Intel AS/400 RISC Server HPR and Enterprise extender considerations, Speed = 10Mbps = 100Mbps

•FTS is a less efficient way to transfer data. However, it offers built in data compression for line speeds less than a given threshold. In some configurations, it will compress data when using LAN; this significantly slows down LAN transfers.

5.8 HPR and Enterprise extender considerations

Enterprise Extender is a protocol that allows the transmission of APPC data over IP only infrastructure. In System i support for Enterprise Extender is added in 5.4. The communications using Enterprise Extender protocol can be achieved by creating a special kind of APPC controller, with LINKTYPE parameter of *HPRIP.

Enterprise Extender (*HPRIP) APPC controllers are not attached to a specific line. Because of this, the controller uses the LDLCLNKSPD parameter to determine the initial link speed to the remote system. After a connection has been started, this speed is adjusted automatically, using the measured network values. However if the value of LDLCLNKSPD is too different to the real link speed value at the beginning, the initial connections will not be using optimally the network. A high value will cause too many packets to be dropped, and a low value will cause the system not to reach the real link speed for short bursts of data.

In a laboratory controlled environment with an isolated 100 Mbps Ethernet network, the following average response times were observed on the system (not including the time required to start a SNA session and allocate a conversation):

Table 5.9

Test Type	HPRIP Link	HPRIP Link Speed	AnyNet	LAN
	Speed = 10Mbps	= 100Mbps
Short Request	0.001 sec	0.001 sec	0.001 sec	0.001 sec
with echo
Short Request	0.001 sec	0.001 sec	0.003 sec	0.003 sec
64K Request	0.019 sec	0.010 sec	13 sec	2 sec
with echo
64K Request	0.019 sec	0.010 sec	5 sec	1 sec
1GB Request	6:14 min	6:08 min	7:22 min	6:04 min
with echo
1GB Request	2:32 min	2:17 min	3:33 min	3:00 min
Send File using	5:12 min	5:16 min	5:40 min	5:23 min
sndnetf (1GB)

The tests were done between two IBM System i5 (9406-820 and 9402-400) servers in an isolated network.

Allocation time refers to the time that it takes for the system to start a conversation to the remote system. The allocation time might be greater when a SNA session has not yet started to the remote system. Measured allocation speed times where of 14 ms, in HPRIP systems in average, while in AnyNet allocation times where of 41 ms in average.

The HPRIP controllers have slightly higher CPU usage than controllers that use a direct LAN attach. The CPU usage is similar to the one measured on AnyNet APPC controllers. On laboratory testing, a LAN transaction took 3 CPW, while HPRIP and AnyNet, both took 3.7 CPW.

IBM i 6.1 Performance Capabilities Reference - January/April/October 2008
© Copyright IBM Corp. 2008	Chapter 5 - Communications Performance	76