Re: [Ila] [5gangip] Scaling mapping systems (was Re: BOF Description)

[Lorenzo Colitti <[e-mail]>]

On Tue, Feb 6, 2018 at 12:37 AM, Tom Herbert <[e-mail]> wrote:

> As time has gone on with experience in deployment, forwarding to another
>> node that has a large shared cache, like an RTR, seems to deal with the
>> issue in a compromised way.
>>
>
> In ILAMP (https://tools.ietf.org/html/draft-herbert-ila-ilamp-00) secure
> redirects are defined to be the primary means of populating a cache. On a
> cache miss, a packet is forwarded into the network and routing should
> forward the packet to an ILA router that contains the complete set of
> mappings for the associated shard. The router performs the transformation
> and can send a redirect back to the caching node. The redirect can be
> cached so that subsequent packets take a direct route and avoid the
> trianglular routing. Redirects must be secure so that they cannot be
> spoofed, so for that reason (and some others) the protocol is over TCP. The
> mapping cache is only an optimization and packets are never dropped or
> queued for pending cache resolution. If the cache weren't present,
> communications would still be viable but sub-optimal; that characteristic
> establishes a bound for the worst case DOS attack.
>
> Any thoughs on this approach?
>

The obvious ones would seem:

   - Will the working set of cache mappins fit in whatever memory is
   available in, say, a large peering router? Remember that memory that is
   capable of sustaining routing lookups at tens of gigabits per second is
   extremely expensive.
   - How do you defend against state exhaustion attacks whereby a large
   number of spoofed sources send packets to nonexistent destinations?
   - How much bandwidth will be used for the redirects? How much CPU time
   will be used to process them?
   - How many servers are needed to store

Suggest gaming this out for a large mobile operator with, say, 100M
clients, 100 Internet connection points and 10T of traffic.