CCNP交换篇
Cisco交换机集群技术
对于交换机之间的连接，比较熟悉的应该有两种：一、是堆叠，二、是级连。对于级连的方式比较容易造成交换机之间的瓶颈，而虽然堆叠技术可以增加背板速率，能够消除交换机之间连接的瓶颈问题，但是，受到距离等的限制很大，而且对交换机数量的限制也比较严格。
Cisco公司推出的交换机集群技术，可以看成是堆叠和级连技术的综合。这种技术可以将分布在不同地理范围内的交换机逻辑地组合到一起，可以进行统一的管理。具体的实现方式就是在集群之中选出一个Commander，而其他的交换机处于从属地位，由Commander统一管理。对于新的Catalyst3500XL系列中的Catalyst3512XL、Catalyst3524XL和Catalyst3508GXL三个型号均可以成为Commander，而对于被管理者2900和1900系列均可以加入交换机集群，使用Cisco最新的交换集群技术将传统的堆叠技术提高到新的水平。据说对于2900XL系列也可以成为Commander。
该系列产品面向中型企事业单位，在提供高性能和低成本的同时，降低了复杂度，并易于集成到已有的网络上。它允许网络管理员使用标准的Web测览器。通过单一的IP地址从网络上的任何地方管理地理上分散的交换机。
具体举例如下：
假设网络中心采用Cisco的Catalyst6506交换机，而集群的Commander采用Catalyst3508GXL在集群的Commander与中心交换机之间，可以通过千兆连接或者通过GEC实现4千兆的连接，而在集群内部采用3500、2900、1900的组合，之间通过FEC等方式相连接。然后为集群分配独立的Ip地址就可以对整个集群进行管理了。
交换机集群技术最多支持16台交换机，可以提供多达16
48个端口。
交换机背板带宽
背板带宽，是交换机接口处理器或接口卡和数据总线间所能吞吐的最大数据量。一台交换机的背板带宽越高，所能处理数据的能力就越强，但同时设计成本也会上去。
但是，我们如何去考察一个交换机的背板带宽是否够用呢？显然，通过估算的方法是没有用的，我认为应该从两个方面来考虑：
1、）所有端口容量X端口数量之和的2倍应该小于背板带宽，可实现全双工无阻塞交换，证明交换机具有发挥最大数据交换性能的条件。
2、）满配置吞吐量(Mpps)=满配置GE端口数×1.488Mpps其中1个千兆端口在包长为64字节时的理论吞吐量为1.488Mpps。例如，一台最多可以提供64个千兆端口的交换机，其满配置吞吐量应达到64×1.488Mpps=95.2Mpps，才能够确保在所有端口均线速工作时，提供无阻塞的包交换。如果一台交换机最多能够提供176个千兆端口，而宣称的吞吐量为不到261.8Mpps(176x1.488Mpps=261.8)，那么用户有理由认为该交换机采用的是有阻塞的结构设计。
一般是两者都满足的交换机才是合格的交换机。
背板相对大，吞吐量相对小的交换机，除了保留了升级扩展的能力外就是软件效率/专用芯片电路设计有问题；背板相对小。吞吐量相对大的交换机，整体性能比较高。不过背板带宽是可以相信厂家的宣传的，可吞吐量是无法相信厂家的宣传的，因为后者是个设计值，测试很困难的并且意义不是很大。
交换机的背版速率一般是：Mbps,指的是第二层，对于三层以上的交换才采用Mpps
三层交换机与路由器的比较
为了适应网络应用深化带来的挑战，网络在规模和速度方向都在急剧发展，局域网的速度已从最初的10Mbit/s提高到100Mbit/s，目前千兆以太网技术已得到普遍应用。在网络结构方面也从早期的共享介质的局域网发展到目前的交换式局域网。交换式局域网技术使专用的带宽为用户所独享，极大的提高了局域网传输的效率。可以说，在网络系统集成的技术中，直接面向用户的第一层接口和第二层交换技术方面已得到令人满意的答案。但是，作为网络核心、起到网间互连作用的路由器技术却没有质的突破。在这种情况下，一各新的路由技术应运而生，这就是第三层交换技术：说它是路由器，因为它可操作在网络协议的第三层，是一种路由理解设备并可起到路由决定的作用；说它是交换器，是因为它的速度极快，几乎达到第二层交换的速度。二层交换机、三层交换机和路由器这三种技术究竟谁优谁劣，它们各自适用在什么环境？为了解答这问题，我们先从这三种技术的工作原理入手
