Cisco Catalyst
Encyclopedia
Catalyst is the brand name for a variety of network switch
es sold by Cisco Systems
. While commonly associated with Ethernet
switches, a number of different 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 products originally developed by Crescendo Communications. The 1700, 1900, and 2800 -series Catalysts came from Grand Junction Networks
, and the Catalyst 3000 came from Kalpana
in 1994.
In addition, Cisco increasingly offers routers with switching capabilities, and indeed Cisco's 7600
router line and 6500 switch line
have interchangeable parts
. Even Cisco's smaller routers, including their newest "ISR" series, can have switch modules installed in them - basically making Cisco's smaller switches fully integrated devices.
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.
The latest version of IOS for the Catalyst 6500 series is 12.2(33)SXI which enables In-Service Software Upgrade (ISSU) via IOS Software Modularity.
Some newer Catalyst switch models (with recent versions of the Cisco IOS) also allow configuration via web-based graphical interface
module which is hosted on a HTTP
server located on the switch. The IOS config-mode command 'ip http-server' will enable this style of configuration. In series 12.x IOS, 'ip http-server' is always on as a factory default
. The Catalyst 3750-series of switches is an example of a Cisco Catalyst switch that allows this style of GUI configuration via HTTP.
Some newer models of Catalyst switches (called Catalyst Express) no longer allow access to IOS or CatOS at all - these switches can only be configured by using a Graphical User Interface (GUI).
es. It was originally called "XDI" by the switching company Crescendo Communications, Inc. Cisco renamed it to CatOS when they acquired Crescendo in late 1993.
CatOS ran on switches such as 1200, 4000, 4500, 5000, 5500, 6000, 6500 series. 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.
interfaces, ranging from 10 Mbit/s to 10 Gbit/s depending on the model. Some models can accommodate Asynchronous Transfer Mode
interfaces which can be used to bridge Ethernet traffic across wide area network
s. 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, and 100BaseVG
, but are no longer sold by Cisco Systems.
Most models have basic layer 2
functions and are capable of switching Ethernet frames between ports. Commonly found additional features are VLANs, trunking
(Cisco proprietary ISL
or IEEE 802.1Q
) and QoS
or CoS
. The switches, whether IOS
or CatOS, are fully manageable.
Many Catalysts 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" cards. These work by separating the line cards, chassis, and processing engine (mirroring most Cisco router designs). The chassis provides power and a high-speed backplane
, the line cards provide interfaces to the network, and the processing engine moves packets, participates in routing protocols, etc. This gives several advantages:
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. Naturally, this can't be done for all traffic, but basic layer-2 switching can usually be handled exclusively by the line card, and in many cases also more complex operations can be handled as well.
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 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 security problems.
that allows for up to nine Catalyst switch
3750 series switch
es to operate as though they were one 32-Gbit/s switch. This allows for greater resiliency, and performance.
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.
If one switch fails the remaining switches will continue to operate by looping back any information that would normally traverse the failed switch, effectively bypassing it. If the master switch fails, the next 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 down switch (any including master) with a new un-programmed switch. The stack will configure the new switch on the fly and allow for minimal downtime
StackWise effectively replaced the GigaStack found on lower-price models such as Catalyst 35xx and 29xx series.
Recently, there is a new variation of the technology, known as Cisco Stackwise Plus, offering 64Gbit/s nonblocking switching fabric speed.
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:
Network switch
A network switch or switching hub is a computer networking device that connects network segments.The term commonly refers to a multi-port network bridge that processes and routes data at the data link layer of the OSI model...
es sold by Cisco Systems
Cisco Systems
Cisco Systems, Inc. is an American multinational corporation headquartered in San Jose, California, United States, that designs and sells consumer electronics, networking, voice, and communications technology and services. Cisco has more than 70,000 employees and annual revenue of US$...
. While commonly associated with Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
switches, a number of different 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 products originally developed by Crescendo Communications. The 1700, 1900, and 2800 -series Catalysts came from Grand Junction Networks
Grand Junction Networks
Grand Junction Networks was a LAN switching company based in the United States. It was acquired by Cisco Systems on November 6, 1995....
, and the Catalyst 3000 came from Kalpana
Kalpana (company)
Kalpana was a computer networking equipment manufacturer, located in Silicon Valley during the 1980s and 1990s.Kalpana is considered to be the inventor of Ethernet switching as the company was the first to introduce the concept of a multi-port network switch with its seven-port EtherSwitch in 1990...
in 1994.
