packet loss between phones
GT-Rob
Member Posts: 1,090
So I have an interesting problem, and I can't seem to narrow down the source of it.
Here's the layout:
Site 1 is connected to Site 2 via a 3mb link. From the 'core' of site 1, I can ping phones in Site 2 all day long without a single drop. From the 'core' of site 2, I get about 3% packet loss when I ping a phone in Site 1. So I have unidirectional packet loss.
Now when I am on a call between the phones, I get about 3% packet loss, bring the MOS down (although its not terrible). However, if I call the unity server in Site 1 from Site 2, I dont get any loss.
Congestion/QoS is not the problem here, because I am getting this behavior when the link is not even being used (it rarely sees 20%).
I don't think the phones are rate limiting the ICMP packets, because the drops are very random, and sometimes consecutive. I have also tried pinging Site 1 from Site 3, which is 100+ ms and still get the same amount of drops.
Speed is not an issue, as the Site 1 to Site 2 response time is 20-30ms this whole test.
No other hosts have issues with drops. I can literally ping my computer attached to my phone from Site 2, and get 0 drops, while getting 3% to my phone at the same time.
So, any ideas out there? I dont think its a routing issue since its inconsistent/not a lot of drops, and I don't think its a WAN issue as I dont drop to any other hosts. I know RTP packets behave differently, so is there something I am missing?
Here's the layout:
Site 1 is connected to Site 2 via a 3mb link. From the 'core' of site 1, I can ping phones in Site 2 all day long without a single drop. From the 'core' of site 2, I get about 3% packet loss when I ping a phone in Site 1. So I have unidirectional packet loss.
Now when I am on a call between the phones, I get about 3% packet loss, bring the MOS down (although its not terrible). However, if I call the unity server in Site 1 from Site 2, I dont get any loss.
Congestion/QoS is not the problem here, because I am getting this behavior when the link is not even being used (it rarely sees 20%).
I don't think the phones are rate limiting the ICMP packets, because the drops are very random, and sometimes consecutive. I have also tried pinging Site 1 from Site 3, which is 100+ ms and still get the same amount of drops.
Speed is not an issue, as the Site 1 to Site 2 response time is 20-30ms this whole test.
No other hosts have issues with drops. I can literally ping my computer attached to my phone from Site 2, and get 0 drops, while getting 3% to my phone at the same time.
So, any ideas out there? I dont think its a routing issue since its inconsistent/not a lot of drops, and I don't think its a WAN issue as I dont drop to any other hosts. I know RTP packets behave differently, so is there something I am missing?
Comments
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tokhss
Member Posts: 473
Popcorn out.. sitting back.. i am curious myself,. doesnt sound like the wan link to me either . does this happen on all phones in site 1? are all the phones the same?
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GT-Rob
Member Posts: 1,090
Issue resolved.
Turned out to be a bad link (duplex negotiation was failing) to my back up WAN router, which we had these new vlans going over. The reason it 'alluded' me was because my workstation is actually on our management vlan which goes over the primary link. So when I was pinging my desktop, and pinging my phone, they actually took different routes.
Oh well, it was a fun learning experience on how our network is setup. Went through almost every trunk and made a spanning-tree map and HSRP active router grid for all of our vlans lol.
An FYI, the phones will actually rate-limit pings to 5 by default. Meaning if you ping your phone or CUCM on the LAN, it will likely drop every 6th packet. This is something else that freaked me out at first haha.