Overview on Cisco Catalyst 3750 Switches: Features, Technology, Intelligent Switching, Network Management
The Cisco Catalyst 3750 Series switches are a premier line of enterprise-class, stackable, multilayer switches that provide high availability, security, and quality of service (QoS) to enhance the operation of the network. Its innovative unified stack management raises the bar in stack management, redundancy, and failover.
With a range of Fast Ethernet and Gigabit Ethernet configurations, the Cisco Catalyst 3750 Series can serve as both a powerful access layer switch for medium enterprise wiring closets and as a backbone switch for mid-sized networks. Customers can deploy network wide intelligent services, such as advanced QoS, rate-limiting, Cisco security access control lists (ACLs), multicast management, and high-performance IP routing—while maintaining the simplicity of traditional LAN switching. Embedded in the Cisco Catalyst 3750 Series is the Cisco Cluster Management Suite (CMS) Software, which allows users to simultaneously configure and troubleshoot multiple Cisco Catalyst desktop switches using a standard Web browser.
Cisco CMS Software provides new configuration wizards that greatly simplify the implementation of converged applications and network wide services.
The Cisco Catalyst switches are available with the SMI or the EMI. The Enhanced Multilayer Software Image enables a richer set of enterprise-class features, including hardware-based IP unicast and multicast routing, inter-VLAN routing, router access control lists (RACLs), and the Hot Standby Router Protocol (HSRP). Flexibility to upgrade to EMI after the initial deployment is provided through an EMI upgrade kit. Additional details about the differences between the SMI and EMI are provided later in this document.
More Q&A helps you know Cisco 3750 series well
Q. What software images do the Cisco Catalyst 3750 switches support?
A. the Cisco Catalyst switches are available with the SMI or the EMI.
The Enhanced Multilayer Software Image enables a richer set of enterprise-class features, including hardware-based IP unicast and multicast routing, inter-VLAN routing, router access control lists (RACLs), and the Hot Standby Router Protocol (HSRP). Flexibility to upgrade to EMI after the initial deployment is provided through an EMI upgrade kit. Additional details about the differences between the SMI and EMI are provided later in this document.
Q. Can I enable static IP routing using the SMI?
A.Yes, RIP and static routing are supported on the SMI. Dynamic IP routing protocols (OSPF, BGPv4, EIGRP, IGRP) are available only on the EMI.
Q. Is the EMI required to allow Layer 3 and Layer 4 lookups for QoS and security?
A.No. Both the SMI and the EMI allow for Layer 3 and Layer 4 lookups for QoS and security.
Q. Do the Cisco Catalyst 3750 switches support Inter-Switch Link (ISL) virtual LAN (VLAN) trunking?
A.Yes, the Cisco Catalyst 3750 switches support both 802.1Q trunking and ISL trunking. VLAN trunks can be created from any port using either standards-based 802.1Q tagging or the Cisco ISL VLAN architecture.
Q. Can the Cisco Catalyst 3750 Series switches stack with the Cisco Catalyst 3550 Series switches?
A.No, the Cisco Catalyst 3750 switches cannot stack with the Cisco Catalyst 3550 switches. The Cisco Catalyst 3750 switches’ new innovative Cisco StackWise technology with 32-Gbps high-speed stacking bus is not compatible with Cisco Catalyst 3550 switches’ Giga Stack stacking.
Overview on Technology
The Cisco StackWise technology provides an innovative method for collectively using and extending the resources of a stack of units. Up to nine switches can be joined together to create a single switching unit with a virtual 32-Gbps stack interconnect. Furthermore, the entire stack can be managed as one unit with a single IP address. To the rest of the network, the stack operates as a single switch. With a unified management interface, the customer can with one command load a single image to all compatible switches on the stack. Cisco StackWise technology is optimized for Gigabit Ethernet deployment bringing customers new levels of performance through the high speed interconnect, resiliency through advanced failover mechanisms and ease of use through automated configuration and a single management interface.
Because of the Cisco StackWise technology, the Cisco Catalyst 3750 Series is highly scalable. There can be up to 252 Gigabit Ethernet ports in a stack. Switches within the stack can be added and removed without affecting user network access. New devices get the global configuration from the stack master, and replacement devices get the exact configuration of the old device. There is one configuration file with all stack member configurations. Its innovative design sets the bar of availability in stackable switches. It supports link and switch level redundancy.
The Cisco Catalyst 3750 supports cross-stack Ether Channel as well as Cross-Stack Uplink Fast (with sub second failover), and cross-stack equal cost routes across different switches in the stack. These features eliminate the need of relying on HSRP for router failures. In the case of Master switch failure, another Master switch takes over with minimal disruption within 2 to 3 seconds.
