Been doing exactly this for a couple ASNs for a few years now with
surprisingly good results (thanks to advice way far back from my good
friend Brandon Martin above, coincidentally). One of them is even on an L3
switch with something like 96k max routes. Taking defaults from two
upstream providers
I can't believe that never occurred to me in all the time I was doing that,
'way back when...
Thanks for pointing that out!
-Adam
Adam Thompson
Consultant, Infrastructure Services
MERLIN
100 - 135 Innovation Drive
Winnipeg, MB R3T 6A8
(204) 977-6824 or 1-800-430-6404 (MB only)
On 10/20/22 17:50, Adam Thompson wrote:
Alternately, a valid technique is to have a default route AND a partial BGP
feed (a filtered full feed is by definition a partial feed). That helps
optimize outbound routing a little bit, you still get the advantage - mostly -
of multiple inbound
I can't find the original message, so replying to the wrong spot in the thread,
but... no, filtering /24s is a bad idea if you want (more or less) all your
packets to get to their destinations.
If you filter all /24s you will lose reachability to 4x /24s I publish that
have no covering route
I already had this idea, I even implemented it in the desperate time of the
512K "bug".
And with that I can tell you:
Do not do it! You will be bothered!
But if you want to go this way, what I can recommend is to try not to put
routes in the FIB that match your Default.
Talking about having a
This situation isn’t helped by RIR policies that require you to announce the
aggregate in region even if the more specifics are scattered around the world.
The whole territorial exclusivity game played by some RIRs may well cause more
harm than good at this point.
Yes, I realize this is a
On Sun, Oct 16, 2022 at 1:01 AM Matthew Petach wrote:
> Their assumption that *everyone* would hear the more specifics,
> and thus the traffic would flow to the right island location was the
> "failure to understand BGP" that I was commenting on, and noting
> that while it is entirely correct to
On Tue, Oct 11, 2022 at 7:03 PM William Herrin wrote:
> On Tue, Oct 11, 2022 at 5:32 PM Matthew Petach
> wrote:
> [...]
> All TCP/IP routing is more-specific route first. That is the expected
> behavior. I honestly don't fathom your view that BGP is or should be
> different from that norm. If
On Wed, Oct 12, 2022 at 11:51:13AM -0400, Jon Lewis wrote:
[snip]
> And just for the record, despite having been bitten by it more than
> once, I'm very much in the camp of "if you advertise a covering
> aggregate, you're offering to get packets there, regardless of whether or
> not more
David Conrad писал(а) 2022-10-12 11:39:
Andrey,
There was a period in the mid- to late-90s where some of RIRs
allocated longer than /24s, i.e., to match the amount of address space
justified by the requester, even if that meant (say) a /29. This
didn’t last very long as one of the (at the time)
Here is a reason you might want to keep that /24.
Suppose you are a small ISP and I am your customer.
I also have another larger provider.
That larger provider is also your provider.
I own a /21 and advertise it to my larger provider.
You get that /21 from my larger provider.
I advertise a /24
On Wed, 12 Oct 2022, Andrey Kostin wrote:
Matthew Petach писал(а) 2022-10-11 20:33:
My point is that it's not a feature of BGP, it's a purely human
convention,
arrived at through the intersection of pain and laziness.
There's nothing inherently "right" or "wrong" about where the line was
Andrey,
On Oct 12, 2022, at 7:54 AM, Andrey Kostin wrote:
>> My point is that it's not a feature of BGP, it's a purely human convention,
>> arrived at through the intersection of pain and laziness. There's nothing
>> inherently "right" or "wrong" about where the line was drawn, so for
>>
On Wed, Oct 12, 2022 at 7:54 AM Andrey Kostin wrote:
> IMO this line wasn't arbitrary, it was (and it still is) a smallest
> possible network size allocated by RIRs. So it's just a common sense to
> receive everything down to /24 to have the complete data about all
> Internet participants.
Hi
Matthew Petach писал(а) 2022-10-11 20:33:
My point is that it's not a feature of BGP, it's a purely human
convention,
arrived at through the intersection of pain and laziness.
There's nothing inherently "right" or "wrong" about where the line was
drawn, so for networks to decide that /24 is
On Tue, Oct 11, 2022 at 5:32 PM Matthew Petach wrote:
> My point is that it's not a feature of BGP, it's a purely human convention,
> arrived at through the intersection of pain and laziness.
> There's nothing inherently "right" or "wrong" about where the line was
> drawn, so for networks to
On Tue, Oct 11, 2022 at 1:59 PM William Herrin wrote:
> On Tue, Oct 11, 2022 at 1:15 PM Matthew Petach
> wrote:
> > Wouldn't that same argument mean that every ISP that isn't honoring
> > my /26 announcement, but is instead following the covering /24, or /20,
> > or whatever sized prefix is
The /24 is as small as it will get before it cuts into profits for the tiny bit
of administration it would take to announce /25, /26. This argument is almost
as old as my kids. Is it fair or just, probably not, but that's they way the
consensus seems to want it.RichardRichard
On Tue, Oct 11, 2022 at 1:15 PM Matthew Petach wrote:
> Wouldn't that same argument mean that every ISP that isn't honoring
> my /26 announcement, but is instead following the covering /24, or /20,
> or whatever sized prefix is equally in the wrong?
