Lexmark IBM 9077 ATM OC-3c Backbone Using Two Ports, SP Switch ATM Bridged SP Switch Connection

Performance:

To get a rough overview of the data transfer rates that can be achieved in this scenario, the following test was performed:

1.We used ftp to conduct several file transfers of a 300 MB file from the nodes in SP2 to one chosen node in SP21, and at the same time used ftp to conduct several file transfers of a 300 MB file from the nodes in SP21 to a chosen node in SP2. We sent the files to /dev/null on the receiving node to eliminate any hard disk influence.

We saw up to about 14.5 MB/s with just one side sending data; with all nodes sending and receiving, we achieved an duplex throughput of about 24 MB/s on the ATM port.

So it just might turn out that one 155 Mbit ATM port is not enough for a performance connection between two SP systems.

7.1.2 ATM OC-3c Backbone - Using Two Ports

This setup is basically the same as using just one port of the ATM card, as described in Section 7.1.1, “ATM OC-3c Backbone - Using One Port” on page

210.To avoid the difficulties regarding the need of different (sub)networks on the two ports, we decided to use the GRF bridging implementation as described in GRF Configuration Guide 1.4, GA22-7366. See Figure 69 and Table 24 on page 216 for the illustration of the new scenario.

	SP		Net 192.168.13.0
Net 10.1.1.2	Switch
ATM OC-3c	Router 1	IP 192.168.13.4	SP processor node
Adapter card		SP Switch Router	SP Switch 1
		Adapter card 1	SP2
		Mask 255.255.255.0
	GRF 400		SP processor node
			Mask 255.255.255.0
	SP		Net 192.168.14.0
Net 10.1.1.1	Switch
	Router 2	IP 192.168.14.4	SP processor node
ATM OC-3c			SP Switch 2
Adapter card		SP Switch Router
		Adapter card 2	SP21
		Mask 255.255.255.0
			SP processor node
	GRF 1600

Figure 69. SP Switch - ATM Bridged - SP Switch Connection

Multiple RS/6000 SPs and Multiple GRFs 215