Pseudowire Status for Static Pseudowires

Pseudowire Redundancy on the Switching Provider Edge (S-PE)

“…Note that when PW redundancy for MS-PW is provided on S-PE, the optional S-PE Bypass mode as defined in [RFC6478] MUST NOT be used; otherwise, the S-PE will not receive the PW status messages originated by T-PEs. This section specifies the operations of S-PEs on which PW redundancy is provisioned.…”

“…Consequently, the T-PE on the single-homed side MUST work in the Master mode, and the T-PEs on the multi-homed side MUST work in the Independent mode. The signaling of the Preferential Forwarding bit as defined in [RFC6870] and [RFC6478] is reused.…”

“…The scenario in which the S-PE has two multihomed sides is out of scope. Signaling of the Preferential Forwarding status as defined in [RFC6870] and [RFC6478] is reused. This document does not require any change to the T-PEs of MS-PW.…”

Media Access Control (MAC) Address Withdrawal over Static Pseudowire

“…In the case of a static PW, an LDP-based MAC withdrawal mechanism cannot be used. This is analogous to the problem and solution described in [RFC6478] where a PW OAM (Operations, Administration, and Maintenance) message has been introduced to carry the PW status TLV using the in-band PW Associated Channel. In this document, we use a PW OAM message to withdraw MAC address(es) learned via a static PW.…”

“…MAC Withdraw OAM Message LDP provides reliable packet transport for control plackets for dynamic PWs. This can be contrasted with static PWs that rely on retransmission and acknowledgments (ACKs) for reliable OAM packet delivery as described in [RFC6478]. The proposed solution for MAC withdrawal over a static PW also relies on retransmissions and ACKs.…”