How are operators using IRR?

Michael Hallgren m.hallgren at
Thu Jan 17 14:44:20 UTC 2013


Some of the networks close to me, use IRR based AS_PATH and
prefix filters at customer-route import.

Needless to say that running periodic diffs between what's found in
IRR and what's received in RW and discuss the results with customers
is a necessary good thing to make sure that what is expected is
really happening. (And potentially a means to bump up the quality of
the IRR data set.)


Le 17/01/2013 14:14, Phil Bedard a écrit :
> I have mainly worked at small and medium sized operators and we did not
> use IRR at all apart from registering our own and customer blocks with
> the one upstream provider we had (Level3) which required it. We
> maintained our own databases of customer prefixes tied to other
> customer information strict prefix lists were generated from. I have
> rarely seen as path filtering used except with large customers where
> maintaining strict prefix lists wasn't manageable.
> Phil From: ML
> Sent: 1/16/2013 19:57
> Subject: How are operators using IRR?
> How are operators using the data available in the various IRRs?
> Using an example:
> AS1 is your customer
> AS1 has AS2, AS3 and AS4 described as customers in an IRR
> Also assume AS2 has IRR data describing AS1000 and AS2000 as it's customers.
> Are operators building AS path regexes such as the following
> automatically from IRR and applying that to your BGP sessions?
> ----
> AS1{1,}
> AS1{1,} AS2{1,}
> AS1{1,} AS3{1,}
> AS1{1,} AS2{1,} AS1000{1,}
> AS1{1,} AS2{1,} AS2000{1,}
> ----
> I would imagine most operators that are building policy from IRR are
> building prefix lists to limit what they are accepting.  Is this being
> paired with some AS path filtering?
> Are operators just traversing an AS-SET as far as it will go and
> building prefix lists to represent all intended prefixes to be heard on
> a session regardless of who originates them? Is the possibility of
> AS1000 hijacking AS2000 prefixes towards AS2 a problem you as the
> upstream to AS1 need to consider? (Last question assumes AS2 made a
> mistake and wasn't filtering properly on it's own customers and AS1 is
> just accepting all prefixes under the cone of AS2)
> Thanks

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