Cisco Catalyst Explained

Catalyst is the brand for a variety of network switches, wireless controllers, and wireless access points sold by Cisco Systems. While commonly associated with Ethernet switches, a number of different types of 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.

The newest Catalyst series is the Catalyst 9000 family. The Catalyst 9000 family includes switches, wireless access points, and wireless controllers.[1]

Operating systems

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 2960-L SM Series of switches is an example of a Cisco Catalyst switch that allows this style of GUI via HTTP.

Cisco IOS

Cisco IOS, formally the Cisco Internetwork Operating System, is a family of network operating systems used on many Cisco Systems network switches, routers, wireless controllers and wireless access points. Earlier, Cisco switches ran CatOS. Cisco IOS is a package of routing, switching, internetworking and telecommunications functions integrated into a multitasking operating system. Although the IOS code base includes a cooperative multitasking kernel, most IOS features have been ported to other kernels such as QNX and Linux for use in Cisco products.Cisco Catalyst products run IOS or a Linux-derived version called Cisco IOS XE. It was originally called XDI[3] by the switching company Crescendo Communications, Inc. Cisco renamed it to CatOS when they acquired Crescendo and later still to Cisco IOS as the operating system was extended to other Cisco products. The newer Catalyst 9000 family uses the Cisco IOS XE operating system.[4]

Interfaces

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. 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.

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 IOS XE, are fully manageable.

Many Catalyst switches that run IOS or IOS XE 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 switch that runs IOS or IOS XE may be able to tackle large-scale enterprise routing tasks, using router technologies like OSPF or BGP.

Modular chassis-based Catalyst switching models, like the Catalyst 9400 and 9600 Series, have the concept of field-replaceable supervisor, line cards, power supplies and fans. 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:

Management

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.

Stackwise

StackWise and Stackwise Virtual previously known as VSS are technologies offered by Cisco Systems that allows some models of Catalyst switches to operate as though they were one switch. One switch from the stack will act as the primary switch. The primary switch will maintain the stack and allows for configuration and monitoring of 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 primary switch fails, another switch in the stack will automatically take over as primary. 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 primary) with a new switch. The stack will configure the new switch on-the-fly to accommodate minimal downtime and reduce maintenance effort and errors.

Stackwise physically connects the switch stack using special stack interconnect cables, typically up to eight switches per stack. StackWise Virtual and VSS allow for the virtual clustering of two chassis together into a single, logical entity without physical interconnect cables.

Primary election

The primary switch of a stack is elected in the following order:[5]

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

Models

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 or C, followed by the model line (e.g. C9600). 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 like UPOE (e.g. C9300-48U). Catalyst 9000 switches also include software subscription license indicators (e.g. C9200-48T-P, E for Essentials, A for Advantage and P for Premier)

Fixed-configuration switches

Cisco Catalyst 9500 Series[6]
  • Layer 2 and layer 3 stackable core switches.
    Cisco Catalyst 9300 Series[7]
  • Layer 2 and layer 3 stackable access and distribution switches.
    Cisco Catalyst 9200 Series[8]
  • Layer 2 and layer 3 stackable access switches.
    Cisco Catalyst 1000 Series[9]
  • Layer 2 stackable access switches.
    Cisco Catalyst 3850 series[10]
  • Layer 2 and layer 3 stackable access and distribution switches.
    Cisco Catalyst 3650 series[11]
  • Layer 2 and layer 3 switches with optional stacking capability.
    Cisco Catalyst 2960-X/XR Series[12]
  • Layer 2 and layer 3 stackable access switches.
    Cisco Catalyst 2960-L Series[13]
  • Layer 2 and layer 3 access switches.
    Cisco Catalyst 3560CX/2960CX Series[14]
  • Compact, fanless layer 2 and layer 3 switches.
    Cisco Catalyst Digital Building Series[15]
  • Compact, fanless layer 2 and layer 3 switches.

