Cisco Catalyst

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The inside of a Cisco 1900-series switch

Catalyst is the brand for a variety of network switches sold by Cisco Systems. While commonly associated with Ethernet switches, a number of different network interfaces have been available throughout the history of the brand. Cisco acquired several different companies and rebranded their products as different versions of the Catalyst product line; the original Catalyst 5000 and 6000 series were based on technology acquired from Crescendo Communications. The 1700, 1900, and 2800 series Catalysts came from Grand Junction Networks, and the Catalyst 3000 series came from Kalpana in 1994.[1]

Operating systems[edit]

In most cases, the technology for the Catalyst Switch was developed separately from Cisco's router technology; the Catalyst switches originally ran software called CatOS rather than the more widely known Cisco IOS software used by routers. However, this has changed as the product lines have merged closer together. In some cases, particularly in the modular chassis switches, a configuration called 'Hybrid' has emerged - this is where the layer 2 functions are configured using CatOS, and the layer 3 elements are configured using IOS. Native IOS can also be found with newer software versions that have eliminated CatOS entirely in favor of IOS, even on hardware that originally required CatOS.[2]

Some newer Catalyst switch models (with recent versions of the Cisco IOS) also allow web-based management using a graphical interface (GUI) module which is hosted on a HTTP server located on the switch; the Catalyst 3750-series of switches is an example of a Cisco Catalyst switch that allows this style of GUI via HTTP.


CatOS (Catalyst Operating System) is the discontinued network operating system for many of the Catalyst brand of legacy network switches. CatOS ran on switches such as 1200, 2948G, 4000, 4500, 5000, 5500, 6000, 6500 series, it was originally called XDI[3] by the switching company Crescendo Communications, Inc. Cisco renamed it to CatOS when they acquired Crescendo in late 1993.

CatOS can still run on some of Cisco's modular switches, "hybrid" mode. In hybrid mode, the NMP (switch processor) runs CatOS and the route processor runs Cisco IOS.


As Catalyst devices are primarily Ethernet switches, all modern Catalyst models have Ethernet interfaces ranging from 10 Mbit/s to 100 Gbit/s depending on the model. Other models can support T1, E1, and ISDN PRI interfaces to provide connections to the PSTN.[citation needed] Legacy models supported a variety of interfaces, such as token ring, FDDI, Asynchronous Transfer Mode and 100BaseVG, but are no longer sold by Cisco Systems.

The front of a Catalyst 3750G switch, with 48 interfaces for Ethernet over twisted pair and four interfaces for small form-factor pluggable transceivers.

All models have basic layer 2 functions and are capable of switching Ethernet frames between ports. Commonly found additional features are VLANs, trunking and QoS; the switches, whether IOS or CatOS, are fully manageable.

Many Catalyst switches that run IOS are also capable of functioning as a router, making them layer 3 devices; when coupled with TCP and UDP filtering, these switches are capable of layer 2-4 operation. Depending on the exact software image, a Catalyst that runs IOS may be able to tackle large-scale enterprise routing tasks, using router technologies like OSPF or BGP.

Most chassis-based Catalyst models have the concept of field-replaceable supervisor and line cards. Mirroring most Cisco router designs, these work by separating the line cards, chassis, and supervisor engine; the chassis provides power and a high-speed backplane, the line cards provide interfaces to the network, and the supervisor engine moves packets, participates in routing protocols, etc. This gives several advantages:

  • If a failure occurs, only the failed component needs to be replaced (typically a line card or supervisor). This means faster turnaround than replacing an entire switch.
  • A redundant supervisor engine may be installed to rapidly recover from supervisor failures.
  • A supervisor engine may be upgraded after purchase, increasing performance and adding features without losing any investment in the rest of the switch.

Additionally, most high-end switches off-load processing away from the supervisors, allowing line cards to switch traffic directly between ports on the same card without using any processing power or even touching the backplane.


Catalyst switches offer advanced customization and manageability; the switches can be configured using a serial console, telnet or Secure Shell. Simple Network Management Protocol (SNMP) allows monitoring of many states, and measurement of traffic flows. Many devices can also run an HTTP server.

Configuration of the switch is done in plain text and is thus easy to audit. No special tools are required to generate a useful configuration. For sites with more than a few devices, it is useful to set up a Trivial File Transfer Protocol (TFTP) server for storing the configuration files and any IOS images for updating. Complex configurations are best created using a text editor (using a site standard template), putting the file on the TFTP server and copying it to the Cisco device. However, it can be noted that a TFTP server can present its own security problems.


