PM7340-PI datasheet(84/334 Pages) PMC

84 / 334 page

PRELIMINARY

INVERSE MULTIPLEXING OVER ATM

PM7340 S/UNI-IMA-8

DATA SHEET

PMC-2001723

ISSUE 3

INVERSE MULTIPLEXING OVER ATM

PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE

Figure 19

- IMA Error/Maintenance State Diagram

IMA

Working State

Out of IMA

Frame (OIF)

Anomaly

State

LIF

Defect

Leaving IMA

Sync state

Entering IMA

Sync state

Persistence of non-IMA Sync

(γ+2) IMA frames

Persistence of IMA SYNC for at least 2 IMA frames

The IMA Working state enables the RDAT to write user cells to the DCB. If the

IFSM leaves the IMA Sync state, the IESM state machine will transition to the

OIF Anomaly state, and the OIF anomaly counter will be incremented.

In the OIF Anomaly state, incoming user cells are written as filler cells to the

DCB, and write pointers are incremented. If the IFSM does not return to the IMA

Sync state within gamma + 2 frames, the IESM state will transition to the LIF

Defect state. (Gamma is programmable, and is the same gamma used in the

IFSM). If the IMA Sync state is entered prior to gamma + 2 frames, the IESM

state will transition back to the IMA Working State. This is considered a “fast

recovery” from the OIF Anomaly.

In the LIF Defect state, incoming user cells are written as filler cells to the DCB,

and write pointers are incremented. The LIF-latched status bit will be set in the

link-context memory. The IESM state machine will transition to the IMA Working

state when IMA Sync has been detected for two consecutive IMA frames. If the

IMA Sync state is entered and then exited during LIF, then the OIF anomaly

counter will be incremented. When the IESM enters the working state, user cells

may be forwarded once again if an overrun (with respect to the configured depth

for the link) is not detected. The overrun detection provides the necessary

differential-delay checking required after a defect.

10.2.4.3.2

Loss of Cell Delineation Status (LCD)

LCD is detected by the TC layer and the information is passed to the RDAT.

When a link is in LCD, a LCD-latched status bit is set in link context memory,

PM7340-PI Datasheet(PDF) 84 Page - PMC-Sierra, Inc

PM7340-PI Datasheet(HTML) 84 Page - PMC-Sierra, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL