How the "netusage" parameter affects backup performance

When backing up data and getting very slow transfer rate between server and client despite the fast network connection its important to look at the server and client network stats:

Server:

Ifconfig (errors:6 dropped:12 overruns:6) shows network congestion):

[root@bugs ~]# ifconfig -a eth0
eth0      Link encap:Ethernet  HWaddr 00:30:48:76:B8:EC
         inet addr:192.168.10.10  Bcast:192.168.10.255  Mask:255.255.255.0
         inet6 addr: fe80::230:48ff:fe76:b8ec/64 Scope:Link
         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
         RX packets:44088695 errors:6 dropped:12 overruns:6 frame:0
         TX packets:27228292 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:1000
         RX bytes:2059358934 (1.9 GiB)  TX bytes:2541857653 (2.3 GiB)
         Base address:0xa800 Memory:f2000000-f2020000

Iptraf (amanda server is limiting how much data can be trasfered to it from the client):

eth0         3416410   3416410         0        0  59822.20 kbits/secc

Client:

Ifconfig (errors:10 dropped:0 overruns:10 frame:10) shows network congestion:

bash-3.00# ifconfig -a eth0
eth0      Link encap:Ethernet  HWaddr 00:15:F2:92:F8:54
         inet addr:192.168.10.111  Bcast:192.168.10.255  Mask:255.255.255.0
         inet6 addr: fe80::215:f2ff:fe92:f854/64 Scope:Link
         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
         RX packets:25108061 errors:10 dropped:0 overruns:10 frame:10
         TX packets:31648975 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:1000
         RX bytes:1278188716 (1.1 GiB)  TX bytes:1865504070 (1.7 GiB)
         Interrupt:11 Memory:feafc000-0

bash-3.00#

Iptraf (amanda client is sending data faster then server allows to recieve):

eth0         4529880   4529880         0        0  88353.20 kbits/secc

The solution to this problem is to increase the netusage parameter in advanced.conf: