Call drops after 20 seconds

[StaplesMan]

I have a Cisco Router 2651XM. It's setup with NAT. I have a single nat command to forward all ports to my Linksys spa2102. Tested and works. From the outside I can easily http into the configuration console of the SPA without any needed ip nat commands.

ip nat inside source static 192.168.xxx.xxx interface FastEthernet0/0

FA0/0 is set to DHCP and connected directly to cable modem and get's a public IP address.
192.168.xxx.xxx is the ip address of the SPA

Also have setup QOS.

I can receive calls without any problems. Very reliable. sound quality is top notch. Can even upload and download without any degradation in sound quality.

The only problem I seem to have is outbound calls last exactly 20 seconds and then the call is silent. (no incoming data)

I have VYL Media as my voip-sip provider.

Searched the internet all over and it seems others have the same issue. But can't find any real fix of what causes the problem.

There is an option in the SPA that allows it to send NAT keep alives. This is set to 10 seconds.

O and if I place the SPA before my router I have no VOIP problems at all. But if I put the SPA in NAT mode (to allow me to use only one IP address) my 10MBps speed his halted at around 6-8Mbps tops. If I place it in Switch mode I can get full 10Mbps (but this will require two public IP address).

I would prefer to get the SPA behind my Cisco router.


Any and all help would be welcome.

CCNA, A+, HP Certified Professional

 

[Sympology]

Common causes for this are.

RTP traffic not being detected due to prot translations.
Sometimes your RTP port 600x will get translated by the firewall to 10000 (STUN setting), therefore the one end belives it's RTP stream to have gone silent, so drops the call. See if there is are any disconnect on silience options in the SPA.
Often a firmware upgrade in either device can fix this isssue.

Robert Wilensky:
We've all heard that a million monkeys banging on a million typewriters will eventually reproduce the entire works of Shakespeare. Now, thanks to the Internet, we know this is not true.

 

[StaplesMan]

O good point. I have upgrade the firmware in the SPA and still have the same problem. Have not changed the firmware on the router. Will have to see if there is a newer version I can get.

But one other thing I did not note in my first post was that this also happens to my SoftPhone on my PC and to SipDroid on my android phone. If my phone is using my home network and home router it will also get dropped after 20 seconds. Same with the computer. But if I use my Verizon Data to and disconnect wifi on my phone and use the sipdroid on my phone it works without problem.



CCNA, A+, HP Certified Professional

 

[StaplesMan]

Update. I have upgraded the cisco IOS to the latest I could download. Still same issue.

CCNA, A+, HP Certified Professional

 

[StaplesMan]

Update. Switched my router noted above for a simple 1711 reset the config in it. It's now very basic with NAT ability. Same problem. I have included the config below.

Current configuration : 978 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
!
!
ip cef
!
!
!
!
!
multilink bundle-name authenticated
!
!
!
!
!
archive
log config
hidekeys
!
!
!
!
!
interface FastEthernet0
ip address dhcp
ip nat outside
ip virtual-reassembly
duplex auto
speed auto
!
interface FastEthernet1
!
interface FastEthernet2
!
interface FastEthernet3
!
interface FastEthernet4
!
interface Vlan1
ip address 192.168.78.2 255.255.255.0
ip nat inside
ip virtual-reassembly
!
interface Async1
no ip address
encapsulation slip
!
ip forward-protocol nd
!
!
no ip http server
no ip http secure-server
ip nat inside source list nat interface FastEthernet0 overload
!
ip access-list extended nat
permit ip any any
!
!
!
!
control-plane
!
!
line con 0
line 1
stopbits 1
speed 115200
flowcontrol hardware
line aux 0
line vty 0 4
login
!
end

CCNA, A+, HP Certified Professional