Protection concerns using Switched Ethernet as internal bus

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Protection concerns using Switched Ethernet as internal bus for a Telecommunication Network Element Jukka

Protection concerns using Switched Ethernet as internal bus for a Telecommunication Network Element Jukka Lehtniemi 25 March, 2008 Supervisor: Professor Jörg Ott Instructors: Lic. Phil Stefan Wiklund MSc Juha Eloranta

Outline § § § § Introduction Telecommunication Computer and Advanced. TCA Evolution of Ethernet

Outline § § § § Introduction Telecommunication Computer and Advanced. TCA Evolution of Ethernet Technology Spanning Tree Protocol Other Link Protection Technologies Network Element Topology Considerations Link Protection Solutions for Network Element Conclusions Master's Thesis Presentation 2 Jukka Lehtniemi 2008 -03 -25

Introduction § Is a switched Ethernet based internal bus good enough solution in terms

Introduction § Is a switched Ethernet based internal bus good enough solution in terms of link protection in a telecommunication network element? § Different link protection mechanisms available and the suitability for use as a telecommunication element internal bus § The network node architecture is assumed according to the Advanced. TCA specification § Literature study & comparison Master's Thesis Presentation 3 Jukka Lehtniemi 2008 -03 -25

Telecommunication Computer § § § Boards Multiprocessor computing cluster Variety of different processors: general

Telecommunication Computer § § § Boards Multiprocessor computing cluster Variety of different processors: general purpose processors, network processors, DSPs etc. Variety of different network interfaces: TDM, ATM, Ethernet Inter Redundancy Subrack Modular board & subrack Link architecture in a server cabinet Resources connected together by internal (switched) bus Master's Thesis Presentation 4 Backplane Subrack Jukka Lehtniemi 2008 -03 -25

Advanced Telecommunication Computing Architecture § § § § Open hardware framework Specified by PCI

Advanced Telecommunication Computing Architecture § § § § Open hardware framework Specified by PCI Industrial Computer Manufacturers Group - a consortium of over 450 hardware manufacturers Designed for reliability concerned applications Mechanical design, platform management, data transport etc. Flexible and loose specifications: profiled further by SCOPE Alliance Advanced. TCA specifies two subrack level interconnection busses: base interface and fabric interface. Ethernet is the selected technology for the base interface. It is generally also seen as the most promising candidate for the fabric interface Master's Thesis Presentation 5 Jukka Lehtniemi 2008 -03 -25

Ethernet Evolution: Shared Bus Collision Domain Master's Thesis Presentation 6 Jukka Lehtniemi 2008 -03

Ethernet Evolution: Shared Bus Collision Domain Master's Thesis Presentation 6 Jukka Lehtniemi 2008 -03 -25

Ethernet Evolution: Switched Bus Collision Domains Full Duplex – CSMA/CD disabled Master's Thesis Presentation

Ethernet Evolution: Switched Bus Collision Domains Full Duplex – CSMA/CD disabled Master's Thesis Presentation 7 Jukka Lehtniemi 2008 -03 -25

Ethernet Evolution § The Ethernet technology has evolved from a simple media sharing LAN

Ethernet Evolution § The Ethernet technology has evolved from a simple media sharing LAN solution to a versatile and diverse family of frame based computer networking technologies. § From the user protocol perspective it still provides a transparent and compatible frame transmission service § Key enhancements – – – Master's Thesis Presentation Switching Microsegmentation Full Duplex Flow Control Virtual LANs Connectivity Fault Management 8 Jukka Lehtniemi 2008 -03 -25

Spanning Tree Protocol § § Topology loops in a switched Ethernet LAN will cause

Spanning Tree Protocol § § Topology loops in a switched Ethernet LAN will cause frame multiplication and thus they are unacceptable The Spanning Tree Protocol (STP) operated by the switches will eliminate such loops by blocking redundant links in the physical topology and restricting the active topology to a simply and fully connected tree § STP provides topology recovery in the case of link failure. This can be used as a link protection solution Master's Thesis Presentation 9 Jukka Lehtniemi 2008 -03 -25

Spanning Tree Protocol § STP propagates the topology information by continuous transmission of distance

Spanning Tree Protocol § STP propagates the topology information by continuous transmission of distance vectors § New protocol version called Rapid STP (RSTP) has been standardized § Proposal-agreement based communication of RSTP responds faster to topology changes § Multiple STP (MSTP) protocol defines per VLAN spanning trees Master's Thesis Presentation 10 Jukka Lehtniemi 2008 -03 -25

Link Aggregation § § Link Aggregation is defined by IEEE 802. 3 Allows bundling

Link Aggregation § § Link Aggregation is defined by IEEE 802. 3 Allows bundling multiple physical links to a single logical link Bandwidth extension Redundancy Link Aggregate Master's Thesis Presentation 11 Jukka Lehtniemi 2008 -03 -25

Resilient Packet Ring Wrapping Steering § § § RPR is specified by IEEE 802.

