Question- 8 hops=low speed, high latency?

RouterOS Wireless Networking
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Hi! Dumb question from a newbie…We are a non-profit Society looking at installing a network to cover residences living in a narrow river valley bottom. The valley is about 15km long, very narrow, and is has many twists and turns. Our POP is at one end of the valley. Bad arrangement for wireless.

There are two ways for us to install the backbone and AP’s:
(1) Set up repeater stations high on the mountains along the valley and fight with problems of winter access, solar power, and vandalism. We can get away with 3 or 4 repeaters by doing this.
(2) Set up repeater stations low in the valley, along the highway. Power the repeaters from the local power Utility. Better winter access, reliable power, less trouble with vandalism, but we will need about 8 repeaters to get down the whole valley.

My question: What kind of latency and bandwidth can we reasonably expect at the end of 8 hops? We need to have a wireless internet product to sell at the end of the 8 hops that is better than the current dialup and satellite! I have asked some of the big-name high volume wireless OEM’s about this and they change the subject in a hurry, or offer hardly-believable smoke, saying their latency will be <10mS and the universe will be good, but avoiding stating any speed numbers.

Anyone “been there, done that?” and willing to offer an opinion?

Thanks,
Jon.

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We currently provide service after 7 wireless hops (going more than 60 miles). Latency to the last WiPOP is less than 20ms and speeds are over 6Mbps (tcp) using only 10mhz channel sizes. We mainly use RB532 for each link.

Make sure each link is a point to point and then the AP is a seperate routerboard.

Travis

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With 5ghz-turbo mode, polling with nstreme, and properly tunned mikrotik links, you can get around 50mbps half duplex with this setup.

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Can you get your connection in the middle of the valley? 3 hops one way, 4 the other.

tjohnson, why have the backbone running on seperate RB? I’ve got my parts in hand, RB600, with 5 AP, 2 have 2x 5GHz p2p shots, all are fed by the first AP. I figured the RB600 would have more than enough power to handle it, but I am running into config issues with pcq. Not a deal breaker, but I’d rather have the backbone completely unaffected and have pcq running on each AP. Shouldn’t really cause problems, but…

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We do routing on the point to point links and each AP acts as a transparent bridge. Makes things much easier and cleaner. Some of our point to point links have 5 other point to point links after so it makes more sense to not have complete failure if a board or PoE dies.

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Oldman,
Thanks for the suggestion but that’s too easy. Life wasn’t meant to be like that!

Our POP is done under a gov’t deal with the local Telco to help get service to us “great unwashed” who choose to live out in the sticks, where customers are sparse and no commercial ISP is interested in chasing the business. The Telco makes a low cost POP available to whoever wants to do the “last mile” but it has to be close to their local “central office”, which, in this case, is at one end of the valley.

We expect to get about 75 customers if we can provide a decent, fairly reliable service.

Another newbie question: How is the separate AP done? --My guess is that the separate AP means that you put a separate routerboard up with the AP radios and feed the AP via a LAN cable from the PtP link routerboard (which has its own radios)??? Both would be co-located on the same tower…?

Jon.

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Is there any chance of having your first AP high enough to give access directly to the other APs?

Have AP 1 broadcast with a 5GHz panel and each AP down has a 5GHz client with 2.4GHz AP? Or does geography not permit?

Bottom line, is there any one place in your network that you can access from the other seven? Even if you can break it down where 3 have direct access and the rest get access by those three. Anyway you can get where a single AP in the middle won’t bring down the rest in line would be better. Even if your connection is at the end of the valley, you could still do a p2p to the center to keep the number of hops to the end down.

I don’t think the 8 hops is going to cause a major problem either way, but it would work better with less, obviously.

8

I have a fully routed network, I ping my Client at 6 hops away in 4ms.
I ping 64.233.183.147 (http://www.google.com), this gives me 91ms in average. Google is 20 hops away from my PC.
Probably dial up is not so much slower, for a ping. Satellite is more like 300-400ms, for fast links!

As you can see, the amount of hops in your properly configured network is a minor issue and hardly noticeable.

