1 May
2017
1 May
'17
1:16 p.m.
Replacing the earlier sequential search through the
routing
table with a binary search has significantly sped up lookups,
which can happen up to twice per packet forwarded (once for
source address, once for destination address).
With "only" 16 million addresses in AMPRnet, why don't you use a 16-million
entry array
holding the next hop for each IP in 44.x.x.x or zero for those addresses that have no
tunnel?
Then you only need a single index operation to get the next hop for a packet.
That requires 64MB of memory to store, hardly a significant amount today.
And it can double-up as the filter to forward traffic only to/from registered addresses.
Of course the update operation becomes more expensive, but it could probably be done
in-place
without disrupting packet forwarding. Or you could build a second table and then switch
to it after the build is complete (requiring 128MB).
Rob
1 May
1 May
1:24 p.m.
New subject: amprgw routing
Interesting concept. Someday if we have enough memory I may try it, but
right now amprgw (an old machine) has only 4 GB of memory. It'd die swapping.
At the moment, I use the ipfw firewall to filter registered addresses; that saves
several context switches.
- Brian
On Mon, May 01, 2017 at 07:16:58PM +0200, Rob Janssen wrote:
With "only" 16 million addresses in AMPRnet,
why don't you use a 16-million entry array
holding the next hop for each IP in 44.x.x.x or zero for those addresses that have no
tunnel?
Then you only need a single index operation to get the next hop for a packet.
That requires 64MB of memory to store, hardly a significant amount today.
And it can double-up as the filter to forward traffic only to/from registered addresses.
Of course the update operation becomes more expensive, but it could probably be done
in-place
without disrupting packet forwarding. Or you could build a second table and then switch
to it after the build is complete (requiring 128MB).
Rob
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http://hamradio.ucsd.edu/mailman/listinfo/44net
4:01 p.m.
New subject: amprgw routing
On 05/01/2017 10:24 AM, Brian Kantor wrote:
(Please trim inclusions from previous messages)
_______________________________________________
Interesting concept. Someday if we have enough memory I may try it, but
right now amprgw (an old machine) has only 4 GB of memory. It'd die swapping.
At the moment, I use the ipfw firewall to filter registered addresses; that saves
several context switches.
- Brian
I'm curious, it sounds like the machine you are using is a FreeBSD
one,
since you are using ipfw.
If that is the case, have you looked at the setfib command? Just curious
as to if using multiple routing tables would help at all. It would
require a recompiling of the KERNEL with the ROUTETABLES= entry in your
kernel config.
-Stacy
4:13 p.m.
New subject: amprgw routing
Yes, it's FreeBSD 10.3. No, I haven't looked at setfib because as
I understand it, it selects kernel routing tables, and I'm doing the
routing in a user-space program.
- Brian
On Mon, May 01, 2017 at 01:01:44PM -0700, Stacy wrote:
I'm curious, it sounds like the machine you are
using is a FreeBSD one,
since you are using ipfw.
If that is the case, have you looked at the setfib command? Just curious as
to if using multiple routing tables would help at all. It would require a
recompiling of the KERNEL with the ROUTETABLES= entry in your kernel config.
-Stacy
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9:41 p.m.
New subject: amprgw routing
On 05/01/2017 01:13 PM, Brian Kantor wrote:
(Please trim inclusions from previous messages)
_______________________________________________
Yes, it's FreeBSD 10.3. No, I haven't looked at setfib because as
I understand it, it selects kernel routing tables, and I'm doing the
routing in a user-space program.
- Brian
Cool. I've been a FreeBSD guy since 2.2.1-RELEASE (too long ago).
It is kernel based. It would be curious as to if the overhead and speed
is better or worse that your userspace program. Some people seem to be
using it as a "poor man's" BGP.
It would be interesting to see the guts of the AMPR gateway and how you
implemented it. I know that some people have asked to see the code, and
you mentioned that it may be encumbered a bit. Too bad.
-Stacy
2 May
2 May
1:43 a.m.
New subject: amprgw routing
If that is the case, have you looked at the setfib
command? Just curious as
to if using multiple routing tables would help at all. It would require a
recompiling of the KERNEL with the ROUTETABLES= entry in your kernel config.
It actually doesn't even require a recompile. Just set net.fibs=<n> in
/boot/loader.conf and reboot.
-J
10 a.m.
New subject: amprgw routing
On May 1, 2017, Brian Kantor <Brian(a)UCSD.Edu> wrote:
Interesting concept. Someday if we have enough memory
I may try it,
but right now amprgw (an old machine) has only 4 GB of memory. It'd
die swapping.
To the members:
I think Brian deserves a new computer. If anyone has a more capable
machine that's a few steps above the current amprgw hardware, please
consider donating it.
I'll be glad to coordinate the effort: feel free to send me infor-
mation about any machine you are willing to donate.
Brian,
Please let us know what your "dream" machine would be. We'll get as
close as we can.
Bill, W4EWH
10:32 a.m.
New subject: amprgw routing
Yes, what do you need Brian?
M
-----Original Message-----
From: 44Net [mailto:44net-bounces+n6mef=mefox.org@hamradio.ucsd.edu] On
Behalf Of Bill Horne W4EWH
Sent: Tuesday, May 2, 2017 7:00 AM
To: AMPRNet working group <44net(a)hamradio.ucsd.edu>
Subject: Re: [44net] amprgw routing
(Please trim inclusions from previous messages)
_______________________________________________
On May 1, 2017, Brian Kantor <Brian(a)UCSD.Edu> wrote:
Interesting concept. Someday if we have enough
memory I may try it,
but right now amprgw (an old machine) has only 4 GB of memory. It'd
die swapping.
To the members:
I think Brian deserves a new computer. If anyone has a more capable
machine that's a few steps above the current amprgw hardware, please
consider donating it.
I'll be glad to coordinate the effort: feel free to send me infor-
mation about any machine you are willing to donate.
Brian,
Please let us know what your "dream" machine would be. We'll get as
close as we can.
Bill, W4EWH
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10:37 a.m.
New subject: amprgw routing
Thank you Bill, but we already have some plans in work to obtain a
newer machine, one with a faster processor (we're already at 2.3 GHz)
and more memory, and is compatable with our data center management.
(Rack mount, remote console access, etc.) I'll know more within the
next few months.
If that doesn't work out, I'll happily take a donation of a new machine.
As to 4GB of memory being enough, it's plenty. The router image and
data space just aren't very big, and they're static structures that
can be locked into memory so paging doesn't affect the routing. The 'C'
language and libraries are fairly memory-efficient if the programmer is.
- Brian
On Tue, May 02, 2017 at 10:00:19AM -0400, Bill Horne W4EWH wrote:
To the members:
I think Brian deserves a new computer. If anyone has a more capable
machine that's a few steps above the current amprgw hardware, please
consider donating it.
I'll be glad to coordinate the effort: feel free to send me infor-
mation about any machine you are willing to donate.
Brian,
Please let us know what your "dream" machine would be. We'll get as
close as we can.
Bill, W4EWH
2761
days inactive
2762
days old
8 comments
6 participants
participants (6)
-
Bill Horne W4EWH -
Brian Kantor -
Jeremy Cooper -
Michael Fox - N6MEF -
Rob Janssen -
Stacy