Setting Up An Aruba Wireless Bridge

One of the most underrated features of Aruba wireless hardware is its ability to be used as a wireless bridge. Running a cable to provide power and data to an AP is always the best way, but sometimes you just can’t get one there and have to go wirelessly.

With the release of Instant v 8.4, the concept of a mesh cluster name and key was introduced along with the AP-387 5/60GHz outdoor bridge. This mesh cluster mode lets the APs in the cluster establish their own mesh SSID and encryption, without the brain damage of provisioning those parameters on each device. This also introduced the concept of a standalone Instant AP, which allows you to run a point-to-point bridge or a multipoint mesh without the AP trying to join an existing Instant Virtual Cluster (VC).

Once a bridge is established, it is fully transparent at L2. Anything that shows up on the interface on the Mesh Portal AP will pop out the other side on the Mesh Point’s bridged Ethernet interface. You can optionally prune VLANs if you need to.

Key Terms:

  • WIRELESS MESH : one or more access points that connect to the network wirelessly.
  • MESH PORTAL/MESH ROOT: an access point in a mesh network that is connected to the network via an Ethernet connection. An Aruba AP configured for mesh will determine if it is a portal by listening for traffic on the Ethernet port. a given mesh cluster can have multiple portals.
  • MESH POINT: an access point in a mesh network that is connected to the network via one or more wireless connections to a Mesh Portal. Mesh points can also provide a wireless connection to another mesh point, but you don’t want to go more than one or two hops to a root bridge. If you have to go long distances, a linear mesh topology may be more useful. An Aruba AP will determine it is a mesh point in a cluster by either not seeing traffic on the Ethernet ports, or if the Ethernet port is set to bridging mode and has devices downstream.
  • MESH CLUSTER: A group of Aruba APs that are configured for the same mesh.

What you will need:

  • two Aruba APs that support Instant 8.4 or higher. Update them to the latest 8.7 code train if you can. I labbed this up on a pair of AP-515s, but the APs don’t necessarily have to be the same model of hardware, just the same software version. The Aruba mesh will operate on 5GHz.
  • A means of powering both APs. This can be PoE, but you’ll want the network on the Mesh Point side of the link to be an isolated Layer 2 segment from the one on the Mesh Portal, otherwise you’ll create a loop when the bridge comes up. It’s generally easiest to put a separate PoE switch on each end, making it easier to connect devices to troubleshoot. If using PoE, make sure it’s sufficient to run the AP.
  • Not strictly necessary, but helpful: A console cable for each AP. The 570 series APs use a standard USB Type C connection and ship with the requisite cable. Otherwise you’ll need either the “Orange Cable” (JY728A AP-CBL-SERU) that has a Micro-B connector on the end (this isn’t actually USB, so don’t even bother trying to use a standard MicroUSB cable), or the older TTL pin header to DB9 cable.

To start, hook up the console cable to the AP, and power it on. When prompted, stop the boot loader. Once at the boot loader prompt, issue the following commands:

factory_reset
setenv standalone 1
setenv uap_controller_less 1
saveenv
boot

This does the following:

  • resets the AP to factory defaults
  • sets the AP to standalone mode (ignores any incoming L2 Instant VC broadcasts and suppresses any outgoing ones)
  • Sets the AP to Controllerless (Instant)
  • Saves the environment variables
  • Boots the AP.

You can also do this from a booted AP on the AOS CLI by issuing the following commands:

write erase all
swarm-mode standalone
reload

Once the AP is booted up into standalone mode, you’ll need to log in via the GUI or the CLI (console or ssh) using the default credentials (admin/admin or admin/serial#), and set a new admin password. Once you’ve done this, you’ll need to create an access SSID to get it out of Instant’s SetMeUp mode. You can disable this later if the AP is not also being used for access (generally not a good idea on a mesh bridge, unless you’re restricting it to the 2.4GHz radio which is unused by the mesh.) If you’re using an AP-387, you don’t need to do this.

Once you’ve created this dummy/temporary SSID (easiest from the Web UI), go to Configuration>System>Show Advanced Settings, disable Extended SSID and reboot.

On the CLI:

conf t
virtual-controller-country US
name Mesh-Portal (or name of your choice)
no extended-ssid
exit
commit apply
reload

Once the AP is back up, configure the mesh:

no mesh-disable
mesh-cluster-name <cluster name> (If doing multiple bridge links, each one must have a unique name)
mesh-cluster-key <cluster-key>
commit apply

If you’re in a multi-VLAN environment, this is also a good time to set VLANs and such. If you’re just running a flat network, skip this part.

uplink-vlan <VLAN ID> (this is the VLAN the AP listens on)

#If configuring a static IP: 
ip-address <ip-address> <subnet-mask> <nexthop-ip-address> <dns-ip-address> <domain-name>

conf t
wired-port-profile Mesh_Portal_Uplink-wpp
 switchport-mode trunk
 allowed-vlan <list of VLANs or "all">
 native-vlan <port Native VLAN>
 trusted
 no shutdown
 type employee
 auth-server InternalServer
 captive-portal disable
 no dot1x
exit

enet0-port-profile Mesh_Portal_Uplink-wpp
enet1-port-profile Mesh_Portal_Uplink-wpp

exit
commit apply

Check the status of the mesh cluster settings with:

show ap mesh cluster status

It should look something like this:

