2Way-Sat A DVB-RCS Satellite Access Network

Transcription

1 2Way-Sat A DVB-RCS Satellite Access Network by Dirk Breynaert, Newtec Brussels 24 th of August 2005 Abstract The article describes a DVB-RCS compliant Satellite Access Network-concept called "2Way-Sat". After describing the different players in the Business Model, an overview of the total Network Architecture is given, with more details on the heart of the HUB station: "The Carrier Blade". Several examples of services offered to end customers are provided. With satellite bandwidth being quite expensive, adequate bandwidth shaping and QoS-prioritisation is realised. Benchmarking is foreseen in order to verify the end performance. Finally, some implementation aspects are described, for all elements of the Network and an overview is given of optional Operational Support Software which is offered on top of the standard extensive NMS software. Introduction Newtec is active in DVB-RCS since 1998 and has since 2002 been delivering and installing several systems worldwide serving thousands of terminals. Today, many end-customers have a daily real broadband experience on our DVB-RCS Satellite Access Networks. DVB-RCS: "The Open Standard" In 1999, the DVB-RCS was standardised [1], [2] and complemented in 2003 by a new standard for the Forward Link called DVB-S2 [3]. The DVB standardisation process is now adopted by a large number of manufacturers, operators, users and research institutes assembled in the Satlabs Group [4] and the DVB-RCS interoperability process is ongoing. Satlabs certification procedures are being developed. The standard has been field proven in a commercial environment [5]. 2 Way-Sat Business Model A 2Way-Sat system is designed to be an extremely versatile IP access platform to serve customers of different nature, each of them with their own distinctive business models and market entry strategy. A single service provider platform is typically used by service providers with sufficient critical size to justify the investment of a dedicated single-provider platform. Data Centre HUB Those can be large ISPs, Telecom operators or Virtual Network Service Providers using satellite technology to bridge the last mile gap by installing rooftop s (Satellite Interactive Terminals) on their end-user IP/VPN cloud Through the extensive IP Value Added Services feature-set of the Newtec terminal, the end-users are typically large corporate customers or Small and Medium Enterprises. Accelerated IP access for one or more LAN users LAN Provision of services towards residential type of customers is hereby typically covered by

2 adding a WiFi break-out system behind the. As such a terminal can then be serving small rural communities. In order to be able to also serve service providers which lack the critical of running there own dedicated platform, Newtec has developed the concept of Multi Service Provider Platform. Through the addition of dedicated NMS systems, this platform allows several Service Providers to share a single platform while at the same time preserving a high degree of independency in running and operating its own type of services. Such platforms are typically targeted towards e.g. satellite operators who operate the 2Way-Sat MSPP platform towards several smaller ISPs who nevertheless still independently control there own bandwidth profiles, contain full visibility of traffic measurements and have there own software tools to also independently commission and control their own terminals. Shared HUB Data IP/VPN cloud ISP/VPN 1 ISP/VPN 2 ISP/VPN 3 Accelerated IP access for one or more LAN users Served by multiple providers The main players in the business model are : SAP In the Multi Service Provider Platform model, the Satellite Access Provider usually sells transponder capacity and operates the HUB. Two distinct business models can be applied by the SAP for offering services to the ISPs: Managed Profile offering: The SAP defines a set of bandwidth profiles, whereby a profile is as is also the case for a typical terrestrial ADSL offering - defined by its peak bandwidth and average throughput guarantee (typical example for Internet Access is 1Mbit/s download, 256 kbit/s upload, no throughput guarantee). This pre-defined profile offering can then be used by the ISPs to be resold to its own customers. Managed Bandwidth offering: In this business model the SAP sells to the respective ISPs a fixed amount of bandwidth in both the forward path and the return path. Within this fixed bandwidth, the ISP itself can defines his own set of profiles to be offered to the end-users. (iii) ISPs The Internet Service Providers (or equivalent distributors) will sell Internet Access and / or other Value Added IP Services to End Customers (in the latter case, the ISP should no longer be necessarily seen as an Internet provider but can just as well be an IP/VPN Service provider offering Intranet connectivity services). When services are offered over a dedicated single service provider platform, the SAP and ISP are one and the same entity. The ISP will guarantee performance / price for these End Customers and act as a single point of contact to manage their own s. End-customers These are usually branch offices of large corporate clients, SMEs or SOHOs which are in need of broadband IP connectivity. DVB-RCS will be most attractive for those users who need a combination of a high peak and a low-to-medium average return rate, since in that case the statistical multiplexing of the satellite is most effective. For SAPs or ISPs using WiFi/WiMax technology behind the terminal, the end-customers can also be residential Internet users. (iv) -installers Install s at the End-Customer on behalf of the ISPs. (v) Network Supplier Delivers the HUB to the SAP.

