Nortel Networks NTRN10AN, 3500 manual 70Hardware feature descriptions

3-70Hardware feature descriptions

Alarm LED definitions

The following table lists the OC-48 STS interface circuit pack LEDs.

LED	Color	Description
Status (top)	Red	Circuit pack failure
	Yellow	Loss of signal
Status (bottom)	Green	In service and carrying traffic

Equipping rules

The OC-48 STS optical interface circuit pack can be installed in slots 3 through 12. See Table 3-3 on page 3-6for operational temperature ranges.

Note 1: Requires the shelf to be equipped with STX-192 circuit packs in slots 13 and 14.

Note 2: Supports STS managed connections only.

OC-48 protection switching

OC-48 traffic can be protected by 1+1 linear, or UPSR protection.

1+1 linear protection

OC-48 linear protection switching is 1+1 non-revertive, unidirectional or bidirectional. If a fiber cut occurs in either the receive or transmit fibers of the active fiber path, or the transmitter or receiver OC-48 optical interface circuit pack fails at either end of the active fiber span, traffic is switched from the active OC-48 transmitter or receiver to the standby OC-48 transmitter or receiver. Switching can also take place under user control.

In bidirectional protection switching, if traffic in one of the two directions is interrupted, traffic in both directions is switched to the protection line. In unidirectional protection switching, if traffic in one of the two directions is interrupted, only the interrupted traffic switches to the protection line; traffic in the uninterrupted direction remains on the working fiber. Both OC-48 interface circuit packs are active if f unidirectional switching occurs and one fiber fails.

The signal degrade threshold is user-provisionable for the working OC-48 facility of a 1+1 linear protected OC-48 pair. The default value is 10-6. The threshold is provisionable within the range 10-5to 10-9. If the bit error rate (BER) drops below the threshold, an autonomous protection switch occurs.

UPSR path protection

OC-48 path switching uses nonrevertive protection. There are no permanent STS-1 STS-3c, STS-12, STS-12c, STS24c or STS-48c protection or working paths. The network element receives two incoming STS-1, STS-3c, STS-12,

OPTera Metro 3500 Multiservice Platform NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004