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Cisco ONS 15310-MA SDH Reference Manual, Release 9.1 and Release 9.2
78-19417-01
Chapter 3 Card Protection
ONS 15310-MA SDH Card and Port Protection
The configuration of the backplane connectors creates two sets of paired (adjacent) expansion slots for
electrical cards. Slots 1 and 2 are a pair and Slots 5 and 6 are a pair. When two electrical cards are
plugged into either of the card-slot pairs, the ONS 15310-MA SDH automatically creates a 1:1
protection group for the two cards, if possible.If a protection group cannot be created (see the rules for
protection group creation later in this section), one of the cards will be marked as UNKNOWN with the
state as MISMATCH in CTC, because the ONS 15310-MA SDH cannot support two unprotected
electrical cards in the 1–2 or 5–6 card slot pairs. The 1:1 automatic protection group is created when the
second electrical card in a pair is either plugged in or is preprovisioned.
Unprotected is the default state for the first electrical card plugged into (or preprovisioned) in either the
Slot 1-to-2 or Slot 5-to-6 card slot pairs. When the second card is plugged in or preprovisioned, the
protection group is created, if possible.
When protection groups are created, the following rules must be noted:
1. The protection group will be automatically created if possible. If the node cannot create the
protection group automatically, then the second card to be plugged in or preprovisioned will be
shown as UNKNOWN with the state as MISMATCH in CTC.
2. If possible, the ONS 15310-MA SDH designates the cards in Slots 1 and 5 as working. If Slot 1 or
5 cannot be working (due to violation of one of the other rules), then Slot 2 or 6 will be the working
slot.
3. Cards can protect like cards. In addition, an E1_63_E3_DS3_3 card can protect an
E1_21_E3_DS3_3 card. However, an E1_21_E3_DS3_3 card cannot protect an E1_63_E3_DS3_3
card.
4. If the first card to be provisioned has existing circuits or is in use as a timing source when the second
card is provisioned, then the first card must become the working card and cannot become the protect
card.
5. The timing source will not switch to a protect card, when a soft reset is executed on the card that is
used as a timing source.
6. Automatic protection groups default to nonrevertive. The protection group can be edited to turn on
reversion and set a revert time. The protection group can also be edited to change the protection
group name.
The following scenario does not result in the creation of a protection group because rules are violated:
1. Plug an E1_63_E3_DS3_3 card into Slot 1 and provision a circuit on it.
2. Plug an E1_21_E3_DS3_3 card into Slot 2.
The E1_63_E3_DS3_3 card needs to be the working card, because it has a circuit on it (see Rule 4).
However, the E1_21_E3_DS3_3 card cannot protect the E1_63_E3_DS3_3 card (see Rule 3), so no
protection group is formed.
The following scenario also does not result in the creation of a protection group because rules are
violated:
1. Plug an E1_21_E3_DS3_3 card into Slot 1 and enable the retiming option on it.
2. Plug an E1_63_E3_DS3_3 card into Slot 2.
Because the E1_63_E3_DS3_3 card does not support retiming, it cannot become a protection card for
the E1_21_E3_DS3_3 card, so no protection group is formed.
The following scenario results in the creation of a protection group because no rules are violated:
1. Plug an E1_21_E3_DS3_3card into Slot 1 and provision a circuit on it.
2. Plug an E1_63_E3_DS3_3 card into Slot 2.