1.二层交换技术
二层交换机是数据链路层的设备，它能够读取数据包中的MAC地址信息并根据MAC地址来进行交换。交换机内部有一个地址表，这个地址表标明了MAC地址和交换机端口的对应关系。当交换机从某个端口收到一个数据包，它首先读取包头中的源MAC地址，这样它就知道源MAC地址的机器是连在哪个端口上的，它再去读取包头中的目的MAC地址，并在地址表中查找相应的端口，如果表中有与这目的MAC地址对应的端口，则把数据包直接复制到这端口上，如果在表中找不到相应的端口则把数据包广播到所有端口上，当目的机器对源机器回应时，交换机又可以学习一目的MAC地址与哪个端口对应，在下次传送数据时就不再需要对所有端口进行广播了。二层交换机就是这样建立和维护它自己的地址表。由于二层交换机一般具有很宽的交换总线带宽，所以可以同时为很多端口进行数据交换。如果二层交换机有N个端口，每个端口的带宽是M，而它的交换机总线带宽超过N×M，那么这交换机就可以实现线速交换。二层交换机对广播包是不做限制的，把广播包复制到所有端口上。
二层交换机一般都含有专门用于处理数据包转发的ASIC（ApplicationspecificIntegratedCircuit）芯片，因此转发速度可以做到非常快。
2.路由技术
路由器是在OSI七层网络模型中的第三层——网络层操作的。路由器内部有一个路由表，这表标明了如果要去某个地方，下一步应该往哪走。路由器从某个端口收到一个数据包，它首先把链路层的包头去掉（拆包），读取目的IP地址，然后查找路由表，若能确定下一步往哪送，则再加上链路层的包头（打包），把该数据包转发出去；如果不能确定下一步的地址，则向源地址返回一个信息，并把这个数据包丢掉。
路由技术和二层交换看起来有点相似，其实路由和交换之间的主要区别就是交换发生在OSI参考模型的第二层（数据链路层），而路由发生在第三层。这一区别决定了路由和交换在传送数据的过程中需要使用不同的控制信息，所以两者实现各自功能的方式是不同的。
路由技术其实是由两项最基本的活动组成，即决定最优路径和传输数据包。其中，数据包的传输相对较为简单和直接，而路由的确定则更加复杂一些。路由算法在路由表中写入各种不同的信息，路由器会根据数据包所要到达的目的地选择最佳路径把数据包发送到可以到达该目的地的下一台路由器处。当下一台路由器接收到该数据包时，也会查看其目标地址，并使用合适的路径继续传送给后面的路由器。依次类推，直到数据包到达最终目的地。
路由器之间可以进行相互通讯，而且可以通过传送不同类型的信息维护各自的路由表。路由更新信息主是这样一种信息，一般是由部分或全部路由表组成。通过分析其它路由器发出的路由更新信息，路由器可以掌握整个网络的拓扑结构。链路状态广播是另外一种在路由器之间传递的信息，它可以把信息发送方的链路状态及进的通知给其它路由器。
3.三层交换技术
一个具有第三层交换功能的设备是一个带有第三层路由功能的第二层交换机，但它是二者的有机结合，并不是简单的把路由器设备的硬件及软件简单地叠加在局域网交换机上。
从硬件上看，第二层交换机的接口模块都是通过高速背板/总线（速率可高达几十Gbit/s）交换数据的，在第三层交换机中，与路由器有关的第三层路由硬件模块也插接在高速背板/本资料共包含以下附件：
CCNA-CCNP讲义整理.doc
CCNP-CIT中文笔记.rtf
cisco路由器配置及维护手册.doc
BCRAN课本命令回顾.txt
CSICO交换篇.txt
CISCO安全PIX防火墙笔记.pdf
路由密码恢复.pdf
CISCO命令手册.chm
cisco路由器基本命令配置.doc....

(CCNP exchange
Cisco switch cluster technology
For the connection between switches, there should be two familiar types: one is stacking, and the other is cascade connection. The cascade connection method is easy to cause bottlenecks between switches. Although the stacking technology can increase the backplane speed and eliminate the bottleneck of connections between switches, it is greatly limited by the distance and the number of switches.
The switch cluster technology introduced by Cisco can be regarded as a combination of stacking and cascade technology. This technology can logically combine switches distributed in different geographical ranges, and can be managed uniformly. The specific implementation method is to select a commander in the cluster, while other switches are in a subordinate position and managed by the commander. For the new catalyst3500xl series, the three models of catalyst3512xl, catalyst3524xl and catalyst3508gxl can become the commander. For the managed 2900 and 1900 series, they can join the switch cluster. The latest Cisco switch cluster technology is used to improve the traditional stacking technology to a new level. It is said that the 2900xl series can also be a commander.
This series of products is aimed at medium-sized enterprises and institutions. While providing high performance and low cost, it reduces the complexity and is easy to integrate into the existing network. It allows network administrators to use the standard web explorer. Geographically dispersed switches are managed from anywhere on the network through a single IP address.
Specific examples are as follows:
Suppose that the network center adopts Cisco's catalyst6506 switch, and the cluster commander adopts catalyst3508gxl. Between the cluster commander and the central switch, Gigabit connection or 4 Gigabit connection can be realized through GEC, while the combination of 3500, 2900 and 1900 is used within the cluster, and the connection between them is through FEC. Then assign an independent IP address to the cluster to manage the whole cluster.
The switch cluster technology supports up to 16 switches and can provide up to 16
48 ports.
Switch backplane bandwidth
Backplane bandwidth is the maximum amount of data that can be handled between the switch interface processor or interface card and the data bus. The higher the backplane bandwidth of a switch, the stronger the data processing capacity it can handle, but at the same time, the design cost will rise.
However, how can we check whether the backplane bandwidth of a switch is sufficient? Obviously, the estimation method is useless. I think it should be considered from two aspects:
1. ) the sum of the capacity of all ports x the number of ports should be less than the backplane bandwidth. Full duplex non blocking switching can be realized, which proves that the switch has the conditions to maximize the data exchange performance.
2. ) full configured throughput (MPPs) = full configured Ge ports × 1.488mpps the theoretical throughput of one Gigabit port when the packet length is 64 bytes is 1.488mpps. For example, a switch that can provide up to 64 Gigabit ports should have a full configured throughput of 64 × 1.488mpps=95.2mpps can ensure non blocking packet switching when all ports work at average wire speed. If a switch can provide 176 Gigabit ports at most and the declared throughput is less than 261.8mpps (176x1.488mpps=261.8), users have reason to think that the switch adopts a blocking structure design.
Generally, the switch that meets both requirements is the qualified switch.
The switch with relatively large backplane and small throughput retains the ability to upgrade and expand, but there is a problem with software efficiency / special chip circuit design; The backplane is relatively small. Switches with relatively large throughput have relatively high overall performance. However, the backplane bandwidth can be trusted by the manufacturer's propaganda, but the throughput cannot be trusted by the manufacturer's propaganda, because the latter is a design value, the test is very difficult and of little significance.
The backing rate of the switch is generally Mbps, which refers to the second layer. Only MPPs is used for switches above the third layer
Comparison between layer 3 switch and router
In order to meet the challenges brought by the deepening of network application, the network is developing rapidly in both scale and speed. The speed of LAN has been increased from 10mbit/s to 100mbit/s. At present, Gigabit Ethernet technology has been widely used. In terms of network structure, it has also developed from the early LAN with shared media to the current switched LAN. Switched LAN technology makes the special bandwidth available to users, which greatly improves the efficiency of LAN transmission. It can be said that in the technology of network system integration, the layer 1 interface and layer 2 switching technology directly facing users have been satisfactorily answered. However, as the core of the network, the router technology which plays the role of interconnection between networks has no qualitative breakthrough. In this case, a new routing technology came into being, which is layer 3 switching technology: it is a router, because it can operate in the third layer of the network protocol. It is a routing understanding device and can play the role of routing decision; It is said that it is a switch because its speed is so fast that it almost reaches the speed of layer 2 switching. Which of the three technologies, layer-2 switch, layer-3 switch and router, is better or worse, and what environment are they applicable to? In order to answer this question, let's start with the working principle of these three technologies
1. layer 2 switching technology
The layer-2 switch is a device in the data link layer. It can read the MAC address information in the data packet and exchange according to the MAC address. There is an address table inside the switch, which indicates the corresponding relationship between MAC address and switch port. When a switch receives a packet from a port, it first reads the source MAC address in the packet header, so that it knows which port the source MAC address machine is connected to. It then reads the destination MAC address in the packet header and finds the corresponding port in the address table. If there is a port corresponding to the destination MAC address in the table, it copies the packet directly to the port, If the corresponding port is not found in the table, the data packet is broadcast to all ports. When the destination machine responds to the source machine, the switch can learn which port the destination MAC address corresponds to. It is no longer necessary to broadcast all ports when the next data transmission. This is how a layer-2 switch establishes and maintains its own address table. Since the layer-2 switch generally has a wide switching bus bandwidth, it can exchange data for many ports at the same time. If the layer-2 switch has N ports, the bandwidth of each port is m, and its switch bus bandwidth exceeds n × M. Then the switch can realize line speed switching. The layer-2 switch does not restrict broadcast packets and copies broadcast packets to all ports.
Generally, layer-2 switches contain ASIC (applicationspecificintegratedcircuit) chips specially used to handle packet forwarding, so the forwarding speed can be very fast.
2. routing technology
The router operates in the network layer, the third layer in the OSI seven layer network model. There is a routing table inside the router, which indicates where to go if you want to go to a certain place. The router receives a packet from a port. It first removes the packet header of the link layer (unpacking), reads the destination IP address, and then looks up the routing table. If it can determine where to send the next step, it adds the packet header of the link layer (packaging) to forward the packet; If the next address cannot be determined, a message is returned to the source address and the packet is discarded.
Routing technology and layer-2 switching look a bit similar. In fact, the main difference between routing and switching is that switching occurs in layer-2 (data link layer) of the OSI reference model, while routing occurs in layer-3. This difference determines that routing and switching need to use different control information in the process of transmitting data, so the ways of realizing their respective functions are different.
Routing technology is actually composed of two basic activities, namely, determining the optimal path and transmitting packets. Among them, the transmission of data packets is relatively simple and direct, while the determination of routing is more complex. The routing algorithm writes various information in the routing table. The router will select the best path according to the destination to which the packet is to arrive and send the packet to the next router that can reach the destination. When the next router receives the packet, it will also check its destination address and continue to transmit it to the following routers using an appropriate path. And so on until the packets reach the final destination.
Routers can communicate with each other and maintain their own routing tables by transmitting different types of information. The routing update information mainly refers to such information, which is generally composed of some or all routing tables. By analyzing the route update information sent by other routers, the router can master the topology of the whole network. Link state broadcast is another kind of information transmitted between routers. It can notify other routers of the link state and progress of the information sender.
3. layer 3 Switching Technology
A device with layer 3 switching function is a layer 2 switch with layer 3 routing function, but it is an organic combination of the two, and it is not simply superimposing the hardware and software of the router device on the LAN switch.
From the perspective of hardware, the interface modules of the layer 2 switch exchange data through the high-speed backplane / bus (the rate can be as high as tens of gbit/s). In the layer 3 switch, the layer 3 routing hardware module related to the router is also plugged into the high-speed backplane / this data contains the following accessories:
Ccna-ccnp handout sorting doc
Ccnp-cit Chinese notes rtf
Cisco router configuration and maintenance manual doc
Bcran textbook command review txt
Csico exchange txt
Cisco Security PIX Firewall notes pdf
Routing password recovery pdf
Cisco command manual chm
Cisco router basic command configuration doc....)

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CCNP交换篇
Cisco交换机集群技术
对于交换机之间的连接，比较熟悉的应该有两种：一、是堆叠，二、是级连。对于级连的方式比较容易造成交换机之间的瓶颈，而虽然堆叠技术可以增加背板速率，能够消除交换机之间连接的瓶颈问题，但是，受到距离等的限制很大，而且对交换机数量的限制也比较严格。
Cisco公司推出的交换机集群技术，可以看成是堆叠和级连技术的综合。这种技术可以将分布在不同地理范围内的交换机逻辑地组合到一起，可以进行统一的管理。具体的实现方式就是在集群之中选出一个Commander，而其他的交换机处于从属地位，由Commander统一管理。对于新的Catalyst3500XL系列中的Catalyst3512XL、Catalyst3524XL和Catalyst3508GXL三个型号均可以成为Commander，而对于被管理者2900和1900系列均可以加入交换机集群，使用Cisco最新的交换集群技术将传统的堆叠技术提高到新的水平。据说对于2900XL系列也可以成为Commander。
该系列产品面向中型企事业单位，在提供高性能和低成本的同时，降低了复杂度，并易于集成到已有的网络上。它允许网络管理员使用标准的Web测览器。通过单一的IP地址从网络上的任何地方管理地理上分散的交换机。
具体举例如下：
假设网络中心采用Cisco的Catalyst6506交换机，而集群的Commander采用Catalyst3508GXL在集群的Commander与中心交换机之间，可以通过千兆连接或者通过GEC实现4千兆的连接，而在集群内部采用3500、2900、1900的组合，之间通过FEC等方式相连接。然后为集群分配独立的Ip地址就可以对整个集群进行管理了。
交换机集群技术最多支持16台交换机，可以提供多达16
48个端口。
交换机背板带宽
背板带宽，是交换机接口处理器或接口卡和数据总线间所能吞吐的最大数据量。一台交换机的背板带宽越高，所能处理数据的能力就越强，但同时设计成本也会上去。
但是，我们如何去考察一个交换机的背板带宽是否够用呢？显然，通过估算的方法是没有用的，我认为应该从两个方面来考虑：
1、）所有端口容量X端口数量之和的2倍应该小于背板带宽，可实现全双工无阻塞交换，证明交换机具有发挥最大数据交换性能的条件。
2、）满配置吞吐量(Mpps)=满配置GE端口数×1.488Mpps其中1个千兆端口在包长为64字节时的理论吞吐量为1.488Mpps。例如，一台最多可以提供64个千兆端口的交换机，其满配置吞吐量应达到64×1.488Mpps=95.2Mpps，才能够确保在所有端口均线速工作时，提供无阻塞的包交换。如果一台交换机最多能够提供176个千兆端口，而宣称的吞吐量为不到261.8Mpps(176x1.488Mpps=261.8)，那么用户有理由认为该交换机采用的是有阻塞的结构设计。
一般是两者都满足的交换机才是合格的交换机。
背板相对大，吞吐量相对小的交换机，除了保留了升级扩展的能力外就是软件效率/专用芯片电路设计有问题；背板相对小。吞吐量相对大的交换机，整体性能比较高。不过背板带宽是可以相信厂家的宣传的，可吞吐量是无法相信厂家的宣传的，因为后者是个设计值，测试很困难的并且意义不是很大。
交换机的背版速率一般是：Mbps,指的是第二层，对于三层以上的交换才采用Mpps
三层交换机与路由器的比较
为了适应网络应用深化带来的挑战，网络在规模和速度方向都在急剧发展，局域网的速度已从最初的10Mbit/s提高到100Mbit/s，目前千兆以太网技术已得到普遍应用。在网络结构方面也从早期的共享介质的局域网发展到目前的交换式局域网。交换式局域网技术使专用的带宽为用户所独享，极大的提高了局域网传输的效率。可以说，在网络系统集成的技术中，直接面向用户的第一层接口和第二层交换技术方面已得到令人满意的答案。但是，作为网络核心、起到网间互连作用的路由器技术却没有质的突破。在这种情况下，一各新的路由技术应运而生，这就是第三层交换技术：说它是路由器，因为它可操作在网络协议的第三层，是一种路由理解设备并可起到路由决定的作用；说它是交换器，是因为它的速度极快，几乎达到第二层交换的速度。二层交换机、三层交换机和路由器这三种技术究竟谁优谁劣，它们各自适用在什么环境？为了解答这问题，我们先从这三种技术的工作原理入手
1.二层交换技术
二层交换机是数据链路层的设备，它能够读取数据包中的MAC地址信息并根据MAC地址来进行交换。交换机内部有一个地址表，这个地址表标明了MAC地址和交换机端口的对应关系。当交换机从某个端口收到一个数据包，它首先读取包头中的源MAC地址，这样它就知道源MAC地址的机器是连在哪个端口上的，它再去读取包头中的目的MAC地址，并在地址表中查找相应的端口，如果表中有与这目的MAC地址对应的端口，则把数据包直接复制到这端口上，如果在表中找不到相应的端口则把数据包广播到所有端口上，当目的机器对源机器回应时，交换机又可以学习一目的MAC地址与哪个端口对应，在下次传送数据时就不再需要对所有端口进行广播了。二层交换机就是这样建立和维护它自己的地址表。由于二层交换机一般具有很宽的交换总线带宽，所以可以同时为很多端口进行数据交换。如果二层交换机有N个端口，每个端口的带宽是M，而它的交换机总线带宽超过N×M，那么这交换机就可以实现线速交换。二层交换机对广播包是不做限制的，把广播包复制到所有端口上。
二层交换机一般都含有专门用于处理数据包转发的ASIC（ApplicationspecificIntegratedCircuit）芯片，因此转发速度可以做到非常快。
2.路由技术
路由器是在OSI七层网络模型中的第三层——网络层操作的。路由器内部有一个路由表，这表标明了如果要去某个地方，下一步应该往哪走。路由器从某个端口收到一个数据包，它首先把链路层的包头去掉（拆包），读取目的IP地址，然后查找路由表，若能确定下一步往哪送，则再加上链路层的包头（打包），把该数据包转发出去；如果不能确定下一步的地址，则向源地址返回一个信息，并把这个数据包丢掉。
路由技术和二层交换看起来有点相似，其实路由和交换之间的主要区别就是交换发生在OSI参考模型的第二层（数据链路层），而路由发生在第三层。这一区别决定了路由和交换在传送数据的过程中需要使用不同的控制信息，所以两者实现各自功能的方式是不同的。
路由技术其实是由两项最基本的活动组成，即决定最优路径和传输数据包。其中，数据包的传输相对较为简单和直接，而路由的确定则更加复杂一些。路由算法在路由表中写入各种不同的信息，路由器会根据数据包所要到达的目的地选择最佳路径把数据包发送到可以到达该目的地的下一台路由器处。当下一台路由器接收到该数据包时，也会查看其目标地址，并使用合适的路径继续传送给后面的路由器。依次类推，直到数据包到达最终目的地。
路由器之间可以进行相互通讯，而且可以通过传送不同类型的信息维护各自的路由表。路由更新信息主是这样一种信息，一般是由部分或全部路由表组成。通过分析其它路由器发出的路由更新信息，路由器可以掌握整个网络的拓扑结构。链路状态广播是另外一种在路由器之间传递的信息，它可以把信息发送方的链路状态及进的通知给其它路由器。
3.三层交换技术
一个具有第三层交换功能的设备是一个带有第三层路由功能的第二层交换机，但它是二者的有机结合，并不是简单的把路由器设备的硬件及软件简单地叠加在局域网交换机上。
从硬件上看，第二层交换机的接口模块都是通过高速背板/总线（速率可高达几十Gbit/s）交换数据的，在第三层交换机中，与路由器有关的第三层路由硬件模块也插接在高速背板/本资料共包含以下附件：
CCNA-CCNP讲义整理.doc
CCNP-CIT中文笔记.rtf
cisco路由器配置及维护手册.doc
BCRAN课本命令回顾.txt
CSICO交换篇.txt
CISCO安全PIX防火墙笔记.pdf
路由密码恢复.pdf
CISCO命令手册.chm
cisco路由器基本命令配置.doc....

(CCNP exchange
Cisco switch cluster technology
For the connection between switches, there should be two familiar types: one is stacking, and the other is cascade connection. The cascade connection method is easy to cause bottlenecks between switches. Although the stacking technology can increase the backplane speed and eliminate the bottleneck of connections between switches, it is greatly limited by the distance and the number of switches.
The switch cluster technology introduced by Cisco can be regarded as a combination of stacking and cascade technology. This technology can logically combine switches distributed in different geographical ranges, and can be managed uniformly. The specific implementation method is to select a commander in the cluster, while other switches are in a subordinate position and managed by the commander. For the new catalyst3500xl series, the three models of catalyst3512xl, catalyst3524xl and catalyst3508gxl can become the commander. For the managed 2900 and 1900 series, they can join the switch cluster. The latest Cisco switch cluster technology is used to improve the traditional stacking technology to a new level. It is said that the 2900xl series can also be a commander.
This series of products is aimed at medium-sized enterprises and institutions. While providing high performance and low cost, it reduces the complexity and is easy to integrate into the existing network. It allows network administrators to use the standard web explorer. Geographically dispersed switches are managed from anywhere on the network through a single IP address.
Specific examples are as follows:
Suppose that the network center adopts Cisco's catalyst6506 switch, and the cluster commander adopts catalyst3508gxl. Between the cluster commander and the central switch, Gigabit connection or 4 Gigabit connection can be realized through GEC, while the combination of 3500, 2900 and 1900 is used within the cluster, and the connection between them is through FEC. Then assign an independent IP address to the cluster to manage the whole cluster.
The switch cluster technology supports up to 16 switches and can provide up to 16
48 ports.
Switch backplane bandwidth
Backplane bandwidth is the maximum amount of data that can be handled between the switch interface processor or interface card and the data bus. The higher the backplane bandwidth of a switch, the stronger the data processing capacity it can handle, but at the same time, the design cost will rise.
However, how can we check whether the backplane bandwidth of a switch is sufficient? Obviously, the estimation method is useless. I think it should be considered from two aspects:
1. ) the sum of the capacity of all ports x the number of ports should be less than the backplane bandwidth. Full duplex non blocking switching can be realized, which proves that the switch has the conditions to maximize the data exchange performance.
2. ) full configured throughput (MPPs) = full configured Ge ports × 1.488mpps the theoretical throughput of one Gigabit port when the packet length is 64 bytes is 1.488mpps. For example, a switch that can provide up to 64 Gigabit ports should have a full configured throughput of 64 × 1.488mpps=95.2mpps can ensure non blocking packet switching when all ports work at average wire speed. If a switch can provide 176 Gigabit ports at most and the declared throughput is less than 261.8mpps (176x1.488mpps=261.8), users have reason to think that the switch adopts a blocking structure design.
Generally, the switch that meets both requirements is the qualified switch.
The switch with relatively large backplane and small throughput retains the ability to upgrade and expand, but there is a problem with software efficiency / special chip circuit design; The backplane is relatively small. Switches with relatively large throughput have relatively high overall performance. However, the backplane bandwidth can be trusted by the manufacturer's propaganda, but the throughput cannot be trusted by the manufacturer's propaganda, because the latter is a design value, the test is very difficult and of little significance.
The backing rate of the switch is generally Mbps, which refers to the second layer. Only MPPs is used for switches above the third layer
Comparison between layer 3 switch and router
In order to meet the challenges brought by the deepening of network application, the network is developing rapidly in both scale and speed. The speed of LAN has been increased from 10mbit/s to 100mbit/s. At present, Gigabit Ethernet technology has been widely used. In terms of network structure, it has also developed from the early LAN with shared media to the current switched LAN. Switched LAN technology makes the special bandwidth available to users, which greatly improves the efficiency of LAN transmission. It can be said that in the technology of network system integration, the layer 1 interface and layer 2 switching technology directly facing users have been satisfactorily answered. However, as the core of the network, the router technology which plays the role of interconnection between networks has no qualitative breakthrough. In this case, a new routing technology came into being, which is layer 3 switching technology: it is a router, because it can operate in the third layer of the network protocol. It is a routing understanding device and can play the role of routing decision; It is said that it is a switch because its speed is so fast that it almost reaches the speed of layer 2 switching. Which of the three technologies, layer-2 switch, layer-3 switch and router, is better or worse, and what environment are they applicable to? In order to answer this question, let's start with the working principle of these three technologies
1. layer 2 switching technology
The layer-2 switch is a device in the data link layer. It can read the MAC address information in the data packet and exchange according to the MAC address. There is an address table inside the switch, which indicates the corresponding relationship between MAC address and switch port. When a switch receives a packet from a port, it first reads the source MAC address in the packet header, so that it knows which port the source MAC address machine is connected to. It then reads the destination MAC address in the packet header and finds the corresponding port in the address table. If there is a port corresponding to the destination MAC address in the table, it copies the packet directly to the port, If the corresponding port is not found in the table, the data packet is broadcast to all ports. When the destination machine responds to the source machine, the switch can learn which port the destination MAC address corresponds to. It is no longer necessary to broadcast all ports when the next data transmission. This is how a layer-2 switch establishes and maintains its own address table. Since the layer-2 switch generally has a wide switching bus bandwidth, it can exchange data for many ports at the same time. If the layer-2 switch has N ports, the bandwidth of each port is m, and its switch bus bandwidth exceeds n × M. Then the switch can realize line speed switching. The layer-2 switch does not restrict broadcast packets and copies broadcast packets to all ports.
Generally, layer-2 switches contain ASIC (applicationspecificintegratedcircuit) chips specially used to handle packet forwarding, so the forwarding speed can be very fast.
2. routing technology
The router operates in the network layer, the third layer in the OSI seven layer network model. There is a routing table inside the router, which indicates where to go if you want to go to a certain place. The router receives a packet from a port. It first removes the packet header of the link layer (unpacking), reads the destination IP address, and then looks up the routing table. If it can determine where to send the next step, it adds the packet header of the link layer (packaging) to forward the packet; If the next address cannot be determined, a message is returned to the source address and the packet is discarded.
Routing technology and layer-2 switching look a bit similar. In fact, the main difference between routing and switching is that switching occurs in layer-2 (data link layer) of the OSI reference model, while routing occurs in layer-3. This difference determines that routing and switching need to use different control information in the process of transmitting data, so the ways of realizing their respective functions are different.
Routing technology is actually composed of two basic activities, namely, determining the optimal path and transmitting packets. Among them, the transmission of data packets is relatively simple and direct, while the determination of routing is more complex. The routing algorithm writes various information in the routing table. The router will select the best path according to the destination to which the packet is to arrive and send the packet to the next router that can reach the destination. When the next router receives the packet, it will also check its destination address and continue to transmit it to the following routers using an appropriate path. And so on until the packets reach the final destination.
Routers can communicate with each other and maintain their own routing tables by transmitting different types of information. The routing update information mainly refers to such information, which is generally composed of some or all routing tables. By analyzing the route update information sent by other routers, the router can master the topology of the whole network. Link state broadcast is another kind of information transmitted between routers. It can notify other routers of the link state and progress of the information sender.
3. layer 3 Switching Technology
A device with layer 3 switching function is a layer 2 switch with layer 3 routing function, but it is an organic combination of the two, and it is not simply superimposing the hardware and software of the router device on the LAN switch.
From the perspective of hardware, the interface modules of the layer 2 switch exchange data through the high-speed backplane / bus (the rate can be as high as tens of gbit/s). In the layer 3 switch, the layer 3 routing hardware module related to the router is also plugged into the high-speed backplane / this data contains the following accessories:
Ccna-ccnp handout sorting doc
Ccnp-cit Chinese notes rtf
Cisco router configuration and maintenance manual doc
Bcran textbook command review txt
Csico exchange txt
Cisco Security PIX Firewall notes pdf
Routing password recovery pdf
Cisco command manual chm
Cisco router basic command configuration doc....)

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