For more information about Cisco StackWise technology, go to:
SFPs are transceivers that provide Gigabit Ethernet connectivity from the Cisco Catalyst 3750 switches to distribution layer switches. They are functionally equivalent to Gigabit Interface Converters (GBICs), but are much smaller. Cisco Catalyst 3750 switches support 1000BASE-LX/LH and 1000BASE-SX SFPs. Like other Cisco switches and routers, the Cisco Catalyst 3750 switches do not interoperate with other vendors’ SFPs. The switch will shut down the port if an SFP is inserted that is not a Cisco SFP. Users can populate all the SFP ports of any Cisco Catalyst 3750 Switch with the same SFP or with a combination of different SFPs. Cisco Catalyst 3750 switches support the following Cisco SFPs: 1000BASE-SX and 1000BASE-LX/LH. The Cisco Catalyst 3750 switches can be supported by the Cisco RPS 675 and the Cisco RPS 300. Both the Cisco RPS 675 and RPS 300 provide superior internal power source redundancy for up to six Cisco networking devices. This results in improved fault tolerance and network uptime. For more information go to:
The Cisco RPS 675 is the next-generation of the RPS 300. It provides more power (675W) than RPS 300 (300W). RPS 675 can provide up to 375W of –48V power, and 300W of 12V power. Unlike the Cisco RPS 300, the RPS 675 comes up in active mode. The customer does not need to push a button to activate the RPS 675 after a power failure.
The Cisco Catalyst 3750-24TS-E, 3750-48TS-E, 3750G-24T-E, 3750G-24TS-E are loaded with the Enhanced Multilayer Software Image, so all feature license fees are part of the standard list price. However, the Cisco Catalyst 3750-24TS-S, 3750-48TS-S, 3750G-24T-S, 3750G-24TS-S switches are loaded with the Standard Multilayer Software Image; these switches can be upgraded to the Enhanced Multilayer Software Image with the purchase of the Enhanced Multilayer Software Image upgrade kit (part number CD-3750-EMI=). The Standard Multilayer Software Image includes RIP and static routing. For dynamic IP routing features (BGPv4, OSFP, EIGRP, IGRP), the EMI is required.
The following features and functionality are supported with the Enhanced Multilayer Software Image:
•Dynamic IP routing protocols for load balancing and constructing scalable LANs:
–Open Shortest Path First (OSPF)
–Interior Gateway Routing Protocol (IGRP) and Enhanced IGRP (EIGRP)
–Border Gateway Protocol (BGPv4)
•Equal-cost routing for load balancing and redundancy
•Cisco standard and extended IP security Router RACLs for defining security policies on routed interfaces for control plane and data plane traffic
•Fallback bridging for forwarding of non-IP traffic between two or more VLANs
•Cisco Hot Standby Router Protocol (HSRP) to create redundant failsafe routing topologies
•Protocol-Independent Multicast (PIM) for IP multicast routing within a network that enables the network to receive the multicast feed requested and for switches not participating in the multicast to be pruned—support for PIM sparse mode (PIM-SM), PIM dense mode (PIM-DM), and PIM sparse-dense mode
•Distance Vector Multicast Routing Protocol (DVMRP) tunneling for interconnecting two multicast-enabled networks across no multicast networks
•Policy-based Routing (PBR) allows superior control by enabling flow redirection regardless of the routing protocol configured
Q and A: Intelligent Switching & Security
Q. Why do I need intelligence at the edge of my network?
A.Networks are evolving to address four new developments at the network edge:
• Increase in desktop computing power
• Introduction of bandwidth-intensive applications
• Expansion of highly sensitive data on the network
• Presence of multiple device types, such as IP phones and wireless LAN access points
These new demands are contending for resources with many existing mission-critical applications. As a result, IT professionals must view the edge of the network as critical to effectively manage the delivery of information and applications. As companies increasingly rely on networks as the strategic business infrastructure, it is more important than ever to ensure their high availability, security, scalability, and control. By adding Cisco intelligent functions to the wiring closet, customers can now deploy network wide intelligent services that address these requirements in a consistent way from the desktop to the core and through the WAN.
With Cisco Catalyst Intelligent Ethernet switches, Cisco helps companies to realize the full benefits of adding intelligent services to their networks. Deploying capabilities that make the network infrastructure highly available to accommodate time-critical needs, scalable to accommodate growth, secure enough to protect confidential information, and capable of differentiating and controlling traffic flows are key to further optimizing network operations.
