In this protection scheme, a protection device, Card or Equipment, is paired with a working Card or Equipment in the same shelf. The type of card or equipment and the number of ports in the protection device must be the same as that of the working device that it protects. The ports on the protection device must match the ports on the working device. For example, port 2 on an OC-12/STM-4 working card is protected by port 2 on the OC-12/STM-4 protection card. In this scheme, any of the ports on the protection card or equipment can be assigned to protect the ports on the working device, while other ports on the working card or equipment can remain unprotected.

1+1 protection shows 1+1 protection.

Figure 1. 1+1 protection

1+1 protection is implemented using the CardProtectionGroup object which have a ComposedOf/PartOfEquipmentProtectionGroup relationship to Card or Equipment objects.