VoIP over 3G link

jennyjohn · ‎08-01-2011

We have a remote site which has a 3G router. The site is able to connect to the Head Office via 3G. We wanted to have couple of phones at the site. The phone is registering with the Call Manger@ HO. But the voice from the remote site takes atleast 4 - 5 seconds to reach the HO, while the HO office voice reaches instantly at the remote site. The phones are configured to using G729 codec. What could be the issue?

We have applied the below QoS for voice, is this correct?

class-map match-any VOICE

match access-group name VOICE

match ip rtp 16384 16383

match access-group name Signaling

!

policy-map VOICE

class VOICE

priority percent 80

class class-default

bandwidth percent 20

!

interface Cellular0/3/0

service-policy output VOICE

!

ip access-list extended Signaling

permit tcp any any eq 2000

permit tcp any eq 2000 any

permit udp any any eq 2000

permit udp any eq 2000 any

permit tcp any any eq 2001

permit tcp any eq 2001 any

ip access-list extended VOICE

permit ip 10.88.130.16 0.0.0.15 any

Cisco website says that they tested and were successful with 10 simultaneous call over the 3G connection.

Thanks in advance.

Marwan ALshawi · ‎08-01-2011

you are applly the signaling and RTP in the same class

you need to make it as bellwo fro example

class-map match-all VOICE

match access-group name VOICE

match ip rtp 16384 16383

class-map match-all SIG

match access-group name VOICE

match access-group name Signaling

!

policy-map VOICE

class VOICE

priority percent 75

class SIG

priority percent 5

class class-default

bandwidth percent 20

also what is your interface actual bandwidth you might need to shape it to the actual provided bandwidth to get your QoS policy kiikced in

see the bellow document for more details about this point

https://supportforums.cisco.com/docs/DOC-8373

HTH

if helpful Rate

jennyjohn · ‎08-04-2011

Thanks for the reply marwanshawi,

Its a 3G connection, so bandwidth varies based on signal strength and range. That is why we are using percent.

Marwan ALshawi · ‎08-04-2011

but you need to defiine a value so that your QoS policy will reference this value and consider your linke conjested or not otherwise you might not get the QoS policy kicked in

HTH

if helpful Rate