Use the BUFFERS statement to specify the parameters used to allocate buffer pools for storing IP datagrams.
Syntax
>>-BUFFERS--max_packet_size--+------------------+---------------> '-add_send_buffers-' >--+------------------+---------------------------------------->< '-send_queue_limit-'
Parameters
- max_packet_size
- The maximum IP packet size. This value should match the max_packet_size parameter
on the BEGINROUTES or GATEWAY statement in the PROFILE.TCPIP data
set and it must be less than the maximum path information unit (PIU)
in the VTAM® definition for
your LU6.2 connection. The maximum PIU is set by the MAXDATA parameter
of the PCCU macro that is part of the NCP generation program in the
VTAMLST library. The value for this parameter differs for each device.
Check the documentation for your device to determine the appropriate
value.
The max_packet_size value must be an integer in the range 20 - 32 758. Any datagrams exceeding this length that are received from either the local or remote TCP⁄IP are discarded.
- add_send_buffers
- The number of additional buffers for storing datagrams waiting to be passed to VTAM. These are in addition to the initial allocation of one for every destination (DEST) defined in the SNALINK LU6.2 configuration data set. If an add_send_buffers value is not specified, no additional buffers are allocated. The minimum value allowed for add_send_buffers is 1; the maximum value allowed is 2 147 483 647.
- send_queue_limit
- The maximum number of buffers that can be allocated to any connection for storing datagrams waiting to be passed to VTAM. This parameter allows you to prevent a single connection from restricting other connections' access to the free buffers from the VTAM send buffer pool. Once this maximum limit is reached on the VTAM send queue, further datagrams received from TCP/IP for this connection are discarded, until the number of buffers on the send queue is reduced below the limit. For this parameter to be effective, its value should leave enough free buffers in the VTAM send buffer pool to service the other active connections when full throughput is reached on the main connections. See the description of the add_send_buffers parameter to calculate the size of the VTAM send buffer pool. If a send_queue_limit value is not specified, no limit is placed on the lengths of individual send queues. The minimum value allowed for send_queue_limit is 1; the maximum value allowed is 2 147 483 647.
Examples
*-- Buffer specifications:
*
* Datagram Add Snd Snd Queue
* Max Size Buffers Limit
* ----- ----- -----
BUFFERS 32758 10 11
*