06-08-2012 07:13 AM - edited 03-04-2019 04:37 PM
Hi,
A couple of our remote users are saying that during the day, suddenly their 7965 that hangs off their 881 will start registering for 3 to 5 seconds, then it will be fine. Any thoughts?
Thanks, Pat.
06-08-2012 09:29 AM
Might be due to dhcp lease renewal.
Try to increase the lease time to 5 days or more.
regards,
Leo
06-08-2012 10:19 AM
Thanks for the response. I checked the 881 and the lease is set for 24 hours. Any reason I should make it more than that?
If not, any other places to start looking?
- Pat
06-08-2012 10:36 AM
For phones you typically want a long lease time because the renewal can be disruptive if there is a call ongoing.
When set to 24hrs it checks the lease every 12hrs. (half the lease time) And there is one renewal per day.
This can also affect registration status, especially over low bw links.
A longer lease provides the best stability. We set it to 10 days for voip systems by default.
regards,
Leo
06-08-2012 10:44 AM
I will increase the lease time as I suppose it can't do any harm but, are you saying that by having a 24 hour lease time, it could cause disruption even more often than the 12 hour check?
Thanks, Pat.
06-08-2012 03:08 PM
No, not more but if the renewal occurs during office hours users will notice it.
Better to do it less frequent.
If you have a voice vlan, increase the lease time only for that.
One day is quite ok for data.
Leo
06-08-2012 03:33 PM
This is happening more often than just the half life of the renewal so, I think this is happening for a different reason. Any more ideas?
Thanks, Pat.
06-08-2012 03:43 PM
It depends on how reliable the network is.
IP phones are sensitive to packet loss and even jitter.
The problem could be with the WAN link.
You haven't provided many details on that but if the lines are under 256k or perhaps ADSL is used this is a likely suspect.
No QOS for the control traffic is another.
Leo
06-11-2012 04:55 AM
Leo, the connection is Comcast Business class.
It it persists I will call the Carrier.
I provided some sh output.
service-policy voice_and_video
policy-map mark_incoming_traffic
class discover_voip
set dscp ef
class discover_signaling
set dscp cs3
class discover_video
set dscp cs2
class non_voip
set dscp default
!
policy-map voice_and_video
class call_setup
bandwidth 32
class internetwork_control
bandwidth 32
class voice
priority 128
class video
priority 460
class class-default
policy-map shaper
class class-default
shape average 2000000
service-policy voice_and_video
policy-map mark_incoming_traffic
class discover_voip
set dscp ef
class discover_signaling
set dscp cs3
class discover_video
set dscp cs2
class non_voip
set dscp default
!
On the tunnel interfaces:
qos pre-classify
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