Hy all,
this is my first post on this fantastic forum.
I need (please) info on the following problem that we have with our link:
Position:
Site A: RB112, SR5, sectorial antenna 16dBi, 1549m asl
Site B: RB153, SR5, grid antenna 29dBi, 3m asl.
Freq. 5825, 5GHz band (no turbo) and no nstreme.
Problem:
the link seems to be stable, -84/-86dBm on the receiver, but I’m unable to contact all the remote host. Sometimes I’m able to ping one of the host on the other side (CCQ 40/35 ca), but, for the rest 95% of the time (CCQ 40/0 ca), I’m unable to contact the other site (but the connection still alive). I heard from a friend that the Atheros chipset has an ack timeout limitation to about 60km… is it true?
May be the ack timeout cause this kind of problem?
How can I bypass this limitation?
I’ve no idea if there is an ACK timing problem at that distance but I think that the 16db antenna up the mountain might be your problem. Maybe it is getting interference as it will be seeing 100s sq km with its wide beam.
Having just had a quick go with the basic link buget calc I think that putting 26db gain up the mountain would make the link much more likley to work.
Do you have “Periodic calibration” enabled on both radios?
you can find periodic callibration on the wireless interface properties, under the “Advanced” tab. by default it is set to “default” but I don’t know if this is enabled or disabled! I always set to “enabled”. My longest link is only 12km but we have no mountains and lots of hedges and trees to get over.
YES IT IS TRUE - Atheros chipset has an ack timeout limitation to about 60km
Thats exactly why for such long links u must use nstreme, it overrides the ack timeout problem. I wouldn use sector antenna though, look at my post about a 93km link we did a few weeks ago, config, antennas etc… http://forum.mikrotik.com/t/93km-link/8988/1
I’m positively impressed for the quick answer and well prepared people that i found on this forum!
Thanks to hellspawn and all other people answered my question!
Only one another thing:
we setting up an hotspot such this (already described in another post):
–RB112, SR5, sectorial antenna 16dBi, 1549m asl–
The hotspot is an “ap bridge”, 5825MHz, no turbo, polling enable.
The client are set as “ap bridge”, 5825MHz, no turbo, polling enable. The link goes through WDS static rule.
Now, we have activated the nstreme, and no more link was possible!
I read this forum for help, and I saw that nstreme between site on “ap bridge” mode are impossible. So, I left the main hotspot in “ap bridge” mode, and set one client in “station wds” mode (with nstreme enable on this two site): all system goes ok. On the second client I set the “station wds” mode too, and from that moment, continuosly disconnect were suceeded (and no one can do a network scan until one of this two site will disable his RB112, it seems to be a conflict from one RB112 to another). A people give me an hint: “polling enable” on all site, but I’m already on “polling enable” on all site!
What can I do to restore ours link with nstreme enable?
I’ve just been playing with a test router and have found that as soon as I enable nstream I can no longer connect with my laptop - I expected this. What I had hoped was that if I created a Virtual AP on the WLAN interface it might work normally whilst the host AP used nstream, unfortunatly it does not.
I think you may need to use 2 WLAN adaptors, one using nstream for the long link and one running the hotspot.
Ok HarvSki, but it wasn’t my question…I think that it is perfect normally that one miniPCI in nstreme mode can’t connect to a client in non-nstreme mode, but my question was another: can I use nstreme in a PtMP environment?
I want to connect 3 (or more, but now only 3) site at different distance to a single ap in nstreme mode. The final setup will be:
Main site: 1549m asl;
Site A: 30km from the Main Site;
Site B: 60km from the Main Site;
Site C: 112km from the Main Site.
I tried this with success (but not for the site C, cause of the ack timeout limitation) with ALL site in “ap bridge” mode with static WDS enable. Now I want to try this multipoint link with nstreme enable (so the C site can connect him to the Main site - nstreme mode permit larger ack timeout setting - ), but I have to change the wireless mode from “ap bridge” to “station wds” for the site A,B,C, as described on MikroTik documentation “WDS for Nstreme protocol requires using station-wds mode on one of the peers. Configurations with WDS between AP modes (bridge and ap-bridge) will not work”. I change my environment to that mode (main site: ap bridge, site A,B,C in station wds mode), but no more connection are available in nstreme and in non-nstreme mode (connection available only if I power off two of the three station wds site). MT report this on one of the pdf available on it’s web site: “The Nstreme protocol is MikroTik proprietary (i.e., incompatible with other vendors) wireless protocol created to improve point-to-point and point-to-multipoint wireless links”. So, again, the question is: how can i do a point-to-multipoint link with nstreme enable on all sites?
I know nstream works in a PtMP environment but I’m not sure about 2 things:
The huge difference in distance between you links, I’ve no way of testing this and no expirence of it.
Using WDS with nstream, I only used WDS in an emergency last week for the first time when a bit of kit died and WDS was a quick fix until I replace the broken kit. I run a routed network and from all reports (including MT) a routed network will give better performance than a bridged (WDS) one.
Are you sure? I just controlled the statistic (on “registration” tab) of the two client connected, and the first (30km) reports 266us, the second (60km) reports 377us, so I think that the ack timeout parameter is individual.
But I’m perplexed…no one of you had never setup a multilink environment with nstreme enable?
Hello, you can use nstreme in PtMP and its done exactly like you describe it. main site - ap-bridge w nstreme w polling enabled(i suggest framer polcy = none ), WDS static and u myst have 1 wds inerface created for each of the stations, all WDS’s have for master interface the wlan interface of the main site and respectively the wds-adress values are the MAC adresses of the matching station-wds points. I wrote that rather bad…let me make a schematic
“Max-station-count” is on it’s default settings: 2007, but the problem still remain…no more of one PtP link with this settings. When another RB112/SR5 try to associate with the main site (PtP–>PtMP) all systems goes down. The only way to restore it, is to shut off all client except one (and, obviously, the main site).
I don’t know, I can’t try that setup. But there is an interesting update: Now, all clients are up and running with nstreme!
The mistake (but I think that it is a bug on RouterOS) was that all client was setting on “Static WDS” with a static entry for the WDS link from the client to the main site. I delete the static entry from all clients and put it on “WDS dynamic” and all systems are up and running.
So, the summary of installation:
Main site:mode=ap-bridge, wds-mode=static, enable-nstreme=yes enable-polling=yes framer policy=none
WDS-A: mode=wds-station, wds-mode=dynamic, enable-nstreme=yes enable-polling=yes framer policy=none SSID: the same of the main site
WDS-B: mode=wds-station, wds-mode=dynamic, enable-nstreme=yes enable-polling=yes framer policy=none SSID: the same of the main site
WDS-C: mode=wds-station, wds-mode=dynamic, enable-nstreme=yes enable-polling=yes framer policy=none SSID: the same of the main site
111,7km, 5825MHz NO Turbo, nstreme (normal, not dual).
Pos A: 1549m asl, RB112, SR5, Ap bridge, sectorial antenna 16dBi 120°H 8°V
Pos B: 3m asl, RB153, SR5, Station WDS, grid antenna by PAW 29dBi, vert. pol., 8°H 8°V.
I reached a 8,6MBps peak UDP receive. No disconnection on 30m test (i spoke with skype while listening a internet audio streaming, so, no audible disconnection).
Thanks to all partecipied to this thread and helped me.
