Giants of the Past: Catalyst 5000 (Project Synergy)

    Catalyst 5500

    The Catalyst 5000 was introduced with a 5-slot chassis, with one slot reserved for the supervisor, with support for hot-swappable modules, two power supplies, a fan module and a 1.2 Gbps bus. Later, the ability to switch packets at the third and fourth level (L3, L4) was added. The Catalyst 5500 was a continuation of the Catalyst 5000, it increased backplane bandwidth to 3.6 Gbps by adding two more 1.2 Gbps buses.

    Catalyst 5000/5500
    Each switch in this series functionally consists of:
    • Chassis
    • Power supply and cooling units
    • Supervisor
    • Linear modules


    Chassis - designed for the physical location of all elements. Provides an electrical connection between the supervisor and other modules or line cards. To keep the Catalyst 5x00 Series switch running at a minimum, you need to insert a supervisor, one line card, and one power supply into the chassis.

    Catalyst 5000


    The chassis was produced in the following options
    5000Catalyst 5000 Series 5-slot chassis
    5002Catalyst 5000 Series 2-slot chassis
    5505Catalyst 5500 Series 5-slot chassis
    5509Catalyst 5500 Series 9-slot chassis
    5500Catalyst 5500 Series 13-slot chassis

    Power - Catalyst 5000 is equipped with 2 power supplies, supports parallel power from 2 units.

    The supervisor is the “brain” of the switch, it is here that the decision is made to forward the frame.
    Supervisor
    The following supervisor types were available for the Catalyst 5000:
    • Supervisor I - only supports L2 forwarding. There is no backup supervisor support and is not compatible with the Catalyst 5500. Contains 2 FastEthernet ports
    • Supervisor II - only supports L2 forwarding. Added supervisor redundancy and Catalyst 5500 support. Contains 2 FastEthernet ports
    • Supervisor IIG - Integrated NetFlow Feature Card (NFFC) and support for optional Route Switch Feature Card (RSFC). RSFC - Based on NPE-200 (Platform 7200). May support MLS. Supports proprietary Gigabit / FastEthernet modules.
    • Supervisor III - supports integrated NFFC, but does not support RSFC. When installed in the Catalyst 5500 includes support for all three data buses (3.6 Gbps). Added support for GBIC (2 ports).
    • Supervisor IIIG - Includes integrated NFFC and RSFC support. When installed in the Catalyst 5500 includes support for all three data buses (3.6 Gbps). Contains 2 GBIC.


    The supervisor functionally consists of:
    • Network Management Proccessor (NMP) - performs administrative functions (calculating STP, VTS, SNMP, synchronization with the second supervisor)
    • Master Communication Proccessor (MCP) - Transmits statistical and Remote Monitor (RMON) information to and from the Local Communications Processor (LCP) installed on each line card through the Serial Communication Protocol (SCP)
    • Nonvolatile random-access memory (NVRAM) - used to store switch configuration information
    • Dynamic random-access memory (DRAM) - used as working memory for the CatOS operating system
    • Flash memory - used to store the image of the operating system and can be used to back up configuration
    • Content-Addressable Memory (CAM) - used to store MAC-tables, information about VLANs, etc.

    The supervisor also contains Application-Specific integrated circuits (ASICs) :
    • Enchanced Address Reconfiguration Logic (EARL ASIC) - creates and updates a MAC table for mapping ports stored in CAM
    • Synergy Advanced Interface Network Termination (SAINT ASIC) - provides uplink ports located on the supervisor
    • Synergy Advanced Multipurpose Bus Arbiter (SAMBA ASIC) - controls access to the bus


    Supervisor IIIG
    The EARL Functionality

    Catalyst 5000 contains one EARL ASIC integrated into the supervisor. Newer platforms (such as the Catalyst 6500) contain many ASICs for each function (Layer 3 lookup, ACL, QoS, etc.). EARL ASIC creates and updates the forwarding table stored in the CAM. EARL ASIC searches for each received frame, determining which port to forward the frame to and which port to drop. EARL performing this task checks the information in the header of each frame. If there is an entry for the frame in the MAC table, the EARL ASIC overwrites the frame and sends it to line cards that will forward the frame.

    EARL version 1 for the Catalyst 5000 creates a forwarding table containing MAC addresses, VLAN ID associated with MAC and Index.

