RE: more specific routes in today reality
Comments followed.
Hi,
On Tue, Oct 09, 2001 at 09:13:05PM +0200, Jan-Ahrent-Czmok wrote:
Some providers are multihomed but cannot cover the costs, even for a small lir.
If you want to be multihomed, the costs for routers & co. are far higher than for being LIR. If you can't afford being LIR, be single-homed.
Great! Now we have to collect routing policies from thousands of small LIRs while still have to deal with thousands of small prefixes.
Nonsense. Nobody is announcing 192.0.0.0/8, or supernets of other's networks - and what is in the RIPE database doesn't affect routing.
To show the first few things from 192/8:
*>i192.0.32.0 195.158.244.133 100 0 1755 1239 5676 226 i *>i192.0.34.0 195.158.244.133 100 0 1755 1239 5676 226 i * i192.0.36.0 195.206.66.61 3 100 0 3300 701 2914 20144 i *>i 195.158.244.133 100 0 1755 1239 2914 2014 4 i * i192.1.0.0/16 195.206.66.61 3 100 0 3300 701 1 i *>i 195.158.244.133 100 0 1755 1239 1 i * i192.2.0.0/16 195.206.66.61 3 100 0 3300 701 1 i *>i 195.158.244.133 100 0 1755 1239 1 i
so if I filter those, why should the traffic go to XLink? Why should *any* traffic go to RIPE? It will be just blackholed (or default-routed to one of my upstreams, if I happen to have a default-route).
Please do your homework about routing and BGP before selling people consulting about multihoming.
Now more and more major ISPs are filtering out routes from other ISPs ( becuase we don't have transit agreements) so the multi-homed customer have to have their own AS. And if the major ISPs stop listening to the more specfic routes then even using the address from PI space won't work (unless you are big enough). All these solutions kind of imply that if you can't have /20 prefix then you can't be multi-homed. What happen if a customer want to have an OC-48 multi-homed link but only use prefix < /20 (that happens to the Internet Exchange people a lot ) ? Ping Lu Cable & Wireless USA Network Tools and Analysis Group W: +1-703-292-2359 E: plu@cw.net
On Tue, 9 Oct 2001 16:38:36 -0400 "Lu, Ping" <PLu@cw.net> wrote: [..snip..]
Great! Now we have to collect routing policies from thousands of small LIRs while still have to deal with thousands of small prefixes.
This is what i meant: if we "renumber" the old swamp space not only in RIPE Region, we have a cleaner routing table. many of the old swamp space "owners" are single homed, which would clean up a lot in the routing table if they are forced to use PA space from the respective provider.
And if the major ISPs stop listening to the more specfic routes then even using the address from PI space won't work (unless you are big enough).
Right, see my above comment.
All these solutions kind of imply that if you can't have /20 prefix then you can't be multi-homed. What happen if a customer want to have an OC-48 multi-homed link but only use prefix < /20 (that happens to the Internet Exchange people a lot ) ?
There should be also made some "golden networks" for the exchanges and "important" services, like DNS. This, correctly implemented together with the vendors, could make live easier: - route flap dampening works together seamless with the correct networks in "default" configurations. - more stability - less routes in routing table - clear "border" of address space together with registry borders. But again, these are only ideas from network operators. --jan -- Jan-Ahrent Czmok http://www.lambda-solutions.de Technical Advisor ISP Hofdcker Str. 14, 65207 Wiesbaden Tel. +49-(0)-174-3074404
Hi, On Tue, Oct 09, 2001 at 04:38:36PM -0400, Lu, Ping wrote:
On Tue, Oct 09, 2001 at 09:13:05PM +0200, Jan-Ahrent-Czmok wrote:
Some providers are multihomed but cannot cover the costs, even for a small lir.
If you want to be multihomed, the costs for routers & co. are far higher than for being LIR. If you can't afford being LIR, be single-homed.
Great! Now we have to collect routing policies from thousands of small LIRs while still have to deal with thousands of small prefixes.
So? There is no difference between thousands of PI prefixes and "thousands of small LIRs", except that the latter actually have to *pay* for what they cause. [..]
Please do your homework about routing and BGP before selling people consulting about multihoming.
Now more and more major ISPs are filtering out routes from other ISPs ( becuase we don't have transit agreements) so the multi-homed customer have to have their own AS.
No. This is an interesting arguments, but the fact that C&W has problems with some of their peers doesn't mean "the whole world has to drown in multihomed ASes". Get your contracts right.
And if the major ISPs stop listening to the more specfic routes then even using the address from PI space won't work (unless you are big enough).
Yes. This is what it's all about. Small PI space really hurts people.
All these solutions kind of imply that if you can't have /20 prefix then you can't be multi-homed. What happen if a customer want to have an OC-48 multi-homed link but only use prefix < /20 (that happens to the Internet Exchange people a lot ) ?
So announce it to the internet exchange. Why does it have to be visible in the whole world? Letting "the whole world" see a /16 (from the upstream) and the direct peers a /24 (or whatever) means global routing will just work fine (over the upstream's PA block) and and IX routing will also work just fine (using the more specific). Bad example. Gert Doering -- NetMaster -- SpaceNet AG Mail: netmaster@Space.Net Joseph-Dollinger-Bogen 14 Tel : +49-89-32356-0 80807 Muenchen Fax : +49-89-32356-299
Great! Now we have to collect routing policies from thousands of small LIRs while still have to deal with thousands of small prefixes.
So? There is no difference between thousands of PI prefixes and "thousands of small LIRs", except that the latter actually have to *pay* for what they cause.
Right. Strong ACK on this.
And if the major ISPs stop listening to the more specfic routes then even using the address from PI space won't work (unless you are big enough).
Yes. This is what it's all about. Small PI space really hurts people.
Yep. And therefore these "small" PI stuff should be cleaned up. The User itself can use it internally and could get a /24 routed from PA space. But it is really not the optimum solution, as it waste's ip address space. And we have enough RFC1918 space...
Letting "the whole world" see a /16 (from the upstream) and the direct peers a /24 (or whatever) means global routing will just work fine (over the upstream's PA block) and and IX routing will also work just fine (using the more specific).
right, but is it generally used ? I see a lot of /24 out of the same block from a /16 announced space globally (AS5511 for example) --jan -- Jan-Ahrent Czmok http://www.lambda-solutions.de Technical Advisor ISP Hofdcker Str. 14, 65207 Wiesbaden Tel. +49-(0)-174-3074404
participants (3)
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Gert Doering -
Jan-Ahrent Czmok -
Lu, Ping