CNTT Edge Architecture -- Please see CNTT RM PR #2118
(RM Chapter 3 new section on Edge Computing w/o OpenStack specifics)
Alt: RM Chapter08 – PR #2118 | Please make your comments on the PR and not here.
X.1 Introduction
Chapter 3(https://github.com/cntt-n/CNTT/blob/master/doc/ref_model/chapters/chapter01.md) of this document focuses on cloud infrastructure abstractions. While these are generic abstractions they and the associated capabilities are specified for data center or a colocation center cloud infrastructure. The environmental conditions, facility and other constraints, and the variability of deployments on the edge are significantly different and, thus, requires separate consideration.
It is unrealistic to expect that a private cloud can cost effectively meet the need of all loads, including peak and disaster recovery. It is for that reason that enterprises will implement an hybrid cloud. In a hybrid cloud deployment, at least two or more distinct cloud infrastructures are inter-connected together. In a multi-cloud the distinct cloud infrastructures of the hybrid cloud may be implemented using one or more technologies. The hybrid multi-cloud infrastructure has differences requiring different abstractions. These hybrid multi-clouds can be considered to be federated.
In IaaS clouds, the cloud infrastructure is defined but the tenant workloads include certain needed services (such as LB, messaging); thus, the VNF/CNFs may incorporate different services with the resultant issues related to an explosion of services, their integration and management complexities. To mitigate these issues, the CNTT Reference Model must specify the common services that every Telco cloud must support and thereby require workload developers to utilise these pre-specified services.
A generic Telco cloud is an hybrid multi-cloud or a Federated cloud that has deployments in large data centers, central offices or colocation facilities, and the edge. In this chapter we will discuss the characteristics of Telco Edge and hybrid multi-cloud.
X.2 Telco Edge Cloud
This section presents the characteristics and capabilities of different Edge cloud deployment locations, infrastructure, footprint, etc.
X.2.1 Telco Edge Cloud Deployment Environment Characteristics
Telco Edge Cloud (TEC) deployment locations can be environmentally friendly such as indoors (offices, buildings, etc.) or environmentally challenged such as outdoors (near network radios, curbside, etc.) or environmentally harsh environments (factories, noise, chemical, heat and electromagnetic exposure, etc). Some of the more salient characteristics are captured in Table X.1.
Table X.1. TEC Deployment Location Characteristics & Capabilities
Facility Type | Environmental Characteristics | Capabilities | Physical Security | Implications | Deployment Locations | Comments | |
|---|---|---|---|---|---|---|---|
Environmentally friendly | Indoors: typical commercial or residential structures | Protected Safe for common infrastructure | Easy access to continuous electric power High/Medium bandwidth Fixed and/or wireless network access | Controlled Access | Commodotised infrastructure with no or minimal need for hardening/ruggedisation Operational benefits for installation and maintenance | Indoor venues: homes, shops, offices, stationary and secure cabinets Data centers, central offices, co-location facilities, Vendor premises, Customer premises | |
Environmentally challenged | Outdoors and/or exposed to environmentally harsh conditions | maybe unprotected Exposure to abnormal levels of noise, vibration, heat, chemical, electromagnetic pollution | May only have battery power Low/Medium bandwidth Fixed and/or mobile network access | No or minimal access control | Expensive ruggedisation Operationally complex | Example locations: curbside, near cellular radios, |
X.2.2 Telco Edge Cloud Infrastructure Characteristics
Commodity hardware is only suited for environmentally friendly environments. Commodity hardware have standardised designs and form factors. Cloud deployments in data centers typically use such commodity hardware with standardised configurations resulting in operational benefits for procurement, installation and ongoing operations.
In addition to the type of infrastructure hosted in data center clouds, facilities with smaller sized infrastructure deployments, such as central offices or co-location facilities, may also host non-standard hardware designs including specialised components. The introduction of specialised hardware and custom configurations increases the cloud operations and management complexity.