    VLAN ID (16-bit) field, 10 of which are used, and 6 are reserved. Catalyst 5000 supports up to 1024 VLANs. Additional bit EARL ASIC uses for:
    • Aging bit - used for “aging” addresses
    • Trap bit - used for blocked or filtered addresses
    • Static bit - indicates that this address was recorded in CAM as static
    • Valid bit - to eliminate "obsolete" addresses


    With the introduction of EARL2 at the NFFC, the supervisor learned to verify L3 information. After an initial decision on RSM or RSFC, EARL2 can overwrite the stream of similar packets without forwarding to Route Proccessor (RP).

    Several new line cards for the Catalyst 5500 are equipped with special ASICs that allow you to rewrite L3 information based on information from EARL without the additional assistance of a supervisor.

    Since EARL is responsible for creating and maintaining the MAC table, all forwarding stops if you pull out the supervisor. In switches supporting failover of supervisors, EARL synchronizes the forwarding table, allowing you to restore forwarding on the backup supervisor.

    Supervisor part numberSupervisor modelEARL Version Subtype
    WS-X5005Supervisor IEARL1
    WS-X5006Supervisor IEARL1
    WS-X5009Supervisor IEARL1
    WS-X5505Supervisor IIEARL1 +
    WS-X5506Supervisor IIEARL1 +
    WS-X5509Supervisor IIEARL1 +
    WS-X5530-E1Supervisor IIIEARL1 ++
    WS-X5530-E2Supervisor III NFFCEARL2 (NFFC)
    WS-X5530-E2ASupervisor III NFFC-AEARL2 (NFFC)
    WS-X5530-E3Supervisor III NFFC IIEARL3 (NFFC II)
    WS-X5530-E3ASupervisor III NFFC II-AEARL3 (NFFC II)
    WS-X5534Supervisor III FEARL1 ++
    WS-X5540Supervisor II GEARL3 (NFFC II)
    WS-X5550Supervisor III GEARL3 (NFFC II)


    Linear modules

    The first linear modules that were announced as part of the Synergy project (Catalyst 5000) were:
    • 12-port, 10/100 Mbps autonegotiation Ethernet / Fast Ethernet with RJ-45 connectors for unshielded twisted-pair (UTP) Category 5 cable
    • 24-port, 10 Mbps Ethernet with two RJ-21 Amphenol connectors
    • 12-port, 10 Mbps 10BASE-FL with ST fiber connectors
    • 48-port, 10 Mbps group switched Ethernet with four RJ-21 Amphenol connectors (4 switched ports, 12 shared ports per switched port)
    • 12-port, 100 Mbps 100BASE-FX with SC fiber connectors
    • 24-port, 100 Mbps Fast Ethernet with RJ-45 connectors for UTP Category 5 cable (3 switched ports, 8 shared ports per switched port)
    • 24-port, 10 Mbps Ethernet with RJ-45 connectors for UTP Category 5 cable


    The port speed in the first modules was limited by the ridiculous by today's standards of 10 and 100 Mbps, because at the time of the announcement of the platform, the GigabitEthernet standard did not exist yet.
    But even then each linear module contained its own ASICs providing forwarding inside the module.
    Of course, later other modules were also released including line cards with GBIC (maximum 9 GBIC per module) and specialized modules such as traffic analysis module (WS-X5380).


    Architecture Catalyst 5000/5500 The

    Catalyst 5000/5500 uses a shared bus architecture. The Catalyst 5000 uses 3 buses: for data transfer, for module management, and determining which port should forward traffic:
    • Switching or data bus (dBus) - used to switch frames between line cards. The width of the bus is 48-bit. 25 MHz (25,000 ps * 48 bit = 1.2 Gbps)
    • Management Bus (mBus) - transfers information from NMP to each module and statistics from the module to NMP using the Serial Communication Protocol.
    • Result / index bus (rBus) - transfers information from the EARL ASIC to the ports about which port should forward the frame and which should clear the buffer from the frame.



    The Catalyst 5500 implements the same 3 buses plus 2 additional data buses, each of 1.2 Gbps, which gives 3.6 Gbps. To maintain backward compatibility with the Catalyst 5000 line cards, the new cards are connected to all 3 buses, and the old ones to only one. Slots one through five (1st allocated to the supervisor) are connected to all buses. Gigabit cards should be inserted in slots 2-5. The 13th slot is reserved for ATM switch Proccessor (ASP).

    Source WhiteBear

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