AEBS Challenges with Cisco Phone and VPN

[jnaeve]

I'm not sure if this is an AEBS incompatibility issue with Cisco IP phones or something relating to circuit quality but I could sure use some guidance on this topic.

I've been working on this the last year with our IT department, trying to get consistent performance over Verizon FiOS. FiOS is fantastic when I'm not having to VPN in for work or use my Cisco DX650 phone.

The phone initiates its own VPN session to connect to our voice gateway and I VPN from my MBA into the office. The phone typically looses connectivity part of the way through a call and then drops completely, afterwards resetting itself. Its as though it reaches some sort of retransmit buffer overload and then resets itself but VPN will also get sluggish throughput after its been up for a while but dropping the VPN connection and reestablishing VPN seems to make things quicker.

I just moved and the old house also had the same Verizon FiOS plan; 75/75 and I get pretty good performance, typically around 75+Mb down, 75+MB up, little to no packet loss, ~15ms Latency and <4ms Jitter, so not too bad actually.

Has anyone seen this before and/or can you offer any suggestions, recommendations?
Thanks!!

 

[pjfan]

Is your MBA connected via Ethernet behind the Cisco phone? Or is it via wifi?

I'm ten years removed from my networking days, but the issue surely isn't in your network speed/latency, rather, it seems like it's in some firewall/route problem. Does FiOS provide you your primary router?... If so, can you make your Cisco phone a DMZ and try it?... Or, turn off the routers firewall and test is the same issue happens during a set time period?

If you see DMZ as an option, I think that's the best bet.

--- sorry, I'm not familiar with Verizon's FiOS routers to help more clearly. Posting snapshots might help.

 

[jnaeve]

Thanks for replying, I use an Airport Extreme, Gen6 thats directly connected via Ethernet to my FiOS optical network terminal (ONT) on the side of my home. The Cisco phone connects via 802.11 to the Airport Extreme (AEBS). I spoke to one of our product specialists on this device and he said that its possible and likely that whatever Apple is doing behind the scenes with SIP may be preventing optimal performance. I know from past experience that other routers have a separate configuration parameter specifically for voice services to tune and tweak performance. Apple does not. I have put this phone on the DMZ but that doesn't help. I really do believe now that there is a protocol issue with how Apple handles SIP performance and the inability to tune that. We have many others who use this phone successfully without issue but who use a different router.

I'm interested to see if anyone else has witnessed this as well, perhaps with a different manufacturer of phone but SIP specifically through AEBS.

That said... I have Vonage as well and it works flawlessly through AEBS - not sure but I'm fairly certain its the two together, Cisco DX650 and Apple AEBS - there's a protocol glitch there.