Mesh cluster      :Enabled
Mesh cluster name :Mesh_Lab
Mesh role         :Mesh Portal
Mesh Split5G Band Range :full
Mesh mobility     :Disabled

Now you’ll want to do the same process on the Mesh Point AP, plus the following to enable the bridging:

enet0-bridging
commit apply
reload

Once everything is booted back up, give it a few minutes to establish the mesh link, and then run:

show ap mesh link

Which will give you information about the link. the RSSI column is the SNR in dB. You can see from the flags that the link is running an 802.11ax/HE PHY (E), that legacy PHYs are allowed (L), and that it is connected to the mesh portal (K).

# show ap mesh link

Neighbor list
-------------
Radio  MAC                AP Name          Portal  Channel  Age  Hops  Cost  Relation                 Flags  RSSI  Rate Tx/Rx  A-Req  A-Resp  A-Fail  HT-Details    Cluster ID
-----  ---                -------          ------  -------  ---  ----  ----  -----------------        -----  ----  ----------  -----  ------  ------  ----------    ----------
0      aa:bb:cc:dd:ee:ff  Mesh_Lab_Portal  Yes     116E     0    0     4.00  P 22h:18m:57s            ELK    55    1531/1701   1      1       0       HE-80MHz-4ss  29c8af3dec64e7c278bfcbfab07a2a3

Total count: 1, Children: 0
Relation: P = Parent; C = Child; N = Neighbor; B = Blacklisted-neighbor
Flags: R = Recovery-mode; S = Sub-threshold link; D = Reselection backoff; F = Auth-failure; H = High Throughput; V = Very High Throughput, E= High efficient, L = Legacy allowed
        K = Connected; U = Upgrading; G = Descendant-upgrading; Z = Config pending; Y = Assoc-resp/Auth pending
        a = SAE Accepted; b = SAE Blacklisted-neighbour; e = SAE Enabled; u = portal-unreachable; o = opensystem

From this point, you should be able to send traffic across the link, and you’re ready to go install the bridge in its permanent home. If running outdoors, don’t forget to ensure a clear line of sight and unobstructed Fresnel Zone.

Hands On : Aruba Instant

After our quick little tour of Aruba InstantON, I’m going to move up to the next level of Aruba gear: Instant.

The naming can be a little confusing to the ArubaNoob, but Instant has been part of Aruba’s product offering for a very long time. While it appears controllerless, it still makes use of a virtual controller that lives inside the APs on the network (and in case the AP running the controller goes offline, the remaining APs on the network decide on a new leader by holding a rap battle or a dance-off. OK, just kidding. They actually do a sort of digital version of Rock, Paper, Scissors, Lizard, Spock.

This virtual controller concept has also been done by Ruckus with their Unleashed platform, which in terms of functionality is somewhere between Instant and InstantON, and Cisco’s Mobility Express. I’m not 100% sure, but I think Aruba had it first.

In previous generations of Aruba access points, you either purchased an Instant AP (IAP), a Campus AP (CAP) , or a Remote AP (RAP). The latter two required a Mobility Controller (MC). You definitely couldn’t RAP without an MC. Now, all APs ship as Universal APs and figure out which mode to be when they boot up, and can be easily converted from one to the other (in the dog park that is Ruckus Unleashed, you would have to reimage the AP with new firmware).

Who it’s meant for

Instant is designed for small and medium business environments, and home labs of geeks who subscribe to the idea of “if it’s worth doing, it’s worth overdoing” (My home wireless network right now consists of 7 APs in an Instant cluster). It also is very useful in large enterprises that consist of many small locations, especially once you start managing them all with Central. If you have a chain of coffee shops or boutiques that only require a few APs, then Instant+Central is definitely something you should look at. If you only have one, InstantON is more your speed.

Instant does not require any per-AP licensing, but it still includes a lot of the features you find on the campus systems. It even includes an internal RADIUS server and user database so you can do enterprise authentication (as of 8.7 which was just released in July 2020, you can even do up to 24 unique passphrases with MPSK before having to get ClearPass involved, which is real handy for IoT networks that use crappy chipsets that don’t support enterprise auth). It will also do an internal captive portal. It still has role-based access control, which provides layer 3 policy enforcement at the AP, including content filtering. And much like the InstantON APs can do, you can even use an Instant AP as your internet gateway (guess where InstantON learned it from?). You can even use it with ClearPass and all the goodies that come with that.

When a Universal AP powers up, it goes through the following process:

If setup mode is not accessed within a period of 15 minutes, the UAP reboots and goes through the process again. It can be a lonely existence. (this mode is not unusual to find in large campus networks where there exists a network disconnect at Layer 2 or Layer 3 between the AP and the controller. Chasing these down on a cruise ship is maddening… but it gets you a lot of steps.)

