Running FAX over VOIP

[msu147mbu369]

I have 2 cisco 1760 routers with FXS and FXO card installed in each. I have to transport 2 PSTN lines from Head Office to remote loaction using FXS and FXO cards and these lines will be used for  voice calls and FAX( one line each for FAX and voice). I have configured the router for voice lines and it is working fine. Now I am using the same config for running fax machine but it is not working. Can anyone help me out how to configure FAX in this scenario also if anyone can share any sample config. I am attaching my config for both routers. Right now both routers are connected with a cross-over cable for lab test but we will connect them later using satellite connection.

HO Router (FXO card)

Current configuration : 1718 bytes
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
enable password cisco
!
no aaa new-model
!
resource policy
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
voice-card 2
!
voice-card 3
!
ip subnet-zero
ip cef
!
!
no ip dhcp use vrf connected
!
!
no ip domain lookup
no ftp-server write-enable
!
!
!
!
voice class codec 10
!
!
!
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
 ip address 10.10.10.1 255.255.255.248
 speed auto
 h323-gateway voip bind srcaddr 10.10.10.1
!
ip classless
!
no ip http server
!
!
control-plane
!
!
!
voice-port 2/0
 output attenuation 0
 echo-cancel coverage 32
 no vad
 no comfort-noise
 timeouts interdigit 3
 timeouts call-disconnect 3
 connection plar opx 2001
 description Remote PSTN#:35296913
 music-threshold -70
!
voice-port 2/1
 output attenuation 0
 echo-cancel coverage 32
 no vad
 no comfort-noise
 timeouts interdigit 3
 timeouts call-disconnect 3
 connection plar opx 2002
 description Remote PSTN#:35296914
 music-threshold -70
!
voice-port 3/0
!
voice-port 3/1
!
!
!
!
!
!
dial-peer voice 2000 voip
 destination-pattern 200.
 no modem passthrough
 voice-class codec 10
 session target ipv4:10.10.10.2
 incoming called-number .
 dtmf-relay cisco-rtp h245-signal h245-alphanumeric
 fax-relay ecm disable
 fax rate 7200
 fax nsf 000000
 no vad
!
dial-peer voice 1321 pots
 description line 1
 huntstop
 destination-pattern 1321
 port 2/0
!
dial-peer voice 1322 pots
 description line 2
 huntstop
 destination-pattern 1322
 port 2/1
!
!
line con 0
 password cisco
line aux 0
line vty 0 4
 password cisco
 login
!
end

Remote Router (FXS Card):

version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
enable password cisco
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
voice-card 2
!
voice-card 3
!
no aaa new-model
ip subnet-zero
ip cef
!
!
!
!
no ip domain lookup
no ftp-server write-enable
!
!
!
!
voice class codec 10
!
!
!
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
 ip address 10.10.10.2 255.255.255.248
 speed auto
 h323-gateway voip bind srcaddr 10.10.10.2
!
interface Ethernet1/0
 no ip address
 shutdown
 half-duplex
!
ip classless
no ip http server
!
!
!
control-plane
!
!
!
voice-port 2/0
 description PSTN#:
!
voice-port 2/1
 description PSTN#:
!
voice-port 3/0
!
voice-port 3/1
!
!
!
!
!
dial-peer voice 2001 pots
 description Remote
 huntstop
 destination-pattern 2001
 port 2/0
!
dial-peer voice 2002 pots
 description Remote
 huntstop
 destination-pattern 2002
 port 2/1
!
dial-peer voice 1320 voip
 destination-pattern 132.
 no modem passthrough
 voice-class codec 10
 session target ipv4:10.10.10.1
 incoming called-number .
 dtmf-relay cisco-rtp h245-signal h245-alphanumeric
 fax-relay ecm disable
 fax rate 7200
 fax nsf 000000
 no vad
!
!
line con 0
 password cisco
line aux 0
line vty 0 4
 password cisco
 login
!
end

[mohammed asif suleman]

we are running fax machine on one of our remote site on fxs port but the outbound line is sip,

so i think it is not much helpful to share my full config... but i am giving the fxs port config pretty much same as yours, but the ext number you assigned to fax machine might causing the issue,

try to provide the full number instead of extension

dial-peer voice 100 pots
 description " local Inbound Fax"
 destination-pattern XXXXXXX
 port 0/2/0

dial-peer voice 103 voip
 description (for incoming FAX)
 incoming called-number .
 voice-class codec 1  
 fax-relay sg3-to-g3
 no vad

for out bound faxes it uses the dial-peers configured for voice calls...

[msu147mbu369]

I have tried my config by connecting routers with cross-over cable in lab and fax works perfect. Now trying on satellite link but it is not working(latency is approximately 1200 ms). My local ISP' has  blocked voice ports so unable to check fax on normal internet . Someone told me to use SIP configuration and it will work. It will be helpful if anyone can share SIP configuration for this scenario. Also let me know if there is any way I can defined ports for target IP's in my current configuration?

I tried your suggested config but was unable to execute command fax-relay sg3-to-g3  on my router. Kindly share your suggestions to resolve this issue.

[mohammed asif suleman]

if thats working in your lab, then it should work with your voice lines also, if not please speak to your telco,there is no difference in voice and fax lines

i suggest you to upgrade your router firmware to work the sg3 fax command

collect the debugs when the fax call fails

#debug voice ccapi inout

i think you should have sip line to work the sip configuration, anyway i am giving the sip conf here

dial-peer voice 9 voip
 description "local Inbound Fax"
 session protocol sipv2
 session target ipv4:xxx.xxx.xxx.xxx
 incoming called-number [fax number]
 voice-class sip bind control source-interface FastEthernet0/0
 voice-class sip bind media source-interface FastEthernet0/0
 codec g711alaw
 no vad

dial-peer voice 10 voip
 description ***Out Going***
 translation-profile outgoing OUT-SIP
 destination-pattern .T
 progress_ind progress enable 8
 rtp payload-type nte 98
 session protocol sipv2
 session target ipv4:xxx.xxx.xxx.xxx:5060
 session transport udp
 voice-class codec 1  
 voice-class sip bind control source-interface FastEthernet0/0
 voice-class sip bind media source-interface FastEthernet0/0
 dtmf-relay rtp-nte
 no vad

define voice calss codecs before applying to dial-peers

voice class codec 1
 codec preference 1 g711ulaw
 codec preference 2 g711alaw
 codec preference 3 g729r8
 codec preference 4 g729br8

define appropriate translation-rules and translation-profile accordingly

[msu147mbu369]

Many thanks for your continuous support. Today I have made a little change in previous configuration and has enabled following  command  on both FXS and FXO. This time my FXO card router is on fiber while FXS card router is on VSAT internet link. I am now able to receive fax on my fax machine connected to router but still unable to send fax. 

modem passthrough nse codec g711ulaw

 fax rate disable

Can you share config to use T.38 Fax relay? During fax call on checking voice call status it shows voice call but we receive error on fax machines like no fax detected, busy, no answer e.t.c