>
> What makes /24 boundaries magically "OK" to
On Tue, Oct 11, 2022 at 7:41 AM William Herrin wrote:
> On Mon, Oct 10, 2022 at 3:37 PM Matthew Petach
> wrote:
> > They became even more huffy, insisting that we were breaking the
> internet by not
> > following the correct routing for the more-specific /24s which were no
> longer present
> >
On Mon, Oct 10, 2022 at 3:37 PM Matthew Petach wrote:
> They became even more huffy, insisting that we were breaking the internet by
> not
> following the correct routing for the more-specific /24s which were no longer
> present
> in our tables. No amount of trying to explain to them that they
On 10/11/22 00:37, Matthew Petach wrote:
They became even more huffy, insisting that we were breaking the
internet by not
following the correct routing for the more-specific /24s which were no
longer present
in our tables. No amount of trying to explain to them that they
should not
- Original Message -
> From: "Randy Bush"
> To: "Edvinas Kairys"
> Subject: Re: any dangers of filtering every /24 on full internet table to
> preserve FIB space ?
>> we're thinking to deny all /24s to save the memory
>
> i recommend this to all my competitors
So good to know things
Link to Arista article about their Spotify deployment (2016), has all the relevant links, can be implemented on variety of vendors https://aristanetworks.force.com/AristaCommunity/s/article/spotifys-sdn-internet-routerCheers,JeffOn Oct 10, 2022, at 15:57, Ryan Rawdon wrote:On Oct 10, 2022, at
> On Oct 10, 2022, at 6:37 PM, Matthew Petach wrote:
>
>
>
> On Mon, Oct 10, 2022 at 8:44 AM Mark Tinka wrote:
> On 10/10/22 16:58, Edvinas Kairys wrote:
>
> > Hello,
> >
> > We're considering to buy some Cisco boxes - NCS-55A1-24H. That box has
> > 24x100G, but only 2.2mln route (FIB)
On Mon, Oct 10, 2022 at 8:44 AM Mark Tinka wrote:
> On 10/10/22 16:58, Edvinas Kairys wrote:
>
> > Hello,
> >
> > We're considering to buy some Cisco boxes - NCS-55A1-24H. That box has
> > 24x100G, but only 2.2mln route (FIB) memory entries. In a near future
> > it will be not enough - so we're
Randy Bush wrote:
> it is a tragedy that cidr and an open market has helped us more than
> ipv6 has.
True.
Maybe cidr and an open market for ipv6 addresses would reduce the tragedy?
John
I frequently do this (accept peer’s, and their customers prefixes), and it
works out well. Then you can choose where you want the rest of it to go.
With multiple peers in your country this works out quite well.
On Mon, Oct 10, 2022 at 5:02 PM richey goldberg
wrote:
> The OP can always take the
The OP can always take the provider's address space plus their
customer's routes and use a default route to fill in the blanks.I
did this at a provider years ago where the global routing table
outgrew the speed they could spend the money on upgrades and it worked
out well.I think it was
> On 11 Oct 2022, at 4:23 am, Tobias Fiebig
> wrote:
>
> Heho,
> Let alone $all the /24 assigned under the RIPE waiting list policy.
>
> In the Geoff Huston spirit, I quickly took a look how less specifics for /24s
> looks in my table:
>
[…]
> So it seems like there is a healthy amount
Heho,
Let alone $all the /24 assigned under the RIPE waiting list policy.
In the Geoff Huston spirit, I quickly took a look how less specifics for /24s
looks in my table:
8 {'no_less_specific': 16, 'has_less_specific': 0, 'sum': 16,
'least_specific_length': {}}
9 {'no_less_specific': 9,
< rant >
there once used to be 'swamp' space, down in the low 190s where /24s
were expected. and folk/rirs tried to keep shorter aggregates, e.g.
/19s, as the norm above swamp (negotiated at ietf/danvers). in those
days, one could actually filter above swamp on /19. for a while, one
could even
On 10/10/22 9:20 AM, Stephane Bortzmeyer wrote:
But theoretically every filtered /24 could be routed via smaller
prefix /23 /22 /21 or etc.
I don't think this is true, even in theory, specially for legacy
prefixes. There is probably somewhere a Geoff Huston survey on /24
without a covering
On Mon, Oct 10, 2022 at 11:18 AM Jeff Tantsura wrote:
> There has been a number of efforts to implement FIB (actually BGP RIB)
> compression.
> There’s a white paper from MS research; I recall Spotify talking of running
> off-box BGP
> compression SW and re-injecting summarized BGP RIB;
Hi
There has been a number of efforts to implement FIB (actually BGP RIB)
compression. There’s a white paper from MS research; I recall Spotify talking
of running off-box BGP compression SW and re-injecting summarized BGP RIB;
Volta Networks had an implementation of full BGP table compression to
You’ll need to be very selective about the IP ranges you apply that filter to,
or more likely, just do it and make sure have one or more default routes to
devices/providers that carry full tables.