    Modular switches

    Cisco modular switches offer a configurable selection of chassis, power supplies, line cards and supervisor modules. Among Cisco's modular series are:

    End-of-life switches

    Base ModelForm FactorVariantsAvailable ports/ModulesNumber of power suppliesNumber/Type of supervisorsExpansion typeSyncEnd-of-life (only major notices listed)Comments
    Catalyst 2940[18] Fixed 2940 8 8P8C/1 8P8C
    8 8P8C/1 8P8C or 1 SFP[19]
    1 (fixed) None None None Announced 2009[20]
    Catalyst 2900[21] Fixed 2918
    2926
    2948
    2980[22]
    24 8P8C
    48 8P8C
    None None None Announced 2007 (all except 2918),[23]
    Announced 2015 (2918 only)
    Catalyst 2950[24] Fixed 2950
    2950SX[25]
    12 8P8C
    24 8P8C
    24 8P8C/2 GBIC or 1000SX
    48 8P8C/2 GBIC or 1000SX[26]
    1 (fixed) None None None Announced 2007[27] Optional 'Gigastack' modules[28]
    Catalyst 2960[29] Fixed 2960
    2960S[30]
    2960CX[31]
    2960-X
    2960-XR[32]
    8 8P8C/2 SFP
    24 8P8C/2 SFP
    48 8P8C/4 SFP
    24 8P8C/2 SFP+[33]
    48 8P8C/2 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)[34]
    Announced 2020 (remainder including 2960-X[35] & 2960-XR[36])
    PoE only available on models with 'P' designator, 2960C is compact version
    Catalyst 3550 Fixed 3550 24 8P8C/2 GBIC
    48 8P8C/2 GBIC
    1 (fixed) None None None Announced 2005[37] PoE optional, optional 'Gigastack' modules[38]
    Catalyst 3560[39] Fixed 3560
    3560V2
    3560E[40]
    3560C[41]
    8 8P8C/2 SFP or 8P8C
    12 8P8C/2 SFP or 8P8C
    8 SFP
    12 SFP
    24 8P8C/2 SFP
    48 8P8C/4 SFP
    12 'X2'[42]
    12 SFP/2 'X2'
    1 (up to 2 on 3560E only) None None (10 Gbit/s options on 3560E only)[43] Stack (V2 and E only) Announced 2012 (all except 3560C)[44] PoE optional, 3560C is compact version
    Catalyst 3750[45] Fixed 3750
    3750V2
    3750G[46]
    3750E
    3750-X
    12 SFP
    24 8P8C/2 SFP
    48 8P8C/4 SFP24/48 8P8C/2 'X2' (3750E)
    1 (up to 2 on 3750V2) None NoneAll are stack capable Announced 2010 (3750),[47]
    Announced 2013 (3750V2)[48]
    PoE optional
    Catalyst 3750X[49] Fixed 3750X12 SFP
    24 8P8C/2 SFP
    48 8P8C/4 SFP
    2 None Uplink module with 1- and 10-Gbit/s options[50] All are stack capable Announced 2015[51] PoE optional
    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 Announced 2013 (4900M)[53]

