Can a router be a router and an access point at the same time?

By the usual definition, a "router" is a device which is connected to two or more different IP networks. A typical "home use" WiFi AP/router is connected to two IP networks - one network is the ISP network, and the other network is the home network.

The "access point" functionality, per se, is not a router. Rather, it's a "bridge". It's connecting two physically different network segments (e.g. an Ethernet, and a WiFi radio network) which are both part of the same IP network (in a home this is usually an IPv4 "private" network, in the 192.168.xx.yy network number space).

There are many devices which are routers (e.g. have multiple Ethernet ports bound to different IP networks) and which are not access points (i.e. they have no WiFi radio at all).

In a typical home network, a "one-box" device (e.g. the classic Linksys WRT54G or similar) is usually performing multiple functions:

- It's acting as a WiFi access point

- It's bridging the WiFi LAN into the home's Ethernet LAN

- It's acting as a DHCP server, handing out IP addresses on the LAN to client devices (both wired and wireless)

- It's acting as a client system on the ISP's WAN network (cable or DSL or ??) - sometimes with a fixed IP address, sometimes with a dynamic IP address assigned via DHCP, sometimes as a PPP-over- Ethernet or PPP-over-ATM client.

- It's acting as a router (and, frequently, a "network address translator" and/or proxy) between the wired/wireless LAN, and the WAN (Internet).

You don't have to use all of these functions at the same time.

For example, in my own home, I have a separate firewall/router/server system (a Linux box with multiple wired Ethernet ports) which performs the routing, network address translation, and DHCP- server jobs. I don't need my WiFi box to perform any of these. So, I simply disable the routing and DHCP-server functions, and use the WRT54GS or equivalent as an access point.

In the case of trying to set up a remote node which talks to your home network (e.g. an Ubiquity) you have a number of choices as to how to go about it. In some cases, if you have only one (wired) client device attached to the Ubiquity, you can use the Ubiquity as a "client bridge" (you'll sometimes hear these referred to as "gaming adapters" because that's how they are often used). The remote client device will, in effect, be on a simple remote extension to your home's LAN, and it will receive an IP address assigned by your main router/AP's DHCP server.

It's tricky to try to attach multiple remote clients to a single "client bridge", though, for reasons having to do with how 802.11 operates.

If you need to do this (have multiple devices out at the Ubiquity location) you may be better off running a "routed" configuration. In this arrangement, the Ubiquity would act as a client device on your home WiFi network (it would be given its own IP address via DHCP or static assignment). It would actually serve an entirely separate IP network on its wired-Ethernet side - it would act as a DHCP server for clients on this network. It would route packets from these clients to the home LAN (wired and wireless) and the Internet by forwarding them to your home's main router/AP. The router/AP would need to have one new bit of configuration information added: you would have to add a "route" entry, telling it that packets for the second IP network (on the far side of the Ubituity) would need to be transmitted to the Ubiquity for forwarding. Some systems can handling this routing setup for you in a mostly-automatic way; you would probably need to enable a feature like RIP so that the various routers can exchange routing information on their own and figure out the right packet routes.

======================================================================= Your router (if it is at all typical) comes set up as an access point. Can you use a laptop to connect to it within ~100 ft? I bet you can. If not, fix that first. BTW, why don't you mention what kind of router/AP it is? Don't make people guess.

From

"...create a powerful and robust outdoor Access Point, Client, or Bridge." It has an ethernet connector and uses PowerOverEthernet. The PDF describes the software you need to use to point the thing. Deal with that next. Get it pointed and picking up the signal that you checked in the previous paragraph.

What do you want to connect to the Bullet M2? A single system? Then it's a matter of configuring the Bullet. It might even configure itself using the DHCP daemon in your (typical) router/AP. Are you worrying before you even tried it?

If you want to connect the Bullet to another network, then you get into the details.

======================================================================= Your router (if it is at all typical) comes set up as an access point. Can you use a laptop to connect to it within ~100 ft? I bet you can. If not, fix that first. BTW, why don't you mention what kind of router/AP it is? Don't make people guess.

