Gteetings!

Polycom and Tandberg video session disconnected after 2 hours and after reconnection it works fine during next 2 hours. please help me to fix this problem

I read a lot of posts about timeouts but it doesnt help.

I have ASA 5510 sec. plus license, Cisco Adaptive Security Appliance Software Version 8.2(3)

Polycom and Tadbberg via VLAN going through asa to the internet, because they located in different rooms and has a non-routable in internet IP.

here is some configuration:

Polycom and tandberg has IP from this subnet:

VSX7000_LOCAL_IP - local ip of polycom

TANDBERG_LOCAL_IP - local ip of tandberg

interface Ethernet0/2.993
vlan 993
nameif pubsvc
security-level 20
ip address 172.16.6.193 255.255.255.224

timeout's config:

timeout xlate 3:00:00
timeout conn 5:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02
timeout sunrpc 0:10:00 h323 6:00:00 h225 6:00:00 mgcp 0:05:00 mgcp-pat 0:05:00
timeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00
timeout sip-provisional-media 0:02:00 uauth 0:00:00 absolute uauth 0:10:00 inactivity
timeout tcp-proxy-reassembly 0:01:00

traffic forwarding:

static (pubsvc,isp2) VSX7000_EXTERNAL_IP VSX7000_LOCAL_IP netmask 255.255.255.255
static (pubsvc,isp2) TANDBERG_EXTERNAL_IP TANDBERG_LOCAL_IP netmask 255.255.255.255

nat config:

nat (pubsvc) 5 VSX7000_LOCAL_IP 255.255.255.255

nat (pubsvc) 4 172.16.6.192 255.255.255.224

global (isp2) 4 TANDBERG_EXTERNAL_IP
global (isp2) 5 VSX7000_EXTERNAL_IP

h323 inspection in global policy:

policy-map global_policy
class inspection_default
//skip //

  inspect rtsp
  inspect skinny
  inspect sqlnet
  inspect sunrpc
// skip

  inspect h323 h225
  inspect h323 ras
  inspect ip-options
  inspect sip

ACL on isp2 interface. Object group ESH_VCS contain IP addresses of hosts that can call us:

access-list acl_in_isp2 extended permit ip object-group ESH_VCS host VSX7000_EXTERNAL_IP

access-list acl_in_isp2 extended permit ip object-group ESH_VCS host TANDBERG_EXTERNAL_IP

On tandberg and polycom i setup session time to 999 minutes. please help me to fix this problem