Cisco StackWise is a technology offered by Cisco Systems that allows some models of Catalyst series switches to operate as though they were one switch. One switch from the stack will act as the master switch; the master switch will maintain the stack and allow you to configure and monitor the whole stack as though one via a single console. This allows for more efficient management and typically provides more bandwidth between individual switches than other uplink technology.

If one switch fails, the remaining switches will continue to operate by bypassing it. If the master switch fails, another switch in the stack will automatically take over as master; this feature means greater redundancy, as one switch's failure will not bring about a failure of the entire stack.

As each switch contains the entire configuration for the stack, one of the benefits of this technology is the ability to replace a faulty switch (any—including master) with a new un-programmed switch; the stack will configure the new switch on-the-fly to accommodate minimal downtime and reduce maintenance effort and errors.

StackWise effectively replaced the GigaStack found on lower-price models such as Catalyst 35xx and 29xx series.

Master Selection[edit]

The master switch of a stack is determined in the following order:[4][not in citation given]

  1. User specified priority in the switch configuration
  2. The switch with the most advanced IOS feature set enabled
  3. Programmed switch – A configured switch will preside over a switch running factory defaults
  4. Uptime – The switch that has been running the longest
  5. MAC address – The switch with the lowest MAC address


There are two general types of Catalyst switches: fixed configuration models that are usually one or two rack units in size, with 12 to 80 ports; and modular switches in which virtually every component, from the CPU card to power supplies to switch cards, are individually installed in a chassis.

In general, switch model designations start with WS-C, followed by the model line (e.g. 2960). A letter at the end of this number signifies a special feature, followed by the number of ports (usually 24 or 48) and additional nomenclature indicating other features.

Fixed-configuration switches[edit]

Cisco Catalyst 2960 series
Layer 2 switches.
Cisco Catalyst 3560 series
Layer 2 and layer 3 switches.
Cisco Catalyst 3560CX series
Compact, fanless layer 2 and layer 3 switches.
Cisco Catalyst 3750 series
Layer 2 and layer 3 switches with built in stacking capability.
Cisco Catalyst 3850 series
Layer 2 and layer 3 switches with built in StackWise stacking capability.
Cisco Catalyst 3650 series
Layer 2 and layer 3 switches with optional stacking capability.

Modular switches[edit]

Cisco modular switches are much larger and are entirely configurable, beginning with a chassis, power supplies, the choice of supervisory engines (CPU mainboards), and switch modules. Among Cisco's modular series are:

  • The 1000 switch family is considered an edge device, having many functionalities that can be built as the device is very modular. The 1900 line as a whole is past end-of-sale and end-of-life, and is considered a retired product line.[5]
    • 1700: 24 10BaseT ports, 1 switchable MDI/MDIX uplink 10baseT/AUI/BNC port, and 2 Fast Ethernet ports. Runs neither CatOS nor IOS. Is a first-generation carryover from Cisco's acquisition of Grand Junction Networks.
    • 19xx: 12 or 24 10BaseT ports and 2 Fast Ethernet ports. ISL trunking on the 100 Mbit/s ports. Runs neither CatOS nor IOS.
  • The Cisco Catalyst 3000 and 3100 series switches are switches for use in blade-enclosures: the Catalyst 3032 is a Layer2 switch and the Catalyst 3130x and 3130G are blade-switches for the Dell M1000e enclosure.
  • The Cisco Catalyst 4500 Series is a mid-range modular chassis network switch. The system comprises a chassis, power supplies, one or two supervisors, line cards and service modules; the Series includes the E-Series chassis and the Classic chassis which is manufactured in four sizes: ten-slot, seven-slot, six-slot, and three-slot.
  • The Cisco Catalyst 4900 series is a fixed-configuration switch. Uplink interfaces are either SFP ports or 10 Gigabit Ethernet, with 48 copper ports of 10/100/1000 Ethernet.
  • The Cisco Catalyst 5500 Series and Cisco Catalyst 5000 Series is a chassis-based switch family. The Cisco Catalyst 5000 Series is acquired from another company; this entire series has now reached end-of-sale.
  • The Cisco Catalyst 6500 Series is a chassis-based switch family. This series can support interfaces up to 40 Gigabit Ethernet in speed and redundant Supervisor modules.

