IP Phone and PC Port Performance

[ciscofreak1241]

I have noticed that the performance of our desktops connected to the IP Phone directly and the Phone connected directly to the switch can be poor especially with file downloading. When I remove the IP Phone from the path of the PC the performance jumps to by 150%.

Now, I have QoS configure on the Layer 2 network and there are voice/data vlan segmentation. However the performance is bad even if the other machine is connected on the same switch and the same VLAN. And yes, 100/full is force all ports from end to end.

Is there anything that could be causing these performance problems with the PC-IPPhone-Switch setup (known issues) including things I can do on the IP Phone, PC, or Switch to improve performance?

Any help and suggestions would be great!

Thanks

cf

 

[ADB100]

You state that all ports are 100/Full forced. Have the ports on the IP Phone beed forced as well? This isn't something that can be done through CCM and has to be done manually on the IP Phone. You have to open network configuration on the phone, enter the unlock code (**#*) and then you can change the SW Port & PC Port Configurations to your desired settings (100/Full in your case). I wouldn't recommend doing it this way and would leave the access ports at Auto Speed & Duplex - for one it's an administrative pain unless you only have a handful of IP Phones and I have seen more issues with forcing ports than I have with leaving them at Auto (in the last 5 years at least anyway).

I have had some UDP streaming issues with PC's running at 10Mbps connected to the IP Phones, but this is quite easy to understand as the switchport will have no idea the PC is running at 10Mbps behind the IP Phone and the switch in the Phone hasn't much buffer available. Resolution here was to run the switchport at 10Mbps so there was no speed mis-match.

Andy

 

[youcandoit]

**# unlocks my phone config

**#** initiates a re-registration

**#* doesnt do anything am i missing something.

 

[ciscofreak1241]

Thanks for the response Andy. The input of **#* does unlock the IP Phone and by default the ports (SW and PC Port) on the Phone are Default.

Under normal operation the performance is good. It's only under situations where massive data is being sent I notice the performance goes down. So, forcing the ports to be 100/full across the board I would feel is necessary. I have seen that from my experience outside of IPT with Corporate Servers.

If I enable 10/half on all ports then the performance will probably get worst and recieve a lot of RUNTS, COLLS, etc to add to the degragation. So I am curious to know what problems have you seen if the IP Phone SW (and Catalyst Switch) ports were forced to 100/full.

I am doing some testing now to view the performance for comparison, but I would like to understand from your point of view and your experience?


Thanks again for the wonderful response!

cf

 

[ADB100]

The issues I have seen are generally due to the fact that most PCI NICs are connected even if the host PC is shutdown. This is due to the PCI bus providing power and the NICs being connected. In this state there is no software or device drivers loaded on the host so the NIC will be in Auto Speed & Duplex mode. If you then subsequently boot the PC and the NIC is set to forced speed/duplex the NIC will effectively reset and cause the switch port to restart. I have also seen a lot of Unix/Linux servers error when the NIC driver is set to be forced, this I put down to driver issues since the problem were not seen using the same NIC's and Windows 2000.

I agree if you have forced both ends of a link it should not error since neither the switch nor the NIC will attempt auto-negotiation. This is sometimes not true with certain NIC's that regardless of the driver setting will always auto-negotiate. This can be confusing since both the switch and the PC will say they are running 100/Full but in fact due to the NIC driver not forcing the NIC and the switchport not negotiating the PC is in fact running 100/Half.

Speed/Duplex problems are only apparent when there is a mis-negotiation - i.e. one end is Full Duplex whilst the other is Half. I have hardly seen any modern NIC's (last 3-4 years) have negotiation problems so I would recommend using Auto on all access ports.

Issues with the Switch in the IP Phones are another matter. I don't know what the expected performance of the embedded IP Phone switch is but it can't be anything like a Catalyst switchport? Saying that though I have sucessfully ran IPERF tests using UDP streams upto 40Mbps via the IP Phone port and not had problems.

Andy

 

[youcandoit]

hey talk to me fella's

I'm on CCM 3.3.3.

I use **# to unlock my phone config.

Are you guys using **#* becuase your on a differnet version or pushing too many keys?

Thanks.

patrick