[U-Boot] Netboot Download times:: UDP vs TCP

[Duncan Hare]

Netboot Download times:
u-boot NFS command (using UDP), 4 GB Linux kernel download - 16:20:45 to 16:24:07, elapsed download time 3m38 sec

U-boot NFS download command.

TCP Dump extract

16:20:45.666179 IP (tos 0x0, ttl 253, id 25842, offset 0, flags [DF], proto UDP (17), length 136)
    192.168.1.129.1000 > 192.168.100.15.nfs: NFS request xid 8941 108 lookup fh Unknown/01000101000000009200400029B2975700000000000000000000000000000000 "kernel.img"
..
16:24:00.792228 IP (tos 0x0, ttl 253, id 29877, offset 0, flags [DF], proto UDP (17), length 88)
    192.168.1.129.1000 > 192.168.100.15.46033: [udp sum ok] UDP, length 60
16:24:00.793398 IP (tos 0x0, ttl 64, id 60314, offset 0, flags [DF], proto UDP (17), length 52)
    192.168.100.15.46033 > 192.168.1.129.1000: [bad udp cksum 0xe712 -> 0x2e62!] UDP, length 24
Copy same file between same machines, using NFS and TCP - 16:28:03 - 16:28:23, elapsed download time approx  20 secs, or possibly faster. 

16:28:03.848450 IP (tos 0x0, ttl 62, id 17722, offset 0, flags [DF], proto TCP (6), length 60)
    192.168.1.129.810 > 192.168.100.15.nfs: Flags [S], cksum 0x161c (correct), seq 1941867141, win 29200, options [mss 1400,sackOK,TS val 4294954943 ecr 0,nop,wscale 7], length 0..16:28:23.660278 IP (tos 0x0, ttl 62, id 46637, offset 0, flags [DF], proto TCP (6), length 52)
    192.168.1.129.860 > 192.168.100.15.nfs: Flags [.], cksum 0xc94b (correct), seq 1673, ack 4130701, win 7356, options [nop,nop,TS val 4294956923 ecr 215895745], length 0

Can the NFS command be enhanced to use TCP?

TCP open source code exists in linux.kernel.org, the "net" directory. Duncan Hare

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