another newbee designing and building 2-hop link, ples help

Hardware MikroTik hardware general
1

Hello, all

first of all I need to excuse myself for repeating a question you must have heard thousands of times, but I need to confirm as much information as possible for my specific situation.

I want to build 2-hop, 5.4GHz wifi to back-haul IP for my customer. I need to make sure that I can transfer 20Mbps full duplex, but I really want to be able to offer at least 30Mbps full duplex, hoping for 50-tish. I have 6Km (4 miles) distance to the repeater, and another 9Km (6 miles) from that point to my customer. Let me try and summarize my conditions:

A point - urban area, at cca. 650m above sea level, downtown, urban center, surely has some radio noise on any or all channels, haven’t tested it yet.
B point - mountain top, at cca 1900m above sea level, radio repeating station, has lots of antennae for different purposes - tv, radio, microwave, etc.
C point - urban area, at cca. 850m above sea level, small town, I do not know if there is radio noise there but I expect some.
A - B distance: cca. 6 Km, or 4 miles
B - C distance: cca. 9 Km, or 6 miles

Even though there is radio noise at all points, I do expect to find some channels with very few or no apparent radio noise. I was planning to buy 3 routerboards, for ABC points. Also, I would buy 4 cards, and 4 antennae. My choices were:
Routerboard: 433UAH, my secondary choice is 433AH
Mini-PCI card: R52H, or secondary choice - just R5H
Antennae: http://www.sunparl.com/en/products_detail.asp?id=177 - I was planning on using grid 30dBi antenna, capable of both vertical or horizontal polarization. My secondary choice is 29dBi dish http://www.alibaba.com/product-gs/200519160/5_8GHz_Dish_Antenna_29_dBi_.html
Cabling: MFC400, less than 2-3 meters in use, almost no loss I guess

My calculation says that I should get about…-39 or -41 for respective links, so I believe that signal should be good, even though some channels might be taken on this frequency. I know that, before I order equipment, I need to visit sites and try and inspect how busy those points are, with 5.4GHz signal, but before that I need to propose equipment and see if everything is financially feasible. So, I will definitely put UPS and 5.4 client antenna in my car and drive around, but first things first - I need to make a plan to start with.

My primary concerns and questions are:

  • Will I be able to get this throughput, what are the limits according to your experience? What is the min/max that I could/should expect in above described situation? Does anyone have any idea what are min/max latencies I should expect here?
  • What are practical differences in performance between R52H and R5H cards? I would rather have more versatile cards, capable of both 2.4GHz and 5.4GHz ranges, if it does not make big of a difference in real life using those two cards.
  • What are practical differences in performance between 433 UAH and 433AH, as well? Just USB or no USB port?
  • Will the RouterBoard at the middle point, B point, be able to bridge two cards efficiently? Excuse my ignorance, I never tried this with routerboard, I do not know if there are limitations to this and/or any bottlenecks here? I was planning on using just one routerboard with two cards for the middle point.
  • If I’d use Alubox/333 Outdoor IP65 Case *(http://www.pc-mastor.gr/product.php?id_product=72) would I experience problems during summer/winter? We do get a lots of snow. Middle point would be on the platform, it is not improvised but TV repeater platform with some roof over it, however still exposed to weather. I worry the most for the middle point, both A and C ends could have better/easier access, in the case I need to modify casing for heat/cold conditions.

Also, any other information and/or suggestions are more than welcome, whether you would propose different models or manufacturers (for antennae, of course :slight_smile:)

I really want to bring down cost for my company and start building with MikroTik, I have some limited experience with this equipment within the city, but cannot tell for sure from own experience about this proposal I need to make. Thank you in advance for the patience it took to read this and perhaps give some answers :slight_smile: I will be more than happy to provide more information if needed. Thanks again!

2

I can help with a few of your questions…


You should be able to get 20mbps full duplex if you use 40MHz wide channels and there isn’t too much noise. 802.11n would be a better solution, but you’ll need MIMO PTP antennas. I haven’t used 11n in a production environment, but some people say it’s not stable yet. Latency will obviously increase when the link is under load, but you can do QoS to prioritize traffic. If the link isn’t heavily utilized you can expect latencies around 10ms max.

I’d suggest the R5H as it has the better MMCX connector and should have better sensitivity than the R52H since it’s only a 11a card.

Yes the only difference is the USB port, which you won’t need in your situation.

Yes you can bridge the two radio cards either using WDS or MPLS. I believe the latter is the best solution as the CPU usage and overhead is less.

That case should be fine as long as it is waterproof. I’ve had many routerboards mounted outside in -10 to 90F conditions, snow, typhoons, etc… Never had a failure knock on wood.