At the edge, the infrastructure may further include ruggedised hardware for harsh environments and hardware with different form factors.
X.2.3 Telco Edge Cloud Infrastructure Profiles
The Reference Model (https://github.com/cntt-n/CNTT/blob/master/doc/ref_model/chapters/chapter04.md#4.2.4) specifies two infrastructure profiles:
The Basic cloud infrastructure profile is intended for use by both IT and Network Function workloads that have low to medium network throughput requirements.
The Network Intensive cloud infrastructure profile is intended for use by applications that have high network throughput requirements (up to 50Gbps).
The Network Intensive profile can specify extensions for hardware offloading; please see Hardware Acceleration Abstraction (https://github.com/cntt-n/CNTT/blob/master/doc/ref_model/chapters/chapter03.md#3.8). The Reference Model Network Intensive profile includes an initial set of Network Intensive profile extensions (https://github.com/cntt-n/CNTT/blob/master/doc/ref_model/chapters/chapter04.md#42421-network-acceleration-extensions).
Based on the infrastructure deployed at the edge, the Table X.2 specifies the Infrastructure Profile features and requirements (https://github.com/cntt-n/CNTT/blob/master/doc/ref_model/chapters/chapter05.md) that would need to be relaxed.
Table X.2. Characteristics of Infrastructure nodes
Reference | Feature | Description | As Specified in RM Chapter 05 | Exception for Edge | ||
|---|---|---|---|---|---|---|
Basic Type | Network Intensive | Basic Type | Network Intensive | |||
infra.stg.cfg.003 | Storage with replication | N | Y | N | Optional | |
infra.stg.cfg.004 | Storage with encryption | Y | Y | N | Optional | |
infra.hw.cpu.cfg.001 | Minimum Number of CPU sockets | This determines the minimum number of CPU sockets within each host | 2 | 2 | 1 | 1 |
infra.hw.cpu.cfg.002 | Minimum Number of cores per CPU | This determines the number of cores needed per CPU. | 20 | 20 | 2 | 2 |
infra.hw.cpu.cfg.003 | NUMA alignment | NUMA alignment support and BIOS configured to enable NUMA | N | Y | N | Optional |
X.2.3 Telco Edge Cloud Infrastructure Characteristics
This section characterises the hardware capabilities for different edge deployments and the Platform services that run on the infrastructure. Please note, that the Platform services are containerised to save resources, and benefit from intrinsic availability and auto-scaling capabilities.
Table X.3. Characteristics of Infrastructure nodes
Platform Services | Storage | Network Interfaces | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Identity | Image | Placement | Compute | Networking | Message Queue | DB Server | Ephemeral | Persistent Block | Persistent Object | Management | Underlay (Provider) | Overlay | |
Control Nodes | |||||||||||||
Workload Nodes (Compute) | |||||||||||||
Storage Nodes | |||||||||||||
Depending on the facility capabilities, deployments at the edge may be similar to one of the following:
Small footprint edge device
Single server: deploy multiple (one or more) workloads
Single server: single Controller and multiple (one or more) workloads
HA at edge (at least 2 edge servers): Multiple Controller and multiple workloads
X.2.4. Comparison of Edge terms from various Open Source Efforts
Characteristics | Other Terms | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
CNTT Term? | Compute | Storage | Networking | RTT* | Security | Scalability | Elasticity | Resiliency | Preferred Workload Architecture | Upgrades | GSMA | ||||
Regional Data Center (DC) Fixed | 1000's Standardised >1 CPU >20 cores/CPU | 10's EB Standardised HDD and NVMe Permanence | >100 Gbps Standardised | ~100 ms | Highly Secure | Horizontal and unlimited scaling | Rapid spin up and down | Infrastructure architected for resiliency Redundancy for FT and HA | Microservices based Stateless Hosted on Containers | HW Refresh: ? Firmware: When required Platform SW: CD | Central Data Center | ||||
