[c-nsp] Non-default BGP hold / keepalive timers

[David J. Hughes]

On 04/10/2005, at 6:34 AM, Bruce Pinsky wrote:

> Start talking to your providers and peers about when they are going to
> offer BFD support.

Yup, in a perfect world.  However, I need a solution now, not next 
year.  And I'm sure that our government owned Telco will move as 
swiftly towards supporting BFD as they have towards other sane options 
(like supporting standard communities etc).  Doesn't happen around 
here.


> This will be the preferred method since using layer 3
> routing protocols as a fault detection tool has significant drawbacks.

Expecting a dynamic routing protocol to dynamically route around a 
failed link isn't asking for too much in my opinion.  Using the 
features defined by the protocol's spec to determine when a path isn't 
stable would also appear reasonable.


> I don't know that many providers are willing to tune the BGP timers on 
> a
> per customer basis at all.  YMMV.

They don't need to.  As per the spec the peering routers will agree on 
the lower of the 2 hold times presented during session negotiation.  
Keepalive times will be internally set to one third of the negotiated 
hold timer.  I've tried setting a reduce hold timer at my end and it's 
negotiated as expected with the provider in question.  The other party 
doesn't need to do anything.


David
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