[AusNOG] 1+1 ports

Sun May 16 12:56:24 EST 2010

It's easier to provide 1+1 for SDH circuits such as EoSDH...

SDH can supply a 1+1 on the client port using the same trunked virtual
circuit (VC) on the back end of the SDH system which provides you
protection against a port your side or their side failing (or patch lead
etc etc)

The signalling mechanism between client and carrier can be multiple
methods such as using the newer EFM/EOAM extensions or as simple as I
turn on and off the protect port according to the status of the working
port...

This single VC can then be protected by different carrier mechanisms
such as SNCP to provide path resiliency through the provider network

But following on from MMC's comment you either need a carrier grade box
your end with separate line cards and ports or a vendor multichassis
technology in order to get the real benefits from it

What you need to do is look at how the failure detection for the service
works and how long the low level failover is, then work out whether that
low level failure can cause reconvergence at the Ethernet and IP layers
to work out the total protection reconvergence time, then you can assess
if the $$$ savings are worth it compared to simply having a second
circuit via a completely different MUX and path

Darren

From: ausnog-bounces at lists.ausnog.net
[mailto:ausnog-bounces at lists.ausnog.net] On Behalf Of Daniel Hooper
Sent: Friday, 14 May 2010 2:28 PM
To: ausnog at ausnog.net
Subject: Re: [AusNOG] 1+1 ports

Thanks for all the replies, I was incorrect in my original post, it's
not a VPLS circuit but EoSDH.

I'm not sure if that makes it harder or easier for the un-named carrier,
but at this point I don't understand enough of the inner workings of
un-named carriers network and am guessing it's a technical limitation
for them to be able to offer the service at this time in the fashion
that I want to use it in.

In regards to the fact that we may be connecting to the same
switch/device on the upstream, this is outside our control and if it
fails our SLA agreement with the carrier will cover us financially, if
our own kit fails we lose coin out of our own pocket. Unfortunately this
is purely a financial based decision to do this, personally I'd have
uplinks between different carriers but at the moment the cheque book
doesn't allow for this.

Cheerio

-Daniel

From: ausnog-bounces at lists.ausnog.net
[mailto:ausnog-bounces at lists.ausnog.net] On Behalf Of Shane Short
Sent: Friday, 14 May 2010 11:22 AM
To: ausnog at ausnog.net
Subject: Re: [AusNOG] 1+1 ports

I find it interesting Nextgen will offer this for 'Internet' services,
but no mention of it being available for P-t-P:
http://www.nextgennetworks.com.au/7629%20Nextgen%20Shadow%20DataSheet%20
D11-2.pdf

It addresses Matthew's concern of using both ports simultaneously with
the following clause:

"Low usage levels are allowed on the shadow link in support of routine
keep-alive and reasonable link availability testing. Any traffic profile
where the 98th percentile utilisation of both the upstream and
downstream directions is at or below 100kb/s will not incur excess usage
charges."

Dan: perhaps ask nicely to see if they'll do something like this for
you?

-Shane

On 14/05/2010, at 11:07 AM, Matthew Moyle-Croft wrote:

It's probably more a commercial issue:

(a) Duplicating ports on the same switch on your provider's end doesn't
really provide much protection

(b) It's hard to deliver this without giving you "free" bandwidth (ie.
how do you prevent you bursting on both ports simultaneously?)

I don't see mitigating a switch failure at your end is that useful
unless you've actually built redundancy elsewhere.   If you think a
switch failure at your end is more likely than anything else then I'd
probably choose a different switch/vendor!

MMC

On 14/05/2010, at 12:31 PM, Daniel Hooper wrote:

Hi,

I'm trying to find out if there are any carriers out there who provide 2
ports at each end for a point to point Ethernet circuit? (VPLS)

I'm trying to build some redundancy into a network, I've asked our
carrier if they can provide 2 ports at each end  to mitigate a switch
failure on our end and they've essentially said no, buy another service
identical to what you've already got if you want to do that. I don't
need anymore bandwidth, just separate physical interfaces to run on.

Speaking to other people in the industry, it seems the norm for carriers
to provide the service over 2 physical ports if requested (obviously for
a price). I'm curious if other people have been able to get this
configuration on PTP Ethernet circuits ?

Just chasing info at the moment, possibly I need to jump ship to get
what I want, or maybe I'm just dreaming and it's a technical reason why
it cant be done.

Regards,

Daniel

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