In addition, Cisco increasingly offers routers with switching capabilities, and indeed Cisco's 7600
Cisco 7600
The Cisco 7600 series is a series of large network routers designed and manufactured by Cisco Systems.-Key Features:* Chassis ranges: 3-slot , 4-slot , 6-slot , 9-slot and 13-slot ....
router line and 6500 switch line
Catalyst 6500
The Catalyst 6500 is a modular chassis network switch manufactured by Cisco Systems since 1999, capable of delivering speeds of up to "400 million packets per second"....
have interchangeable parts
Interchangeable parts
Interchangeable parts are parts that are, for practical purposes, identical. They are made to specifications that ensure that they are so nearly identical that they will fit into any device of the same type. One such part can freely replace another, without any custom fitting...
. Even Cisco's smaller routers, including their newest "ISR" series, can have switch modules installed in them - basically making Cisco's smaller switches fully integrated devices.
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 IOSCisco IOS
Cisco IOS is the software used on the vast majority of Cisco Systems routers and current Cisco network switches...
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
Network Layer
The network layer is layer 3 of the seven-layer OSI model of computer networking.The network layer is responsible for packet forwarding including routing through intermediate routers, whereas the data link layer is responsible for media access control, flow control and error checking.The network...
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.
The latest version of IOS for the Catalyst 6500 series is 12.2(33)SXI which enables In-Service Software Upgrade (ISSU) via IOS Software Modularity.
Some newer Catalyst switch models (with recent versions of the Cisco IOS) also allow configuration via web-based graphical interface
Gui
Gui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...
module which is hosted on a HTTP
Hypertext Transfer Protocol
The Hypertext Transfer Protocol is a networking protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web....
server located on the switch. The IOS config-mode command 'ip http-server' will enable this style of configuration. In series 12.x IOS, 'ip http-server' is always on as a factory default
Default (computer science)
A default, in computer science, refers to a setting or value automatically assigned to a software application, computer program or device, outside of user intervention. Such settings are also called presets, especially for electronic devices...
. The Catalyst 3750-series of switches is an example of a Cisco Catalyst switch that allows this style of GUI configuration via HTTP.
Some newer models of Catalyst switches (called Catalyst Express) no longer allow access to IOS or CatOS at all - these switches can only be configured by using a Graphical User Interface (GUI).
CatOS
CatOS (Catalyst Operating System) is the discontinued operating system for many of the Catalyst brand of legacy network switchNetwork switch
A network switch or switching hub is a computer networking device that connects network segments.The term commonly refers to a multi-port network bridge that processes and routes data at the data link layer of the OSI model...
es. It was originally called "XDI" by the switching company Crescendo Communications, Inc. Cisco renamed it to CatOS when they acquired Crescendo in late 1993.
CatOS ran on switches such as 1200, 4000, 4500, 5000, 5500, 6000, 6500 series. 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.
Interfaces
As Catalyst devices are primarily Ethernet switches, all modern Catalyst models have EthernetEthernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
interfaces, ranging from 10 Mbit/s to 10 Gbit/s depending on the model. Some models can accommodate Asynchronous Transfer Mode
Asynchronous Transfer Mode
Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...
interfaces which can be used to bridge Ethernet traffic across wide area network
Wide area network
A wide area network is a telecommunication network that covers a broad area . Business and government entities utilize WANs to relay data among employees, clients, buyers, and suppliers from various geographical locations...
s. Other models can support T1
Digital Signal 1
Digital signal 1 is a T-carrier signaling scheme devised by Bell Labs. DS1 is a widely used standard in telecommunications in North America and Japan to transmit voice and data between devices. E1 is used in place of T1 outside North America, Japan, and South Korea...
, E1
E-carrier
In digital telecommunications, where a single physical wire pair can be used to carry many simultaneous voice conversations by time-division multiplexing, worldwide standards have been created and deployed...
, and ISDN PRI
Primary rate interface
The Primary Rate Interface is a standardized telecommunications service level within the Integrated Services Digital Network specification for carrying multiple DS0 voice and data transmissions between a network and a user....
interfaces to provide connections to the PSTN. Legacy models supported a variety of interfaces, such as token ring, FDDI, and 100BaseVG
100BaseVG
100BaseVG is a 100 Mbit/s Ethernet standard specified to run over four pairs of category 3 UTP wires . It is also called 100VG-AnyLAN because it was defined to carry both Ethernet and token ring frame types....
, but are no longer sold by Cisco Systems.
Most models have basic layer 2
Data link layer
The data link layer is layer 2 of the seven-layer OSI model of computer networking. It corresponds to, or is part of the link layer of the TCP/IP reference model....
functions and are capable of switching Ethernet frames between ports. Commonly found additional features are VLANs, trunking
Trunking
In modern communications, trunking is a concept by which a communications system can provide network access to many clients by sharing a set of lines or frequencies instead of providing them individually. This is analogous to the structure of a tree with one trunk and many branches. Examples of...
