NSE-8G™ Standard Product Data Sheet
Preliminary
Figure 9 Character Alignment State Machine
5-in-15 LCVs
out-of-
in-
character-
alignment
character-
alignment
Found C1FP Character
9.3.5
Frame Alignment
Frame alignment locates SBI or TelecomBus frame and multiframe boundaries in the incoming
8B/10B data stream. The frame alignment state machine may be in one of two states, in-frame-
alignment state and out-of-frame-alignment state. Each SBI336S frame is 125 µS in duration.
In SBI mode: Encoded over the SBI336S frame alignment is SBI336S multiframe alignment
which is every four SBI336S frames or 500 µS. When carrying DS0 traffic in synchronous mode,
signaling multiframe alignment is also necessary and is also encoded over SBI336S alignment.
Signaling multiframe alignment is every 24 frames for T1 links and every 16 frames for E1 links,
therefore signaling multiframe alignment covering both T1 and E1 multiframe alignment is every
48 SBI336S frames or 6ms. Therefore C1FP characters are sent every four or every 48 frames.
In TelecomBus mode: Encoded over the serial link is the tributary multiframe alignment which is
every 4 frames or 500 µS. Multiframe alignment is required so that a downstream device can
extract the T1 or E1 data from the tributary. The multiframe information is preserved by only
sending out C1FP characters every four frames.
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2010850, Issue 1
47
PMC [ PMC-SIERRA, INC ]