From

"...create a powerful and robust outdoor Access Point, Client, or Bridge." It has an ethernet connector and uses PowerOverEthernet. The PDF describes the software you need to use to point the thing. Deal with that next. Get it pointed and picking up the signal that you checked in the previous paragraph.

What do you want to connect to the Bullet M2? A single system? Then it's a matter of configuring the Bullet. It might even configure itself using the DHCP daemon in your (typical) router/AP. Are you worrying before you even tried it?

If you want to connect the Bullet to another network, then you get into the details.

It's difficult to determine what your Amateur Radio Antenna qustion is.

======================================================================= Your router (if it is at all typical) comes set up as an access point. Can you use a laptop to connect to it within ~100 ft? I bet you can. If not, fix that first. BTW, why don't you mention what kind of router/AP it is? Don't make people guess.

From

"...create a powerful and robust outdoor Access Point, Client, or Bridge." It has an ethernet connector and uses PowerOverEthernet. The PDF describes the software you need to use to point the thing. Deal with that next. Get it pointed and picking up the signal that you checked in the previous paragraph.

What do you want to connect to the Bullet M2? A single system? Then it's a matter of configuring the Bullet. It might even configure itself using the DHCP daemon in your (typical) router/AP. Are you worrying before you even tried it?

If you want to connect the Bullet to another network, then you get into the details.

From the M2 literature, the device can be an access point, bridge, or client. If you are connecting one device to the M2, say a notebook, you want to configure the M2 as a client. If you are going to connect the M2 to a switch, I think you want to make it a bridge, but I am not 100% sure.

Bridging is a little tricky if you DHCP (which I assume you will). But I don't want to clutter up this point if you are just going to be a client.

Be sure you understand the polarization of your WAP and the M2. Most WAPs will be vertically polarized. Just read the M2 manual to insure uou set it up to be vertically polarized.

I've done wifi over a few miles to just a wifi router on a wall. But generally backhaul (point to point) wifi is done with two directional antennas and often using horizontal polarization. There is some loss if the transmitter and receiver are not polarized the same way. Since most wifi is vertically polarized, you do the back haul horizontally and take advantage of such loss to reduce interference.

< snip >

Maybe you need to bone up on mesh networks. Developments are coming fast and furious and some of the router channels are in ham bands, so he could, in fact be on-topic. I wish I knew enough to answer Jesse.

I didn't think it mattered because it's your typical home broadband router. It's the WRT54G, version 5 router.

Yes. I have access to 120v power about a half mile from the house and I just want to set up the Bullet M2 pointing at the Linksys WRT54G inside the house.

Connected to the Bullet M2 will be a 24v POE, and on the other end of the Ubiquiti POE will be a laptop.

The antenna is a 14 dBi planar antenna connected to the Bullet M2.

The view will be unhindered and is a direct line of sight at chair level, so I don't even have to mount the antenna (although I probably will so as to keep it aimed when not in use).

Hmmmmmmmmmmmm. I don't think so. I tried and I can't even *see* the home SSID access point from the laptop.

Admittedly, the laptop has a lousy wireless NIC and antenna (probably on the order of 50mW and 1/2 dBi) and, I probably could spend a hundred to get a USB antenna and radio but it's a Linux laptop and I've already tried and failed (in the past) with finding suitable USB drivers for USB wireless devices.

Besides, the Bullet M2 output power is something on the order of

28 dBm, so it should *easily* go the half mile needed.

I have never understood this stuff! So, thanks for the advice.

I'm planning on connecting the Bullet M2 only to a laptop via the Linux laptop wired (eth0) Ethernet NIC.

The laptop just needs to know:

1. IP address (e.g., 192.168.1.200/255/255/255/0)
2. Gateway (e.g., the IP address of the Bullet M2, whatever that is)

The Bullet M2 needs to know a lot more, it seems: a. SSID & password of the Linksys WRT54G a half mile away b. Whether it is a router or a bridge or access point

I don't remember seeing "client" as an option. I have to look again!

