Giants of the past: Catalyst 5000 (Project Synergy)

The Catalyst 5000 was introduced in 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 development of the Catalyst 5000, it increased the bandwidth of backplane to 3.6 Gbps by adding two more tires of 1.2 Gbps each.

Catalyst 5000/5500
Each switch of this series functionally consists of:

• Chassis
• Power and cooling units
• Supervisor
• Linear modules

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Chassis - designed for the physical location of all elements. Provides electrical connection between a supervisor and other modules or line cards. For minimum performance on a Catalyst 5x00 series switch, you must insert a supervisor, one line card, and one power supply into the chassis.



The chassis was produced in the following versions

5000	Catalyst 5000 Series 5-slot chassis
5002	Catalyst 5000 Series 2-slot chassis
5505	Catalyst 5500 Series 5-slot chassis
5509	Catalyst 5500 Series 9-slot chassis
5500	Catalyst 5500 Series 13-slot chassis

Power supply - Catalyst 5000 is completed with 2 power supply units, parallel power supply from 2 units is supported.

The supervisor is the “brain” of the switch; it is here that the decision is made to send the frame.

The following types of supervisors were released for the Catalyst 5000:

• Supervisor I - only supports L2 forvarding. No support for backup supervisor and not compatible with Catalyst 5500. Contains 2 FastEthernet ports
• Supervisor II - only supports L2 forvarding. Supervisor redundancy feature added and support for Catalyst 5500. Contains 2 FastEthernet ports
• Supervisor IIG — Integrated NetFlow Feature Card (NFFC) and support for the 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 lines (3.6 Gbps). GBIC support added (2 ports).
• Supervisor IIIG - includes integrated NFFC and supports RSFC. When installed in the Catalyst 5500 includes support for all three data lines (3.6 Gbps). Contains 2 GBIC.

The supervisor functionally consists of:

• Network Management Proccessor (NMP) - performs administrative functions (calculation of 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 via 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 operating system image and can be used for backup configuration storage.
• Content-Addressable Memory (CAM) - used to store the MAC table, VLAN information, etc.

The supervisor also contains Application-Specific integrated circuits (ASICs) :

• Enchanced Address Reconfiguration Logic (EARL ASIC) - creates and updates the MAC table for mapping ports saved in CAM
• Synergy Advanced Interface Network Termination (SAINT ASIC) - provides uplink operation of ports located on the supervisor
• Synergy Advanced Multipurpose Bus Arbiter (SAMBA ASIC) - Manages Bus Access

EARL Functionality

The Catalyst 5000 contains one EARL ASIC integrated into the supervisor. Newer platforms (such as the Catalyst 6500) contain multiple 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, and which port to drop. EARL performing this task verifies the information in the header of each frame. If an entry for a frame is in the MAC table, EARL ASIC overwrites the frame and sends it to the line cards that will frame the frame.

EARL version 1 for 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 address aging
• Trap bit - used for blocked or filtered addresses
• Static bit - indicates that this address was recorded in CAM as static
• Valid bit - to exclude "outdated" addresses

With the introduction of EARL2 on NFFC, the supervisor learned to check L3 information. After the initial solution on RSM or RSFC, EARL2 can rewrite the flow of similar packets without forwarding them to the Route Proccessor (RP).

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

Since the EARL is responsible for creating and maintaining the MAC table, the whole forwarder stops if the supervisor is pulled out. In switches that support fault tolerance of supervisors, EARL synchronizes the forwarding table, allowing you to restore forwarding on the backup supervisor.

Supervisor Part Number	Supervisor model	EARL Version Subtype
WS-X5005	Supervisor I	EARL1
WS-X5006	Supervisor I	EARL1
WS-X5009	Supervisor I	EARL1
WS-X5505	Supervisor II	EARL1 +
WS-X5506	Supervisor II	EARL1 +
WS-X5509	Supervisor II	EARL1 +
WS-X5530-E1	Supervisor III	EARL1 ++
WS-X5530-E2	Supervisor III NFFC	EARL2 (NFFC)
WS-X5530-E2A	Supervisor III NFFC-A	EARL2 (NFFC)
WS-X5530-E3	Supervisor III NFFC II	EARL3 (NFFC II)
WS-X5530-E3A	Supervisor III NFFC II-A	EARL3 (NFFC II)
WS-X5534	Supervisor III F	EARL1 ++
WS-X5540	Supervisor II G	EARL3 (NFFC II)
WS-X5550	Supervisor III G	EARL3 (NFFC II)

Line modules

The first linear modules that were announced as part of the Synergy project (Catalyst 5000) are:

• 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 Amphenol connectors (4 switched ports, 12 ports)
• 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 ports, 8 ports, 8 ports)
• 24-port, 10 Mbps Ethernet with RJ-45 connectors for UTP Category 5 cable

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


Catalyst 5000/5500 Architecture

Catalyst 5000/5500 use common bus architecture. The Catalyst 5000 uses 3 buses: to transfer data, to control the modules, and determine which port to forward traffic to:

• Switching or data bus (dBus) - used for switching frames between line cards. Width of the tire 48-bit. with a frequency of 25 MHz (25,000,000 ps * 48 bit = 1.2 Gbps)
• Management Bus (mBus) - transmits information from the NMP to each module and statistics from the module to the NMP using the Serial Communication Protocol.
• Result / index bus (rBus) - transmits information from EARL ASIC to the ports about which port should forward the frame and which port should clear the buffer from the frame.

The Catalyst 5500 implements the same 3 buses plus 2 additional data buses, each with 1.2 Gbps, which gives 3.6 Gbps. To maintain backward compatibility with the Catalyst 5000 lined cards, new cards are attached to all 3 tires, and the old ones only to one. Slots from the first to the fifth (the 1st is allocated under the supervisor) join all tires. Gigabit cards should be inserted into slots 2-5. Slot 13 is reserved for ATM switch proccessor (ASP).

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