Expand Configuration and Management Manual (G06.24+)

Expand Modifiers
Expand Configuration and Management Manual—523347-008
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L4CONGCTRL_OFF/L4CONGCTRL_ON
L4CONGCTRL_OFF/L4CONGCTRL_ON
Default: L4CONGCTRL_ON for Expand-over-IP and Expand-over-ATM lines
L4CONGCTRL_OFF for other line types and multi-line paths
Units: Not applicable
Range: ON or OFF
These path modifiers are applicable to all Expand line types. The L4CONGCTRL_ON
modifier enables the congestion control mechanism on the Expand node for sending
packets on a path. Congestion control mechanisms regulate system resources in order
to avoid network bottleneck and resource contention situations.
L4CONGCTRL is a path parameter and the path profile sets L4CONGCTRL_OFF
because it is shared by all line types. Therefore, multi-line IP paths default to
L4CONGCTRL_OFF and must specify L4CONGCTRL_ON.
The L4CONGCTRL_ON modifier is also recommended for Expand line-handler
processes that are part of a multi-CPU path.
You should read the description of the congestion control feature in Section 18,
Subsystem Description, before using this modifier.
L4EXTPACKETS_OFF/L4EXTPACKETS_ON
Default: L4EXTPACKETS_ON
Units: Not applicable
Range: ON or OFF
These path modifiers are applicable to all Expand line types. The
L4EXTPACKETS_ON modifier enables an extended packet header format of 64 bytes
for all lines in a path. The extended packet header format allows increased throughput
over high bandwidth and multi-line paths.
The L4EXTPACKETS_ON modifier is required for the variable packet size and
congestion control features and for Expand line-handler processes that are part of a
multi-CPU path. The L4EXTPACKETS_ON modifier is also required to support the
larger message size of 60K bytes. If the modifier is not set ON, the message size will
be 32K bytes.
The L4EXTPACKETS_OFF modifier specifies that the older 16-byte packet header
format should be used. It can be used to provide performance compatibility with lower-
speed lines.
L4RETRIES n
Default: 3
Units: Not applicable
Range: 3 through 255
This path modifier is applicable to all Expand line types. This modifier specifies the
number of times that the Expand line-handler process will try an end-to-end (Layer 4)