In a PW APS scenario, a PW protection group consists of primary and secondary PWs. The PWs can be either SS-PWs or MS-PWs.
In the PW APS scenarios shown in Figure 1 and Figure 2, a PW protection group is created between PE1 and PE2. The PWs can be either SS-PWs or MS-PWs. When configuring PW redundancy, note the following guidelines:
A static or hybrid MS-PW cannot obtain the TTL value through dynamic negotiation. To ensure the correct forwarding of PW APS negotiation packets between the endpoint PEs of an MS-PW, run the mpls l2vpn pw-ttl ttl-value [ secondary | bypass ] command to configure a TTL value, so that the PW APS mechanism knows the specific number of PW segments.
In the case of SS-PWs, configure the primary and secondary PWs on the endpoint PEs.
In the case of MS-PWs, configure the primary and secondary PWs on the endpoint PEs and configure VPWS switching on the SPEs.
The types of PWs within the same protection group must be the same, and the PW types on the two endpoints of a PW segment must also be the same.
When configuring a PW protection group, ensure that parameter settings for the primary and secondary PWs are consistent. If inconsistencies exist, the secondary PW may fail to take over traffic if the primary PW fails.
Configure a PW protection group that consists of the primary and secondary PWs on PE1 and PE2. In the case of MS-PWs, you also need to configure VPWS switching on SPE1 and SPE2.
Perform the following steps on PE1 and PE2 to configure static PWs.
Perform the following steps on PE1 and PE2 to configure dynamic PWs:
In the case of MS-PWs, perform the following steps on each SPE.