Specifications

Cisco ONS 15327 Product Overview
Card Protection
10
Cisco ONS 15327 Product Overview, R3.3
June 2002
Figure 13 Ethernet card faceplate
Card Protection
The ONS 15327 provides 1:1 electrical protection and 1+1 optical protection
methods. 1:1 electrical protection is pre-provisioned for DS-1 and DS-3 traffic;
therefore, only optical cards can operate unprotected. This section describes the
protection options and explains protection switching in the ONS 15327. For a
description of Ethernet card protection, see the “Spanning Tree Protocol” section
on page 29.
Electrical Protection
Both XTC cards provide circuitry and electrical protection for DS-1 circuits, but
only the XTC-28-3 card provides circuitry and electrical protection for DS-3
circuits. On the ONS 15327, DS-N circuits are automatically protected by a 1:1
protection group, named XTCPROTGRP, which you cannot edit or delete. In 1:1
protection, a working card is paired with an adjacent protect card of the same type,
which for the ONS 15327 is two XTC-14 cards (DS-1 circuits protected) or two
XTC-28-14 cards (DS-1 and DS-3 circuits protected). If the working card fails,
the traffic from the working card switches to the protect card. Electrical protection
in the ONS 15327 is non-revertive.
Optical Card Protection
The ONS 15327 supports 1+1 protection to create redundancy for optical cards.
With 1+1 protection, one optical port can protect another optical port; therefore,
in any two high-speed slots a single working card and a single dedicated protect
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