Setup Mode

Once the AP is in setup mode, it will broadcast an open SSID called SetMeUp-DD:BE:EF (where the last half is the last half of the wired MAC address of the AP). Connecting to this SSID will bring you to the configuration page (it will even conveniently pop it up in the captive portal window if your OS has such a thing). You can also access this by opening a browser to https://setmeup.arubanetworks.com, which it looks up via mDNS. (Caveat: This doesn’t work so great if the AP does not have an uplink and an IP address on the network, even if that IP is not routable… And accessing it via IP address only redirects to the hostname, and mDNS doesn’t really like not having a network to do its thing. So give it an uplink, even if it’s just a WLANpi.)

I once was traveling through a midwestern airport where I was scanning the wifi (it’s a wifi nerd thing) when I saw a lone AP broadcasting “Instant” (which is what Instant used to do before AOS 8.x). I eventually found the AP in a restaurant, where it was sitting all by itself on the ceiling, still in setup mode with the defaults… A quick peek into the setup page showed that this thing had never been configured… I found the manager to let them know that someone didn’t finish a job they were likely paid handsomely for, and she told me it had been there for almost 3 years and nobody had any idea what it was for or remembered who installed it or when. The airport’s installed public system was Meraki.

Once you’re in the setup interface, you can then configure it to your heart’s content. Then, when you bring up a second and subsequent access points on the network, they will find the first one, grab the configuration, and join the party. This scales surprisingly well – you can run several dozen access points on a network like this (There’s no actual hard limit, and it’s been officially tested up to 128 APs, but this is definitely not recommended – that’s well into Campus AP territory). It may not be truly instantaneous (we do love instant gratification), but it’s pretty darn close.

Limitations

There are a few limitations to this mode of operation, in addition to the aforementioned scaling issues (if you’re used to a SOHO/SMB system like Ubiquiti, 100 APs will sound like a lot to you. Once you get into controller based networks with Aruba, even a thousand APs is middle of the road – I routinely work with networks well in excess of this).

A few of the things you can’t do with Instant:

  • AP Groups
  • AirMatch (Instant uses the older ARM techniques for RF management)
  • Tunneling to controller (yet…)
  • I’m probably forgetting some things…

Perhaps the most useful aspect of Instant is that it can either be managed in the cloud with Aruba Central (if you’re used to Meraki, you’ll love Central), or if your network requirements grow to where you need to get a controller involved, switching the APs over to that mode is quick and easy, and you don’t have to buy new gear.

Labbing It Up

If you want to play around with Instant, it’s pretty easy: Buy an AP. Or more. If you have to fund your own lab gear, there’s a ton of used and refurbished Aruba gear on Amazon or eBay (If you go with HPE Renew, you still get HPE’s legendary lifetime warranty on network equipment). Recently, I saw a whole bunch of Renewed AP-345s on ebay for under $200. Just make sure you get the correct country code (US or RW) – the two can’t coexist on the same Instant cluster (in a controller environment, the controller country code takes over and ignores the AP setting).

If you’re new to the Aruba product line, here’s a quick cheat sheet to figure out what kind of AP you’re getting. It’s not 100% exact, but it should give you a general idea of what you should be getting.

The first digit of the 3-digit model number indicates product generation:

  • AP-0XX (or just AP-XX): 802.11g
  • AP-1XX: 802.11n
  • AP-2XX: 802.11ac Wave 1
  • AP-3XX: 802.11ac Wave 2 with integrated BLE
  • AP-5XX: 802.11ax with integrated BLE and ZigBee

The second digit indicates capabilities (1XX series and up)

  • AP-X0X: 2 spatial streams
  • AP-X1X: 3 spatial streams (although the 51X series is 2SS on 2.4GHz and 4SS on 5GHz)
  • AP-X2X: 3 spatial streams, second Ethernet port
  • AP-X3X: 4 spatial streams, SmartRate port, Gigabit Port
  • AP-X4X: 4 spatial streams, dual SmartRate ports, dual-5GHz,
  • AP-X5X: 8 spatial streams, three radios (only AP-555 for now… that thing is a monster)
  • AP-X6X: Outdoor AP with 2 Spatial streams
  • AP-X7X: Outdoor AP with 4 spatial streams
  • AP-X8X: Outdoor AP with 60GHz (only AP-387)

The last digit indicates the antenna type. Odd numbers are internal, even numbers are external.

  • AP-XX3: Internal Omni
  • AP-XX4: Connectorized
  • AP-XX5: Internal Omni
  • AP-XX7: Internal Directional
  • AP-XX8: Connectorized and ruggedized,

APs with the H suffix indicate a wallplate mount designed for the hospitality industry. These APs also have a built-in switch. I love these APs.

Naturally, if you want to get the gory details, head on over to Aruba and look for the data sheet.

Stay tuned for the next Hands On post in which I will discuss Aruba Central.

Disclaimer: Aruba is my employer, but this post reflects my personal experience as a wi-fi nerd with Aruba products. Some APs were purchased on the open market, some were provided to me by my employer for lab use. This is not a paid promotion, and is not official Aruba communication. I am not part of the Instant product team.