Point to Point Mikrotik

Routed or bridged, there are few back haul radios available that can match the Mikrotik RouterOS software for features, tools, flexibility and cost.  With features and flexibility comes complexity and confusion.  I wanted to help dispel some of that confusion with this article.  You may have lots of choices to make, but most of these choices are relatively simple decisions.  And so, brave reader, proceed... When building a back haul, there are several questions that you must answer before you even order your gear.  The first, and perhaps the most important of these,  is "How much bandwidth do I want/need this back haul to carry?"  The answer to this question will, almost by itself, determine the gear you will be ordering.  One question I get fairly often is "How much traffic can the XXX routerboard pass?"  Well, that is not an easy question to answer in real world terms.  This is especially true with unlicensed wireless being part of the equation.  If you're interested in just the raw numbers, here is Mikrotik's comparison test results.  If you will be needing more than 100M, you will be pretty limited on choices (at least if you're sticking to just the RouterBoard line).  Mikrotik's RB600A and soon to be available RB800 are the only 2 outdoor Routerboards with Gig ports available. A second question that needs to be answered revolves around the question of the wireless protocol to be used.  Mikrotik, with version 4.x, has added support for 802.11n.  My experience so far is that this is still pretty experimental and is not, yet, very stable.  Some have gotten good results, but most users have reported various levels of frustration with this protocol in Mikrotik.  What IS very stable is Mikrotik's NStreme protocol running with RouterOS v3.30.  You may even consider running a pair of NStreme links with OSPF as a failover solution (see my article HERE for how to accomplish this).  The alternative to the OSPF solution is NStreme Dual (article HERE), which is a true full duplex wireless solution.  If you don't need full duplex, then I HIGHLY recommend a plain vanilla NStreme link. Another question that you must answer is about the actual gear.  This includes antenna selection, radio selection and host routerboard.  Part of this has already been covered in the previous paragraphs.  That, of course, is the host routerboard.  The actual radio and antenna selection is dependant upon several variables that are beyond the scope of this article.  Just ensure that you have selected a combination of radio and antenna that will provide appropriate RF energy at both ends of the link to provide for a stable wireless link.  The word "appropriate" in the preceding sentence does NOT mean "highest output possible".  I will, perhaps, pontificate in another article on the evils of excessive signal, but for the moment, I'll just say that "enough is plenty" when it comes to RF energy. Finally, you must determine if this backhaul will be participating in the routing portion of your network, or if it will be just a simple bridge.  If you will be routing, the OSPF article mentioned earlier will provide you with a good configuration for a dual radio configuration.  You can adapt that configuration quite easily for a single radio, so I won't cover that in this article.  If you need full duplex and you will be bridging the link, then I'd recommend the NStreme Dual article.  The reason for this is the simple fact that the OSPF method works quite well, but is painful to bridge, though it can be done.  The NStreme Dual method is QUITE easy to bridge.  Once the link is configured according to the article mentioned above, just add the following configuration to build a bridged link from ether1 on side A to ether1 on side B. /interface bridge add name=wirelessbridge /interface bridge port add bridge=wirelessbridge interface=ether1 add bridge=wirelessbridge interface=nstreme1 Pretty simple, huh?  This assumes that nstreme1 is the name you gave to the nstreme dual interface.  You can add management IP addresses to the bridge interface if needed, but this IP is not needed in order for the link to function. To build a point to point bridge with nstreme and a single wireless link, you would use the following code: /interface bridge add name=wirelessbridge /interface bridge port add bridge=wirelessbridge interface=ether1 add bridge=wirelessbridge interface=wlan1 /interface wireless nstreme set wlan1 enable-nstreme=yes /interface wireless set wlan1 disabled=no mode=bridge \ ssid=MikroTik wds-mode=dynamic \ wds-default-bridge=wirelessbridge \ band=5ghz frequency=5725 I have highlighted 3 parameters that need your attention before pasting this into your router.  The first "mode=bridge" will be assigned on one end of the link only, while the other end of the link will have "mode=station-wds".  The other parameters are highlighted so that you take notice of them.  Be sure you set the appropriate band and channel when you configure your radios.  With the above configuration, you will have a 100% working link (assuming you did your homework right when designing the RF portion of the link).  Again, you can (and should) add a management IP address to the bridge interface. As you can see, building a backhaul with Mikrotik is not only easy, but it is extremely flexible in terms of options.  If you have a specific need or question that I have not addressed above, feel free to send me an email (butche@butchevans.com) with your questions or leave a comment.  If your question is extremely specific, then an email is best.  Please don't use the comment section as a support channel.  Thank you. Finally, let me just say that I have recently opened my web store.  You can find all the hardware you need for a Mikrotik backhaul or any other need your WISP may have at http://store.wispgear.net/.  If you have a hardware need that isn't listed, then send email or call.  If you need help designing a link or figuring out other network engineering related tasks, that's why I am here.  Thanks as always for reading and please DIGG this article if you found it useful.

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