On Wed, Mar 9, 2011 at 2:19 AM, George Bonser <gbonser@seven.com> wrote:
The ipv4-ipv6-2 CAM profile in 5.1 gives 768K v4 routes and 64k v6 routes which should be good for quite a while. That is provided you
How many IPv6 BGP routes are folks typically planning for in the DFZ before a hardware upgrade is required? Here are some relevant figures (note that my script makes some minor errors but this is good enough for discussion purposes): IPv6: Unique Origin ASes seen: 3287 Examined 4705 active routes IPv4: Unique Origin ASes seen: 36707 Examined 352688 active routes Making some assumptions, let's say every active ASN in DFZ will announce a mean of 1.4 IPv6 routes (the number seen today.) If IPv6 grows from under 10% of ASNs today to 100% of ASNs in a year or two, we will see about 53k IPv6 routes in DFZ. Keep in mind that many, if not most, ASNs originating IPv6 routes today have substantially no production services on IPv6, and they may deaggregate more in the future, etc. Some folks seem to believe that not every ASN will announce routes to the DFZ. I don't think that is a safe assumption upon which to base purchasing decisions for routers which should have a life-cycle of several years. Whether or not networks *should* announce more than one route, or any routes at all, seems debatable; but when making router purchasing decisions, I don't want to tell my clients two years from now that they have to spend capital dollars on routers just to gain IPv6 FIB. I also don't want to tell them they have to filter some routes, and make any BGP customers unhappy, and live with other downfalls of that unfortunate compromise. I am certainly not deploying any boxes that will only do 64k IPv6 FIB in default-free part of my clients' networks. It certainly will work now, and will almost certainly be safe in one year. In two years, it seems a little questionable. Beyond that time-frame, it is much easier to justify new routers, as ports become cheaper and faster; but I still do not want my clients to be forced to buy new routers simply because of overly-optimistic assumptions about IPv6 DFZ size. Really, I would like vendors to make IPv4 and IPv6 FIB come from the same pool (with obviously different allocation sizes) or allow me to configure the partitioning as I see fit. This has been the case for quite a few platforms for many years. I am not comfortable guessing at whether I will first need to exceed 500K IPv4 routes (maybe we won't even see that number) or 64K IPv6 routes (this seems a virtual certainty, but when it happens is hard to say.) Once you add L3VPN into your list of concerns, your future FIB needs become even more difficult to predict. -- Jeff S Wheeler <jsw@inconcepts.biz> Sr Network Operator / Innovative Network Concepts