[120428] in North American Network Operators' Group
RE: Routing to multiple uplinks
daemon@ATHENA.MIT.EDU (Deepak Jain)
Sun Dec 20 08:01:12 2009
From: Deepak Jain <deepak@ai.net>
To: Rodrick Brown <rodrick.brown@gmail.com>, Steven King <sking@kingrst.com>
Date: Sun, 20 Dec 2009 08:00:15 -0500
In-Reply-To: <bb075cdf0912191148t144d626ct1b0665d9df6a2be5@mail.gmail.com>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
> The overall design is being driven by our rigorous application needs
> more
> than anything.
>=20
> The implementation is straight forward we receive a duplicate set of
> feeds
> from site A and site B and can also access various services coming from
> site
> A or site B however, at any given time a user will be sending/recieving
> data
> from one of those destinations. Never both simultaneously. So my
> question
> what is the best way to provide this type of redundancy at the host
> level?
>=20
> The application will only use one target address.
>=20
You've stated two seemingly contradictory things. 1) The User decides which=
paths to take yet the 2) application cannot see more than one path.=20
First, this sounds like a User issue. The application with such rigorous re=
quirements should have the features you need to manage this.
Barring that... :)
The mechanism the User uses to (manually) decide which path to take should =
make the election and handle the switchover in visibility. Presumably, sinc=
e your application cannot tell when its switched destinations/paths it need=
s to be notified if the network makes a VRRP/HSRP decision. This all points=
to the mechanism you presumably already have in place for manual path deci=
sions.
If you are using your Linux box or whatever to make your path choices, simp=
ly have a script that sees if the path preferences have changed and use you=
r method to notify the Application.
If you are using a Cisco (or other) dedicated router, run something on the =
Application box or servers that will notice this change (if even by queryin=
g the router) so it can proactively detect this.
You've asked for a technical suggestion but have not provided any detail ab=
out the actual constraints you have -- though you've implied them without c=
ontext.
Deepak Jain
AiNET