3 (vi) Supplier Supplies s to the ISP. These s are approved by the Network Supplier before introduction into the Network. The Network Architecture A typical 2 Way-Sat Network consists of the following elements (see Figure 1): Satellite For non-mass-market networks, Ku-band has the advantage that existing satellites can be used. For the Forward-Link from the central hub towards the remote terminals ( FW ), often the 13 GHz band is used in single or dual carrier per transponder operation (low gain - ALC activated). For the Return-Link from the back to the central hub ( RT ), mainly the GHz VSAT band is used in multi-carrier, low-gain operation. For mass-market networks (for example 1 Million users) Ka-band satellites with multi-spot beams are recommended. This will certainly require the introduction of adaptive modulation and coding in the FW-link, as has been standardised in DVB-S2. (Satellite Interactive Terminal) A generic consists of the following elements: - Outdoor Unit The ODU consists of a reflector (antenna), a masthead and a front-end (amplifier, LNA, up- and down-converter). In absence of interference from adjacent satellites at 2 degree offset, reflector diameters as small as 75 cm can be used; else 90, 120 or 180 cm are required. High peak RT rates (e.g. 600 to 1000 kbps) can already be achieved with 2 Watt front-ends, 4 Watt versions are however also available to achieve even higher rates - Indoor Unit The IDU consists of a Demodulator (DVB-S or DVB-S2), a Burst Modulator, a DVB-RCS processor, which maps IP packets (over Ethernet) to and from the DVB-RCS air interface and an integrated router, offering enhanced network services to the end customer and distributed management to the network operator. Some of the features are: Upgradeable over the air Remotely manageable, robust design HTTP Pre-fetching Transparent TCP acceleration Web Caching DNS Caching relay / server NAT (Network Address Translation) DHCP (to automatically assign an IP address to a host on the customer s LAN) Firewalling Traffic conditioning (shaping) Integrated VPN functionality

4 (iii) HUB-station A will be assigned to one FW bandwidth pool, and will return data to the HUB over a pool of RT-carriers using MF-TDMA. The HUB is realised in a modular way and consists of the following parts: - an RF Subsystem : which usually consists of a large Antenna, a Tracking SS (Sub-System), an HPA SS and LNB SS. - a Carrier Blade SS, which realises in the FW-Link and corresponding RT-Links : statistical multiplexing bandwidth shaping & prioritisation of value added services - a Common SS with functionalities for all Carrier Blades : such as Time & Frequency Generation, Satellite Position Tracking, Customer Configuration Management, Terminal Management, etc. - an Internet Edge Router, performing terrestrial interconnection to the Internet Backbone. This is usually provided by the SAP. Note that during the HUB & lifetime, there will be constant evolution in features (e.g. DVB-S2 with ACM). The Carrier Blades will support upcoming features over the years to come. Carrier Blade Architecture The general block diagram of a Carrier Blade SS is shown in Figure 2. (iii) The FW-Link is consisting of the following elements: - the SLR (Satellite Link Router), providing network connectivity to the SAP s IP infrastructure - a server pool, offering IP access services like HTTP Pre-fetching, Web caching, transparent TCP acceleration etc - A Peak Rate Limiter (PRL), responsible for shaping and traffic prioritisation. - The FLE (Forward Link Combiner & IP Encapsulator) will combine the FW IP traffic with signalling information from the RLP-Scheduler and encapsulate both into a DVB-S(2) stream. - the FW_MOD (Forward Modulator), will combine the encapsulated data with NCR (Network Clock Reference) information and modulate the FW carrier according DVB-S(2). Accurate time information is also sent to the BDMs (Burst Demodulators) in the Return Link via an ASI-signal. The RT-Link consists of: - the BDM-bank (Burst Demodulator) in an N+1 redundancy configuration, handling RT carriers organised in MF-TDMA pools of which traffic is sent to the SLR. An ATM_MUX is required to combine traffic originating from several BDMs. The capacity requests from the s are sent by the BDM-bank to an RLP-bank (Return Link Processor) via Ethernet. Note that the BDMs are outperforming competition in link budget performance. - the RLP-bank will calculate the optimum RT-burst time every super-frame (around 140 ms), and send this to the terminals. The RLP-Statistical Multiplexing algorithms are very performing and suitable for a mix of bursty traffic (like HTTP) and real-time traffic (like VoIP and Video Conference). The RLP is responsible for bandwidth Shaping & QoS prioritisation in the Return Link. - the SLR performs ATM-AAL5 termination for the Return Link. IP Value Added Services To minimise the effect of satellite delay, of the following services are offered: HTTP Pre-fetching transparent TCP acceleration Web Caching Server For reasons of scalability, this is done in each Carrier Blade and not in the Common SS.