    Current switches

    Base ModelForm FactorVariantsAvailable ports/ModulesNumber of power suppliesNumber/Type of supervisorsExpansion typeSyncEnd-of-life (only major notices listed)Comments
    Catalyst 3650[54] Fixed 3650[55] 24 8P8C/4 SFP
    48 8P8C/4 SFP
    24 8P8C/2 SFP+
    48 8P8C/2 SFP+
    None None Stackwise-160 (requires optional module)PoE optional
    Catalyst 3850[56] Fixed 3850 12 SFP
    24 8P8C
    48 8P8C
    12 SFP+
    16 SFP+
    24 SFP+
    32 SFP+
    48 SFP+[57]
    Up to 2, most capable of stacking power None 1 Gbit/s, 10 Gbit/s and 40 Gbit/s options on all models[58] Stackwise-480 Announced 2019[59] PoE optional
    Catalyst 4500[60] Chassis 4503
    4503-E
    4506
    4506-E
    4507R
    4507R+E
    4507R-E
    4510R
    4510R+E
    4510R-E[61]
    24 SFP module
    48 SFP module
    48 8P8C module
    up to 2 4503:1, 4506:1, all else:up to 2[62]
    Sup II+, Sup III, Sup IV, Sup V (EoSale), Sup 6-E Sup 7-E, Sup 8-E[63]
    Line cards VSS (with Sup7) Announced 2010 (non-E line cards),[64]
    Announced 2010 (non-E chassis),[65]
    Announced 2012 (Supervisor V),[66]
    Announced 2014 (Supervisor 6-E, Supervisor 6L-E)[67]
    PoE optional (per module)
    Catalyst 4500-X[68] Fixed 4500-X 16 SFP+
    32 SFP+[69]
    up to 2 None 8 SFP+ module None Announced 2019[70] Can select front to back or back to front air flow options
    Catalyst 6500-E[71] Chassis 6503-E
    6504-E
    6506-E
    6509-E/V-E
    6513-E[72]
    4 port, 8 port, 16 port, 24 port and 48 port modules in 10/100/1G/10G/40G speeds of various physical medium[73] up to 2 6503:1, all else:up to 2[74]
    Sup 2T, Sup 720 VSS, Sup 720, Sup 32 (EoSale)[75]
    Line cards, Firewall, Wireless, Network Analysis (NAM), VPN, Application control engine, ASA Services[76] VSS (with Sup 720-10G or Sup 2T)[77] Announced 2012 (Supervisor 32),[78]
    Announced 2012 (6513 chassis (non-e))[79]
    PoE optional (per module)
    Catalyst 6800[80] Both (6840-X and 6800ia models are fixed) 6880-X
    6840-X
    6800-XL
    6800-ia
    Announced 2019[81] Can support some 6500 modules (ASA, NAM, WiSM)[82]
    Catalyst 9200[83] Fixed92009200L24 port, 48 port, 1 Network Module slot (modular uplinks). 9200L has no modular uplinks, fixed configurationup to 2 depending on modelNone4 additional SFP/SFP+ ports or 2 25G/40G SFP on network moduleStackwise-160/80 (requires optional module)PoE and MGig support on various models
    Catalyst 9300[84] Fixed93009300L24 port, 48 port, 1 Network Module slot. 9300L has no module, fixed configurationup to 2 depending on modelNoneup to 8 additional SFP ports on network modulePoE and MGig support on various models
    Catalyst 9400[85] Chassis 9404R
    9407R
    9410R[86]
    24 8P8C module
    48 8P8C module
    24 SFP module
    48 SFP module
    24 SFP+ module
    48 SFP+ module[87]
    9404R: up to 4
    9407R: up to 8
    9410R: up to 8
    2 dedicated Supervisor engine slots
    C9400X-SUP-2XL
    C9400X-SUP-2
    C9400-SUP-1XL
    C9400-SUP-1XL-Y
    C9400-SUP-1[88]
    Line cards StackWise Virtual PoE optional (per module)
    Catalyst 9500[89] Fixed12, 24, 32, 40, 48 port 1/10/25/40/100 Gbit fixed configurationUp to 2None

