Re: Slightly OT: PfARGHHHHHHHH!

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
> >>
> >> _______________________________________________________________________
> >> Subscription information may be found at:
> >> http://www.groupstudy.com/list/CCIELab.html
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
>
>
>
>
>
>
>

-- 
Marc Abel
CCIE #35470
(Routing and Switching)
Blogs and organic groups at http://www.ccie.net