Additional MAXFRAME parameter considerations

You need to base the maximum frame size on your iSeries™ system on the following values:

N203
Maximum frame size supported by the protocol or connection type
Maximum frame size supported by the remote station

Use the minimum of these values, minus the adjustment for the protocol header, to configure the MAXFRAME parameter for frame-relay connections. Table 1 shows the maximum frame size limits for supported connection types.

Table 1. Maximum frame size limits for connection types
Connection type	Maximum frame size (MAXFRAME parameter) limits
Systems Network Architecture (SNA) direct	8 182
IP direct	8 190
HPR	8 186
Bridged token-ring	8 148
Bridged DDI	4 444
Bridged Ethernet	1 496 for ETHSTD(IEEE8023) 1 500 for non-SNA data using ETHSTD(ETHV2) 1 493 for SNA data using ETHSTD(*ETHV2)
Note: At this time, the largest value allowed for the MAXFRAME parameter on the CRTLINFR command is 8182.

You can configure the maximum frame size used for a connection at several levels of the iSeries configuration:

Line description MAXFRAME parameter: Specify the maximum frame size used for an individual permanent virtual circuit (PVC) on the MAXFRAME parameter of the frame-relay, token-ring, or distributed data interface (DDI) line description.
You cannot configure the MAXFRAME parameter on Ethernet line descriptions. Ethernet local area networks (LANs) normally use a frame size of 1500 bytes. A N203 value of 1600 for Ethernet connections to accommodate the standard 1500-byte frame size is recommended. For a N203 value less than 1600, you need to configure the maximum frame size on either the line description source service access point (SSAP) parameter or the controller description.
Line description SSAP parameter: You can specify the maximum frame size for an individual SSAP for the maximum frame size element of the line description SSAP parameter.
Controller description MAXFRAME parameter: You can specify the maximum frame size for connections to individual remote stations on the controller description MAXFRAME parameter.

The iSeries system uses the smallest of the above values when selecting the maximum frame size used for connection to the remote station. For SNA connections, the system might also negotiate the frame size downward, based on the exchange identifier (XID) exchange with the remote station.