The alfa tube-u works fine under linux. The drivers are in the kernel. But if you set up the M2 as a client, it should work. Don't forget to check the M2 manual for the antenna polarity.

Power doesn't matter much if yo don't have it on both ends.

Can you give more detail. What do you have including details, and what are do you want to do.

Give as many details and wishes as possible. It may seem trivial to you but it all is important to what may meet your need.

i.e. do you need to have access to just the internet from wireless devices, or do you need to connect to things on your local Microsoft home or work network?

The answer to that one will change what you equipment you need. If you want to do it securely.

tom K0TAR

That's my biggest concern.

I'm hoping the sensitivity of the Bullet makes up for the lack of transmit power of the WRT54G.

I'm not worried about security (it's a guest network anyway, with an extremely weak password, on purpose).

The devices are three:

1. WRT54G is the home broadband router
2. Bullet M2 with a 14 dBi planar antenna is the radio 1/2 mile away
3. Standard Linux laptop is the PC connected to the Bullet

The only goal is to have the laptop on the Internet from 1/2 mile away from the Linksys WRT54G router using the Bullet M2 as it's radio.

One word of caution. In many countries it is illegal to connect an external antenna as you described. You need to check your country's laws before doing so. I'd hate to see you get in trouble unnecessarily.

Thank you for finally disclosing what you're trying to accomplish and what you have to work with.

The WRT54G v5 and v6 are junk. I can supply reasons why they're junk later but the big problem is that they just love to hang. I've slowly been removing them from customers and hotspots and have built up quite a collection. Think about a replacement such as another Ubiquiti Bullet M2.

Let's do some path loss calcs. The assumption is that you have line of sight and that there are no obstructions in the path or in the Fresnel zone. Follow my example at:

M2 end .... TX power M2 = +17dBm (non HP version) TX coax loss = 0 dB with antenna mounted to M2 radio TX ant gain = +14 dBi panel Distance = 0.5 miles RX ant gain = +2 dbi rubber ducky RX coax loss = 0 dB with rubber ducky mounted on router RX sens = -84 dBm (at 12 Mbits/sec) WRT54G v5 end .... Fade margin = unknown

Argh. The YDI link calculator has moved again. Now it's at: Plugging in the numbers, I get a fade margin of 18.8 dBm. That's sufficient and should work just fine if there are no obstructions in the path.

If you are shooting through a wall, window, trees, or don't have line of sight, you're going to have problems. The numbers never get better, only worse. Also, interference might be a problem if it is located along the line of sight of the +14dBi antenna, which will increase both the signal from the WRT54G and any interference that it sees. You might want to do a "site survey" along your intended path with the +14dBi antenna and UBNT Bullet M2 to check for potential problems.

Well, it all depends on how you configure the BOX....... Most Home Wifi Boxes have an AccessPoint, (WiFi Radio) a Ethernet Switch, (LAN Ports) and Router, (Wan Port) all built-in to the One Box. The Ethernet Switch connects ALL the LAN Ports, WiFi Radio Port, and Router LAN Port together. SO, if you do NOT need the Router Portion, just connect you local Network to one of the LAN Ports and away you go, since the WiFi Radio is just another Port, on the Ethernet Switch.

If you need the Router Portion, for local Subnet Routing, then you connect your LAN to the WAN Port and setup the WiFi and Ethernet Switch as a different subnet than your Main LAN. (This what I do for Customer Access via different Access Points around my LAN so I can know who is using what Access Point, and when. Each Access Point does it's Own DCHP for the WiFi, and local SubNet it is setup for)

If you have a simple LAN Network and this BOX is your Main Router, then the WAN Port goes to your Internet Access Device or Port, and the Router LAN Port on the Ethernet Switch outputs the routed Packets to the appropriate Switch Ports. (LAN Ports and WiFi Radio Port)

Clear as Mud.... right? Oh Well.....