05-04-2009 08:15 PM - edited 03-21-2019 01:04 AM
I have a UC500 with SIP trunk. I have intermitent voice qualtity problems in the form of broken speech, typically on the far end.
The SIP trunk provider claims the issue is not with him and points to widely varying ping times from his server to my UC500.
The ISP claims he can ping the cable modem consistantly in less that 70ms while the UC500 takes 100-800ms. The ISP will not reveal the IP address of the cable modem (Linksys CM100) so I cannot test this for my self.
The network consists of one phone one PC and one wireless cam so it seems an overloaded connection issue.
How can I find out why my router is doing this?
Thanks!
Solved! Go to Solution.
05-06-2009 09:53 AM
Here is a good document (you will also see it is part of the bigger QoS Design Guide):
Your shaping needs to match whatever is guaranteed upstream by the circuit. In your case, since there are no guarantees, I would just apply the "Bottom" service policy to the WAN interface directly and avoid shaping (Top).
You can determine which codec is being used, by pressing the blue "?" button or "i" button on the IP phone itself while on a call.
Regarding multiple trunks support, this is OK ONLY IF THE SECOND PROVIDER DOES NOT REQUIRE AUTHENTICATION. UC500 can only register with one provider at a time.
Thanks,
Marcos
05-05-2009 04:51 AM
Check the cable between router and the modem. Load on the UC500 gets high when you have Firewall rules , VPN configured and when the internet usage gets high. You can check the CPU utilization using the command show cpu process history .
05-05-2009 09:03 AM
Here is a ping to my SIP Trunk SP with the utilization query.
At 12% its not the cpu causing the delay.
Sending 5, 100-byte ICMP Echos to 216.82.224.202, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 492/804/988 ms
UC520#show processes
CPU utilization for five seconds: 12%/5%; one minute: 12%; five minutes: 9%
PID QTy PC Runtime (ms) Invoked uSecs Stacks TTY Process
05-05-2009 04:58 AM
SIP Trunk Service Providers who give some SLA or guarantee for bandwidth and QoS (TOS or DSCP) marking of RTP Media and SIP Signaling will place a 'demarcation router' at the small business (in front of the UC520) so the connection is their network and can be maintained and controlled. This is the only way they can guarantee the network connection from their SIP Infrastructure (Registrar, Proxy, SBC, etc) all the way to your location.
If they dont do this, there is a good chance you have no SLA and in that case you are dependent on whoever your ISP is to carry your connection to the SIP Trunk SP network. Some people call this BYOB (Bring your own Broadband). This will usually result in QoS problems since either the bandwidth is not prioritized for marked traffic or isnt enough to carry the number of calls (or even a single call) in times of congestion and high traffic in the ISP network.
In the case of a Cable MSO who may also be offering voice as part of a triple play type solution, they may not want to help you with QoS for SIP signaling and RTP Media packets since you basically commoditized their network (made them cheap plumbing), unless you pay for a higher tiered service that would give you an SLA.
If a SP tells you the pings times to get to you are too long, then I assume you are in the BYOB case, since that is a reflection of the network between you and the SP, not the UC520?
05-05-2009 05:56 AM
Do you have a policy map (QoS) configured on your WAN link? If so, do you see matches for the different classes? "show policy-map interface fast0/0".
Let us know,
Marcos
05-05-2009 09:22 AM
Marcos,
Based on the repsonse below I would say there is no policy.
UC520#show policy-map interface fast0/0
UC520#
Thanks,
Matthew
05-05-2009 10:29 AM
Please apply the following config. Please notice that it assumes an upload speed of 768K and that I will have 2 G.711 calls, each one using 90K. So for your setup, you will need to modify the "priority" command under "class VoIP" (unit is Kbps) and the "shape average" command under the "policy-map Top_Class" "class class-default" (unit is bps). If you are using G.729 on the WAN, use 26Kbps per call, instead of 90Kbps.
! QoS settings:
class-map match-any VoIP
match ip dscp ef
!
class-map match-any Signaling
match ip dscp cs3
match ip dscp af31
!
policy-map Bottom_Class
class VoIP
priority 180
class Signaling
bandwidth 10
class class-default
fair-queue
!
policy-map Top_Class
class class-default
shape average 768000
service-policy Bottom_Class
!
!
interface FastEthernet0/0
service-policy output Top_Class
!
Marcos
05-05-2009 12:00 PM
Marcos,
The command:
show policy-map FastEthernet0/0
does not show anything but show run does show the following.
Do I have it set properly?
do these other class-map interfere?
Can you tell me where ping traffic fits in the scheme of things? How relevant is it for determing congestion on a network any way?
Thanks,
Matthew
!
ip tftp source-interface Loopback0
!
class-map match-all _class_Voice0
match ip dscp ef
class-map match-all _class_Voice1
match ip dscp cs3
class-map match-any VoIP
match ip dscp ef
match ip dscp cs3
match ip dscp af31
class-map match-any sdm_p2p_kazaa
match protocol fasttrack
match protocol kazaa2
class-map match-any sdm_p2p_edonkey
match protocol edonkey
class-map match-any sdm_p2p_gnutella
match protocol gnutella
class-map match-any sdm_p2p_bittorrent
match protocol bittorrent
class-map match-any Signaling
match ip dscp cs3
match dscp af31
!
