Notes

Project Clearwater - IMS in the CloudSizing / Costing Model

A Clearwater deployment comprises four software-based elements, as follows:

Bono - edge proxy (P-CSCF)Sprout - core proxy (I/S-CSCF an d BGCF) plus TASHomestead - subscriber profile database / HSS cacheHomer - XML Document Management Server

Each of these has a certain upper limit of capacity in terms of subscriber population and calling load, depending on virtual machine size. For any given virtual machine size, the upper limit of capacity of any given type of node may be determined by population limit or by call load limit, depending on the assumed calling profile.

The model is based on deployment of Clearwater on Amazon AWS. We have tested upper limits of subscriber population and call load for the various software elements on a selection of different virtual machine types (and we have done some extrapolations across VM types). By plugging in the total subscriber population and the call load profile in BHCA per subscriber, and by selecting a virtual machine type for each of the different software elements, we can estimate the total number of virtual machine instances of each type that will be needed , and the cost per year to obtain this capacity.

We also plug in estimates of the signaling bandwidth needed per subscriber per hour since this bandwidth is into and out of the AWS Cloud (via Bono) and attracts bandwidth charges. Note that the estimate of 10kB per hour per subscriber for registration traffic is based on the use of TCP transport for SIP, since this needs much less bandwidth to keep NAT pinholes open than UDP transport and is the preferred transport type for Clearwater.

Sizing and CostingkSubs total25000Key:BHCA/sub2Model parameterskBHCA total50000Node scalabilityEC2 costs
Matt Williams: Matt Williams:See http://aws.amazon.com/ec2/#pricingbonosprouthomesteadhomertotalEC2 instance typem1.mediumm1.mediumm1.smallm1.smallkSubs/instance11055150001250kBHCA/instance3505008501150instances2271005944430reserved upfront cost (3 year)$514$514$257$257reserved cost/hour$0.02$0.02$0.01$0.01amortized reserved cost/year$372.95$372.95$190.86$190.86instances cost/year$84,660$37,295$11,261$8,398$141,614static bandwidth/sub/hour1010call bandwidth/CA55bandwidth/sub/hour200 KB0 KB0 KB20bandwidth/hour5000 GB0 GB0 GB500bandwidth/year43830000 GB0 GB0 GB4383000amortized bandwidth cost/GB$0.062$0.062$0.062$0.062bandwidth cost/year$270,749$0$0$0$270,749total/year$355,409$37,295$11,261$8,398$412,363total/sub/year$0.0142$0.0015$0.0005$0.0003$0.016Node scalabilitykSubs/instancebonosprouthomesteadhomerRAM/GBm1.large11032205955157.5m1.medium1105511102927573.75m1.small50250
Andy Caldwell: Andy Caldwell:64M of memcached space divided by 250bytes per binding.5000
Matt Williams: Matt Williams:From testing so far - may go higher.1250
Matt Williams: Matt Williams:Extrapolated from FPP's testing on an m1.medium.1.7m1.xlarge441181102915kBHCA/instancebonosprouthomesteadhomerECUm1.large1000340046004m1.medium350500170023002m1.small175250850
Matt Williams: Matt Williams:From testing so far - 6 nodes seem to be required for 5M BHCA1150
Matt Williams: Matt Williams:Extrapolated from FPP's testing on an m1.medium.1m1.xlarge680092008EC2 instance pricing
Matt Williams: Matt Williams:As of 2013/04/05, from http://aws.amazon.com/ec2/pricing/, assuming Heavy Utilization Reserved Instances in US Eastm1.largem1.mediumm1.smallm1.xlargereserved upfront cost (3 year)$1,028$514$257$2,056reserved cost/hour$0.046$0.023$0.012$0.092EC2 bandwidth pricing
Matt Williams: Matt Williams:As of 2013/04/05, from http://aws.amazon.com/ec2/pricing/, using Data Transfer OUT from Amazon EC2 to Internetcost/GBFirst/month1$0.00Up to/month10000$0.12Next/month40000$0.09Next/month100000$0.07Next/month350000$0.05Drop-down list optionsm1.smallm1.mediumm1.largem1.xlarge