 5.Could you please tell me which vender has implemented the MPLS OAM function,and how about the interoperability test? TIA & Best Regards Sincerely Yours Defeng Li Huawei Technologies +86-10-82882343 lidefeng@huawei.com |
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