MG-IP TDM Over IP Gateway Reference Manual
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At the TSP TX, several conflicting framed policy instructions may occur. For example, a packet
received with the L bit set while in LOPS state, packets can be received with the L and R bits set, etc.
Operation hierarchy is determined in the following order:
1.
FramedLOPSpolicy
2.
FramedLbitPolicy
3.
FramedRbitPolicy
4.
FramedRDbitPolicy
This hierarchy is set to make sure that operations on the TSP TX will be consistent and will not
fluctuate. In particular, while in the LOPS state, occasional receipt of a packet with the L bit or the R
bit set should not change the indication on the wire.
Conflicts between AIS and RAI IWF indications and RAI detected by the framer due to an incoming
defect on the T1/E1 are determined according to the standard TDM (framer) behavior, as per the
following priority:
1.
AIS
2.
RAI
3.
Idle pattern
This hierarchy is also applicable when two or more sessions introduce conflicting policies on the
outgoing T1/E1 circuit. In particular, configuration of AIS on the entire T1/E1 should not be set as a
policy when more than one CESoPSN pseudowire is aggregated to the same trunk.
Application Signaling
When Out of Stream CAS signaling is used with structure-aware emulation, care must be taken in
handling application signaling during error conditions as shown below:
Application signaling must be frozen to the peer IWF once the local TDM interface indicates
any of the following defects:
LOS
OOF
AIS
The idle signaling pattern should be sent to the peer IWF when any of the following failures persist:
LOS
LOF
AIS
LOMF
The idle signaling pattern should also be sent locally to the TSP TX when the IWF RX detects that
packets for a particular pseudowire are received with the L, R or M bits set and the corresponding
policy is set to “channel idle”.
The idle signaling pattern should also be sent locally to the TSP TX when the IWF RX has entered the
LOPS state for a particular pseudowire and the LOPS policy is set to “channel idle”.
The idle signaling pattern is defined in the parameter SigIdle.