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Echo's with VOIP. Please Help!!!!

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tecknogeek

Technical User
Mar 31, 2006
22
Hello,
Our office to the north is getting an echo with our VOIP system. They connect to the main office router using the routers serial interface adapter. Both locations have a 1841 router and have autoQOS running. The North end connects via T1 to the main office 1841. I cant figure out why this is happening. Would some one please take a look at the config's from both routers see if this can be fixed within the config's. Thank you!

(North)
Current configuration : 2551 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Daphne_North
!
boot-start-marker
boot system flash:c1841-advipservicesk9-mz.124-5.bin
boot system tftp c1841-advipservicesk9-mz.124-5.bin 255.255.255.255
boot-end-marker
!
logging buffered 51200 warnings
enable password
!
no aaa new-model
!
resource policy
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
ip cef

ip domain name yourdomain.com
!
username password
!
class-map match-any AutoQoS-VoIP-RTP-Trust
match ip dscp ef
class-map match-any AutoQoS-VoIP-Control-Trust
match ip dscp cs3
match ip dscp af31
!
policy-map AutoQoS-Policy-Trust
class AutoQoS-VoIP-RTP-Trust
priority percent 70
class AutoQoS-VoIP-Control-Trust
bandwidth percent 5
class class-default
fair-queue
!
interface FastEthernet0/0
description ***To Netgear_FS726TP Port 1***
ip address 10.2.4.1 255.255.0.0
speed 100
full-duplex
!
interface FastEthernet0
no ip address
shutdown
duplex auto
speed auto
!
interface Serial0/0/0
description ***T1 to Daphne_MAIN***
ip address 10.10.10.2 255.255.255.252
auto qos voip trust
service-policy output AutoQoS-Policy-Trust
!
ip route 0.0.0.0 0.0.0.0 10.10.10.1
!
no ip http server
ip http authentication local
no ip http secure-server
ip http timeout-policy idle 5 life 86400 requests 10000
control-plane
!
rmon event 33333 log trap AutoQoS description "AutoQoS SNMP traps for Voice Drop s" owner AutoQoS

line con 0
login local
line aux 0
line vty 0 4
login local
length 0
transport input telnet
line vty 5 15
privilege level 15
login local
transport input telnet
!
end
Daphne_North#

-------------------------------------------------------
(Main)
Current configuration : 2449 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Daphne_Main
!
boot-start-marker
boot system flash:c1841-advipservicesk9-mz.124-5.bin
boot-end-marker
!
logging buffered 51200 warnings
enable password
!
no aaa new-model
!
resource policy
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
ip cef
!
username password
!
class-map match-any AutoQoS-VoIP-RTP-Trust
match ip dscp ef
class-map match-any AutoQoS-VoIP-Control-Trust
match ip dscp cs3
match ip dscp af31
!
policy-map AutoQoS-Policy-Trust
class AutoQoS-VoIP-RTP-Trust
priority percent 70
class AutoQoS-VoIP-Control-Trust
bandwidth percent 5
class class-default
fair-queue

interface FastEthernet0/0
description ***To Netgear_FS750T Port 48***
ip address 10.1.4.34 255.255.0.0
speed 100
full-duplex
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
interface Serial0/0/0
description ***T1 to DaphnePD_North***
ip address 10.10.10.1 255.255.255.252
auto qos voip trust
service-module t1 clock source internal
service-policy output AutoQoS-Policy-Trust
!
ip route 10.2.0.0 255.255.0.0 10.10.10.2
!
no ip http server
no ip http secure-server
!
control-plane
!
rmon event 33333 log trap AutoQoS description "AutoQoS SNMP traps for drop voice s" owner AutoQoS
!
line con 0
login local
line aux 0
line vty 0 4
login local
length 0
transport input telnet
line vty 5 15
privilege level 15
login local
transport input telnet
!
end

DaphnePD_Main#
 
..let me get this discussion started...

...wow, that is a lot of priority percent for voip..(70%).

...so your class map "class-map match-any AutoQoS-VoIP-RTP-Trust" is matching on "match ip dscp ef" and per the service policy is giving that match 70 percent priority on that serial interface outbound..

I forgot the qos stuff...does the voip packet come into that router from switch already set with ef value set?

...dont you have to match on that packet with access list or something?

...just throwing some ideas around...

...also...on cisco phones..and mitel..they have some type of anti echo configuration that helps..

....auto qos is good...manual qos is better do you think you will get your hand dirty?

CCNP,CCSP,MCSE,Sec+,Net+,A+...
 
It's probably worth posting the output of a 'show policy-map interface Serial0/0/0'....

Andy
 
Can you elaborate what device is talking to what? i.e. is this Cisco IP Phone talking to Cisco IP Phone or is it a Cisco IP Phone talking to a PSTN user? If the latter, which end heads the echo?
 
is this voice set up using call manager?

ping across your lines and paste the info here
...i need to see your reply times


Mauricio
MCP, MCSE, SMS 2.0, DCSE, CCNA, CCNP, CCIE Written
 
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