5520 partition

[letron]

Good Day,

Need to find out if there is a fail safe on the 5520 in the event that someone causes a loop back so that the port or ports disable, we had a problem today when someone pluggged in a I phone into 2 ports, this pretty much shut down the phone system site wide, you will have to excuse my termanology, data is not my thing.

 

[anthonyanderberg]

Just to make sure we're clear I'll re-state your situation first, be sure to correct me if I'm wrong.

You've got IP phones with multiple Ethernet ports in the back so that you could hook a PC to the phone and then phone into your 5520 switch. One of your people plugged both of those ports on the phone into your 5520 switch.

If this is right from a data network standpoint it sounds like you had a loop - the ports in the back of the phone are really a little Ethernet switch, and what happens in this (or any loop) is that some of the packets on the network would get sent out the 5520 ports to the phone, then the switch in the phone would send them right back to the 5520 which wouldn't know they were the same packets so it sends them out to the rest of the network and also back to the phone, and this repeats until 100 percent of the network bandwidth is taken up with the same packets going around in circles.

The most common solution is called Spanning Tree Protocol (STP), which works by sending a special packet whenever a new port comes up, and then looking to make sure that packet doesn't come in any other port. If a port seems to be creating a loop the switch will disable it to protect the network. (Its more complicated than this, but for purposes of this conversation you get the important parts.)

So the first thing we want to do is make sure you've got spanning tree turned on for all of your user ports. On your 5520's main menu look at the Spanning Tree Configuration menu, then Spanning Tree Port Configuration menu. You'll probably want your user ports set to "Fast Learning", "Normal" will work too but the ports can take a few seconds to initialize while they look for loops and sometimes that causes issues to.

If STP appears to be enabled or you don't see the settings mentioned above let us know.

 

[letron]

Thank you, that is exactly what I'am looking for, I will check and get back to ya.

Cheers,

 

[DaddyOfThree]

While I would definitely advise that you enable Spanning Tree on all your end-user ports, as Anthony suggests, but I would also strongly urge you to disable it on your upstream uplinks especially if your using Nortel's Multi Link Trunk feature.

Here are some of the CLI commands to enable Spanning Tree with Fast Learning across ports 1-46 on a single ERS 5520 switch;

5520-48T-PWR> enable
5520-48T-PWR# configure terminal
5520-48T-PWR (config)# interface fastEthernet 1-46
5520-48T-PWR (config-if)# spanning-tree learning fast
5520-48T-PWR (config-if)# exit

Here's an example of creating a MLT on ports 47 and 48;

5520-48T-PWR (config)# mlt 1 disable
5520-48T-PWR (config)# mlt 1 name "MLT-8600"
5520-48T-PWR (config)# mlt 1 learning disable
5520-48T-PWR (config)# mlt 1 member 47,48
5520-48T-PWR (config)# mlt 1 enable

If you have a core switch such as a Nortel ERS 8600 you might want to look into the SLPP and CP-LIMIT features. They can be used to help isolate any loop coming from an edge switch and prevent it from taking down the entire network.

You can find an example configuration of the ERS 5520 for IP telephony here;

http://michaelfmcnamara.blogspot.com/2007/10/nortel-ers-5520-pwr-switch.html

Cheers!

 

[letron]

Thanks DaddyofThree, will definetly look into it.

Thanks again guys