my lwip stats look like these when the lwip_write() hangs
LINK
xmit: 12010
recv: 6679
fw: 0
drop: 0
chkerr: 0
lenerr: 0
memerr: 0
rterr: 0
proterr: 0
opterr: 0
err: 0
cachehit: 0
ETHARP
xmit: 3
recv: 9
fw: 0
drop: 0
chkerr: 0
lenerr: 0
memerr: 0
rterr: 0
proterr: 0
opterr: 0
err: 0
cachehit: 12001
IP
xmit: 12006
recv: 6670
fw: 0
drop: 0
chkerr: 0
lenerr: 0
memerr: 0
rterr: 0
proterr: 0
opterr: 0
err: 0
cachehit: 0
ICMP
xmit: 1
recv: 1
fw: 0
drop: 0
chkerr: 0
lenerr: 0
memerr: 0
rterr: 0
proterr: 0
opterr: 0
err: 0
cachehit: 0
UDP
xmit: 2
recv: 5
fw: 0
drop: 0
chkerr: 0
lenerr: 0
memerr: 0
rterr: 0
proterr: 0
opterr: 0
err: 0
cachehit: 0
TCP
xmit: 12002
recv: 6664
fw: 0
drop: 0
chkerr: 0
lenerr: 0
memerr: 0
rterr: 0
proterr: 0
opterr: 0
err: 0
cachehit: 0
MEM RAW_PCB
avail: 10
used: 0
max: 0
err: 0
MEM UDP_PCB
avail: 5
used: 1
max: 1
err: 0
MEM TCP_PCB
avail: 16
used: 0
max: 1
err: 0
MEM TCP_PCB_LISTEN
avail: 16
used: 2
max: 2
err: 0
MEM TCP_SEG
avail: 16
used: 0
max: 3
err: 0
MEM NETBUF
avail: 16
used: 0
max: 0
err: 0
MEM NETCONN
avail: 16
used: 2
max: 3
err: 0
MEM TCPIP_MSG_API
avail: 8
used: 0
max: 1
err: 0
MEM TCPIP_MSG_INPKT
avail: 128
used: 0
max: 3
err: 0
MEM SYS_TIMEOUT
avail: 8
used: 3
max: 4
err: 0
MEM PBUF_REF/ROM
avail: 64
used: 0
max: 0
err: 0
MEM PBUF_POOL
avail: 128
used: 0
max: 3
err: 0
SYS
sem.used: 0
sem.max: 0
sem.err: 0
mutex.used: 0
mutex.max: 0
mutex.err: 0
mbox.used: 0
mbox.max: 0
mbox.err: 0
Ok.
So it doesn't look like any of my pools are running out of space.
Alhad