    References

    Notes and References

    1. Web site: Cisco unveils network of the future that can learn, adapt and evolve. newsroom.cisco.com. en-US. 2019-08-09.
    2. Web site: Comparison of the Cisco Catalyst and Cisco IOS Operating Systems for the Cisco Catalyst 6500 Series Switch . August 19, 2004 . Cisco Systems.
    3. http://www.ciscopress.com/articles/article.asp?p=25172&rl=1 Cisco Press: Configuring the Catalyst
    4. Web site: Cooney . Michael . Venerable Cisco Catalyst 6000 switches ousted by new Catalyst 9600 . network world . IDG . 30 August 2019.
    5. Web site: Cisco Catalyst 9000 Platform StackWise Virtual. Cisco Systems. 7 August 2019.
    6. https://www.cisco.com/c/en/us/products/switches/catalyst-9500-series-switches/index.html Cisco Catalyst 9500 Series
    7. https://www.cisco.com/c/en/us/products/switches/catalyst-9300-series-switches/index.html Cisco Catalyst 9300 Series
    8. https://www.cisco.com/c/en/us/products/switches/catalyst-9200-series-switches/index.html Cisco Catalyst 9200 Series
    9. https://www.cisco.com/c/en/us/products/switches/catalyst-1000-series-switches/index.html Cisco Catalyst 1000 Series
    10. https://www.cisco.com/c/en/us/products/switches/catalyst-3850-series-switches/index.html Cisco Catalyst 38500 Series
    11. https://www.cisco.com/c/en/us/products/switches/catalyst-3650-series-switches/index.html Cisco Catalyst 3650 Series
    12. https://www.cisco.com/c/en/us/products/switches/catalyst-2960-x-series-switches/index.html Cisco Catalyst 2960-X/XR Series
    13. https://www.cisco.com/c/en/us/products/switches/catalyst-2960-l-series-switches/index.html Cisco Catalyst 2960-L Series
    14. https://www.cisco.com/c/en/us/products/switches/catalyst-3560-cx-series-switches/index.html Cisco Catalyst 3650 Series
    15. https://www.cisco.com/c/en/us/products/switches/catalyst-digital-building-series-switches/index.html Cisco Catalyst Digital Building Series
    16. https://www.cisco.com/c/en/us/products/switches/catalyst-9600-series-switches/index.html Cisco Catalyst 9600 Series
    17. https://www.cisco.com/c/en/us/products/switches/catalyst-9400-series-switches/index.html Cisco Catalyst 9400 Series
    18. http://www.cisco.com/c/en/us/products/switches/catalyst-2940-series-switches/index.html Cisco 2940 Product Line
    19. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-2940-series-switches/product_data_sheet09186a00801973c8.html Cisco 2940 Model comparison
    20. http://www.cisco.com/c/en/us/products/switches/catalyst-2940-series-switches/eos-eol-notice-listing.html Cisco 2940 EoL announcement
    21. http://www.cisco.com/c/en/us/products/switches/catalyst-2900-series-switches/index.html Cisco 2900 Product Line
    22. http://www.cisco.com/c/en/us/support/switches/catalyst-2900-series-switches/tsd-products-support-eol-series-home.html Cisco 2900 EoL notifications
    23. http://www.cisco.com/c/en/us/products/switches/catalyst-2900-series-switches/eos-eol-notice-listing.html Cisco 2900 EoL notification
    24. http://www.cisco.com/c/en/us/products/switches/catalyst-2950-series-switches/index.html Cisco 2950 product line
    25. http://www.cisco.com/c/en/us/products/switches/catalyst-2950-series-switches/eos-eol-models-listing.html Cisco 2950 Model Comparison
    26. http://www.cisco.com/c/en/us/support/switches/catalyst-2950-series-switches/tsd-products-support-eol-series-home.html Cisco 2950 EoL notices
    27. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-2950-series-switches/prod_end-of-life_notice0900aecd806ea1da.html Cisco 2950 EoL announcement
    28. http://www.cisco.com/en/US/products/hw/modules/ps872/products_data_sheet09186a00800a1789.html Cisco Gigastack product information
    29. http://www.cisco.com/c/en/us/products/switches/catalyst-2960-series-switches/index.html Cisco 2960 Product Line
    30. http://www.cisco.com/c/en/us/products/switches/catalyst-2960-series-switches/models-comparison.html Cisco 2960 Model Comparison
    31. http://www.cisco.com/c/en/us/products/switches/catalyst-3560-cx-series-switches/models-comparison.html Cisco 2960CX Model Comparison
    32. http://www.cisco.com/c/dam/en/us/products/collateral/switches/catalyst-2960-x-series-switches/feature-comparison-c83-731053.pdf Cisco 2960 Migration Benefits
    33. https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-2960-s-series-switches/data_sheet_c78-726680.html 2960-S datasheet
    34. http://www.cisco.com/c/en/us/products/switches/catalyst-2960-series-switches/eos-eol-notice-listing.html Cisco 2960 EoL announcement
    35. https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-2960-x-series-switches/eos-eol-notice-c51-744432.html 2960-X EOL
    36. https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-2960-xr-series-switches/eos-eol-notice-c51-744422.html 2960-XR EOL Announcement
    37. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3550-series-switches/prod_end-of-life_notice0900aecd8029f777.html Cisco 3550 EoL announcement
    38. http://www.cisco.com/en/US/products/hw/modules/ps872/products_data_sheet09186a00800a1789.html Cisco Gigastack product information