!
policy-map Bottom_class
class VoIP
priority 180
class Signaling
bandwidth 10
class class-default
fair-queue
policy-map Bottom_Class
class VoIP
priority 180
policy-map Voice
class _class_Voice0
set cos 6
class _class_Voice1
set cos 3
policy-map Top_Class
class class-default
shape average 768000
service-policy Bottom_Class
05-05-2009 12:04 PM
The show command is missing the keyword "interface". Also, you need to apply it to the interface (see my post). Finally, ICMP should be tracked in the dfault class.
Marcos
05-05-2009 05:08 PM
Marcos,
Ok My policy map is set as shown. Does it look right?
I don't know how to track IMCP in the default class, my attempts resulted in "invalid input". Can you help with this?
Thanks,
Matthew
UC520#show policy-map interface fast0/0
FastEthernet0/0
Service-policy output: Top_Class
Class-map: class-default (match-any)
704 packets, 68824 bytes
5 minute offered rate 1000 bps, drop rate 0 bps
Match: any
Traffic Shaping
Target/Average Byte Sustain Excess Interval Increment
Rate Limit bits/int bits/int (ms) (bytes)
768000/768000 4800 19200 19200 25 2400
Adapt Queue Packets Bytes Packets Bytes Shaping
Active Depth Delayed Delayed Active
- 0 704 68824 0 0 no
Service-policy : Bottom_Class
Class-map: VoIP (match-any)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: ip dscp ef (46)
0 packets, 0 bytes
5 minute rate 0 bps
Match: ip dscp cs3 (24)
0 packets, 0 bytes
5 minute rate 0 bps
Match: ip dscp af31 (26)
0 packets, 0 bytes
5 minute rate 0 bps
Queueing
Strict Priority
Output Queue: Conversation 72
Bandwidth 180 (kbps) Burst 4500 (Bytes)
(pkts matched/bytes matched) 0/0
(total drops/bytes drops) 0/0
Class-map: class-default (match-any)
704 packets, 68824 bytes
5 minute offered rate 1000 bps, drop rate 0 bps
Match: any
05-06-2009 05:57 AM
Your pings will be recorded in the default class. I see 704 matches, some could be ICMP.
Remember that the sample config I sent was for a 768Kbps link, and two G.711 calls. You need to adjust according to your actual setup.
Have you tried phone calls? Cal you test that and see if the Voice class see matches and the quality is improved?
Thanks,
Marcos
05-06-2009 09:39 AM
Marcos,
Thank you so much for your continued assistance.
I was only able to do limited testing for unrelated reasons. I will be able to more testing later today. The limited test results were good but it is an intermittent problem to start with so some time will tell. I will attempt to create conditions prevoiulsy demostrated to create the quality problems albeit not exculsivley.
My Internet connection is BYOB affair with 8Mbit DN 1Mbit UP. It differs from the local residential product only in that no ports are blocked. It is a best effort service with no min guaranteed.
How can I tell what coding I am using 711/729? My VPN is not working for some reason so I need to do it from the command line as I have no CCA access at the momment.
At the moment I have only sip trunk but do want to get another if I can get this to work. Do you see any issues with getting another trunk from different provider? So each trunk is from two different SPs?
I still need to know how to assign ICMP to the appropriate class as you mentioned can you help with the commands.
Can you provide a link to a good document that outlines the shaping configuration? No a marketing doc but a how to doc.
Thanks,
Matthew
05-06-2009 09:53 AM
Here is a good document (you will also see it is part of the bigger QoS Design Guide):
Your shaping needs to match whatever is guaranteed upstream by the circuit. In your case, since there are no guarantees, I would just apply the "Bottom" service policy to the WAN interface directly and avoid shaping (Top).
You can determine which codec is being used, by pressing the blue "?" button or "i" button on the IP phone itself while on a call.
Regarding multiple trunks support, this is OK ONLY IF THE SECOND PROVIDER DOES NOT REQUIRE AUTHENTICATION. UC500 can only register with one provider at a time.
Thanks,
Marcos
05-06-2009 11:05 AM
Thanks Marcos.
I will try applying only to the bottom service policy.
Since my existing SIP trunk SP does not use registration, I am assuming I can add a second SP regardless if the require it or not.
Thanks,
Matthew
05-06-2009 01:23 PM
Marcos,
Below is the latest test result. I tried to load up my network (such as it it) and had a voice call going. The voice qualtiy was perfect. I also did not see the same variation in ping time that I was seeing before. Best I can tell, shaping was taking effect, showing delayed packets. Can you confirm?
Thanks,
Matthew
Service-policy output: Top_Class
Class-map: class-default (match-any)
169795 packets, 111087321 bytes
5 minute offered rate 771000 bps, drop rate 3000 bps
Match: any
Traffic Shaping
Target/Average Byte Sustain Excess Interval Increment
Rate Limit bits/int bits/int (ms) (bytes)
768000/768000 4800 19200 19200 25 2400
Adapt Queue Packets Bytes Packets Bytes Shaping
Active Depth Delayed Delayed Active
- 61 169427 110624008 138774 103809933 yes
Service-policy : Bottom_Class
Class-map: VoIP (match-any)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: ip dscp ef (46)
0 packets, 0 bytes
5 minute rate 0 bps
Match: ip dscp cs3 (24)
0 packets, 0 bytes
5 minute rate 0 bps
Match: ip dscp af31 (26)
0 packets, 0 bytes
5 minute rate 0 bps
Queueing
Strict Priority
Output Queue: Conversation 72
Bandwidth 180 (kbps) Burst 4500 (Bytes)
(pkts matched/bytes matched) 0/0
(total drops/bytes drops) 0/0
Class-map: class-default (match-any)
169795 packets, 111087321 bytes
5 minute offered rate 771000 bps, drop rate 3000 bps
Match: any
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide