nanog mailing list archives

Re: NANOG Digest, Vol 73, Issue 42


From: Matthew Crevier <mjcrevier () gmail com>
Date: Fri, 7 Feb 2014 11:26:55 -0500

Ntp.nasa.gov never fails me.

Matt
On Feb 7, 2014 10:56 AM, <nanog-request () nanog org> wrote:

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Today's Topics:

   1. Re: Need trusted NTP Sources (Jimmy Hess)
   2. RE: SIP on FTTH systems (Frank Bulk)
   3. Re: carrier comparison (Vlade Ristevski)
   4. Re: carrier comparison (Faisal Imtiaz)
   5. Re: SIP on FTTH systems (Mark Tinka)
   6. Re: carrier comparison (Mark Tinka)
   7. Re: Need trusted NTP Sources (Roy)
   8. Re: SIP on FTTH systems (Jay Ashworth)
   9. Re: SIP on FTTH systems (Mark Tinka)


----------------------------------------------------------------------

Message: 1
Date: Fri, 7 Feb 2014 06:38:06 -0600
From: Jimmy Hess <mysidia () gmail com>
To: Saku Ytti <saku () ytti fi>
Cc: NANOG list <nanog () nanog org>
Subject: Re: Need trusted NTP Sources
Message-ID:
        <
CAAAwwbU+CiTpjXjyAQE1rCT8EE+jX4XhywFPvOC+p4dw6YZPbA () mail gmail com>
Content-Type: text/plain; charset=ISO-8859-1

On Fri, Feb 7, 2014 at 5:35 AM, Saku Ytti <saku () ytti fi> wrote:

On (2014-02-06 21:14 -0500), Jay Ashworth wrote:

My usual practice is to set up two in house servers, each of which
talks to:
Two is worst possible amount of NTP servers to have. Either one fails and
your timing is wrong, because you cannot vote false ticker. And chance of
either of
two failing is higher than one specific of them.


+1 to having at least 3 NTP servers.
Because complete outage is only one kind of failure.

Don't forget   poor performance due to high latency, or
Server X  emitting  corrupted or  inaccurate data


--
-JH


------------------------------

Message: 2
Date: Fri, 7 Feb 2014 07:30:08 -0600
From: "Frank Bulk" <frnkblk () iname com>
To: "'Jay Ashworth'" <jra () baylink com>, "NANOG" <nanog () nanog org>
Subject: RE: SIP on FTTH systems
Message-ID: <00b401cf2408$b846cde0$28d469a0$@iname.com>
Content-Type: text/plain;       charset="UTF-8"

Rather than assign residential and business customers their own /30, to
conserve space we give those customers a /32 out of a /24.  But when one of
these static IP customers wants to send email to another, or the employee
wants to VPN into work, they can't.  MACFF is supposed to solve that (we
haven't turned it on, yet, because the vendor's implementation requires us
to do some work on our provisioning system to make it easier).

Frank

-----Original Message-----
From: Jay Ashworth [mailto:jra () baylink com]
Sent: Thursday, February 06, 2014 11:59 PM
To: NANOG
Subject: Re: SIP on FTTH systems

----- Original Message -----
From: "Frank Bulk" <frnkblk () iname com>

And then you need MACFF to overcome the split-horizon to that
customers in the same subnet can talk to each other. =)

In my not-at-all humble opinion, in an eyeball network, you almost *never*
want to make it easier for houses to talk to one another directly; there
isn't any "real" traffic there.  Just attack traffic.

Well, ok; slim chance of P2P, but carriers hate that anyway, right? :-)

Cheers,
-- jra
--
Jay R. Ashworth                  Baylink
jra () baylink com
Designer                     The Things I Think                       RFC
2100
Ashworth & Associates       http://www.bcp38.info          2000 Land
Rover DII
St Petersburg FL USA      BCP38: Ask For It By Name!           +1 727 647
1274






------------------------------

Message: 3
Date: Fri, 07 Feb 2014 09:19:15 -0500
From: Vlade Ristevski <vristevs () ramapo edu>
To: nanog () nanog org
Subject: Re: carrier comparison
Message-ID: <52F4EB63.7020806 () ramapo edu>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I'm not setting it on my router locally but sending it over to Cogent as
a community string per page 22 of their user guide.


http://cogentco.com/files/docs/customer_service/guide/global_cogent_customer_user_guide.pdf

They use it to manipulate how traffic gets back to me so that is
incoming from my routers view.

I also pad the AS  for the networks that I prefer to come back through
the other ISP..


On 2/7/2014 5:27 AM, Olivier Benghozi wrote:
Hi Vlade,

Well, if you are trying to balance the incoming traffic load with
local-pref attribute, I can understand your disappointment :)
Since it doesn't work at all this way: local-pref is local to an AS and
deals with outgoing traffic only.

B)  We have our own AS and IP space. I advertise them to both Cogent
and our other ISP. I use the local preference attribute to share the load
for incoming traffic between both ISPs. In the last 5 outages over the last
few years, this has happened twice. I'm waiting on the RFO so I can further
investigate why this happened. I think someone mentioned this in a post a
few months ago too.


--
Vlade Ristevski
Network Manager
IT Services
Ramapo College
(201)-684-6854




------------------------------

Message: 4
Date: Fri, 7 Feb 2014 14:49:09 +0000 (GMT)
From: Faisal Imtiaz <faisal () snappytelecom net>
To: Olivier Benghozi <olivier.benghozi () wifirst fr>
Cc: nanog () nanog org
Subject: Re: carrier comparison
Message-ID:
        <693349979.661671.1391784549000.JavaMail.root () snappytelecom net>
Content-Type: text/plain; charset=utf-8

Based on my understanding on BFD, it will not help you... BFD will detect
the direct connected port being down quicker and force the BGP session
down, (faster than the time  BGP session timers take to determine something
is broken)

This is the common issue / challenge in how to determine up-stream path
outage and then doing appropriate route engineering on an automatic basis.

Maybe a SLA monitor type scripting/configuration be useful in your case.

Faisal Imtiaz
Snappy Internet & Telecom
7266 SW 48 Street
Miami, FL 33155
Tel: 305 663 5518 x 232

Help-desk: (305)663-5518 Option 2 or Email: Support () Snappytelecom net

----- Original Message -----
From: "Olivier Benghozi" <olivier.benghozi () wifirst fr>
To: nanog () nanog org
Sent: Friday, February 7, 2014 5:25:53 AM
Subject: Re: carrier comparison

Hi Faisal,

You might have to deploy some other means of (script ?) to bring your
BGP
session down from the 'broken' Service Provider.

To the best of my knowledge, BGP does not have any mechanism to
determine
broken connectivity upstream past the router you are BGP session is up
with.

Well, technically there's BFD that might do the trick. But of course it
won't
be available; it's not usually, so specially with Cogent... :)
But maybe its link was just overloaded in fact.


--
Olivier






------------------------------

Message: 5
Date: Fri, 7 Feb 2014 17:20:08 +0200
From: Mark Tinka <mark.tinka () seacom mu>
To: nanog () nanog org
Subject: Re: SIP on FTTH systems
Message-ID: <201402071720.12145.mark.tinka () seacom mu>
Content-Type: text/plain; charset="us-ascii"

On Friday, February 07, 2014 03:30:08 PM Frank Bulk wrote:

Rather than assign residential and business customers
their own /30, to conserve space we give those customers
a /32 out of a /24.  But when one of these static IP
customers wants to send email to another, or the
employee wants to VPN into work, they can't.

This is akin to Private VLAN's where ports in a shared VLAN
are assigned numbers from the same subnet, but they can only
communicate via the BNG rather than directly at the bridge
level.

I prefer EVC Split Horizon to Private VLAN's, though.

Mark.
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------------------------------

Message: 6
Date: Fri, 7 Feb 2014 17:21:46 +0200
From: Mark Tinka <mark.tinka () seacom mu>
To: nanog () nanog org
Subject: Re: carrier comparison
Message-ID: <201402071721.47057.mark.tinka () seacom mu>
Content-Type: text/plain; charset="us-ascii"

On Friday, February 07, 2014 04:49:09 PM Faisal Imtiaz
wrote:

Based on my understanding on BFD, it will not help you...
BFD will detect the direct connected port being down
quicker and force the BGP session down, (faster than the
time  BGP session timers take to determine something is
broken)

You would also need your provider to support BFD (and by
support I mostly mean willing to run, as modern gear today
is technically capable).

Mark.
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------------------------------

Message: 7
Date: Fri, 07 Feb 2014 07:23:22 -0800
From: Roy <r.engehausen () gmail com>
To: nanog () nanog org
Subject: Re: Need trusted NTP Sources
Message-ID: <52F4FA6A.60807 () gmail com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

On 2/7/2014 3:35 AM, Saku Ytti wrote:
On (2014-02-06 21:14 -0500), Jay Ashworth wrote:

My usual practice is to set up two in house servers, each of which
talks to:

And then point everyone in house to both of them, assuming they accept
multiple server names.
Two is worst possible amount of NTP servers to have. Either one fails
and your
timing is wrong, because you cannot vote false ticker. And chance of
either of
two failing is higher than one specific of them.


"A man with a watch knows what time it is. A man with two watches is
never sure."



------------------------------

Message: 8
Date: Fri, 07 Feb 2014 10:41:44 -0500
From: Jay Ashworth <jra () baylink com>
To: mark.tinka () seacom mu,Mark Tinka
        <mark.tinka () seacom mu>,nanog () nanog org
Subject: Re: SIP on FTTH systems
Message-ID: <3db10818-3072-482b-b619-5a884e10d538 () email android com>
Content-Type: text/plain; charset=UTF-8

I would assume that this whole mostly depends on which particular
protocols and approaches your edge equipment can implement most efficiently
- efficiently enough, that is, to be able to do it on every single port in
a chassis.

On February 7, 2014 10:20:08 AM EST, Mark Tinka <mark.tinka () seacom mu>
wrote:
On Friday, February 07, 2014 03:30:08 PM Frank Bulk wrote:

Rather than assign residential and business customers
their own /30, to conserve space we give those customers
a /32 out of a /24.  But when one of these static IP
customers wants to send email to another, or the
employee wants to VPN into work, they can't.

This is akin to Private VLAN's where ports in a shared VLAN
are assigned numbers from the same subnet, but they can only
communicate via the BNG rather than directly at the bridge
level.

I prefer EVC Split Horizon to Private VLAN's, though.

Mark.

--
Sent from my Android phone with K-9 Mail. Please excuse my brevity.

------------------------------

Message: 9
Date: Fri, 7 Feb 2014 17:53:01 +0200
From: Mark Tinka <mark.tinka () seacom mu>
To: Jay Ashworth <jra () baylink com>
Cc: nanog () nanog org
Subject: Re: SIP on FTTH systems
Message-ID: <201402071753.01608.mark.tinka () seacom mu>
Content-Type: text/plain; charset="us-ascii"

On Friday, February 07, 2014 05:41:44 PM Jay Ashworth wrote:

I would assume that this whole mostly depends on which
particular protocols and approaches your edge equipment
can implement most efficiently - efficiently enough,
that is, to be able to do it on every single port in a
chassis.

Well, Split Horizon would be enabled on all the customer-
facing ports.

I am not aware of any protocol restrictions when running
Split Horizon. I haven't run into any issues yet.

Mark.
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End of NANOG Digest, Vol 73, Issue 42
*************************************



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