[CUWiN-Dev] multiple gateways?
Bill Comisky
bcomisky at pobox.com
Thu Dec 15 15:18:45 CST 2005
On Wed, 14 Dec 2005, David Young wrote:
> On Mon, Dec 12, 2005 at 05:57:14PM -0600, Bill Comisky wrote:
>>
>> In lawndale we put up a second gateway (stower) in the old Sears Tower on
>> the south side of the building facing south; our existing gateway (wtower)
>> there is on the west side facing NW. These gateways are plugged into the
>> same LAN served by the same dhcp server, and as of now have the same SSID
>> and channel.
>>
>> Though they face different directions (sector antennas) and have a fair
>> amount of building in between, their radios can hear each other. There is
>> a small amount of overlap on the ground, where one or two nodes can hear
>> both gateways. Will CUWiN "do the right thing" in this scenario, or would
>> it be better to make distinct networks with different channels and/or
>> SSIDs?
>
> It will depend a lot on the metrics. If the metrics are stable enough
> that one gateway usually has a worse path metric than another, even in the
> areas of overlap, then you are going to be ok. If not, then it might be
> best to change SSID and/or channel until we have multiple gateway support.
It looks like we are seeing some stability issues that are pushing us
towards changing one of the gateways to a different channel. Rob Simmons
in Lawndale showed us the output from 'ping -nR' from a standalone node
that is in the area on the ground where both gateways are visible. He
first ssh'd into the node from our stower gateway using its link local
address, which seems fairly stable. Below is a representative sample of
the output. You can see the route flopping between the gateways with
disturbing intervals of "No route to host", where the node has no default
route (though we're still connected through stower via the link local
address).
Bill
--
Bill Comisky
bcomisky at pobox.com
cast of characters:
-------------------
10.0.236.158 ath0 address of node we're pinging from
192.168.4.1 LAN address we're pinging
192.168.4.3 LAN address of wtower gateway
10.64.172.254 alias to above
10.0.253.114 ath0 address of wtower gateway
192.168.4.6 LAN address of stower gateway
10.0.236.156 ath0 address of stower gateway
10.0.233.27 other standalone node used for intermediate hop
10.0.241.196 " "
10.0.241.164 " "
root at 10.0.236.158 # ping -nR 192.168.4.1
PING 192.168.4.1 (192.168.4.1): 56 data bytes
ping: sendto: No route to host
64 bytes from 192.168.4.1: icmp_seq=1 ttl=62 time=62.804 ms
RR: 10.0.233.27
192.168.4.6
192.168.4.1
192.168.4.1
10.0.236.156
10.0.233.27
10.0.236.158
64 bytes from 192.168.4.1: icmp_seq=2 ttl=62 time=10.621 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=3 ttl=62 time=8.970 ms (same route)
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
64 bytes from 192.168.4.1: icmp_seq=15 ttl=61 time=22.800 ms
RR: 192.168.4.3
192.168.4.1
192.168.4.1
10.64.172.254
10.0.236.156
10.0.233.27
10.0.236.158
64 bytes from 192.168.4.1: icmp_seq=17 ttl=63 time=5.844 ms
RR: 192.168.4.3
192.168.4.1
192.168.4.1
10.0.253.114
10.0.236.158
64 bytes from 192.168.4.1: icmp_seq=18 ttl=63 time=49.562 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=19 ttl=63 time=31.946 ms (same route)
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
64 bytes from 192.168.4.1: icmp_seq=24 ttl=63 time=22.095 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=25 ttl=63 time=7.142 ms (same route)
ping: sendto: No route to host
[..repeated 27 times..]
ping: sendto: No route to host
64 bytes from 192.168.4.1: icmp_seq=55 ttl=62 time=121.087 ms
RR: 10.0.233.27
192.168.4.6
192.168.4.1
192.168.4.1
10.0.236.156
10.0.233.27
10.0.236.158
64 bytes from 192.168.4.1: icmp_seq=56 ttl=62 time=14.996 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=57 ttl=62 time=6.954 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=58 ttl=62 time=9.382 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=59 ttl=62 time=23.467 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=60 ttl=62 time=48.221 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=61 ttl=62 time=6.656 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=62 ttl=62 time=10.570 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=63 ttl=62 time=19.640 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=64 ttl=62 time=12.563 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=65 ttl=62 time=8.296 ms (same route)
ping: sendto: No route to host
64 bytes from 192.168.4.1: icmp_seq=67 ttl=62 time=14.369 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=68 ttl=61 time=19.724 ms
RR: 10.0.241.196
192.168.4.6
192.168.4.1
192.168.4.1
10.0.236.156
10.0.233.27
10.0.241.164
10.0.236.158
64 bytes from 192.168.4.1: icmp_seq=69 ttl=62 time=12.162 ms
RR: 10.0.241.196
192.168.4.6
192.168.4.1
192.168.4.1
10.0.236.156
10.0.233.27
10.0.236.158
64 bytes from 192.168.4.1: icmp_seq=70 ttl=62 time=10.963 ms
RR: 10.0.233.27
192.168.4.6
192.168.4.1
192.168.4.1
10.0.236.156
10.0.233.27
10.0.236.158
ping: sendto: No route to host
ping: sendto: No route to host
64 bytes from 192.168.4.1: icmp_seq=73 ttl=62 time=7.010 ms (same route)
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
64 bytes from 192.168.4.1: icmp_seq=77 ttl=62 time=8.518 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=78 ttl=62 time=21.133 ms (same route)
64 bytes from 192.168.4.1: icmp_seq=79 ttl=62 time=9.728 ms (same route)
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
ping: sendto: No route to host
64 bytes from 192.168.4.1: icmp_seq=84 ttl=62 time=20.509 ms (same route)
ping: sendto: No route to host
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