IBM SC41-5420-04 manual Outbound batching of TCP and UDP datagrams

v Checksum calculation of outgoing TCP and UPD datagrams (prior to V4R4)
v Checksum verification of incoming TCP and UPD datagrams (prior to V4R4)
v Outbound batching of TCP and UDP datagrams.
v Fragmentation of TCP and UDP datagrams into segments that match the MTU
	size.
v Starting with V4R2, iSeries collects all TCP datagrams in one batch and UDP
	datagrams in a second batch. Ports and IP addresses are ignored. Releases prior
	to V4R2 batch together datagrams at the IOP when these conditions are true:
	– The protocol (TCP or UDP) matches
	– The source and destination ports match
	– The source IP address and destination IP address match
	– They arrive consecutively into the IOP
	The IOP then passes the datagram batch to IP.
v Handling of IP and ICMP datagrams in error (unless IP NAT, which disables this
	function, is active)
v Resolving physical addresses using ARP protocol
These functions are called TCP/IP-assist functions. Whether these functions are done
by the IOP or the System Licensed Internal Code (SLIC), depends on the IOP type,
the OS/400 release, and the TCP/IP configuration. For details about specific
functions, contact your local service representative. TCP/IP-assist functions are
available on these IOPs:
v	#2617 Ethernet/IEEE 802.3 adapter/HP
v	#2619 16/4 Mbps Token-Ring Network adapter/HP
v #2618 Fiber distributed data interface adapter (FDDI)
v #2665 Shielded distributed data interface adapter (SDDI)
v #2666 High-speed communication adapter that is running frame relay only
v #2668 iSeries wireless LAN adapter
Note: You can get the same function without using one of the above IOP adapters
	(done instead at a higher level in the system (SLIC)). When you use the X.25
	protocol, you do not gain the advantage of the TCP/IP-assist function.

The TCP/IP-assist functions are also available on the following LAN IOAs and ATM IOAs:

v#2723 PCI Ethernet IOA

v#2724 PCI Token-Ring IOA

v#2838 PCI 100/10 Mbps Ethernet IOA

v#6149 16/4 Mbps Token-Ring IOA

v#2811 PCI 25 Mbps UTP ATM IOA

v#2812 PCI 45 Mbps Coax T3/DS3 ATM IOA

v#2813 PCI 155 Mbps MMF ATM IOA

v#2814 PCI 100 Mbps MMF ATM IOA

v#2815 PCI 155 Mbps UTP 0C3 ATM IOA

v#2816 PCI 155 Mbps MMF ATM IOA

v#2818 PCI 155 Mbps SMF 0C3 IOA

v#2819 PCI 34 Mbps Coax E3 ATM IOA

72OS/400 TCP/IP Configuration and Reference V5R1