5 (iv) Management Services The NMS includes the following parts: - The SEMS (Satellite Earth Station Management) handles equipment and redundancy management of each network element in the Carrier Blades and configures the RF layer equipment - The Management Dashboard which holds different submodules as described in further detail below. - The POP Router Management System or also know as the TLC (Terminal Local Configuration). The TLC interface allows the customer to manage the local configuration data of the terminal in a controlled way. - The Accounting Report Tools which collects all IP related metrics for all terminals and brings them available to interface with the customer s billing system or other CRM software. The 2Way-Sat Management Dashboard is one of the main NMS systems in the hub and consists in its turn of several sub-modules: The Configuration Management Module ( Hub Resources ) The CMM module allows configuration of all hub logical resources and also covers the configuration of s. Typical parameters include e.g. carrier bandwidth configuration for the hub and SLA profile selection for the. The ISP Management Module ( ISP Resources ) The IMM module allows assignment of all relative hub resources to the different ISPs such as Return Capacity Group and Forward Pool bandwidth. The User Administration Module ( Users ) The UMM allow administration of all network management user profile definition and authentication. Different types of user levels can be defined for both the SAP and ISP, from full administrator rights down to limited visibility read only users. The Fault Management Module ( Events tab) The FMM module covers both the hub and the individual terminals. All hub metrics provided on the Performance Management Tool are tied to pre-defined thresholds whereby events are logged in the FMM in case any of the metrics fall beyond the thresholds. Additionally all terminal related alarm events are forwarded by the respective terminals towards the FMM where they are presented as individual events specifying the nature of the alarm and the associated severity level. The Performance Management Tool ( Performance ) The PMT collects the performance data of all elements of the DVB-RCS network, both at physical layer and at IP layer. This tool allows the operator to analyse and even predict the performance of the network over time. The tool groups, filters and analyses useful parameters from the abundance of operational data and provides relevant benchmarking and performance analysis. Forward IP volume counted in # of bytes per 5 minute period over one day

6 Es/N0 of the return path for a measured over a one week period Histogram showing the distribution of the Burst Time Offset over the total population of s User Access Service Examples (iii) DHCP service PCs connected to the Customer s LAN can automatically obtain an IP address, a DNS server address and a default Gateway address. DNS Cache service The POP Router has an integrated DNS Proxy Server, which communicates with the DNS Server at the HUB (located at PMS). transfer service The End-Customer's outgoing mails are forwarded to the Mail Transfer Server located at the Internet. Incoming mails are forwarded to the Mail Server of the End-Customer. (iv) Firewall service Default Firewall rules can be enabled. (v) VPN transparent service Creation of virtual private networks by opening the ports and protocols of the POP Router (PPTP or IPsec) is allowed. This can be used in combination with a customer provided VPN Router. (vi) BW reservation service The SAP can reserve a bandwidth on FW & RT link for real-time traffic. (This type of traffic has highest priority). (vii) Static Multicast service This allows End-Customers to join an active multicast session via their web-browser. (viii) VoIP support The 2Way-Sat system is ideally suited for transporting Voice over IP traffic over satellite. Its ease of deployment and complementarity to pure data applications enables all types of organizations to bring integrated data and voice applications to the most remote corners of the world. The RCS return path technology brings furthermore an attractive cost saving versus other technologies that use fixed bandwidth allocation. At the remote site, the user can connect a standard analogue telephone set to the satellite terminal through the use of a ATA (Analogue Telephone Adapted) or a VoIP enabled IP router with analogue interface card. Users which dispose of a digital IP telephone can directly hook-up the telephone set to the satellite terminal, either through connecting to the LAN or directly in to the Satellite Terminal. At the central site, the connection again depends on whether or not the customer has a Voice over IP enabled PBX. While most contemporary digital PBXs have this option available, older types of analogue PBXs still require an interconnection through a VoIP router.

