Dropped calls, maybe network issue. need advice

I have been having dropped calls at a number of sites with asterisk 1.4.22-3

I have looked at my zap config but then experienced a dropped call over a sip trunk.

So I broke out wireshark because networks can be funky. I notice that my SIP phones tend to re-register every few minutes. My asterisk system also has bad checksums on UDP packets comming from the system.

should my phones be registering so often?

Also, the registrations seem to be grouped together somewhat. I would think that if this was a normal thing, the registrations would not be in tight groupings. Instead it looks like some sort of network hickup is causing them all to loose their connections for a split second and then re-register because of it.

Anyone have any ideas or advice?

I am loosing 75% of calls to this issue.

Thanks in advance

(by the way, this is a centos 5 system with trixbox ce 2.6.2)

I have some identical hardware at all of my shops.

All sites have Optiplex 360 that have a network card that reads as:
eth0: Tigon3 [partno(BCM95784M) rev 5784100 PHY(5784)] (PCI Express) 10/100/1000Base-T Ethernet 00:23:ae:7a:8d:f3
eth0: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[0] WireSpeed[1] TSOcap[1]
eth0: dma_rwctrl[76180000] dma_mask[64-bit]

I also us NETGEAR FS726TP switches which are 100 speed PoE switches.

thanks again in advance for any help.

[quote]I also us NETGEAR FS726TP switches which are 100 speed PoE switches.

how many of the ports have a phone connected and powered?


at one site i only have 5 phonea (aastra 53i) and am no where near the per port or total max draw.