Q. Can you provide more details on how Cisco intelligent switching will help my network?
A. New applications are requiring higher bandwidth and the need to differentiate and control the traffic flow.
Applications such as enterprise resource planning (ERP) (Oracle, SAP, etc.), voice (IP telephony traffic) and CAD/CAM require prioritization over less time-sensitive applications such as FTP or Simple Mail Transfer Protocol (SMTP). It would be highly undesirable to have a large file download destined to one port on a wiring closet switch and have quality implications such as increased latency in voice traffic, destined to another port on this switch. This condition is avoided by ensuring that voice traffic is properly classified and prioritized throughout the network. Cisco Intelligent Ethernet switches implement superior QoS to ensure that network traffic is classified prioritized, and congestion is avoided.
Q. How will the security needs of a network be handled?
A.With the rise in internal threats to a network, Cisco Ethernet switches enhance data security through a wide range of features including Secure Shell (SSH) and Simple Network Management Protocol version 3 (SNMPv3) protocols, ACLs, 802.1x, port security, private VLAN edge, Dynamic Host Configuration Protocol (DHCP) interface tracker, MAC address notification, and RADIUS/TACACS+. Depending on your security needs, the Cisco Catalyst 3550 Series complements devices such as firewalls, VPNs, and Intrusion Detection Systems.
Q. For security purposes, how can I protect unauthorized users from accessing my network?
A. the Cisco Catalyst 3750 supports 802.1x that works in conjunction with a RADIUS server to authenticate users as they access a network. The 802.1x standard is considered port-level security and is commonly used for wireless LANs. Additionally, portions of the network can be restricted by using ACLs. Access can be denied based on Media Access Control (MAC) addresses, IP addresses, or Transmission Control Protocol (TCP)/User Datagram Protocol (UDP) ports. ACL lookups are done in hardware—forwarding and routing performance is not compromised when implementing ACL-based security. An additional protection method is to use port security, which ensures the appropriate user is on the network by limiting access to the port based on MAC addresses.
Q. For security purposes, how can I monitor or track activities in my network?
A.Intrusion detection systems are tailored to monitor and track activities in a network. The Cisco Catalyst 3750 can complement this through features such as MAC address notification, which will send an alert to a management station so that network administrators know when and where users came on to the network and can take appropriate actions. The DHCP Interface Tracker (Option 82) feature will track where a user is physically connected on a network by providing both switch and port ID to a DHCP server.
Q. For security purposes, how do I protect administration passwords and traffic going to the switch during configuration or troubleshooting?
A. To protect administration traffic during the configuration or troubleshooting of a switch (such as passwords or device configuration settings), the best approach is to encrypt the data. Both SSH and SNMPv3 provide encryption of data during Telnet sessions and SNMP sessions.
The Cisco Catalyst 3750 switches can be managed using the Web-based Cisco Cluster Management Suite (CMS) Software, which uses Cisco Switch Clustering technology. Cisco CMS is Web-based software that is embedded in Cisco Catalyst 3750, 3550, 2950, 3500 XL, 2900 XL, 2900 LRE XL, and 1900 switches. Through Cisco Switch Clustering technology, users access Cisco CMS with any standard Web browser to manage up to 16 of these switches at once, regardless of their geographic proximity with the option of using a single IP address if desired. With the addition of the Cisco Catalyst 3750 switches, Cisco CMS can now extend beyond routed boundaries for even more flexibility in managing a Cisco cluster.
Cisco CMS provides an integrated management interface for delivering intelligent services, enabling users to manage their entire LAN with one robust tool. By bringing the simplicity of traditional LAN switching to intelligent services such as multilayer switching, QoS, multicast, and security ACLs, Cisco CMS allows administrators to take advantage of benefits formerly reserved for only the most complex networks. The new Guide Mode in Cisco CMS leads the user step by step through the configuration of high-end features and provides enhanced online help for context-sensitive assistance. In addition, a Solution Wizard provides automated configuration of the switch for video streaming or video conferencing. Future software will provide Solution Wizards for voice over IP (VoIP), mission-critical applications, and security.
Cisco CMS supports standards-based connectivity options such as Ethernet, Fast Ethernet, Fast EtherChannel, Gigabit Ethernet, and Gigabit EtherChannel connectivity. Because Cisco Switch Clustering technology is not limited by proprietary stacking modules, stacking cables or interconnection media, Cisco CMS expands the traditional cluster domain beyond a single wiring closet and lets users mix and match interconnections to meet specific management, performance, and cost requirements.
Cisco Catalyst 3750 switches can be configured either as command or member switches in a Cisco switch cluster. Cisco CMS also allows the network administrator to designate a standby or redundant command switch, which takes the commander duties should the primary command switch fail. Other important features include the ability to configure multiple ports and switches simultaneously, as well as perform software updates across the entire cluster at once. Bandwidth graphs and link reports provide useful diagnostic information and the topology map gives network administrators a quick view of the network status.
More Details: PDF file of Cisco Catalyst 3750 Switches, such as more info of positioning, software updates, etc.