Basler raL2048-48gm Manuel d'utilisateur télécharger pdf (Page 39)

AW00118302000 Basler Network Drivers and Parameters

Basler racer GigE 29

Resend Request Threshold - This parameter determines the location of the resend request

threshold within the receive window as shown in Fig. 7. The parameter value is in per cent of the

width of the receive window. In Fig. 7 the resend request threshold is set at 33.33% of the width of

the receive window.

A stream of packets advances packet by packet beyond the resend request threshold (i.e. to the

left of the resend request threshold in Fig. 7). As soon as the position where a packet is missing

advances beyond the resend request threshold, a resend request is sent for the missing packet.

In the example shown in Fig. 7, packets 987 to 1005 are within the receive window and packets 997

to 999 and 1002 were detected as missing. In the situation shown, a resend request is sent to the

camera for each of the missing consecutive packets 997 to 999. The resend requests are sent after

packet 996 - the last packet of the intact sequence of packets - has advanced beyond the resend

request threshold and before packet 1000 - the next packet in the stream of packets - can advance

beyond the resend request threshold. Similarly, a resend request will be sent for missing packet

1002 after packet 1001 has advanced beyond the resend request threshold and before packet 1003

can advance beyond the resend request threshold.

Resend Request Batching - This parameter determines the location of the resend request

batching threshold in the receive window (Fig. 7). The parameter value is in per cent of a span that

starts with the resend request threshold and ends with the front end of the receive window. The

maximum allowed parameter value is 100. In Fig. 7 the resend request batching threshold is set at

80% of the span.

The resend request batching threshold relates to consecutive missing packets, i.e., to a continuous

sequence of missing packets. Resend request batching allows grouping of consecutive missing

packets for a single resend request rather than sending a sequence of resend requests where each

resend request relates to just one missing packet.

The location of the resend request batching threshold determines the maximum number of

consecutive missing packets that can be grouped together for a single resend request. The

maximum number corresponds to the number of packets that fit into the span between the resend

request threshold and the resend request batching threshold plus one.

If the Resend Request Batching parameter is set to 0, no batching will occur and a resend request

will be sent for each single missing packet. For other settings, consider an example: Suppose the

Resend Request Batching parameter is set to 80 referring to a span between the resend request

threshold and the front end of the receive window that can hold five packets (Fig. 7). In this case 4

packets (5 x 80%) will fit into the span between the resend request threshold and the resend

request batching threshold. Accordingly, the maximum number of consecutive missing packets that

can be batched is 5 (4 + 1).

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Basler raL2048-48gm Manuel d'utilisateur Page 39