7 For dedicated voice applications the customer could eventually use a leased line or a private/public IP/VPN network to interconnect with the Hub in stead of going through the Internet. HUB Analogue Set VoIP enabled Router The user has the choice whether or not to implement specific QoS measures to insure prioritization of VoIP traffic in case of bandwidth congestion. PSTN VoIP enabled PABX VoIP enabled Analogue PABX PSTN As such, further enhancements include specific QoS mechanisms for real-time traffic: Analogue Set ATA VoIP Telephone The remote terminal will realize the corresponding QoS to the VoIP-packets which it receives from a local VoIP gateway typically implemented as additional CPE equipment. These packets will be sent by the to the satellite according to a CRA capacity request scheme, which will be allocated from the bandwidth scheduler in the HUB station (CRA: Continuous Rate Assignment as defined in the DVB-RCS standard). The VoIP packets towards the are sent via IP over MPEG Encapsulator in the DVB-S forward link. The QoS of the FW link is realized within the traffic shaper PRL. The VoIP Gateway in the HUB will realize the necessary statistical multiplexing effects, which results in an efficient usage of the satellite. The satellite cost is minimized by using a big data pipe in the FW link using TDM and a dynamically adapted efficient MF-TDMA scheme in the RT link. Next to the allocation of CRA to a terminal which needs to support VoIP, the 2Way-Sat terminal inherently holds an IP traffic shaper to insure best optimum use of return bandwidth. In the, the return bandwidth is divided in partitions. For each partition the minimum bandwidth and weight is configured. The data in the minimum bandwidth is sent first. The excess to the minimum is sent according to the weight. The minimum bandwidth and the weighting is statically configured. The allocation of data to a partition can be on the basis of: - Source IP-address/range - Destination IP-address/range - TCP IP port / port range - Protocol (TCP, UDP, ICMP) The prioritisation of VoIP over data can as such be executed through the use of of one these four parameters. In case the customer uses specific external VoIP access devices behind the, the use of source/destination address is recommended to be used to prioritise voice traffic over data. For the use of other simpler type of soft-codecs, the allocation of TCP/IP port/range would rather be used. Bandwidth Shaping & QoS prioritisation Each end-user will experience the following QoS performance, based on: The FW-pool to which he has been assigned. The FW capacity is split into several pools. In each pool, a certain peak and average bandwidth is guaranteed, with fair sharing by all users in the same pool. The FW- peak bandwidth is configurable for each. (iii) QoS in the forward is achieved by having different queues in the Forward Shaper (PRL) before traffic is forwarded to the FLE. Native DSCP marked UDP traffic (e.g. as used for VoIP) will receive higher priority as opposed to other UDP or TCP traffic. The Forward Shaper is fully integrated with the 2 Way-Sat management system.

