Access Points

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bt4
Occasional Contributor II
Posts: 19
Registered: ‎11-13-2008

AP125 dual feed

Hi

We have recently started buying AP125's instead of the AP65 which we used to use. However, I am not sure how to use the second Ethernet port which comes on these devices. Is it there for resilience? or to provide extra power perhaps? If it is a feed port, how should I connect it? If, the two ports are bridged, then presumably I cannot put them on the same VLAN as it would create a loop?

Can anyone advise me?

Thanks

Ben
MVP
Posts: 1,357
Registered: ‎11-07-2008

Re: AP125 dual feed

one of the best applications is to use it as a tunnel port. Put enet1 into (for example) the same wireless user vlan and plug in a printer. Then it will be on the same broadcast domain as the wireless users. Or put a wired desktop machine, or any network device into the port. It tunnels back to the controller just like wireless vlans...

You can also bridge the interfaces, use it as redundant phy, etc. Lots of options. It cannot serve as supplemental power as far as I know, so if you want to use that second port, you want to pame sure it gets full power on the primary port.
Jerrod Howard
Sr. Techical Marketing Engineer
bt4
Occasional Contributor II
Posts: 19
Registered: ‎11-13-2008

Re: AP125 dual feed

Hi

Thanks for the info. However, I am still not clear about how the port can be used as a redundant feed. How does the bridging work and how do it configure it on the AP and on the remote switch/switches? Does it use LACP?

Thanks

Ben
Contributor I
Posts: 26
Registered: ‎12-22-2008

Re: AP125 dual feed

Both ports on the AP-125 can not be configured for link agg(LACP.PAgP..etc). It can be used for redundancy based on STP as one of the ports on the switch would go to blocking.
The access point would not generate BPDU's but flood the BPDU which it receives on eth0 to eth1.

They can also be used to extend the network, ex in a wireless mesh installation it can be connected to a different switch on a seperate vlan. This vlan can be specified under the system profile.
bt4
Occasional Contributor II
Posts: 19
Registered: ‎11-13-2008

Re: AP125 dual feed

Hi

Thanks for the info. I'm really not keen on Spanning Tree, but I decided to rig up a test setup in order to see how I could use this method to provide a redundant feed. I plugged both ports of an AP125 into a common switch in the same VLAN and enabled STP.

However, it did not work as I expected. The switch reported that both feeds to the access point were in forwarding mode, suggesting that there was no loop present. I also noticed that the access point seemed to be able to fail over automatically if I unplugged one of the ports. The power did not fail over however and it appeared that the AP would take power from the first port to be connected (although this is not a problem as the AP would still fail over after a reboot).

So, it seems that STP is not required?

Thanks

Ben
MVP
Posts: 1,357
Registered: ‎11-07-2008

Re: AP125 dual feed

You're correct, the power will not failover without a reboot. The main intent in using the second port as a failover port isn't to provide seamless availability, only that if one POE switch or switchport dies, there's a second one to take over. Downtime should be under 1 minute easily.
Jerrod Howard
Sr. Techical Marketing Engineer
bt4
Occasional Contributor II
Posts: 19
Registered: ‎11-13-2008

Re: AP125 dual feed

Hi

Thanks again :)

I think I'm getting closer to understanding the capabilities now and how this works. However, I still don't understand how the access point is blocking a potential loop when both ports are connected. Is the AP running some sort of Spanning Tree like protocol which sends out packets in order to detect the loop? or does the AP perhaps wait until the link fails on the first port before forwarding packets on the second port?

Cheers

Ben
Guru Elite
Posts: 21,279
Registered: ‎03-29-2007

The latter

is true.


Colin Joseph
Aruba Customer Engineering

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bt4
Occasional Contributor II
Posts: 19
Registered: ‎11-13-2008

Re: AP125 dual feed

Thanks.
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