as-out metrics

	Ok, i try to explain...

When you have a router and you export a route to someone else (for
instance an RS6000 :-) running gated), you have to configure the
metric BGP is going to put in its outgoing packets. With gated it will
be something like:

bgp yes {
	[...]
	group type external peeras 690
		metricout 5
		version 4
                lcladdr 35.42.1.56
                {
                        peer 140.222.51.62
                        gateway 35.42.1.56;
                };
};

The metric in as-out is *what you configure in your router* (here it is 5)
So:
- You have TOTAL control of it.
- It is optional, so if you don't care (if you use the router's default value)
then DON'T USE IT.
- Some philosophers will talk about this metric as a preference or an advise
for the neighbourg ASes. I don't care. My job is to generate config files
for routers (included gated) so if people want to have 'metricout 31416' in
their dam config file they need to specify it somewhere. And somewhere is
in as-out.

		Laurent

PS: This is only my 2 cents.

> 
> 
>   > One of the "services" that this registry can offer is configuration
>   > generation.  With the NSFNET experience and what we anticipate
>   > will be expected from the RA, this information is needed to
>   > generate the correct configuration files. 
> 
> But what does it mean?
> Either you announce something or you don't, right?
> Or do you mean that only the lowest cost gets announced as long 
> as that peering stays up and if it is down the next higher cost ...
> Or does it mean a metric (in external routing, huh?)
> Or something entirely different that I don't understand?
> 
>   > So whereas this information
>   > is not binding, and it is not used by tools such as prtraceroute,
>   > it would be needed in the generation of router configurations.
> 
> Whose? how?
> The fist question is the important one. If it is something the
> AS which registers it configures, it is probably OK. If it is
> something someone else may or may not configure it is not OK
> architecturally because as-in and as-out are designed to describe
> exactly what the AS itself configures and has authority over.
> Any advisory information should be put somewhere else.
> 
> Daniel
> 


-- 
Laurent Joncheray,                                 E-Mail: lpj at merit.edu
    Merit Network Inc, 1071 Beal Avenue,           Phone:  +1 (313) 936 2065
    Ann Arbor, MI 48109, USA                       Fax:    +1 (313) 747 3745
"This is the end, Beautiful friend. This is the end, My only friend, the end" JM



-------- Logged at  Thu Apr 28 22:13:33 MET DST 1994  ---------