8 (iv) For the return traffic, the Return Link Processor (RLP) is responsible for providing the guaranteed traffic to the end user as specified by the traffic contract. The RLP assigns traffic slots to the IDUs in conformance with his return SLA class as defined by the SAP and assigned by the ISP to the end-customer. Also for the return traffic, the peak bandwidth is configurable for each. (v) QoS in return path is realised by traffic shaping and Diffserv marking running on the terminal. Using a definable set of rules, the traffic is split into four partitions. Traffic shaping decisions can be based on source IP-address/range, destination IP-address/range, protocol (TCP, UDP, ICMP) and TCP IP port / port range. All the traffic belonging to a certain partition is being marked with the corresponding DSCP code point. (EF/AF/BE). Further extensions are possible via DiffServ mechanism in the, which can execute the mapping to DVB-RCS allocation classes in the RLP, like VBDC (Volume Based Dynamic Capacity) and CRA (Continuous Rate Assignment). Bench Marking of Satellite Access Performance End-Customer Experience One of the success factors of 2Way-Sat is the real Broadband experience the customers must feel. It is well known that the satellite delay (250 msec one-way) results in a throughput limit up to around 300 kbps for typical TCP connections. TCP accelerators help to overcome this effect and increase throughput speed, however a non-broadband response experience (e.g. 40 sec) is normally felt when multi-object pages have to be downloaded. A typical example of such a page is " with app. 110 objects and around 200 Kbytes of content to transfer. To solve this problem, an HPS (HTTP Pre-fetching Server) is installed in the HUB. When a user downloads this page, the HPS will fetch it over the IP Backbone (very wideband and low delay) and when it is complete, push the content to the at the customer side. The typical result is that the minimum download time of around 60 seconds in reduced down to approximately 15 seconds. Benchmark of the download times of NYTIMES.COM measured over a 7 day period, Using a 512K/128K profile on two different platforms: Without pre-fetching Seconds With pre-fetching 0 1/12/2003 0:00 2/12/2003 0:00 3/12/2003 0:00 4/12/2003 0:00 5/12/2003 0:00 6/12/2003 0:00 7/12/2003 0:00 8/12/2003 0:00 9/12/2003 0:00 The chart above obviously also shows the effect of higher traffic loads during day-time as compared to night-time. However even during low traffic load, the minima of the chart of a platform not equipped with pre-fetching, never descends below 60 seconds. ISP Experience The ISP of course is also interested in the End Customer Broadband Experience, but he also has to pay the SAP for HUB use and satellite bandwidth consumption. So price experience will be very important. The SAP cost is mainly relative to the traffic volume and not that much to

9 bandwidth experience (on condition that enough clients are present to allow the use of an efficient statistical multiplexing). For example : SAP cost = X 1 x (GByte-FW) + X 2 x (Gbyte -RT) e.g. X 1 = 60 Euro/GByte - FW X 2 = 90 Euro/GByte - RT The challenge of the 2Way-Sat design has been to realise a good compromise between efficient transponder usage and still good End-Customer Broadband Experience. The transmission efficiency can be measured by the Performance Management Tool on the Management Dashboard through logging the total FW & RT traffic every day and compare it to the transponder limits. In general, it is expected that the transmission limits will be updated every month in order to follow the measured growing traffic. 2Way-Sat Implementation Aspects HUB Implementations The full scale implementation of a 2Way-Sat.Plus version supports max. 8 Carrier Blades and up to max s. For start-up configurations, a simpler implementation is the 2Way-Sat Start version, which supports one Carrier Blade and a max. of 500 s. Being a scalable system, it means that the satellite bandwidth and number of terminals can grow by simply adding more equipment, without interrupting the normal operation of the network. Note that for such operational systems, full automatic redundancy is foreseen, resulting into an availability better than 99.99%.. Implementation - For professional End-Customers, the most successful networks [5] are using Ku-band, since many satellites are available and antenna sizes can be as small as 75 cm. However, depending on the satellite contours and potential interference from and to adjacent satellites, 90 cm cm and even 180 cm could be required. - The outdoor unit consists of an integrated front-end, where OMT, BUC and LNB are mechanically integrated. The Indoor Unit (IDU) contains an integrated POP Router running all the value added IP services. - It is possible to install s on ships, by using conventionally 3-axis stabilised antennas, or on transportable platforms. This however requires the permanent update of the position (via local GPS), and calculation of the changing transmit time. - Interoperability with other manufacturers is progressing quite well and reporting of this activity is given via the SATLABS organisation. (iii) Satellites It is not required that the HUB receives its own FW link signal or accurate Satellite Position Tables from the Satellite Provider, since it will track the Satellite Position itself. In general, satellites stay within a 0.1 degree variation box. Larger variations can be allowed as long as the satellite stays within the beam-width of the antennas. Security Aspects The system has built-in security like "Static Routing & Firewalls that cover the basic security requirements of an End-Customer, accessing the Internet. When business clients are communicating with each other, often VPNs are created. 2Way-Sat has the possibility to realise a solution whereby security (VPN & IPsec, controlled by ISP) and broadband experience (acceleration) are combined. However, those clients, who want to have full control over the security part, can do this outside the 2Way-Sat domain. Due to the satellite delay, they should combine security and acceleration (or even Pre-fetching) themselves.