My network speed is 36Mbps at the slowest link, for data transport. (ping is very little data, the time measured is the time it takes to receive that little package back by its source after its visited the recipient. Data, big data, like files, pictures or streaming data, needs more then just a fast ping time. It also needs capacity. It´s like driving a motorbike through a small alley, you can still make high speed. Now try to push 1000 motorbikes through that same alley! You need a big highway now to keep the data flowing!

I use back haul units that are actually a client (station mode) of a ´higher´ AP. The cards can handle that and for the AP it´s just a client with more traffic then the other ´real´ clients. But by the time an AP gets too many clients it might be wiser to create a separate back haul link to the remote location. When I´m reaching 30+ clients it´s time to plan a separate back haul link. This is both for redundancy reason as well for CPU usage of the AP.

Most secure and redundant would be to have all radio´s in separate boxes, in separate masts (lightning strikes!) and have each box a dual function, so it can take over a function of the other ´sister´ nearby. This can even made fully automated fail over, but it needs a bit more thinking and planning and off course costs!

I use MT routerboards and I have a really big number operator as my friend and both me as him have a very low failure rate of boards in a production environment. Biggest risks are probably coming from outside; lightning, static discharges, (forest)fires, power loss of the host (house or whatever) and may be in your case, vandalism. All these things have their solutions or workarounds. The boards themselves seem to have eternal lives under normal conditions…

In your case I would work with a backhaul system all the way up to the end as you main connection in a routed network with seperate AP’s for the clients. The different radio’s can still be shared in one box. For instant, rb333 can have three cards. One will be the ´station´ looking at his AP for the Backhaul. The second will be the AP for the the backhaul link towards the next ´station´. And the third can serve as an AP for clients. As long as you have not more then 40 clients on each AP, and or very big traffic load this should be no problem for the boards.

Each ´station´ should also be able to log into the ´client serving AP´ higher up the link, in case its higher backhaul AP would fail. Work with access lists and connect lists.
Pure radiowise spoken, each unit would have now two AP’s and one client radio.

Give each backhaul link its own network, as each AP with clients in one network. Now by setting the proper default gateway’s and backup gateways together with the backup radio´s in the connect and access list you have a pretty reliable, and fast system.

I try to have all my radio links in the region of -60 to -75dBm which give me basically at least 36Mbps connection speeds. Since we have simplex connectivity and traffic overhead etc. this means a ´real´ network speed of 20, 25Mbps is possible.

General network speed comes more down to proper radio link configuration, proper configuration of the different traffic prioritizations if the links see heavy traffic, etc.
And there is much more to be ´fine´ tuned to get the max. out of the network speed.
But, to come back to your first question, the amount of hops is really of no issue.


rgds.

Rudy




. Start with BH 1 (in bridge mode With every AP in between has the possibility to take over a backhau

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Sorry, this line was not intended. Skip this.

Rudy

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WirelessRudy, I’m still on dial up right now, best ping I get to google is 300ms. Best satellite (several of my PC business customers) ping is around 1200ms.

Average for DSL and cable here is about 40-60ms ping to google. You’re not doing too bad.

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Guys, Thanks! You have given this NOOB some things to think about—and puzzle out some wireless network propellerhead-speak!!! ;>)

Just browsing this MT website has me thinking that a lot of the problems with poor access times and slow speeds is from improper setup, both in physical radio setup and in twiddling the dials under the hood.

A high point to see more than one AP is possible. It just brings back my earlier concerns about winter access, power supplies, and vandalism. One suggestion about vandalism was made to me is to put a webcam or two in the trees around the installation. Then the people affected by a dickhead who shoots out the AP’s (and watched him do it on the webcams) can meet him at the base of the forestry access road with appropriate sporting gear. He might decide in a heck of a hurry to donate money to fix equipment…

Another couple of questions:

–Is there a text available from somewhere that covers some of the basics of wireless networking that could help me improve my understanding of the issues?
–MT does not seem to offer much in the line of radios to fit their routerboards. Are there other brands that you have used that work well in the 900 and 5.8 freqencies?

Thanks very much,
Jon.