Thanks for your prompt response. You have confirmed most of my thoughts so now
it is just do it and see how much performamce we can get.
Again Thank you
Loren
Alexis <alexis@tpys.com.ar> wrote:
List members;
I have been reading the digest for some time now and I would like to ask some
conceptual questions. I am a telecommunications systems designer and not a
software guy, but I have tried and used a number of the tools availabel in the
LARTC and Iptables, and many of the other great things included in Linux. We
are designing commercial products and I don''t want to ask my software
people to do things that are not realistic or might cause instability in
systems.
Great, me too :)
1) Is it feasible to use both dynamic and static routing systems in a Linux
router? That is, if I am using the facilities in IProute2 and Iptables to do
fair queing and bandwidth control, for selected subnets, will that work ok with
one of the router daemons like ripd or ospfd? Will their be a problem with
routing tables being confused between the two? I guess what I am really asking
is what is the relationship between Ingress / Egress ques, Pre-routing /
Post-routing tables and the daemons in the data flow within the box.
yes it is. in fact, compared, just say, with a cisco router, a linux router
keeps the logic of "main routing table" and then the routing protocols
tables. But the difference is linux can handle a _lot_ of routing tables and you
can handle the way routing protocols, static routes and policers/classifiers
acts on that networks. Off course iptables can act on this schema too.
2) Given the above, are there any issues as far as throughput and processing
horse power, are concerned? We are building on a 2.6 kernel and will be using
PIV 2.4 to 2.8 GHz hyperthreaded systems with large amounts of RAM, but there
will be other stuff running on the same machine, such as Squid cache server.
Also, my satellite modulator and demodulators are on the PCI bus and will take
some processor. We will be handling data rates of up to 8 mbps on the upstream
(bits not bytes) and up to 40 mbps on the downstream. Hub routers may be
receiving up to 1 Gbps of incoming data from remotes. These rates are maximum
and not the norm, but rather the exception. Part of the reason for wanting to
use OSPF for example is that this system is multi-destination and there will be
new alternate routes available as well multiple routes appearing and
disappearing.
Uhm, i sorry i cannot be quite clear about the benchmarks, but im sure that you
can handle those bw without a problem.
An example. with 2.4 (2.6 is more performant i think) with a dual P3 1.2ghz, 1gb
ram, a few years ago, i handled bgp with full routing (around 130k prefixes),
OSPF as an IGP, firewall and some QoS rules.
With this schema i had 4 ethernet interfaces and 1 Gb ethernet, the total bw was
around 100 to 130mbps and it worked just fine.
I think you could handle your traffic without major problems with those
equipment, think that the only "additional" proccesses are the routing
daemons, all other tasks ran at kernel level
3) I have read questions many times, from people who ask about ingress control
(policing) and the same answer is always given, about the fact that you
can''t tell the internet to send data slower. Has anyone used the ECN
congestion notification bits in the IP header? At least for an internal (read
that edge) network, it should work just as well as the BECN controls in frame
relay. This would allow the network to slow down the sender without dropping
packets, and should work as well in UDP as in TCP.
ive not used ecn , as you say it may work, feel free to test it if you can :)
Ive used IMQ and it works just fine, but its a software implementation and takes
some cpu resources.
and off course, the ingress policers works just fine, but they are limited.
4) Has anyone tried an accelerator for TCP with IProute2? I guess it would
have to be behind the routing machine (LAN side), right?
nop, i didnt
5) Has anyone out there, worked with the HDLC driver in the kernel? It is
built in and we have used it, but I don''t know how to relate it to the
Iproute2 commands. Is it as simple as setting up the same as you would for the
zebra router?
Yes, ive used this driver with a v35 interface, ive used ifconfig and iproute
commands to manage this interface without a problem.
i remember commands like
ifconfig hdlc0 up
ifconfig pvc0 10.0.0.1 pointopoint 10.0.0.2
this is an example that ive found to use iproute2 to create tunnels, they act as
a ptp interface, so, take a look
http://mirrors.bieringer.de/www.deepspace6.net/docs/iproute2tunnel-en.html
Lastly, I wold like to thank all of the people in the open surce community and
especially the folks that maintain this list for their efforts and their
dedication to this project. You are appreciated, even if it isn''t said
often enough.
:) as part of the community and the list, thanks.
Loren Wells
CTO
Linksat America
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