10 Operational Support Software tailored to fit satellite based operators One of the challenges of running an ISP or IP/VPN service operator s organisation is to streamline the significant number of administrative processes in combination with a high-volume product. Next to using an efficient hardware platform, the commercial success of the operator consequently also depends on having the appropriate OSS/BSS software tools to insure operational excellence. Traditional ISP-organisations use different software-solutions or custom-made software to manage this information. In a heterogeneous environment with several software-solutions, integration is a keycomponent of the complete system to ensure the integrity of the stored information. But in practice this integration is hard to achieve due to associated costs or insufficient support by the implemented software-solutions. This leads to data-duplication and manual overtyping of data from one system to another. A custom-made solution leads to extra costs on development and maintenance of the solution. Although it can outweigh the costs associated with a heterogeneous situation, this type of development is not a core-process of an ISP and can only be justified when the benefits of the custom-solution outweigh the extra costs of the heterogeneous solution. In order to overcome these issues, a specific BSS software suite has been developed which take in to account all the specificities of operating a service on a satellite based platform: BOSS. BOSS supports the major administrative processes like processing of orders, tracking of the CPE equipment or managing helpdesk tickets. From BOSS the operator gets at any moment a complete overview of his business, through standard defined reports or custom build reports with the dynamic report-generator. BOSS consists of three modules; Order-to-Install (OTI), Logistics (LOG) and Contact-management (CM). Features of each of these modules include: Order To Install Logistics: Contact Management: Order-management Inventory-management Service-request management Customer-management Bill-of-material management Trouble-ticketing Installer-management Transport-management Knowledge-base Sales-partner management Features CM Provisioning Call-logging Billing-engine Product-management

11 List of Acronyms ACM : Adaptive Coding & Modulation ALC : Automatic Level Control BDM : Burst Demodulator BUC : Block Up Converter CCMT : Customer Configuration Management Tool CPE : Customer Premises Equipment CRA : Continuous Rate Assignment DHCP : Dynamic Host Configuration Protocol DNS : Domain Name Server DVB : Digital Video Broadcast FLE : FW Combiner & IP Encapsulator FW : Forward (Link) GPS : General Positioning System HPS : HTTP Pre-fetching Server HTTP : Hyper Text Transfer protocol IP : Internet Protocol ISP : Internet Service Provider LNA : Low Noise Amplifier LNB : Low Noise Block Converter MF-TDMA : Multi Frequency-Time Division Multiple Access NAT : Network Address Translation NCR : Network Clock Reference OMT : Ortho Mode Transducer PMS : POP Management Server PMT : Performance Monitor Tool QoS : Quality of Service RCS : Return Channel by Satellite RLP : Return Link Processor RT : Return (Link) SAP : Satellite Access Provider SDR : Sit Drive : Satellite Interactive Terminal SLR : Satellite Link Router SME : Small-Medium-Sized Enterprise SOHO : Small Office Home Office TCP : Transmission Control Protocol VBDC : Volume Based Dynamic Capacity VPN : Virtual Private Network VSAT : Very Small Aperture Terminal WCS : Web Caching Server References [1] DVB-RCS Standard : EN V131 Mar-03 [2] DVB-RCS Guideline : TR v121 Jan-03 [3] DVB-S2 DRAFT Next Generation Satellite Modulation / Coding Standard TM2860 [4] Satlabs Group [5] About Newtec and the author Newtec is a global market leader offering highly innovative products and solutions for the satellite communication industry. TV broadcasters, Telecom Service Providers and Satellite Operators all over the world rely since 1985 on Newtec s unequalled products and customer support. High speed DVB and DVB S2 modulators, DVB RCS based IP Broadband Access Networks, Digital TV and Radio Distribution networks and interactive Satmode TV networks represent some of Newtec s main product lines. Dirk Breynaert is one of the founders and CEO of Newtec Cy. Contact information : Tel : Fax : web :

12 Forward Return Common SS RF SS Outdoor Unit Outdoor Unit Outdoor Unit Carrier Blade SS1 Carrier Blade SS2 Indoor Unit POP Box Indoor Unit POP Box Indoor Unit POP Box Carrier Blade SS8 Optional VPN Router Optional VPN Router Optional VPN Router Edge Router CPE LAN 1 CPE LAN 2 CPE LAN IP/VPN cloud HUB Figure 1 : 2Way-Sat Network Architecture Figure 2 : Carrier Blade SS Architecture