3

Thanks for the answer.

I have had another thought - of doubling cards and antennae, than using one for tx and another one for rx. I am reluctant though, because I think that than possible VoIP users might have problems. Do you or anyone else has the idea how to ensure / increase bandwidth?

4

Depending on you budget and reliability requirement I would suggest a more advanced approach using OSPF giving you full speed of N, simulated Full Duplex, and full fail over if a board or link fails. This is basically a full ring but Router 2 and Router 5 are connected via Ethernet.

Site 1
2x 433 AH each with a single R52HN and a dual pole dish
Router 1 . WLAN1 192.168.0.1/30 (RX 20, TX 10)
Router 4 . WLAN1 192.168.0.13/30 (RX 10, TX 20)

Site 2
2x 433 AH each with a two R52HN and a dual pole dish
Router 2. WLAN1 192.168.0.2/30(RX 10, TX 20) WLAN2 192.168.0.9/30(RX 20, TX 10) Ether1 192.168.0.5/30 (RX 30, TX 30)
Router 5. WLAN1 192.168.0.14/30(RX 20, TX 10) WLAN2 192.168.17/30(RX 10, TX 20) Ether1 192.168.0.6/30(RX 30, TX 30)

Site 3
2x 433 AH each with a single R52HN and a dual pole dish
Router 3. WLAN1 192.168.0.10/30(RX 10, TX 20)
Router 4. WLAN1 192.168.0.18/30(RX 20, TX 10)

Add 192.168.0.0/27 to you OSPF backbone, set the weight for OSPF on as (above) and full duplex will be active and you will have a fully redundant setup

For the ethers on site 1 and 3 you can put in real routes, eoip, ospf virtual link or any other method to tunnel or route.

I am currently planning a similar link and will be posting full settings/instructions/videos. If budget is a concern, you can cut back in either of two directions, you can drop the N and use a single Dual Pole antenna for each site, or you could put combine the routers at each site, using the same ip scheme, just add cards, site 2 would still need 4 cards so you would need an RB 600 or 800. Or you could do both drop the N and combine routers.

Those cases are great and very weatherproof but the weatherstrip sometimes pops out and is hard to get back in and the corner screws have a couple problems, 1 the allen wrench gets lost, cramps your hand or stripped. 2, the screws will bend if you get started tightening them down and the wind blows swinging the door open. For these reasons, I recommend using this case only on rooftops, not on towers. Also use a screw gun with the correct allen tip for tightening due to thumb fatigue.

5

Thanks both of you for the valuable input.

I think I will go with 433AH boards and R5H cards, or some similar combo whatever is available here. Thanks for that Netrat, and thanks both for the casing insight - I think I will go plastic or aluminum, whatever suits the location, I have to visit B and C sites yet.

Miahac, that is an elegant solution, thank you. I do not think my budget will be in the way - my other options are to look at the PDH links at 13GHz or sumpthin similar, therefore this is well under any other budget. My primary concern is that I maintain full throughput as promised, and low latencies, even at the peak time. I welcome idea of the redundancy, now my only concern is on the radio part. I will have to go and sniff the site this week to know how to proceed.

Before that, would you have any recommendation on the minimum for the antennae? Models and manufacturers you have experience with? I have this available: http://www.streakwave.com/mmSWAVE1/Video/HDDA5W_DataSheet-v2.pdf - HDDA5W-32-DP - 32dBi, dual polarity. I guess I will have to report back after I inspect sites, there is not much more that one could tell without knowing how much noise is there.

I am now wondering would it work without doubling the routerboards, just double the wifi cards, perhaps double routerboard only in the middle where access to the site is not so easy? Basically, I would do all the routing, firewalling and everything else on the routers outside that are bordering this wifi link, therefore if I just have a spare parts (routerboard and a card or two) somewhere I should be good with repair times… Throughput should be bottle-necked by radio signal quality, right, and it shouldn’t be a problem with Ethernet ports or the board itself?

Thanks a lot for answers, I appreciate it a lot.

6

yes, your posts are moderated. please read the FAQ!

7

Excuse me for repeating the posts, it just confused me - because of the weekend I guess I waited a little bit longer for moderator, while topic was approved express.

8

Hm, having read this thread I think I should go with UBI XR5 instead of R5H. With 600mW of output power and recommendations from users, seems to be more reliable…price difference is not that big - R5H is 65 euros, while XR5 is 105 euro at my dealers…also, I really do not want to have to climb to the repeater point in order to replace faulty cards, just cuz I changed channels or something…seems that there is no clear reason or any indication why would R5H cards let white smoke go.