As for alternate devices, have you looked at Arista 7280, particularly the
Jericho >1 versions.
On Mon, Oct 10, 2022 at 8:37 AM Mike Hammett wrote:
> Feasibility of adding some middleware that culls unneeded routes (existing
> more specific and aggregate routes pointing to the same next hop), when that
> table starts to fill?
This is called "FIB aggregation." It exists and works but is
I like that idea.
-
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com
Midwest-IX
http://www.midwest-ix.com
- Original Message -
From: "Jay Hennigan"
To: nanog@nanog.org
Sent: Monday, October 10, 2022 10:39:06 AM
Subject: Re: any dangers of filtering
There are most definitely a number of organizations that have /24s that are not
part of a larger aggregate.
If you don’t have a default route to some router that takes the full table on
your behalf, then you will loose connectivity to/from those entities.
Owen
> On Oct 10, 2022, at 07:58 ,
My assumption is that it's not a one-and-done scenario - that the middleware
continually adjusts.
-
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com
Midwest-IX
http://www.midwest-ix.com
- Original Message -
From: "Elmar K. Bins"
To: "NANOG Operators'
On 2022-10-10 09:39, Jay Hennigan wrote:
On 10/10/22 07:58, Edvinas Kairys wrote:
We're considering to buy some Cisco boxes - NCS-55A1-24H. That box
has 24x100G, but only 2.2mln route (FIB) memory entries. In a near
future it will be not enough - so we're thinking to deny all /24s to
save the
na...@ics-il.net (Mike Hammett) wrote:
> Feasibility of adding some middleware that culls unneeded routes (existing
> more specific and aggregate routes pointing to the same next hop), when that
> table starts to fill?
Well... if that covering prefix goes away, let's hope you still have a
> we're thinking to deny all /24s to save the memory
i recommend this to all my competitors
randy
On 10/10/22 17:26, William Herrin wrote:
The Internet FIB is around 900k IPv4 routes. You have years before
exhausting a 2.2M table.
Depends on what else they may be carrying in their IGP, MPLS domain, SR
domain, e.t.c.
Mark.
On 10/10/22 07:58, Edvinas Kairys wrote:
Hello,
We're considering to buy some Cisco boxes - NCS-55A1-24H. That box has
24x100G, but only 2.2mln route (FIB) memory entries. In a near future it
will be not enough - so we're thinking to deny all /24s to save the
memory. What do you think about
On 10/10/22 16:58, Edvinas Kairys wrote:
Hello,
We're considering to buy some Cisco boxes - NCS-55A1-24H. That box has
24x100G, but only 2.2mln route (FIB) memory entries. In a near future
it will be not enough - so we're thinking to deny all /24s to save the
memory. What do you think
Feasibility of adding some middleware that culls unneeded routes (existing more
specific and aggregate routes pointing to the same next hop), when that table
starts to fill?
Not great for passing downstream, but should fill a need internally.
-
Mike Hammett
Intelligent Computing
If you filter out /23 or longer you cut the v4 table size about in half. I
have done this with some edge and eyeball network clients that had really
old or underpowered routing gear and upgrades were just not in the budget,
and they could barely spell BGP.
I know of a number of ASNs with SUP720
On Mon, Oct 10, 2022 at 05:20:33PM +0200,
Stephane Bortzmeyer wrote
a message of 10 lines which said:
> > But theoretically every filtered /24 could be routed via smaller
> > prefix /23 /22 /21 or etc.
>
> I don't think this is true, even in theory, specially for legacy
> prefixes.
I even
On Mon, Oct 10, 2022 at 7:58 AM Edvinas Kairys wrote:
> We're considering to buy some Cisco boxes - NCS-55A1-24H. That box has
> 24x100G, but only 2.2mln route (FIB) memory entries. In a near future it will
> be not enough - so we're thinking to deny all /24s to save the memory. What
> do you
There's 69,055 pure /24's allocated or assigned directly from an RIRs. At least
c,d,e, and g root servers only have /24s allocated to them. Major services like
Cloudflare only advertise the /24 without advertising an aggregate.
Unless you're also getting a default from upstream, it sounds like
On Mon, Oct 10, 2022 at 05:58:45PM +0300,
Edvinas Kairys wrote
a message of 35 lines which said:
> But theoretically every filtered /24 could be routed via smaller
> prefix /23 /22 /21 or etc.
I don't think this is true, even in theory, specially for legacy
prefixes. There is probably
On Mon, Oct 10, 2022 at 7:59 AM Edvinas Kairys
wrote:
> Hello,
>
> We're considering to buy some Cisco boxes - NCS-55A1-24H. That box has
> 24x100G, but only 2.2mln route (FIB) memory entries. In a near future it
> will be not enough - so we're thinking to deny all /24s to save the memory.
>
Hello,
We're considering to buy some Cisco boxes - NCS-55A1-24H. That box has
24x100G, but only 2.2mln route (FIB) memory entries. In a near future it
will be not enough - so we're thinking to deny all /24s to save the memory.
What do you think about that approach - I know it could provide some
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