(Cisco proprietary ISL
Cisco Inter-Switch Link
Cisco Inter-Switch Link is a Cisco Systems proprietary protocol that maintains VLAN information in Ethernet frames as traffic flows between switches and routers, or switches and switches....
or IEEE 802.1Q
IEEE 802.1Q
IEEE 802.1Q is the networking standard that supports Virtual LANs on an Ethernet network. The standard defines a system of VLAN tagging for Ethernet frames and the accompanying procedures to be used by bridges and switches in handling such frames...
) and QoS
Quality of service
The quality of service refers to several related aspects of telephony and computer networks that allow the transport of traffic with special requirements...
or CoS
Class of service
-Class of service :As related to network technology, CoS is a 3-bit field within an Ethernet frame header when using 802.1Q tagging. The field specifies a priority value of between 0 and 7 inclusive that can be used by quality of service disciplines to differentiate traffic.While CoS operates only...
. The switches, whether IOS
Cisco IOS
Cisco IOS is the software used on the vast majority of Cisco Systems routers and current Cisco network switches...
or CatOS, are fully manageable.
Many Catalysts 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" cards. These work by separating the line cards, chassis, and processing engine (mirroring most Cisco router designs). The chassis provides power and a high-speed backplane
Backplane
A backplane is a group of connectors connected in parallel with each other, so that each pin of each connector is linked to the same relative pin of all the other connectors forming a computer bus. It is used as a backbone to connect several printed circuit boards together to make up a complete...
, the line cards provide interfaces to the network, and the processing 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 having to uncable, unbolt, pull out, replace, re-bolt, and re-cable an entire switch, which may be as large as a quarter-rack, weigh over 150 pounds, and service over 500 cables.
- A redundant supervisor engine may be installed to rapidly recover from supervisor failures. This is subject to restrictions (as some switches don't support redundant supervisors), but typically results in restoration times under 90 seconds.
- 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. Naturally, this can't be done for all traffic, but basic layer-2 switching can usually be handled exclusively by the line card, and in many cases also more complex operations can be handled as well.
Management
Cisco switches are very popular for a number of reasons, including advanced customization and manageability. The switches can be configured using a serial console or a telnet session (or ssh if the correct OS is loaded along with the ssh keys generated). SNMP allows monitoring of many states, and measurement of traffic flows. Many devices can also run an HTTP server, but this is often disabled because of the security problems it creates - either because it's not encrypted, or because of the relatively frequent security vulnerabilities in the Cisco http daemon itself. Some Cisco switches focused on smaller organizations forego a command line interface and offer ONLY a web/html interface for configuration and management.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 TFTP
Trivial File Transfer Protocol
Trivial File Transfer Protocol is a file transfer protocol known for its simplicity. It is generally used forautomated transfer of configuration or boot files between machines in a local environment....
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 security problems.
Stackwise
Cisco StackWise is a technology offered by Cisco SystemsCisco Systems
Cisco Systems, Inc. is an American multinational corporation headquartered in San Jose, California, United States, that designs and sells consumer electronics, networking, voice, and communications technology and services. Cisco has more than 70,000 employees and annual revenue of US$...
that allows for up to nine Catalyst switch
Catalyst switch
Catalyst is the brand name for a variety of network switches sold by Cisco Systems. While commonly associated with Ethernet switches, a number of different interfaces have been available throughout the history of the brand. Cisco acquired several different companies and rebranded their products...
3750 series switch
Switch
In electronics, a switch is an electrical component that can break an electrical circuit, interrupting the current or diverting it from one conductor to another....
es to operate as though they were one 32-Gbit/s switch. This allows for greater resiliency, and performance.
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.
If one switch fails the remaining switches will continue to operate by looping back any information that would normally traverse the failed switch, effectively bypassing it. If the master switch fails, the next 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 down switch (any including master) with a new un-programmed switch. The stack will configure the new switch on the fly and allow for minimal downtime
StackWise effectively replaced the GigaStack found on lower-price models such as Catalyst 35xx and 29xx series.
Recently, there is a new variation of the technology, known as Cisco Stackwise Plus, offering 64Gbit/s nonblocking switching fabric speed.
Master Selection
The master switch of a stack is determined in the following order.- User specified.
- The switch with the most advanced IOS, i.e. Advanced IP Services IPv6 (AIPv6), then Enhanced Multilayer Software Image (EMI) and then Standard Multilayer Software Image (SMI).
- Programmed switch. A configured switch will preside over a switch with just the defaults.
- Uptime. The switch that has been running the longest.
- MAC address. The switch with the lowest MAC address.
