The SetForwardBufferMemory method is used to specify how much memory IP allocates to store packet data in the router packet ...

The SetForwardBufferMemory method is used to specify how much memory IP allocates to store packet data in the router packet queue. When this buffer space is filled, the router begins discarding packets at random from its queue. Packet queue data buffers are 256 bytes in length, so the value of this parameter should be a multiple of 256. Multiple buffers are chained together for larger packets. The IP header for a packet is stored separately. This parameter is ignored and no buffers are allocated if the IP router is not enabled. The buffer size can range from the network MTU to the a value smaller than 0xFFFFFFFF. Default: 74240 (fifty 1480-byte packets, rounded to a multiple of 256).The method returns an integer value that can be interpretted as follows: 
0 - Successful completion, no reboot required
1 - Successful completion, reboot required
64 - Method not supported on this platform
65 - Unknown failure
66 - Invalid subnet mask
67 - An error occurred while processing an Instance that was returned
68 - Invalid input parameter
69 - More than 5 gateways specified
70 - Invalid IP  address
71 - Invalid gateway IP address
72 - An error occurred while accessing the Registry for the requested information
73 - Invalid domain name
74 - Invalid host name
75 - No primary/secondary WINS server defined
76 - Invalid file
77 - Invalid system path
78 - File copy failed
79 - Invalid security parameter
80 - Unable to configure TCP/IP service
81 - Unable to configure DHCP service
82 - Unable to renew DHCP lease
83 - Unable to release DHCP lease
84 - IP not enabled on adapter
85 - IPX not enabled on adapter
86 - Frame/network number bounds error
87 - Invalid frame type
88 - Invalid network number
89 - Duplicate network number
90 - Parameter out of bounds
91 - Access denied
92 - Out of memory
93 - Already exists
94 - Path, file or object not found
95 - Unable to notify service
96 - Unable to notify DNS service
97 - Interface not configurable
98 - Not all DHCP leases could be released/renewed
100 - DHCP not enabled on adapter
Other - For integer values other than those listed above, refer to Win32 error code documentation.