PPPoE server (high traffic in WDM network)

Nikos Vassiliadis nvass9573 at gmx.com
Thu Jul 23 17:52:38 UTC 2009

> Hello Nikos,

Hi, I just saw your answer while browsing. I am not on isp at ...
Please CC questions at .

> Am 2009-07-16 12:27:06, schrieb Nikos Vassiliadis:
>> Michelle Konzack wrote:
>>> I am ongoing to install a CWDM (1GE) and DWDM  (10GE)  network  for  the
>>> Alvarion BreezeACCESS VL (38 base stations) and more then  200  Iskratel
>>> FTTH DSLAMS of 96 ports (each with 100MBit, but only one  1GE  Upstream)
>>> each.
>> So, you'll have 96*200 possible PPP clients. How many concurrent PPP
>> sessions do you care to support?
>> And more importantly, how much aggregate bandwidth?
> Because the customers are permanently On-Line du to the  VoIP-Telephone,
> we count with the full number of clients...
> The distance between the FTTH DSLAM and the customers can be up to 10km.
> The idea is now, that we do not simply connect the FTTH DSLAM's  to  the
> CISCO switches but building a redunant Ethernet Carrier Network.
> This mean, we can install in each village there own FTTH DSLAM  even  if
> there are 2500 hausholds and we install 26 FTTH DSLAM's there.
> This mean in theorie 250 GBit Customer Downstream, 26 Gbit Upstream  but
> we count with a 10 GE which is maybe used to 30-50%.
> OK, if we switch to an "Ethernet Carrier Network" I could install one or
> two PPPoE Servers in each village.  But if one goes down, the second has
> to handel 2500 client connections.

I *think* the number of clients is doable. I don't know about
the bandwidth.

> Note:   This is ONLY the base installation  between  Kehl,  Rheinau,
>         Renchen and Oberkirch (arround  35.000  hausholds)  and  the
>         whole region has 150.000 hausholds.
>> Don't understand what you mean round-robin and loadbalancing?
>> Read below.
> <snip>
>> FreeBSD has a RADIUS library in base. The two notable users of libradius
>> are ppp and net/mpd. The only choice in a ISP environment I think is the
>> net/mpd5 port. Read the outline here:
>> http://www.freebsd.org/cgi/url.cgi?ports/net/mpd5/pkg-descr
>> It is very good and is actually used in large setups.
> Thankyo for the link, I will red on if I am in Office...
>> Can't reply, but keep in mind that filling a 10GE pipe is
>> a hard task on its own.
> It depends on how many customers you have and with an Internet access of
> 100 Mbit plus services like IPTV and VOD you can fill up a 10 GE pipe.

I meant "filling a 10 Gbit pipe with a general purpose computer
architecture is a hard task". Packet forwarding at these rates is

>> I *think* having more low fidelity BRASs, will serve your
>> needs better that a few high fidelity ones.
> You mean, putting a bunch of small 1U Servers into a 19" 42RU?

Yes, you may find that having two small boxes instead of bigger one
gives better results performance-wise. You also have to test if SMP
helps and how much. A beast with 16 cores is more powerful from a
regular computer with 2 cores, but does it help in your setup?

>> You can try NanoBSD and TinyBSD which are FreeBSD based and I
>> believe can fit the bill. These two run with their filesystems
>> read-only mounted which is ideal for flash memories.
> Can you recomment it for an ISP setup?

It's FreeBSD running from a read-only mounted medium.
No more, no less. Yes, it's fine for an ISP setup.

> Hmmm, I am right, that NanoBSD can be bootup over network?
> (this would be another solution)

NanoBSD is meant to run in embedded stand-alone devices.
So, I *guess* that is conceptually very far from net booting.


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