Models
Like most Cisco product lines, the Catalyst Switch series evolves fairly rapidly. 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.- As of 2011, the most popular fixed configuration switches are the WS-C2960, the WS-C3560 and WS-C3750 series at the high end, an entry level managed "express" series - with models beginning WS-CE (configurable by web interface only, no command line interface), the "ME" metroline series of switches, and a new "Small Business" series coming from Cisco's acquisition of Linksys. In addition, there are many excellent legacy switches suitable for most business and service provider needs no longer offered directly through Cisco (WS-C2950, WS-C3550 for example). Cisco fixed configuration switches come with a bewildering assortment of features (10/100 ports versus 10/100/1000 ports, some with power over Ethernet, some with varying types of gigabit and 10gig uplink ports, some with standard or enhanced software, varying power supplies) and it is difficult to tell what features a switch has (aside from the number of ports) from a visual inspection, and similar-appearing switches can have dramatically different features.
Cisco model names and switch features
In general, switch names start with WS-C, followed by the model line (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.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 Cisco Catalyst 6500Catalyst 6500The Catalyst 6500 is a modular chassis network switch manufactured by Cisco Systems since 1999, capable of delivering speeds of up to "400 million packets per second"....
Series is a chassis-based switch family. This series can support interfaces up to 10 Gigabit Ethernet10 Gigabit EthernetThe 10 gigabit Ethernet computer networking standard was first published in 2002. It defines a version of Ethernet with a nominal data rate of 10 Gbit/s , ten times faster than gigabit Ethernet.10 gigabit Ethernet defines only full duplex point to point links which are generally connected by...
in speed and redundant Supervisor modules.
- 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 4900 series is a fixed-configuration switch. Uplink interfaces are either SFPSFP transceiverThe small form-factor pluggable or Mini-GBIC is a compact, hot-pluggable transceiver used for both telecommunication and data communications applications. It interfaces a network device mother board to a fiber optic or copper networking cable...
ports or 10 gigabit Ethernet, with 48 copper ports of 10/100/1000 EthernetGigabit EthernetGigabit Ethernet is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second , as defined by the IEEE 802.3-2008 standard. It came into use beginning in 1999, gradually supplanting Fast Ethernet in wired local networks where it performed...
.
- The Cisco Catalyst 4500 SeriesCisco Catalyst 4500 Series SwitchesThe Cisco Catalyst 4500 is a mid-range modular chassis network switch manufactured by Cisco Systems. A Cisco Catalyst 4500 comprises a chassis, power supplies, one or two supervisors, line cards and service modules. The Cisco Catalyst 4500 Series includes two series of Catalyst chassis: The Classic...
is a mid-range modular chassis based Switch manufactured by Cisco System.
- 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 M1000eDell M1000eThe Dell blade server solutions are built around their new M1000e enclosure that can hold their complete range of server blades and an extensive range of I/O modules like ethernet switches, fibre-channel switches etc....
enclosure.
- The 1000 switch family is considered an edge device, having many functionalities that can be built as the device is very modular.
- 1700: 24 10BaseT ports, 1 switchable MDIMedium dependent interfaceA medium dependent interface describes the interface in a computer network from a physical layer implementation to the physical medium used to carry the transmission....
/MDIX uplink 10baseT/AUIAttachment Unit InterfaceAn Attachment Unit Interface is a 15 pin connection that provides a path between a node's Ethernet interface and the Medium Attachment Unit , sometimes known as a transceiver. It is the part of the IEEE Ethernet standard located between the Media Access Control , and the MAU...
/BNCBNC connectorThe BNC connector ' is a common type of RF connector used for coaxial cable. It is used with radio, television, and other radio-frequency electronic equipment, test instruments, video signals, and was once a popular computer network connector. BNC connectors are made to match the characteristic...
port, and 2 Fast Ethernet ports. Runs neither CatOS nor IOSCisco IOSCisco IOS is the software used on the vast majority of Cisco Systems routers and current Cisco network switches...
. Is a first-generation carryover from Cisco's acquisition of Grand Junction NetworksGrand Junction NetworksGrand Junction Networks was a LAN switching company based in the United States. It was acquired by Cisco Systems on November 6, 1995....
. - 19xxCisco Catalyst 1900The Cisco Catalyst 1900 is a 19" rack mountable, managed 10baseT Ethernet switch with 100baseTX/100baseFX uplink ports. This product was popular in small office networks because of its features and price....
: 12 or 24 10BaseT ports and 2 Fast EthernetFast EthernetIn computer networking, Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100 Mbit/s, against the original Ethernet speed of 10 Mbit/s. Of the fast Ethernet standards 100BASE-TX is by far the most common and is supported by the...
ports. ISL trunking on the 100 Mbit/s ports. Runs neither CatOS nor IOS. It is in End-of-Life today.