[c-nsp] RAM for 4431 with full BGP table?

[Octavio Alvarez]

On 12/28/2017 04:10 PM, Gert Doering wrote:
> Hi,
> 
> On Thu, Dec 28, 2017 at 08:54:03PM +0000, Nick Cutting wrote:
>> I would also like to know the answer to this.
>>
>> I always get scared and buy 16 gig if I'm taking in the full routing table. (4431/4451/4351 so far)
>>
>>  I'm sure I could get away with 8. Not sure about 4, would love to know
> 
> So how much memory do your routers use, if you have full tables?
> 
> That should easily answer the question on whether 8 or 4 would suffice...
> 
> A 7301 will take a full table in 1G RAM :-)

https://www.cisco.com/c/en/us/products/collateral/routers/4000-series-integrated-services-routers-isr/white-paper-c11-734550.html

"13. Scalability Tests [...] All Cisco 4000 platforms support a full
Internet routing table (500,000 prefixes) @ 8-GB DRAM. The 4451 supports
two full Internet routing tables (1 million prefixes) @ 16-GB DRAM."

However, be careful: first, the full table is around 700K nowadays;
second, the interpretation of "route". For an ASR 1K a "route" means "an
entry in the RIB for each protocol" instead of "an entry in the routing
table" so if your router has 2 upstreams, each sending its full-table
through BGP it actually means you must size your router RAM to fit 2
full routing tables, not one.

Best regards,
Octavio.