Lexmark IBM 9077 - Manual (Page 214)

196 IBM 9077 SP Switch Router: Get Connected to the SP Switch
Figure 63 shows the IP traffic flow when issuing ping 192.168.13.1 on node 8
in SP21. All packets are first forwarded to the SP Switch Adapter card with IP
address 192.168.14.129 corresponding to the routing settings. From this SP
Switch Adapter card all packets are forwarded via HIPPI connection to the
only SP Switch Adapter card in GRF 400, which forwards the traffic to node 1
in SP2. The way back follows first the same route. The internal logic of the
GRF 1600 determines that the SP Switch Adapter card with IP address
192.168.14.129 is not able to deliver received packets back to node 8
because their IP address is in another subnet. So GRF 1600 uses the SP
Switch Adapter card with IP address 192.168.14.4 to forward the IP traffic to
node 8, because this is the only way to IP address 192.168.14.8.
Figure 63. IP Traffic Flow When Issuing ping 192.168.13.1 on Node 8
5.2.3 Recovery Procedure for an SP Switch Adapter Card Failure
What happens, when one of the SP Switch Adapter cards fails? A detailed
look at Figure 61, Figure 62 and Figure 63 gives an answer:
1. When the SP Switch Adapter card with IP address 192.168.14.4 fails,
neither node 6 nor node 8 can communicate with node 1 in SP2. Node 10
is not interrupted.
2. When the SP Switch Adapter card with IP address 192.168.14.129 fails,
neither node 10 nor node 8 can communicate with node 1 in SP2. Node 6
is not interrupted.
Note: Node 8 is always affected, independent of the failing SP Switch
Adapter card. Try to avoid routing settings that need both SP Switch Adapter
cards for proper functioning.
192.168.13.1
255.255.255.0
192.168.14.129
255.255.255.128
node 1 node 8
SP Switch
Adapter
SP Switch
Adapter
SP Switch
Adapter
HIPPI HIPPI
GRF 400 GRF 1600
SP Sw
it
c
h
SP
Sw
it
c
h
192.168.14.4
255.255.255.128
192.168.14.8
255.255.255.0