[c-nsp] BGP Maximum Prefix limit on Edge routers

[Aaron]

Absolutely. Make sure to add enough overhead, 25%, so you do not keep
getting warning messages in the logs.
These are the defaults for XR

To prevent a peer from flooding BGP with advertisements, a limit is
placed on the number of prefixes that are accepted from a peer for
each supported address family. The default limits can be overridden
through configuration of the maximum-prefix limit command for the peer
for the appropriate address family. The following default limits are
used if the user does not configure the maximum number of prefixes for
the address family:    IPv4 Unicast: 1048576    IPv4 Labeled-unicast:
131072    IPv4 Tunnel: 1048576    IPv6 Unicast: 524288    IPv6
Labeled-unicast: 131072    IPv4 Multicast: 131072    IPv6 Multicast:
131072    IPv4 MVPN: 2097152    VPNv4 Unicast: 2097152    IPv4 MDT:
131072    VPNv6 Unicast: 1048576    L2VPN EVPN: 2097152


On Tue, Aug 11, 2020 at 9:20 AM Curtis Piehler <cpiehler2 at gmail.com> wrote:

> Yes this is a common practice to follow for extra security measures.  In
> the off chance a provider starts flooding your network with more than what
> is required it will safe guard your network.  You can set a slightly higher
> warning threshold.  Usually more prevalent in MPLS environments as there
> are more memory constraints on carrying Internet routes in multiple VRFs
> could be detrimental to memory.  Unlikely it would happen but always need
> to think of better ways to safe guard your network.  For as long as humans
> are in existence there will always be room for error.
>
> On Tue, Aug 11, 2020, 9:09 AM Yham <yhameed81 at gmail.com> wrote:
>
> > Hello Gentlemen,
> >
> > I wanted to ask if this is common practice to apply Maximum prefix limit
> on
> > BGP neighborship with Internet providers from where you are getting the
> > entire routing table. I know its consider a best practice but want to
> know
> > if its also common.
> > If yes, what would be the max limit of routes? Google search tells me
> that
> > the size of the routing table today is approx 800K prefixes
> >
> > Thanks
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