    39. http://www.cisco.com/c/en/us/products/switches/catalyst-3560-series-switches/index.html Cisco 3560 Product Line
    40. http://www.cisco.com/c/en/us/products/switches/catalyst-3560-series-switches/models-comparison.html Cisco 3560 Model Comparison
    41. http://www.cisco.com/c/en/us/products/switches/catalyst-3560-cx-series-switches/models-comparison.html Cisco 3560C Model Comparison
    42. http://www.cisco.com/c/en/us/products/collateral/interfaces-modules/10-gigabit-modules/product_data_sheet0900aecd801f92aa.html Cisco X2 module information
    43. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3560-e-series-switches/product_data_sheet0900aecd805bac22.html Cisco 3560E product information
    44. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3750-series-switches/eol_c51-696372.html Cisco 3560 EoL announcement
    45. http://www.cisco.com/c/en/us/products/switches/catalyst-3750-series-switches/index.html Cisco 3750 Product Line
    46. http://www.cisco.com/c/en/us/products/switches/catalyst-3750-series-switches/models-comparison.html Cisco 3750 Model Comparison
    47. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3750-series-switches/end_of_life_notice_c51-574778.html Cisco 3750 EoL Announcement
    48. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3750-series-switches/eos-eol-notice-c51-730227.html Cisco 3750V2 EoL Announcement
    49. http://www.cisco.com/c/en/us/products/switches/catalyst-3750-x-series-switches/index.html Cisco 3750X Product Line
    50. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3750-x-series-switches/data_sheet_c78-584733.html Cisco Catalyst 3750-X and 3560-X Series Switches Data Sheet
    51. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3560-x-series-switches/eos-eol-notice-c51-736139.html Cisco 3750X EoL Announcement
    52. http://www.cisco.com/c/en/us/products/switches/catalyst-4900m-switch/index.html Cisco 4900 Product Line
    53. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3750-series-switches/end_of_life_notice_c51-574778.html Cisco 4900M EoL Announcement
    54. http://www.cisco.com/c/en/us/products/switches/catalyst-3650-series-switches/index.html Cisco 3650 Product Line
    55. http://www.cisco.com/c/en/us/products/switches/catalyst-3650-series-switches/models-comparison.html Cisco 3650 Model Comparison
    56. http://www.cisco.com/c/en/us/products/switches/catalyst-3850-series-switches/index.html Cisco 3850 Product Line
    57. http://www.cisco.com/c/en/us/products/switches/catalyst-3850-series-switches/models-comparison.html Cisco 3850 Model Comparison
    58. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3850-series-switches/data_sheet_c78-720918.pdf Cisco 3850 optional hardware
    59. https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3850-series-switches/eos-eol-notice-c51-743072.html Cisco 3850 EoL announcement
    60. http://www.cisco.com/c/en/us/products/switches/catalyst-4500-series-switches/index.html Cisco 4500 Product Line
    61. http://www.cisco.com/c/en/us/support/switches/catalyst-4500-series-switches/tsd-products-support-series-home.html Cisco 4500-E Model Comparison
    62. http://www.cisco.com/c/en/us/products/switches/catalyst-4500-series-switches/models-comparison.html#~chassis Cisco 4500-E Chassis specifications
    63. http://www.cisco.com/c/en/us/products/switches/catalyst-4500-series-switches/relevant-interfaces-and-modules.html Cisco 4500 Supervisor list
    64. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-4500-series-switches/eol_c51_574038.html Cisco 4500 non-E line card EoL announcement
    65. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-4500-series-switches/eol_c51_574042.html Cisco 4500 Non-E EoL announcement
    66. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-4500-series-switches/eol__C51-715812.html Cisco 4500 Supervisor V EoL announcement
    67. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-4500-series-switches/eol__C51-726869.html Cisco 4500 Supervisor 6E EoL announcement
    68. http://www.cisco.com/c/en/us/products/switches/catalyst-4500-x-series-switches/index.html Cisco 4500-X Product Line
    69. http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-4500-x-series-switches/data_sheet_c78-696791.html Cisco 4500-X Model Comparison
    70. https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-4500-x-series-switches/eos-eol-notice-c51-743098.html Cisco 4500-X EoL announcement
    71. http://www.cisco.com/c/en/us/products/switches/catalyst-6500-series-switches/index.html Cisco 6500-E Product Line
    72. http://www.cisco.com/c/en/us/products/switches/catalyst-6500-series-switches/models-listing.html Cisco 6500-E Model Comparison
    73. http://www.cisco.com/c/en/us/products/switches/catalyst-6500-series-switches/relevant-interfaces-and-modules.html#10gigabit Cisco 6500 Line Card comparison
    74. http://www.cisco.com/c/en/us/products/switches/catalyst-6500-series-switches/models-comparison.html Cisco 6500 Model Comparison
    75. http://www.cisco.com/c/en/us/products/switches/catalyst-6500-series-switches/relevant-interfaces-and-modules.html#supervisor Cisco 6500 Supervisor Comparison
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