Re: Slightly OT: PfARGHHHHHHHH!

Man.... that got my blood boiling... Being that first: I'm
Irish/Mexican/AmericanIndian"Cherokee"&"Yaqi"/USMarine/ & Originally from
Texas.... :)

Joe Sanchez

On Mon, Aug 20, 2012 at 7:45 PM, marc abel <marcabel_at_gmail.com> wrote:

> You lazy Americans always trying to get someone else to answer your
> questions for free! KIDDING!!!!
>
> /Ducks
>
> On Mon, Aug 20, 2012 at 7:35 PM, marc edwards <renorider_at_gmail.com>wrote:
>
>> That is exactly what I was looking for! Much appreciated.
>>
>> Regards,
>>
>> Marc
>>
>> On Mon, Aug 20, 2012 at 5:17 PM, Joe Sanchez <marco207p_at_gmail.com> wrote:
>>
>> > Marc, does this help:
>> >
>> >
>> > - BGP Autonomous System Number Community Prepend
>>
>> >
>> > When an entrance link goes out-of-policy (OOP) due to delay, or in
>> > images prior to Cisco IOS Releases 15.2(1)T1 and 15.1(2)S, and PfR
>> selects
>> > a best entrance for an inside prefix, a BGP prepend community is
>> attached
>> > one at a time (up to a maximum of six) to the inside prefix BGP
>> > advertisement from the network to another autonomous system such as an
>> ISP. In
>> > Cisco IOS Releases 15.2(1)T1, 15.1(2)S, and later releases, when an
>> > entrance link goes out-of-policy (OOP) due to unreachable or loss
>> reasons,
>> > and PfR selects a best entrance for an inside prefix, six BGP prepend
>> > communities are attached to the inside prefix BGP advertisement. The BGP
>> > prepend community will increase the number of autonomous system hops in
>> the
>> > advertisement of the inside prefix from the ISP to its peers.
>> > Autonomous system prepend BGP community is the preferred method to be
>> used
>> > for PfR BGP inbound optimization because there is no risk of the local
>> ISP
>> > filtering the extra autonomous system hops. There are some issues, for
>> > example, not all ISPs support the BGP prepend community, ISP policies
>> may
>> > ignore or modify the autonomous system hops, and a transit ISP may
>> filter
>> > the autonomous system path. If you use this method of inbound
>> optimization
>> > and a change is made to an autonomous system, you must issue an outbound
>> > reconfiguration using the clear ip bgp command.
>> > The prepend community has to be configured per Border Router and per
>> > external interfaces because the community value is specific per Service
>> > Provider.
>> >
>> > Configuration Sample:
>> >
>> > !
>> > pfr master
>> > border 10.4.5.6 key-chain pfr
>> > interface Ethernet0/1 external
>> > downgrade bgp community aa:nn (community number in aa:nn format)
>> > interface Ethernet0/0 internal
>> > !
>> >
>> >
>> > In this solution guide, PfR will enforce the path by using BGP AS-PATH
>> > prepend for controlled prefixes. PfR will not try to control an inside
>> > prefix unless there is an exact match in the BGP routing information
>> base
>> > (RIB) because PfR does not advertise a new prefix to the Internet.
>> > Joe Sanchez,
>> > Chicago, IL
>> >
>> > On Mon, Aug 20, 2012 at 6:45 PM, marc edwards <renorider_at_gmail.com>
>> wrote:
>> >
>> >> So what is this half baked product my SE sold me? The documentation
>> looks
>> >> good on Cisco's site and reads
>> >>
>> >> To enforce an entrance link selection, PfR offers the following
>> methods:
>> >> BGP Autonomous System Number Prepend
>> >>
>> >> After PfR selects a best entrance for an inside prefix, extra
>> autonomous
>> >> system hops (up to a maximum of six) are prepended to the inside prefix
>> >> BGP
>> >> advertisement over the other entrances. The extra autonomous system
>> hops
>> >> on
>> >> the other entrances increase the probability that the best entrance
>> will
>> >> be
>> >> used for the inside prefix. This is the default method PfR uses to
>> control
>> >> an inside prefix, and no user configuration is required.
>> >> BGP Autonomous System Number Community Prepend
>> >>
>> >> After PfR selects a best entrance for an inside prefix, a BGP prepend
>> >> community is attached to the inside prefix BGP advertisement from the
>> >> network to another autonomous system such as an ISP. The BGP prepend
>> >> community will increase the number of autonomous system hops in the
>> >> advertisement of the inside prefix from the ISP to its peers.
>> Autonomous
>> >> system prepend BGP community is the preferred method to be used for PfR
>> >> BGP
>> >> inbound optimization because there is no risk of the local ISP
>> filtering
>> >> the extra autonomous system hops. There are some issues, for example,
>> not
>> >> all ISPs support the BGP prepend community, ISP policies may ignore or
>> >> modify the autonomous system hops, and a transit ISP may filter the
>> >> autonomous system path. If you use this method of inbound optimization
>> and
>> >> a change is made to an autonomous system, you must issue an outbound
>> >> reconfiguration using the clear ip bgp command.
>> >>
>> >>
>> >>
>> >>
>> http://www.cisco.com/en/US/docs/ios-xml/ios/pfr/configuration/15-1mt/pfr-bgp-inbound.html#GUID-52E6BAC0-FE00-43DD-BE37-822FC2ED5C0F
>> >>
>> >>
>> >> This sounds great until I read further and find no configuration
>> >> references
>> >> to make this happen. Looking through all commands in
>> >>
>> >>
>> http://www.cisco.com/en/US/docs/ios-xml/ios/pfr/command/pfr-cr-book.html
>> >>
>> >> I don't see anything either.
>> >>
>> >>
>> >> Is this blatant false advertising or am I missing something?
>> >>
>> >>
>> >> Regards,
>> >>
>> >> Marc
>> >>
>> >>
>> >> Blogs and organic groups at http://www.ccie.net
>> >>
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>>
>>
>>
>>
>>
>
>
> --
> Marc Abel
> CCIE #35470
> (Routing and Switching)

Blogs and organic groups at http://www.ccie.net
Received on Mon Aug 20 2012 - 19:48:22 ART