End-of-Life Switches[edit]

Base Model Form Factor Variants Available ports/Modules Number of power supplies Number/Type of supervisors Expansion type Sync End-of-life (only major notices listed) Comments
Catalyst 2940[6] Fixed 2940 8 8P8C/1 8P8C
8 8P8C/1 8P8C or 1 SFP[7]
1 (fixed) None None None Announced 2009[8]
Catalyst 2950[9] Fixed 2950
12 8P8C
24 8P8C
24 8P8C/2 GBIC or 1000SX
48 8P8C/2 GBIC or 1000SX[11]
1 (fixed) None None None Announced 2007[12] Optional 'Gigastack' modules[13]
Catalyst 3550 Fixed 3550 24 8P8C/2 GBIC
48 8P8C/2 GBIC
1 (fixed) None None None Announced 2005[14] PoE optional, optional 'Gigastack' modules[15]
Catalyst 3750X[16] Fixed 3750X 12 SFP
24 8P8C/2 SFP
48 8P8C/4 SFP
2 None Uplink module with 1- and 10-Gbit/s options[17] All are stack capable Announced 2015[18] PoE optional

Current Switches[edit]

Base Model Form Factor Variants Available ports/Modules Number of power supplies Number/Type of supervisors Expansion type Sync End-of-life (only major notices listed) Comments
Catalyst 2900[19] Fixed 2918
24 8P8C
48 8P8C
None None None Announced 2007 (all except 2918),[21]
Announced 2015 (2918 only)
Catalyst 2960[22] Fixed 2960
8 8P8C/2 SFP
24 8P8C/2 SFP
48 8P8C/4 SFP
1 (fixed) (*note: cannot stack power, only backplane) None None Stack (up to four 2960-S, up to 8 2960-X or 2960XR) Announced 2013 (2960 only)[26] PoE only available on models with 'P' designator, 2960C is compact version
Catalyst 3560[27] Fixed 3560
8 8P8C/2 SFP or 8P8C
12 8P8C/2 SFP or 8P8C
12 SFP
24 8P8C/2 SFP
48 8P8C/4 SFP
12 'X2'[30]
12 SFP/2 'X2'
1 (up to 2 on 3560E only) None None (10 Gbit/s options on 3560E only)[31] Stack (V2 and E only) Announced 2012 (all except 3560C)[32] PoE optional, 3560C is compact version
Catalyst 3650[33] Fixed 3650[34] 24 8P8C/4 SFP
48 8P8C/4 SFP
24 8P8C/2 SFP+
48 8P8C/2 SFP+
None None Stackwise-160 (requires optional module) No EoL notices announced to date PoE optional
Catalyst 3750[35] Fixed 3750
12 SFP
24 8P8C/2 SFP
48 8P8C/4 SFP
1 (up to 2 on 3750V2) None None All are stack capable Announced 2010 (3750),[37]

Announced 2013 (3750V2)[38]

PoE optional
Catalyst 3850[39] Fixed 3850 12 SFP
24 8P8C
48 8P8C
12 SFP+
16 SFP+
24 SFP+
32 SFP+
48 SFP+[40]
Up to 2, most capable of stacking power None 1 Gbit/s, 10 Gbit/s and 40 Gbit/s options on all models[41] Stackwise-480 No EoL notices announced to date PoE optional
Catalyst 4500[42] Chassis 4503
24 SFP module
48 SFP module
48 8P8C module
up to 2 4503:1, 4506:1, all else:up to 2[44]
Sup II+, Sup III, Sup IV, Sup V (EoSale), Sup 6-E Sup 7-E, Sup 8-E[45]
Line cards VSS (with Sup7) Announced 2010 (non-E line cards),[46]
Announced 2010 (non-E chassis),[47]
Announced 2012 (Supervisor V),[48]
Announced 2014 (Supervisor 6-E, Supervisor 6L-E)[49]
PoE optional (per module)
Catalyst 4500-X[50] Fixed 4500-X 16 SFP+
32 SFP+[51]
up to 2 None 8 SFP+ module None No EoL notices to date Can select front to back or back to front air flow options
Catalyst 4900M[52] Fixed 4900M 48 8P8C/4 SFP
48 8P8C/2 'X2'
28 SFP/2 'X2'
up to 2 None Various 'X2' modules None No EoL notices to date
Catalyst 6500-E[53] Chassis 6503-E
4 port, 8 port, 16 port, 24 port and 48 port modules in 10/100/1G/10G/40G speeds of various physical medium[55] up to 2 6503:1, all else:up to 2[56]
Sup 2T, Sup 720 VSS, Sup 720, Sup 32 (EoSale)[57]
Line cards, Firewall, Wireless, Network Analysis (NAM), VPN, Application control engine, ASA Services[58] VSS (with Sup 720-10G or Sup 2T)[59] Announced 2012 (Supervisor 32),[60]
Announced 2012 (6513 chassis (non-e))[61]
PoE optional (per module)
Catalyst 6800[62] Both (6840-X and 6800ia models are fixed) 6880-X
No EoL notices to date Can support some 6500 modules (ASA, NAM, WiSM)[63]