Resilient Packet Ring Wrapping Steering § § § RPR is specified by IEEE 802. 17 Dual Ring topology Service priorities and fairness Topology discovery and continuity check Healing strategies: Steering and Wrapping 50 ms protection time against link failure Master's Thesis Presentation 12 Update! Span Failure Update! Jukka Lehtniemi 2008 -03 -25

Ethernet Protection Switching § § § ITU-T Rec. G. 8031 / Y. 1342 Linear

Ethernet Protection Switching § § § ITU-T Rec. G. 8031 / Y. 1342 Linear Protection Switching VLAN based Point-to-Point connections Failure detection by Ethernet CFM Master's Thesis Presentation 13 Jukka Lehtniemi 2008 -03 -25

Ethernet Automatic Protection Switching § By Extreame Networks § Switched Ethernet, Ring topology §

Ethernet Automatic Protection Switching § By Extreame Networks § Switched Ethernet, Ring topology § One way transmission: primary port transmitting and secondary port blocking § Continuous health check polling by Master Node § Recovery based on filtering database flush ordered by Master Node and standard Ethernet address learning mechanisms Master's Thesis Presentation 14 Jukka Lehtniemi 2008 -03 -25

Advanced. TCA Subrack § § Two switch boards (per interface) Dual Star topology BASE-T

Advanced. TCA Subrack § § Two switch boards (per interface) Dual Star topology BASE-T specified, BASE-KX or BASE-KR likely in future 8 uplink/interconnect ports per switch board defined by SCOPE Master's Thesis Presentation 15 Jukka Lehtniemi 2008 -03 -25

5 Subrack Topology: Bus & Ladder Master's Thesis Presentation 16 Jukka Lehtniemi 2008 -03

5 Subrack Topology: Bus & Ladder Master's Thesis Presentation 16 Jukka Lehtniemi 2008 -03 -25

5 Subrack Topology: Star Master's Thesis Presentation 17 Jukka Lehtniemi 2008 -03 -25

5 Subrack Topology: Star Master's Thesis Presentation 17 Jukka Lehtniemi 2008 -03 -25

5 Subrack Topology: Full Mesh Master's Thesis Presentation 18 Jukka Lehtniemi 2008 -03 -25

5 Subrack Topology: Full Mesh Master's Thesis Presentation 18 Jukka Lehtniemi 2008 -03 -25

5 Subrack Topology: Ring Master's Thesis Presentation 19 Jukka Lehtniemi 2008 -03 -25

5 Subrack Topology: Ring Master's Thesis Presentation 19 Jukka Lehtniemi 2008 -03 -25

Link Protection Solutions for Multisubrack Advanced. TCA Network Element: Requirements § Primary requirement: <

Link Protection Solutions for Multisubrack Advanced. TCA Network Element: Requirements § Primary requirement: < 50 ms protection switching time § Manageable complexity § Reasonable design, manufacturing and maintainance costs Master's Thesis Presentation 20 Jukka Lehtniemi 2008 -03 -25

Solutions § § § • Point-to-point: Too fine grained (complex) total solution Link Aggregation

Solutions § § § • Point-to-point: Too fine grained (complex) total solution Link Aggregation Ethernet Protection Switching Ethernet Automatic Protection Switching Redundant Packet Ring Physically Distinct Switching Planes (Rapid) Spanning Tree • Master Node is a single point of failure • No guaranteed switch over time < 50 ms Master's Thesis Presentation 21 Jukka Lehtniemi 2008 -03 -25

Recommended solutions: RPR C Guaranteed switch over time C No need for protection switching

Recommended solutions: RPR C Guaranteed switch over time C No need for protection switching supervision clients on the boards: A board may transmit using either of the subrack bridges at any time C Extendibility: no practical restrictions on the amount of subracks to be connected to the ring interconnect D Equipment prices are presumable higher D Additional LAN technology layer and tunnelling of Ethernet frames on the ring Master's Thesis Presentation 22 Jukka Lehtniemi 2008 -03 -25

Recommended solutions: Physically Distinct Switch Planes C Pure Ethernet solution C Prices of the

Recommended solutions: Physically Distinct Switch Planes C Pure Ethernet solution C Prices of the equipment probably lower D Topology extension by number of subracks in case of the redundant star topology may require additional interface boards in central subrack D Supervision and switch-over mechanism needs to be in place on each board Master's Thesis Presentation 23 Jukka Lehtniemi 2008 -03 -25

Conclusions § Variety of link protection solutions for Ethernet exists § Most of them

Conclusions § Variety of link protection solutions for Ethernet exists § Most of them do not meet the requirements for a telecommunication network element § Recommended solutions identified by the study: – RPR interconnect – Construct of redundant, distinct, loopfree switching planes § Further analyzing of these alternatives with proper simulations or real hardware testing is suggested Master's Thesis Presentation 24 Jukka Lehtniemi 2008 -03 -25

Master's Thesis Presentation 25 Jukka Lehtniemi 2008 -03 -25

Master's Thesis Presentation 25 Jukka Lehtniemi 2008 -03 -25