Metro Data Centers Fixed | 10's to 100's Standardised >1 CPU >20 cores/CPU | 100's PB Standardised NVMe on PCIe Permanence | > 100 Gbps Standardised | ~10 ms | Highly Secure | Horizontal but limited scaling | Rapid spin up and down | Infrastructure architected for some level of resiliency Redundancy for limited FT and HA | Microservices based Stateless Hosted on Containers | HW Refresh: ? Firmware: When required Platform SW: CD | Edge Site | Large Edge | Aggregation Edge | ||
Edge Fixed / Mobile | 10's Some Variability >=1 CPU >10 cores/CPU | 100 TB Standardised NVMe on PCIe Permanence / Ephemeral | 50 Gbps Standardised | ~5 ms | Low Level of Trust | Horizontal but highly constrained scaling, if any | Rapid spin up (when possible) and down | Applications designed for resiliency against infra failures No or highly limited redundancy | Microservices based Stateless Hosted on Containers | HW Refresh: ? Firmware: When required Platform SW: CD | Far Edge Site | Medium Edge | Access Edge / Aggregation Edge | ||
Mini-/Micro-Edge Mobile / Fixed | 1's High Variability Harsh Environments 1 CPU >2 cores/CPU | 10's GB NVMe Ephemeral Caching | 10 Gbps Connectivity not Guaranteed | <2 ms Located in network proximity of EUD/IoT | Untrusted | Limited Vertical Scaling (resizing) | Constrained | Applications designed for resiliency against infra failures No or highly limited redundancy | Microservices based or monolithic Stateless or Stateful Hosted on Containers or VMs Subject to QoS, adaptive to resource availability, viz. reduce resource consumption as they saturate | HW Refresh: ? Firmware: ? Platform SW: ? | Fog Computing (Mostly deprecated terminology) Extreme Edge Far Edge | Small Edge | Access Edge | ||
*RTT: Round Trip Times
EUD: End User Devices
IoT: Internet of Things
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Edge deployment scenarios
Cloud Infrastructure (CI) deployment environment for different edge deployments:
Controlled: Indoors, Protected, and Restricted environments. Data Centers, Central Offices, Indoor venues. Operational benefits for installation and maintenance, and reduced need for hardening/ruggedised.
Exposed: Outdoors, Exposed, Harsh and Unprotected environments. Expensive rugged equipment
Cloud Infrastructure (CI) hardware type for different edge deployments:
Commodity/Standard: COTS, standard hardware designs and form factors. Deployed only in Controlled environments. Reduced operational complexity.
Custom/Specialised: non-standard hardware designs including specialised components, ruggedised for harsh environments and different form factors. Deployed in Controlled and/or Exposed environments. Operationally complex environment.
Cloud Infrastructure (CI) hardware specifications for different edge deployments:
CNTT Basic: General Purpose CPU; Standard/Commoditised Design.
CNTT Network Intensive: CNTT Basic + high speed user plane (low latency, high throughput); Standard//Commoditised Design.
CNTT Network Intensive+ : CNTT Network Intensive + optional hardware acceleration (compared with software acceleration can result in lower power use and smaller physical size); possible Custom Design (Please see HW Acceleration Abstraction (url?).
CNTT Network Intensive++ : CNTT Network Intensive + required hardware acceleration; Custom Design.
Server capabilities for different edge deployments and the OpenStack Platform services that run on these servers; the OpenStack Platform services are containerised to save resources, intrinsic availability and autoscaling:
Control nodes host the OpenStack Platform control plane components (subset of Cloud Controller Services), and needs certain capabilities:
OpenStack Platform services: Identity (keystone), Image (glance), Placement, Compute (nova), Networking (neutron) with ML2 plug-in
Message Queue, Database server
Network Interfaces: management, provider and overlay
Compute Workload nodes host a subset of the Compute Node Services: