2012年10月11日 星期四

How the Router-switch.com Became the World’s Leading Cisco Supplier?



During the past ten years, from 2002 to 2012, router-switch.com has grown up into a global leading Cisco supplier. Indeed, it has experienced several vital moment. Here let’s share some router-switch.com’s big events:
2002, Router-switch.com was founded.
2003, Router-switch.com has experienced a rapid development.
2004, CCIE technical support team was built.
2005, The sales volume maintains 70% growth per year.
2006, Staff in company increased to 20.
2007, Router-switch.com established its marketing department. It attained its reputation in providing timely information of Cisco for clients and Cisco users.
2008, Router-switch.com adopted necessary advanced management tools to improve its service for clients.
2009, Router-switch.com upgraded warehouses in Hongkong and Mainland China. Its inventory is worth over $5 million.
2010, The sales of Router-switch.com have zoomed to $ 30 million.
2011, Router-switch.com released the new version to update service. It supplies free CCIE support. Social network platforms were opened to communicate with customers and clients well.
2012, New Office of router-switch.com landed in US to offer professional local service.

Nowadays, router-switch.com is becoming the world’s largest Cisco reseller online.  It believes that router-switch.com will bemore professional, more reliable and stronger with your support.
Note:A letter from CEO of router-switch.com to thank its customers and sharetheir progress.

More about Router-switch.com:
Router-switch.com, also called YejianTechnologies Co., Ltd, is the worldwide leader in delivering new, used, refurbished Cisco hardware, including Cisco routers, Cisco switches, firewall security, Cisco IP Phones VoIP, wireless AP, Cisco modules & cards, memory, and optical cables, SFP, GBIC, XENPK , etc. It carries over $5 million in inventory of Cisco hardware and Cisco equipment that can meet SOHO, small, midsized and large businesses of all sizes. Also Router-Switch.com owns more than 8,000 customers worldwide, not only because of its original Cisco products with reliable quality and competitive price, but also due to professionalservice, huge inventory, flexible payment and shipment. More information about router-switch.com can be found at http://www.router-switch.com/. For ongoing Cisco info, please go to
Blog.router-switch.com---News, tutorials, tips, info & thoughts on Developments in the Cisco, Cisco network, IT, Software & Network Hardware Industry

More Related Router-switch.com News:
Router-switch.com Announced Its Newly Redesigned Website
“Router Switch”, Our New Company Landing in U.S.—Professional Cisco Supply Service is Around You
Router-switch.com: A Batch of New Cisco Network Equipment Surprises the Coming Christmas Day
Router-Switch.com Uploaded Thousands of New Cisco Products

2012年3月9日 星期五

The Use of Network Switches in a Network


A network switch is a computer networking device that connects network segments. Switchescommonly refer to a multi-port network bridge that process and route data at the data link layer (layer 2) of the OSI model. Switches that additionally process data at the network layer (Layer 3) and above are often referred to as Layer 3 cisco 3750 series switch or multilayer switches.

The network switch plays an integral part in most modern Ethernet local area networks (LANs). Mid-to-large sized LANs contain a number of linked managed switches. Small office/home office (SOHO) applications typically use a single switch, or an all-purpose converged device such as a gateway to access small office/home broadband services such as DSL or cable internet. In most of these cases, the end-user device contains a router and components that interface to the particular physical broadband technology. User devices may also include a telephone interface for VoIP.

Functions and Roles of Switches in Networks
An Ethernet switch operates at the data link layer of the OSI model to create a separate collision domain for each switch port. With 4 computers (e.g., A, B, C, and D) on 4 switch ports, A and B can transfer data back and forth, while C and D also do so simultaneously, and the two conversations will not interfere with one another. In the case of a hub, they would all share the bandwidth and run in half duplex, resulting in collisions, which would then necessitate retransmissions. Using a switch is called micro segmentation. This allows computers to have dedicated bandwidth on point-to-point connections to the network and to therefore run in full duplex without collisions.

Switches may operate at one or more layers of the OSI model, including data link, network, or transport (i.e., end-to-end). A device that operates simultaneously at more than one of these layers is known as a multilayer switch.

In switches intended for commercial use, built-in or modular interfaces make it possible to connect different types of networks, including Ethernet, Fibre Channel, ATM, ITU-T G.hn and 802.11. This connectivity can be at any of the layers mentioned. While Layer 2 functionality is adequate for bandwidth-shifting within one technology, interconnecting technologies such as Ethernet and token ring are easier at Layer 3.

Interconnection of different Layer 3 networks is done by routers. If there are any features that characterize "Layer-3 cisco 3560X switch" as opposed to general-purpose routers, it tends to be that they are optimized, in larger switches, for high-density Ethernet connectivity.

In some service provider and other environments where there is a need for a great deal of analysis of network performance and security, switches may be connected between WAN routers as places for analytic modules. Some vendors provide firewall,network intrusion detection,[4] and performance analysis modules that can plug into switch ports. Some of these functions may be on combined modules.

In other cases, the switch is used to create a mirror image of data that can go to an external device. Since most switch port mirroring provides only one mirrored stream, network hubs can be useful for fanning out data to several read-only analyzers, such as intrusion detection systems and packet sniffers.

NOTES
LAYER 2 NETWORKS
 A switch works with MAC addresses cisco 3560G switch at layer 2 of the OSI 7 layer model. Devices used on a Layer 2 Ethernet network include network interface cards, hubs, bridges and switches. Ethernet devices use 'burned in' MAC addresses to identify each host. These addresses are attached to network interface cards and cannot be changed. The address of a computer can only be changed if the network interface card is changed. Layer 2 networks are connected together using hubs, bridges and switches. Hubs take each frame that is received and send duplicate frames simultaneously out all other ports. Bridges forward broadcasts between two connected networks until they have located all hosts. Switches forward broadcast traffic only when it doesn't know where a host is. None of these devices have to disassemble or reassemble data, only forward it. Because nothing is done to the data along the way, layer 2 networks are often considered to be 'faster' than a layer 3 network.

LAYER 3 NETWORKS
A Layer 3 switch is a high-performance device for network routing. A router works with IP addresses at layer 3 of the model. Layer 3 networks are built to run on on layer 2 networks. In an IP layer 3 network, the IP portion of the datagram has to be read. This requires stripping off the datalink layer frame information.cisco 3560E switch Once the protocol frame information is stripped, the IP datagram has to be reassembled. Once the IP datagram is reassembled, the hop count has to be decremented, the header checksum has to be recalculated, a lookup for routing must be made, and only then can the IP datagram be chopped back up and inserted into frames and transmitted to the next hop. All of this takes extra time.

Layer 2 networks forward all traffic, especially ARP and DHCP broadcasts. Anything transmitted by one device is forwarded to all devices. When the network gets large enough, the broadcast traffic begins to create congestion and decreases network efficiency.

By contrast, layer 3 devices restrict broadcast traffic such as ARP and DHCP broadcasts to the local network. This reduces overall traffic levels by allowing administrators to chop networks into smaller parts and restrict broadcasts to only that sub-network. This means there is a limit to the size of a layer 2 network. A layer 3 network, prperly configured, can grow to any size.

2012年1月16日 星期一

What is the Difference between Cisco 3560-E and 3560 Switch

Demands on IT infrastructure are changing. Improving network efficiency and articulating the clear value network infrastructure brings to your business have never been more important. The refurbished cisco switch 3560-E Series access and aggregation switches offer networking solutions that can expand with your business without costly upgrades or network disruptions, maximize your network investment, and decrease network costs over time.

Increased desktop bandwidth, expanded use of real-time communication and collaboration applications, and the desire to maximize networking investments are changing the way network solutions are designed and implemented.Cisco 3560 e Supporting Gigabit Ethernet to the desktop often requires 10 Gigabit Ethernet connections between the access and aggregation layers to be able to maintain a quality experience for users.

These deployments can sometimes face space constraints. Voice-over-IP (VoIP) phones, security cameras, and other devices are requiring Power over Ethernet (PoE) support in networking devices. Purchasing a network solution today that grows with your business and network needs can help ensure your company’s competitiveness and success for tomorrow.

10 Gigabit Ethernet Uplinks and the used network switches TwinGig Small Form-Factor Pluggable Converter
The c3560g 48ts s features wire-speed 10 Gigabit Ethernet uplink ports for high-bandwidth applications, relieving congestion and helping ensure smooth delivery of data. The TwinGig converter (see Figure 2) converts a 10 Gigabit Ethernet X2 interface into two Gigabit Ethernet Small Form-Factor Pluggable (SFP) ports.

Power over Ethernet
The 3560e cisco Series can provide a lower total cost of ownership for deployments that incorporate Cisco IP phones, Cisco Aironet wireless LAN (WLAN) access points, or any IEEE 802.3af-compliant end device. PoE removes the need for wall power to each PoE-enabled device and eliminates the cost for additional electrical cabling and circuits that would otherwise be necessary in IP phone and WLAN deployments. With the introduction of Enhanced Power over Ethernet the 3560-E Series can scale beyond 15.4W per port delivering maximum solution simplicity for 802.11n access point deployments.

Redundant Power System
The Cisco Catalyst 3560-E Series WS-C3560-24PS-E Switches support the Cisco Redundant Power System 2300 (Cisco RPS 2300). The Cisco RPS 2300 (Figure 3) increases availability in a converged data, voice, and video network by providing transparent power backup to two of six attached Cisco Catalyst 3560-E switches at the same time. A power supply can be replaced while the switch is being powered by the Cisco RPS 2300.

Cisco Catalyst 3560-E Series Switches
Cisco Catalyst 3560-E Series Switches are an enterprise-class line of standalone access and aggregation switches that facilitate the deployment of secure converged applications while maximizing investment protection for evolving network and  application requirements. Configurations for the Cisco Catalyst 3560-E access switches include 24 and 48 ports of 10/100/1000 Ethernet with dual 10 Gigabit Ethernet ports. Power over Ethernet is available on both the 24-port and 48-port models and can deliver IEEE 802.3af 15.4W class 3 PoE on all ports simultaneously. Combining 10/100/1000 and PoE configurations with 10 Gigabit Ethernet uplinks, the Cisco Catalyst 3560-E enhances worker productivity by enabling applications such as IP telephony, wireless, and video.

The Cisco Catalyst 3560-E Series aggregation solutions - the sell cisco switches Catalyst 3560E-12D, a 12-port 10 Gigabit Ethernet aggregation switch, and the Cisco Catalyst 3560E-12SD, a 12-port SFP Gigabit Ethernet aggregation switch with 2 10 Gigabit Ethernet uplink ports, deliver secure nonstop unified network services and versatile connectivity in a one-rack unit (1-RU) form factor for space- and power-constrained environments, enabling businesses to reduce total cost of ownership while maximizing investment protection.

Cisco Catalyst 3560-E Series highlights:
•    Cisco TwinGig converter module for migrating uplinks from Gigabit Ethernet to 10 Gigabit Ethernet
•    PoE configurations with 15.4W of PoE on all 48 ports
•    Industry first portfolio to scale beyond 15.4W per port delivering maximum solution simplicity for 802.11n access point deployments
•    Access switch models have modular power supply with externally available backup
•    Dual redundant modular power supplies and fans for Cisco Catalyst 3560E-12D and Cisco Catalyst 3560E-12SD aggregation switches for nonstop operation
•    Multicast routing, IPv6 routing, and access control list (ACL) in hardware
•    Out-of-band Ethernet management port along with RS-232 console port

Benefits of the Cisco Catalyst 3560-E
Scale your network as your business grows: With the TwinGig converter module, you can convert the 10 Gigabit Ethernet interfaces into dual SFP ports in the access and aggregation layers, allowing you to migrate from Gigabit to 10 Gigabit Ethernet when your business demands change without changing network devices. The Cisco Catalyst 3560E-12D also enables the aggregation of up to 12 10 Gigabit Ethernet links within a compact 1-RU form factor in space-constrained environments. Decrease network costs over time: the cisco 3560 e delivers full PoE (15.4W) on every 10/100/1000 port so that as your needs for PoE and Gigabit Ethernet grow, you are positioned to support them without costly upgrades or complete network replacements.

More Related: Details of Cisco switch command Catalyst 3560-E Series Switches from Cisco’s official website
http://www.router-switch.com/Price-cisco-switches-cisco-switch-catalyst-3560_c22