  1. ^ Kennedy Clark; Kevin Hamilton (Feb 1, 2002), Configuring the Catalyst, Cisco Press, retrieved 2016-08-29
  2. ^ "Comparison of the Cisco Catalyst and Cisco IOS Operating Systems for the Cisco Catalyst 6500 Series Switch". Cisco Systems. August 19, 2004.
  3. ^ Cisco Press: Configuring the Catalyst
  4. ^ "Cisco StackWise and StackWise Plus Technology". Cisco Systems. Retrieved 28 May 2016.
  5. ^ "End-of-Sale and End-of-Life Products". Retrieved December 21, 2012.
  6. ^ Cisco 2940 Product Line
  7. ^ Cisco 2940 Model comparison
  8. ^ Cisco 2940 EoL announcement
  9. ^ Cisco 2950 product line
  10. ^ Cisco 2950 Model Comparison Archived 2015-07-22 at the Wayback Machine
  11. ^ Cisco 2950 EoL notices
  12. ^ Cisco 2950 EoL announcement
  13. ^ Cisco Gigastack product information
  14. ^ Cisco 3550 EoL announcement
  15. ^ Cisco Gigastack product information
  16. ^ Cisco 3750X Product Line
  17. ^ Cisco Catalyst 3750-X and 3560-X Series Switches Data Sheet
  18. ^ Cisco 3750X EoL Announcement
  19. ^ Cisco 2900 Product Line
  20. ^ Cisco 2900 EoL notifications
  21. ^ Cisco 2900 EoL notification Archived 2015-07-22 at the Wayback Machine
  22. ^ Cisco 2960 Product Line
  23. ^ Cisco 2960 Model Comparison
  24. ^ Cisco 2960CX Model Comparison
  25. ^ Cisco 2960 Migration Benefits
  26. ^ Cisco 2960 EoL announcement
  27. ^ Cisco 3560 Product Line
  28. ^ Cisco 3560 Model Comparison
  29. ^ Cisco 3560C Model Comparison
  30. ^ Cisco X2 module information
  31. ^ Cisco 3560E product information
  32. ^ Cisco 3560 EoL announcement
  33. ^ Cisco 3650 Product Line
  34. ^ Cisco 3650 Model Comparison
  35. ^ Cisco 3750 Product Line
  36. ^ Cisco 3750 Model Comparison
  37. ^ Cisco 3750 EoL Announcement
  38. ^ Cisco 3750V2 EoL Announcement
  39. ^ Cisco 3850 Product Line
  40. ^ Cisco 3850 Model Comparison
  41. ^ Cisco 3850 optional hardware
  42. ^ Cisco 4500 Product Line
  43. ^ Cisco 4500-E Model Comparison
  44. ^ Cisco 4500-E Chassis specifications
  45. ^ Cisco 4500 Supervisor list
  46. ^ Cisco 4500 non-E line card EoL announcement
  47. ^ Cisco 4500 Non-E EoL announcement
  48. ^ Cisco 4500 Supervisor V EoL announcement
  49. ^ Cisco 4500 Supervisor 6E EoL announcement
  50. ^ Cisco 4500-X Product Line
  51. ^ Cisco 4500-X Model Comparison
  52. ^ Cisco 4900 Product Line
  53. ^ Cisco 6500-E Product Line
  54. ^ Cisco 6500-E Model Comparison
  55. ^ Cisco 6500 Line Card comparison
  56. ^ Cisco 6500 Model Comparison
  57. ^ Cisco 6500 Supervisor Comparison
  58. ^ Cisco 6500 Service module reference
  59. ^ Cisco 6500 VSS configuration
  60. ^ Cisco 6500 Supervisor 32 EoL notification
  61. ^ Cisco 6513 non-E chassis EoL announcement
  62. ^ Cisco 6800 Product Line
  63. ^ Cisco 6807-XL product information

External links[edit]