Enrico Marocco wrote: >I agree, it is a general problem that boils down to the scarcity of IP addresses and to fact that CIDR blocks are usually reassigned to users either on a topological basis or on a subscription basis, but generally not both.
The address assignment approach by an ISP may depend on the last mile network topology. For a last mile shared media network like cable, it is typical to assign addresses based on network topology, not based on subscription. It may be different for a last mile point to point network, I don't know. >I don't know how common they are today and am wondering whether ALTO would provide enough incentive for ISPs to switch to them. >Especially because applications only, not ISPs, might (am still not sure if they actually will) directly benefit from the use of provisioned bandwidth information in peer selection. I suspect that this incentive would not be sufficient, at least in many cases. The ISP's address assignment policies are usually driven by IPv4 address conservation, rather than application optimization. The regional Internet registries typically expect 80% utilization of addresses, before they grant additional IP address space to the ISP. For example, https://www.arin.net/policy/nrpm.html#four24. Application optimization is great, but you can't operate a growing ISP without a growing pool of IP addresses. :) -- Rich -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Enrico Marocco Sent: Wednesday, October 14, 2009 6:07 AM To: Reinaldo Penno Cc: [email protected] Subject: Re: [alto] Highly volatile network partitioning Reinaldo Penno wrote: > I'm aware of this issue but IMO this is not a specific ALTO issue and > therefore I do not think we should try to solve it. This is an ISP > Policy/Provisioning issue. > > The fast reuse of IP addresses have other impacts such as security, > accounting, subscriber limits, etc. The ISPs today are aware of this > issue since they are using or (trying to move) to a 'sticky' IP > address approach where the same device gets always the same address > and/or make sure it takes a 'safe' long time to recycle the same IP address to another customer. > > One could also argue that if the ISP is running the ALTO Service (or > in partnership with a Content Provider) it is in its best interest to > invalidate any IP/customer associated info whenever an IP address is > dished out by the DHCP/Radius Server. But again, I think this is a > generic provisioning problem ISPs face day to day. I agree, it is a general problem that boils down to the scarcity of IP addresses and to fact that CIDR blocks are usually reassigned to users either on a topological basis or on a subscription basis, but generally not both. I can think of a provisioning policy that could preserve network partitioning both on a topological level and on a provisioned bandwidth level (i.e. topology based partitioning and subsequent sub-partitioning on a contract basis, e.g. first X% addresses in each partition assigned to contract A subscribers, Y% to contract Bs, and so on), but I don't know how common they are today and am wondering whether ALTO would provide enough incentive for ISPs to switch to them. Especially because applications only, not ISPs, might (am still not sure if they actually will) directly benefit from the use of provisioned bandwidth information in peer selection. -- Ciao, Enrico _______________________________________________ alto mailing list [email protected] https://www.ietf.org/mailman/listinfo/alto
