PtP wifi + EOIP Tunnel

qoole · Tue Jul 02, 2013 4:52 pm

Hi there,

My first post here. Here goes!

I work in a school which is in the process of getting a new fiber connection to one of it's outlying buildings (due to various issues it was the closest we can get to the main building).
The 'Modem/Router' supplied allows for what it calls 'modem mode'. Ie, it bridges its WAN port with the first LAN port and disables all other LAN ports.
When you connect a PC to this LAN port and try to gain an IP via DHCP you get a 'real world' IP (ie, the WAN IP of your connection).

What I need to do is bring this IP to a Mikrotik x86 box we're using for our router. The tricky part is that the connection between the outlying building and the main building is via a pair of SXTG2HnDs, not a copper cable.

How would people do it? I can imagine it's going to involve an EoIP tunnel from the outlying AP to the router, but beyond that I don't know?

At a guess it would be something along the lines of:

Setup a wifi ptp bridge (any suggestions between NV2, NSTREAM or 802.11??).
On the 'main building' AP bridge wlan1 and ether1.
Create an EoIP tunnel from the 'outlying' AP to the router
On the 'outlying' AP bridge the EoIP tunnel and ether1.
On the router set it to DHCP on the EoIP tunnel and that _should_ give me my WAN address?

Thanks,

Alex

cbrown · Thu Jul 04, 2013 2:25 am

What you could do is just put your wireless modes to bridge and station-bridge. Then bridge the wireless and ethernet interfaces on the SXTs. Now you have a layer 2 connection between your buildings, no need for vlans or eoip tunnels. As for the protocol, NV2 will give you more throughput but higher latency. Nstreme will give you lower latency with a little less throughput.

Best advice is to try them both and see which one works best for you.

qoole · Thu Jul 04, 2013 12:34 pm

Hiya,

Thanks for your reply!

I'm not sure that's exactly what I'm looking for though.
I guess I should have been clearer the SXT is not connected directly to the x86 box that is going to be used as the router.
There is at least two switches (RB2011-UAS 2HnD + TP-Link SG3424) in between the SXT and the RBx86 box.
This is why I assume a tunnel is necessary!

Thanks,

Alex

cbrown · Thu Jul 04, 2013 2:36 pm

Does the TPLink support 802.11q? Post a drawing of your network.

qoole · Thu Jul 04, 2013 3:58 pm

Hiya,

Yes, the TP-Link supports VLANs (802.11q).
I will try to mock up a doodle of the network later.

Thanks,

Alex

qoole · Tue Oct 08, 2013 5:21 pm

Ok, sorry for the MAHOOSIVE delay on updating this post.

The situation has changed a bit and I would like to explain what I have done.

Cable broadband (50mbit Down 5mbit Up) comes into building 1 (B1 from now on).
This is linked to building 2 (B2 from now on) PtP bridge (two SXT G-2HnD).
From here there is a copper link to building 3 (Yes, B3 from now on) to a RB2011UAS-RM.

Between B1 and B3 there is an EoIP tunnel and the RB2011 gets an IP on the subnet of the modem (10.0.10.0/24) which it then uses as a WAN.

I have tuned the connection between the two SXTs as much as possible.
The two SXTs are about 100m apart so I have turned the TX power down on both of them to 10dBm in card-rates mode. This gives me -62/-63 (TX/RX CH0 and CH2). CCQ still seems a bit low at ~50% TX/RX (this seems to increase as the link-rate increases). SNR is ~39dB.
I have tried both nstreme and nv2. nstreme seems to give better latency but with more dropped packets. NV2 seems to give better overall throughput/packet loss but latency is higher.
Latency between the RB2011 and the SXT at the far end of the link is about 2ms/25ms/250ms (min/avg/max) in NV2 mode which I'm quite happy with.
I notice that when not in use the link speed drops down to 1-5mbit/s between the two SXTs, What I would like to know is how can I (reliably and without affecting packet loss etc) prevent this from happening so I can avoid the delay as the link speed ramps up.

Near end of the SXT link is set up as follows:

/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
add authentication-types=wpa2-psk group-ciphers=tkip,aes-ccm mode=dynamic-keys name=smc_golf supplicant-identity=Mikrotik unicast-ciphers=tkip,aes-ccm
/interface wireless
set 0 adaptive-noise-immunity=ap-and-client-mode band=2ghz-onlyn basic-rates-a/g=54Mbps basic-rates-b=11Mbps channel-width=20/40mhz-ht-above country="united kingdom" disabled=no frequency=2432 ht-basic-mcs=\
    mcs-8,mcs-9,mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15 ht-rxchains=0,1 ht-supported-mcs=mcs-8,mcs-9,mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15,mcs-16,mcs-17,mcs-18,mcs-19,mcs-20,mcs-21,mcs-22,mcs-23 ht-txchains=0,1 l2mtu=2290 mode=bridge \
    nv2-cell-radius=10 nv2-security=enabled security-profile=smc_golf ssid=SMCPTP supported-rates-a/g=54Mbps supported-rates-b=11Mbps tx-power=10 tx-power-mode=card-rates wireless-protocol=nv2
/interface wireless nstreme
set wlan1 enable-nstreme=yes
/interface wireless align
set receive-all=yes ssid-all=yes

Far end of the link is set up as follows:

/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
add eap-methods=passthrough name=open_net supplicant-identity=MikroTik
add authentication-types=wpa2-psk,wpa2-eap group-ciphers=tkip,aes-ccm mode=dynamic-keys name=smc_golf supplicant-identity=Mikrotik unicast-ciphers=tkip,aes-ccm
/interface wireless
set 0 adaptive-noise-immunity=ap-and-client-mode band=2ghz-onlyn channel-width=20/40mhz-ht-above country="united kingdom" disabled=no frequency=2432 ht-basic-mcs=\
    mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7,mcs-8,mcs-9,mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15 ht-rxchains=0,1 ht-txchains=0,1 l2mtu=2290 mac-address=02:00:00:A8:0A:6B mode=station-pseudobridge nv2-security=enabled security-profile=\
    smc_golf ssid=SMCPTP tx-power=10 tx-power-mode=card-rates wireless-protocol=nv2-nstreme-802.11 wmm-support=enabled
/interface wireless nstreme
set wlan1 enable-nstreme=yes