VIAVI TestCenter: the PPP-LCP layer, in PPPoL2TP emulation, stays up only when magic number is disabled on the VIAVI side

Knowledge Base - FAQ

Thursday, October 16, 2025

Question:

• an L2TP tunnel and session are successfully negotiated between the Spirent TestCenter (STC) LAC and the LNS • IPCP completes negotiation so the network layer of PPP comes up • the LNS then sends an LCP echo-req to the STC PPP client • immediately the STC PPP client sends a term-req and tears down the LCP layer and goes to the "Idle" state • Interestingly, when the STC PPP client does not negotiate a Magic Number, the client LCP stays. That is no term-req is sent and echo-req are replied to.

Answer:

N/A

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